Spero Therapeutics, Inc. 10-K

Item 1. Business. Overview We are a multi-asset, clinical-stage biopharmaceutical company focused on identifying, developing and commercializing treatments in high unmet need areas involving multi-drug resistant, or MDR, bacterial infections and rare diseases. Our most advanced product candidate, Tebipenem Pivoxil Hydrobromide, or tebipenem HBr, is designed to be the first oral carbapenem-class antibiotic for use in adults to treat MDR Gram-negative infections. Treatment with effective orally administrable antibiotics may prevent hospitalizations for serious infections and enable earlier, more convenient and cost-effective treatment of patients after hospitalization. We are also developing SPR720, a novel oral antibiotic designed for the treatment of a rare, orphan disease caused by non-tuberculous mycobacterial pulmonary infections, or NTM disease. In addition, we are advancing SPR206, a next generation polymyxin investigational product candidate, being developed as an IV-administered medicine to treat MDR Gram-negative infections in the hospital. We believe that our novel product candidates, if successfully developed and approved, would have a meaningful patient impact and significant commercial applications for the treatment of MDR infections in both the community and hospital settings. Antibiotic-resistant bacteria are one of the largest threats to global health, and their prevalence is increasing. While the majority of life-threatening infections historically resulting from antibiotic-resistant bacteria are acquired in the hospital setting, there is an increasing incidence of MDR pathogens in the community setting. Antibiotics used currently for first-line empiric treatment of MDR bacterial infections suffer from significant limitations and risks, including narrow spectrums of coverage and safety and tolerability concerns, and they can be associated with serious adverse effects. In addition, there are no oral antibiotics commercially available that can reliably be used in adults with MDR Gram-negative bacterial infections. This limits the ability of physicians to prevent hospitalizations and transition patients to their home from the hospital after receiving IV-administered therapy. The increasing prevalence of drug resistance and MDR Gram-negative bacteria, as well as the limitations of existing therapies and traditional drug development approaches, highlight the critical need for novel therapies, and in particular orally administrable agents, that are capable of overcoming these obstacles to effective patient treatment. The Problem: Increasingly Limited Antibiotic Options for Severe Infections Antibiotic Background Antibiotics are drugs used to treat infections that are caused by bacteria. Prior to the introduction of the first antibiotics in the 1930s and 1940s, bacterial infections were often fatal. Today, antibiotics are used routinely to treat and prevent infections. There are two main varieties of bacteria, Gram-negative bacteria and Gram-positive bacteria, which are distinguished by structural differences in their cell envelope. Gram-positive bacteria are surrounded by a single lipid membrane and a thick cell wall, while Gram-negative bacteria are encircled by two lipid membranes, an inner membrane and an outer membrane, with a thinner cell wall in between, as shown in the illustration below. 3 Antibiotics that target Gram-negative bacteria must be specifically designed to cross both the inner and outer membranes to enter the bacteria. The outer membrane, with its LPS-containing outer leaflet, represents a significant barrier to the entry into the bacteria by antibiotics and is a significant contributor toward reduced potency of many agents in treating Gram-negative bacterial infections. Recent studies have found that Gram-negative bacteria in certain patient types, such as those with sepsis and Interstitial Lung Disease, are associated with higher mortality and increased intensive care unit, or ICU, admission. Moreover, a study of 13,796 patients in intensive care units around the world reported in 2009 that 51% of patients experienced bacterial infections, and of these patients 62% were infected by Gram-negative organisms. Antibiotics are evaluated according to several criteria, including: • Spectrum . Antibiotics that are effective against a wide variety of bacteria are considered to be broad-spectrum, while those that act upon only a limited number of bacteria are considered to be narrow-spectrum. • Potency . Potency is the measure of the microbiological ability of an antibiotic to kill or inhibit growth of bacteria in vitro . Potency is commonly expressed as the minimum inhibitory concentration, or MIC, in µg/mL, which is the lowest concentration at which the drug inhibits growth of the bacteria. Antibiotics with lower MICs are considered to be more potent. • Resistance . Antibiotic resistance refers to the inability of an antibiotic to effectively control bacterial growth. Some bacteria are naturally resistant to certain types of antibiotics. Antibiotic resistance can also occur due to genetic mutations or changes in gene expression. There are numerous mechanisms responsible for antibiotic resistance, and resistance mechanisms are often found together and can be transferred between different bacteria, leading to multi-drug resistance. Growing Antibiotic Resistance in the Hospital and Community Settings Antibiotic resistance is one of the largest threats to global health, and resistance rates are increasing. Antibiotic resistance can affect anyone, of any age and in any country. According to the U.S. Centers for Disease Control’s Antibiotic Resistance Threats in the United States, 2019 report, more than 2.8 million antibiotic-resistant infections occur in the United States each year, and more than 35,000 people die as a result. Approximately 70% of the pathogens that cause these infections are resistant to at least one antibiotic used to treat them. Resistance rates are climbing in both hospital-acquired and community-acquired infections. According to UNC Infectious Diseases investigator David van Duin, MD, PhD and colleagues in 2016: “Some MDR bacteria have become quite prevalent causes of community-acquired infections. The spread of MDR bacteria into the community is a crucial development, and is associated with increased morbidity, mortality, healthcare costs and antibiotic use.” The incidence rate of serious infections is increasing, and the proportion of the infections caused by MDR pathogens is increasingly seen as an emerging threat to world health. The Centers for Disease Control and Prevention, or CDC, estimates that the annual impact of antibiotic-resistant infections on the United States economy is $20-35 billion in excess direct health care costs. According to the CDC, among all of the bacterial resistance problems, Gram-negative pathogens, which cause a majority of all bacterial infections, are particularly worrisome because they are becoming resistant to nearly all drugs that would be considered for treatment. In February 2017, the World Health Organization, or WHO, published a list of Gram- negative bacteria based on the urgency of need for new antibiotics and highlighted a critical group of MDR Gram-negative bacteria that pose a particular threat to human health, including Acinetobacter , Pseudomonas and multiple Enterobacteriaceae (including Klebsiella sp. , E. coli , Serratia and Proteus ). These pathogens are associated with significant mortality because the increased incidence of antibiotic resistance has limited the number of effective treatment options. There is an acute need for new antibiotics to treat MDR bacterial infections, as few new antibiotics capable of addressing such infections have been approved recently for commercialization or are in clinical development. Further, the majority of MDR bacterial infections historically have been acquired in the hospital setting, where they have been treated using IV-administered antibiotics. However, increasingly such infections are being acquired in the community setting, emphasizing the need for orally administrable antibiotics that can effectively treat such infections. 4 Chronic Bacterial Infection without a Viable Cure NTM infections represent a growing global health concern and major unmet medical need because of the lack of new medications being developed to combat these bacteria. NTM infections are ubiquitous environmental pathogens that can cause progressive lung damage and respiratory failure, particularly in patients with compromised immune systems or underlying pulmonary disorders. Although rare, the incidence of pulmonary NTM disease is increasing worldwide. It is estimated that approximately 130,000 patients suffer from NTM disease in the United States and Europe, a figure that is growing at a rate of 8% annually. In addition, many patients go undiagnosed and could benefit from treatment with additional testing. The elderly and people with compromised immune or lung function are at greatest risk, as are patients with bronchiectasis for whom it is estimated that up to 50% may also have active lung infection caused by NTM. Treatment of pulmonary NTM disease requires prolonged therapy (continuing for approximately 12 to 24 months) with a combination regimen and is frequently complicated by tolerability and/or toxicity issues. Additionally, there are currently no oral antibiotics specifically approved for use to treat pulmonary NTM disease. M. avium complex is the most common NTM to cause human infection in the United States, and it makes up around 80% of the infections. The most common treatment for NTM infections is combination therapy with drugs traditionally used for tuberculosis, or TB, which have limited efficacy and high toxicity. NTM infection is also associated with high healthcare costs and high mortality. In 2014, the annual cost in the United States of treating NTM infections alone was estimated at $1.7 billion. Our Solution Antibiotics currently used for first-line empiric treatment of MDR acute bacterial infections and NTM infection suffer from significant limitations. We believe that our product candidates will overcome these limitations, as described below: • Tebipenem HBr is designed to address the lack of orally administrable antibiotics to prevent hospitalization and permit IV-to-oral switch therapy in resistant Gram-negative infections . Resistance to most commonly used classes of oral antibiotics, such as cephalosporins and fluoroquinolones, has increased significantly. Many of the most commonly used antibiotics for MDR Gram-negative infections are only available in an IV-administered formulation. Treatment with effective orally administrable antibiotics may prevent hospitalizations for serious infections and enable earlier, more convenient and cost-effective treatment of patients following hospitalization. Tebipenem HBr is an orally administrable tablet that we believe has the potential, if approved, to treat such infections in both the community and hospital settings, thereby preventing certain hospitalizations and enabling patients to transition to oral treatment. In the community setting, tebipenem HBr, if successfully developed and approved, may allow patients who develop an infection with a resistant pathogen, but are stable enough to be treated in the community, to avoid the need for an IV catheter and even hospitalization. Hospitalization is a key cost driver for hospital systems and payers, with increasing emphasis being placed on hospital avoidance. In the hospital setting, the lack of effective oral stepdown options results in the potential for lengthy hospital stays or the insertion of a peripherally inserted central catheter, or PICC, to facilitate outpatient administration of IV antibiotics. Tebipenem HBr may enable faster discharges, providing cost-saving advantages for the hospital and mitigating the risk of catheter-related and other hospital-acquired infections for patients. • SPR720 is designed to be the first oral treatment for NTM infection where treatment failure is common and no approved therapies exist . The current treatment for NTM infection is lengthy and involves combination therapy, often including three or more antibiotics, including injectables. None of these combination treatments are currently approved for use in NTM infection. Treatment failure is common and is often due to poor compliance or patients’ inability to tolerate the regimen. Many patients experience progressive lung disease as a result of NTM infection, and mortality rates are high, ranging from 29% to 69% within five years of diagnosis. We believe SPR720, if successfully developed, has the potential to be the first approved oral agent for NTM pulmonary infection. We initiated a Phase 2a clinical trial in patients with NTM pulmonary disease in December 2020 based on data from the Phase 1 clinical trial, pharmacokinetic analyses and preclinical studies supporting its advancement. On February 5, 2021, we announced that the FDA informed us that a clinical hold had been placed on our Phase 2a clinical trial of SPR720, which is further described elsewhere in this “Business” section of our Annual Report on Form 10-K under the heading “Update on Phase 2a Clinical Trial.” • SPR206 is designed to address the decline in the ability of novel and effective IV-administered antibiotics to treat MDR Gram-negative infections in the hospital setting. First-line IV empiric antibiotics, such as levofloxacin, ceftazidime and piperacillin-tazobactam, have experienced diminished utility as the number of bacterial strains resistant to these antibiotics in the hospital has increased. Due to gaps in the spectrum of coverage of antibiotics currently on the market, physicians are often confronted with the need to design complicated multi-drug cocktails for patients with serious infections. Based on results from preclinical studies to date, we believe that SPR206 has the potential to be developed as a single drug. 5 Our Pipeline – Multiple Near-term Catalysts Across the Rare and Infectious Disease Portfolio The following table sets forth our product candidates, their status and certain anticipated milestones related to them. Our Product Candidates Tebipenem HBr (tebipenem pivoxil hydrobromide): Novel Antibiotic with Potential to be the First Oral Carbapenem for Use in Adults Our lead product candidate, tebipenem HBr, is an oral carbapenem intended for use in adults to treat MDR Gram-negative infections. In September 2020, we announced positive top-line data from the single pivotal Phase 3 clinical trial, which is entitled ADAPT-PO, that is required for approval of tebipenem HBr to treat complicated urinary tract infection, or cUTI, and acute pyelonephritis, or AP. The ADAPT-PO trial achieved its primary objective, demonstrating that oral tebipenem HBr was statistically non-inferior to intravenous ertapenem in the treatment of patients with cUTI and patients with AP with respect to the primary endpoint of overall response at the test-of-cure, or TOC, visit in the microbiological-intent-to-treat, or micro-ITT, population. Comparative safety and tolerability data from 1,372 hospitalized adult patients enrolled in the study were similar between the tebipenem HBr and ertapenem treatment groups. The ADAPT-PO trial was designed as a double-blind, double-dummy trial to compare oral tebipenem HBr with an existing standard of care intravenous, or IV, antibiotic, ertapenem, in 1,372 hospitalized adult patients with cUTI or AP, randomized 1:1 in each arm. We intend to make a New Drug Application, or NDA, submission to the United States Food and Drug Administration, or FDA, for tebipenem HBr for the treatment of cUTI and AP in the second half of 2021. Carbapenems have been utilized for over 30 years and are considered the standard of care for many serious MDR Gram-negative bacterial infections, but to date they have only been available as IV-administered formulations. Currently, there are no commercially available oral carbapenems for use in adults, and we believe tebipenem HBr has the potential to address this unmet need. Tebipenem HBr is an oral tablet formulation of tebipenem, a carbapenem-class antibiotic marketed by Meiji Seika Pharma Co. Ltd., or Meiji, in Japan as Orapenem® since 2009 for common pediatric infections. To accelerate our clinical development of tebipenem HBr, in June 2017 we signed an exclusive license to certain data and know-how from Meiji and a global pharmaceutical company, to which we refer as Global Pharma, which we intend to use to support our clinical development of tebipenem HBr. We have global commercialization rights to tebipenem HBr, except in certain contractually specified Asian countries. The FDA has designated tebipenem HBr as a Qualified Infectious Disease Product, or QIDP, for the treatment of cUTI, community acquired bacterial pneumonia, or CABP, and moderate to severe diabetic foot infections, or DFI, under the Generating Antibiotics Incentives Now Act, or the GAIN Act. Among other benefits of a QIDP designation, the first marketing application for the QIDP-designated drug qualifies for priority review by the FDA. If tebipenem HBr is approved for treatment of cUTI, CABP or DFI, the QIDP designation previously granted to tebipenem HBr for those indications will entitle the drug product to receive a one-time five-year extension to any non-patent exclusivity period awarded for tebipenem HBr in the United States (the so-called GAIN exclusivity extension), such as a five-year New Chemical Entity, or NCE, exclusivity granted under the Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Act, for a total of 10 years, among other possible qualifying periods of regulatory exclusivity. In Europe, exclusivity for NCEs is 10 years (eight years for data exclusivity and an additional two years for market exclusivity), with the possibility of a one-year extension if the chemical entity is approved for use in an additional indication. The QIDP designation for tebipenem HBr, however, does not guarantee a faster development process or ensure FDA approval. Tebipenem HBr has been granted Fast Track Designation by the FDA for the treatment of cUTI and AP. 6 In January 2021, tebipenem HBr was granted a patent covering a crystalline form and pharmaceutical compositions of tebipenem HBr, with an expiration of February 2038. We believe that our intellectual property portfolio for tebipenem HBr, which includes multiple patent applications pending, will provide tebipenem HBr protection globally, including in the United States and Europe, through 203 8 . Advantages of tebipenem HBr Key attributes of tebipenem HBr support our confidence in tebipenem HBr’s commercial potential, if tebipenem HBr receives regulatory approval. We believe tebipenem HBr has the potential to be a safe and effective treatment for cUTI and other serious and life-threatening infections for which we may develop tebipenem HBr. • Potential to be the first oral carbapenem in adults, if approved . Tebipenem HBr is designed to be the first broad-spectrum oral carbapenem-class antibiotic for use in adults to treat MDR Gram-negative infections. Unlike other carbapenems, which are only available as IV-administered infusions, tebipenem HBr is an orally administered tablet. Oral administration may potentially allow physicians to avoid IV-administered antibiotics for otherwise healthy or stable patients and/or allow for a reduction in costs associated with avoiding or shortening hospitalization. • Potential for differentiated launch characteristics. There are limited branded or generic oral options currently approved or available to treat fluoroquinolone- and cephalosporin-resistant pathogens to assist with transitioning patients from the hospital to the community setting, or to prevent unnecessary hospitalization for cUTI. We believe tebipenem HBr, if approved, would be primarily reimbursable outside the hospital diagnosis-related group, or DRG, system, because of the desire from patients, physicians and payors alike to discharge patients from the hospital. Together, we believe these factors could differentiate tebipenem HBr from other recently launched antibiotic drugs, many of which are injectable, reimbursed within the hospital DRG system, and/or substitutable with equally effective generic alternatives. • Potential uses for treatment. As a result of extensive existing data, we believe that tebipenem HBr has the potential to be used for the treatment of cUTI and other serious and life-threatening infections caused by resistant Gram-negative pathogens. • Clinical profile observed in the ADAPT-PO clinical trial suggests there are no tradeoffs in treating with oral tebipenem HBr versus IV ertapenem; safety and tolerability data supported by the Japanese experience. The ADAPT-PO trial achieved its primary objective, demonstrating that oral tebipenem HBr was statistically non-inferior to intravenous ertapenem in the treatment of patients with cUTI and patients with AP with respect to the primary endpoint of overall response at the TOC visit in the micro-ITT population. In the ADAPT-PO trial, the safety and tolerability profile for oral tebipenem HBr was similar to IV ertapenem. Both the type and frequency of adverse events were well balanced across treatment groups, with treatment-emergent adverse events reported in 26% of treated patients in both arms. The most commonly observed TEAEs were diarrhea and headaches. Serious adverse events occurred in 1.3% of tebipenem HBr-treated patients, none of which were considered to be drug-related, and there were no deaths reported in the study. A granule formulation of tebipenem has been approved for use in Japan in pediatric patients since 2009, where it has demonstrated a favorable safety and efficacy profile. Approximately 1,200 subjects were dosed with the active pharmaceutical ingredient of tebipenem HBr, tebipenem, in clinical and pharmacologic studies during development of this drug by Meiji and its partner in Japan. This data set includes 741 adults, including 88 patients with cUTIs, the initial indication for which we are developing tebipenem HBr. In each case tebipenem has demonstrated a favorable safety, pharmacokinetic and tolerability profile. In addition, Meiji has conducted a 3,540 patient post-marketing study supporting the safety and tolerability profile of tebipenem, specifically demonstrating a safety profile that aligns well with that observed across the clinical trial program and tolerability in line with other broad spectrum oral antibiotics. • Potential to enable IV-to-oral transition of antibiotic treatment to assist with reduction in hospital stays and/or eliminate the need for hospitalization. We believe the unique oral formulation of tebipenem HBr may enable patients who begin IV-administered treatment for extended spectrum beta-lactamases in the hospital setting to transition to oral dosing of tebipenem HBr either in the hospital or upon discharge for convenient home-based care. We believe that the availability and use of an oral carbapenem as a transition therapy may eliminate hospitalization or reduce the length of a patient’s hospital stay and the overall cost of care. 7 We believe the foregoing advantages of tebipenem HBr also significantly differentiate tebipenem HBr from fluoroquinolones. Fluoroquinolones are the most widely used antibiotic class in treating community and hospital Gram-negative infections, but they have encountered increasing resistance among MDR Gram-negative bacteria and are associated with significant adverse effects. The table below reflects resistance rates in the United States in the community and hospital settings. cUTIs in the United States 2019 E. coli Resistance Rates to Fluoroquinolones 2013-2014 E. coli Resistance Rates to Fluoroquinolones 2000-2004 E. coli Resistance Rates to Fluoroquinolones Community Setting 21.2% 11.7% 0% Hospital Setting 30.8% 34.5% 3.5% Currently, fluoroquinolones are the most frequently selected antibiotic for empirical urinary tract infection, or UTI, treatment in the community and hospital settings. Current UTI treatment guidelines published by the Infectious Diseases Society of America identify fluoroquinolones as an appropriate empirical therapy option. This recommendation, however, is contingent on local resistance rates being less than 10%. The endemicity (high rates) of fluoroquinolone-resistant E. coli found in the United States today in the community and hospital settings based on the table above would suggest that fluoroquinolones should not be used empirically for cUTI patients. The following table highlights the observed in vitro potency differences between tebipenem HBr and levofloxacin, the most widely used fluoroquinolone. As shown below, tebipenem HBr has a MIC90 value of 0.03 µg/ mL, which compares favorably (i.e., at or below) to the potency value obtained by levofloxacin. Compound E. coli MIC 90 (µg /mL) tebipenem HBr 0.03 Levofloxacin >4 In addition, the FDA has issued several warnings against the use of fluoroquinolones in certain patients. In particular, an FDA Advisory Committee stated in November 2015 that the risk of serious side effects caused by fluoroquinolones generally outweighs the benefits for patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis and uncomplicated UTIs, and the agency subsequently issued a drug safety communication to the public and required safety labeling revisions be made to all products within this drug class. The FDA has determined that fluoroquinolones should be reserved for use in patients with these conditions who have no alternative treatment options and safety warnings in the labeling of fluoroquinolone class products have been further strengthened over the past several years. We believe tebipenem HBr could become a potential alternative to oral fluoroquinolones based on its safety and efficacy profile. Significant Market Opportunity for Tebipenem HBr Given the observed activity of tebipenem HBr against different bacteria, we view the market opportunity for tebipenem HBr, if approved, to be substantial, including for the following uses: • Community setting: Treating urinary tract infections acquired in the community setting without the need for patient hospitalization. • Hospital setting: Transitioning patients hospitalized for UTIs to an appropriate oral therapy as they are discharged from the hospital. UTIs are among the most common bacterial diseases worldwide, with significant clinical and economic burden. IQVIA (formerly QuintilesIMS) estimates that between 33 and 34 million patients either visit their physician or are hospitalized for a UTI or otherwise suspected of experiencing a UTI in the United States annually. While drugs such as trimethoprim/sulfamethoxazole (Bactrim/Septra) and fluoroquinolones (levofloxacin, ciprofloxacin) have been the primary oral options for treatment of UTIs caused by Gram-negative organisms, nearly 30% to 35% of UTIs are resistant, which has led to increased use of IV-administered therapeutics such as carbapenems. IQVIA completed a market assessment in August 2017 in the community and hospital settings in which it estimated that there were 11 to 12 million patients annually who presented in the community physician’s office with a UTI and 3.5 to 4.5 million patients annually in the hospital with a UTI in the United States alone. Of these UTIs, 10 to 11 million are suspected to be caused by Gram-negative bacteria, and 4 to 5 million of these patients had an infection that is resistant to or failed first-line therapy, such as the fluoroquinolone class, or require IV therapy due to the severity of infection. Physicians in the survey reported high concern with growing fluoroquinolone resistance and lack of oral options for MDR Gram-negative infections. We believe tebipenem HBr is well positioned to meet the unmet need for an oral therapy for community-acquired UTI and may offer physicians an option for treating 8 MDR UTIs while avoiding patient hospitalization. In addition, we believe tebipenem HBr has the potential to accelerate hospital discharge and obviate the need for continued IV-administered therapy at home by transitioning discharged patients to an at-home oral therapy. Our pivotal Phase 3 clinical trial for tebipenem HBr, ADAPT-PO, was conducted in a subset of UTIs called cUTIs, and our target focus within this group is the 2.7 million patients receiving second line or IV treatment in the United States annually. A significant majority of UTIs, including these cUTIs, are caused by a group of MDR Gram-negative bacteria called Enterobacteriaceae, which tebipenem HBr is effective against . Tebipenem HBr Clinical Development Program Single Pivotal Phase 3 Clinical Trial (ADAPT-PO) In September 2020, we announced positive data from the ADAPT-PO Phase 3 trial evaluating an all oral regimen of tebipenem HBr head-to-head versus an all IV regimen of ertapenem for the treatment of adults with cUTI, including AP. The global, randomized, placebo-controlled ADAPT-PO Phase 3 clinical trial evaluated the safety and efficacy of tebipenem HBr in hospitalized adult patients with cUTI or AP. Patients were randomized (1:1) to receive tebipenem HBr (600 mg) orally every 8 hours, or ertapenem (1 g) IV every 24 hours, for a total of 7 to 10 days. The ADAPT-PO trial achieved its primary objective, demonstrating that oral tebipenem HBr was statistically non-inferior to intravenous ertapenem in the treatment of patients with cUTI and patients with AP with respect to the primary endpoint of overall response at the TOC visit in the micro-ITT population. Overall response (combined clinical cure plus microbiological eradication) rates at TOC were 58.8% for oral tebipenem versus 61.6% for IV ertapenem (treatment difference, -3.3%; 95% confidence interval [CI]: -9.7, 3.2; -12.5% NI margin). Data presented at IDWeek 2020 expanded on the topline data, and demonstrated that both the clinical cure and microbiological eradication rates were comparable between treatment groups at the end of treatment, or EOT, TOC and at the late follow-up, or LFU, visits. Specifically, clinical cure rates, which are the key determinant in routine clinical management of cUTI/AP patients, were >93% in both treatment groups at TOC. The high clinical cure rates at TOC were sustained through LFU (88.6% and 90% for tebipenem HBr and ertapenem, respectively), demonstrating a durable clinical response in patients with cUTI and AP. Favorable microbiological response rates at TOC were likewise comparable between treatment groups and were similarly sustained up to LFU in both treatment groups (57.2% and 58.2% for tebipenem HBr and ertapenem, respectively). There were no statistically significant differences between treatment groups in overall response rates across key subgroups of interest, including those determined by age, baseline diagnosis, and presence of bacteremia at baseline. Per pathogen microbiological response rates were generally balanced across treatment groups for the predominant uropathogens. Comparative safety and tolerability data from 1,372 hospitalized adult patients enrolled in the study were similar between the tebipenem HBr and ertapenem treatment groups. Treatment emergent adverse events, or TEAEs, were reported in approximately 26% of patients in both treatment groups and the most commonly reported TEAEs in both treatment groups were diarrhea (5.0%) and headache (3.8%). Serious TEAEs were infrequent (1.3% for tebipenem HBr vs. 1.7% for ertapenem) and no deaths were reported in the trial. Three Clostridioides difficile associated TEAEs were observed in the ertapenem group, while none were observed in the tebipenem HBr group. Based on our pre-IND, pre-Phase 3 meeting with the FDA, we believe that positive results from a single pivotal Phase 3 clinical trial of tebipenem HBr in cUTI would support the approval of tebipenem HBr for the treatment of cUTI. The primary analysis and assessment of non-inferiority was evaluated using a pre-specified -12.5% non-inferiority (NI) margin. This NI margin was a modification of the original NI margin of -10% that was discussed with the FDA because of concern that the COVID-19 pandemic could have an adverse effect on the trial. As a result, the NI margin was modified prior to database lock from the original NI margin. Data from the ADAPT-PO Phase 3 clinical trial of tebipenem HBr, together with requisite safety data, drug-drug interaction studies and other studies, will form the basis for the NDA for tebipenem HBr to treat cUTI, including acute pyelonephritis, which we plan to submit to the FDA in the second half of 2021. The ADAPT-PO clinical trial may also support marketing applications in other global regions. QIDP Designation The FDA has designated tebipenem HBr as a QIDP for the treatment of cUTI, CABP and DFI under the GAIN Act. Among other benefits of a QIDP designation, the first marketing application for the QIDP-designated drug qualifies for priority review by the FDA. The QIDP designation for tebipenem HBr, however, does not guarantee a faster development process or ensure FDA approval. Further, if tebipenem HBr is approved for the treatment of cUTI, CABP or DFI, the FDA’s QIDP designation previously granted to tebipenem HBr for those indications will entitle the drug product to receive a one-time five-year extension to any non-patent exclusivity period awarded to tebipenem HBr in the United States, such as a five-year New Chemical Entity exclusivity granted under the Hatch-Waxman Act, among other possible periods of regulatory exclusivity that would qualify for a GAIN exclusivity extension. 9 Japanese Data Supporting Safety of Tebipenem Tebipenem pivoxil is a prodrug that is metabolized to tebipenem, its therapeutically active form. We view the clinical safety profile of tebipenem pivoxil established by Meiji as relevant and supportive of tebipenem HBr because both metabolize to the active metabolite, tebipenem, in plasma. Our formulation development efforts are designed to improve target concentration while maintaining the exposure per dose. Tebipenem pivoxil is an orally administered carbapenem, which is a sub-group of the beta-lactam class of antibiotics. The safety of tebipenem pivoxil was evaluated in approximately 1,200 subjects supporting the application for approval in Japan. In this safety data set, there are 741 adult subjects across 17 trials and 440 pediatric subjects across six trials. These 23 trials in total included one double-blind, comparator-controlled trial in children, five open-label trials in children, five trials enrolling adult patients (including two open-label cUTI trials), and 12 Phase 1 clinical pharmacology trials. Among the pharmacology trials, tebipenem pivoxil was studied for an effect on QT interval, and for the known effect of the pivoxil prodrug on plasma carnitine concentrations. In these studies, tebipenem pivoxil was generally well tolerated, with an adverse event, or AE, profile comparable to common, approved oral beta lactam antibiotics and IV-administered carbapenems. The most common AEs were gastrointestinal (e.g., diarrhea, loose stools) in both children and adults, and in the Phase 3 clinical trial of otitis media, the incidence was similar to that reported for the comparator, cefditoren pivoxil, an oral cephalosporin antibiotic. No effect of the administration of tebipenem pivoxil on the prolongation of the QT interval was observed, and the effect on plasma carnitine concentrations was reversed post treatment and not associated with AEs. A side effect seen with beta-lactam antibiotics is seizures; however, there have been no reports of inducement of seizures due to the administration of tebipenem pivoxil in clinical trials. Meiji has reported post-marketing outcomes data reporting the safety and efficacy of Orapenem Fine Granules 10% for Pediatric Use (tebipenem pivoxil) in pediatric patients with pneumonia, otitis media, or sinusitis. A total of 3,547 cases were enrolled into the observational study, and the analysis was conducted using 3,540 cases for which it was possible to recover the questionnaires. A total of 348 instances of adverse drug reactions were observed in 334 cases amongst the 3,337 cases (including 6 adult cases) used in the safety analyses, and the incidence of adverse drug reactions was 10.01% (334 cases/3,337 cases). The adverse drug reaction that occurred most frequently was “diarrhea” (9.5%, 318 instances/3,337 cases). One serious drug reaction was observed of “multi-organ failure”. These data are consistent with the safety profile of tebipenem as established in the pediatric clinical trials and reflected in the Orapenem product labeling in Japan. A clinical trial evaluating the effect of tebipenem pivoxil dosing over one week on intestinal flora was also performed. Total aerobic and anaerobic bacterial counts were evaluated. Total bacterial count was reduced by day 7 of the study in both the 100 and 200 mg TID groups. However, no additional change in bacterial count was observed on subsequent examination days. Neither fecal C. difficile nor its toxin was detected in any of the subjects during or following completion of the 7-day dosing period. Funded Label Expansion Opportunity In addition to cUTI, we believe that tebipenem HBr has the potential to treat other serious and life-threatening infections, including CABP. Our Biomedical Advanced Research and Development Authority, or BARDA, award provides funding for Phase 1 and Phase 2 trials supporting a potential CABP indication for tebipenem HBr. SPR720: Novel Oral Antibiotic Designed for Treatment of Non-tuberculous Mycobacterial Pulmonary (NTM-PD) Disease A second area of our focus is rare infectious diseases, specifically non-tuberculous mycobacterial pulmonary disease, a rare orphan disease. We are developing SPR720, which represents a novel class of antibacterial agents that target enzymes essential for bacterial DNA replication, for the treatment of NTM disease. NTM causes chronic and serious lung disease with debilitating symptoms that leads to a decline in lung function. It can have a significant physical and emotional impact on patients. SPR720 is designed to be the first novel, oral candidate to treat NTM pulmonary disease. SPR720 represents a novel class of antibacterial agents that target enzymes essential for bacterial DNA replication. SPR720 has several key attributes including: • Acceptable safety and tolerability within therapeutic dose range. Both the SPR720 Phase 1 trial and pharmacokinetic/pharmacodynamic (PK/PD) data for indicated that predicted therapeutic exposures could be attained with a 500 – 1,000 mg once daily oral dose. These doses in the Phase 1 trial were associated with a low incidence of adverse events with no serious adverse events reported. The most common adverse event among all cohorts was mild diarrhea not requiring discontinuation of therapy. • Broad spectrum of activity. SPR720 has demonstrated a broad spectrum of activity in preclinical studies against the most common organisms causing NTM infections, including Mycobacterium avium complex, or MAC, Mycobacterium kansasii and Mycobacterium abscessus . SPR720 is applicable to both non-refractory and refractory patients. 10 • Convenient for patients. SPR720 has high oral bioavailability. Many patients can find inhalers difficult to use and poor inhalation technique can negatively impact drug delivery and response to therapy. Oral therapy is simple and more convenient. • Novel mechanism. SPR720 employs a novel mechanism and has no known cross-resistance with marketed antibiotics. Recent studies have shown the high prevalence of drug resistance in NTM infection species that threatens adequate control of the disease. Novel mechanisms may help evade existing modes of resistance. • Lung exposure. SPR720 is an oral drug that penetrates the pulmonary space. A bronchoalveolar lavage study in non-human primates supports lung exposure. Furthermore, macrophage data from a 28-day hollow-fiber model of infection demonstrates intracellular and extracellular activity of the drug. SPR720 has shown potent activity against most common NTM infection species, such as M. avium , M. abscessus and M. kansasii . As shown in the exhibit below, SPR720 showed Pulmonary Activity versus M. avium ATCC 700898 in a Murine Chronic Infection Model. In this model SPR720 was effective as a monotherapy and in combination with SOC agents. Non-tuberculous mycobacteria are typically found in water and soil. NTM infections cause a rare infection of the lung that is acquired through inhalation of this microbe. There are approximately 150 types of mycobacteria, with Mycobacterium avium complex, or MAC, the most common cause of NTM infections, comprising approximately 80% of all NTM infections. NTM disease occurs in many different types of patients. NTM disease often occurs in people with compromised immune systems, such as those with HIV, or those with respiratory conditions such as cystic fibrosis, chronic obstructive pulmonary disease, asthma or bronchiectasis. According to Strollo et al. and Adjemian et al., the diagnosed patient population is approximately 86,000 in the United States. The annual prevalence of NTM disease is increasing at an estimated rate of 8% per year. While people of any age can be infected by NTM, it mostly affects middle-aged to elderly adults, and is increasing among patients over 65 years old, a population that is growing in numbers. While relatively rare compared to other infectious diseases, the prevalence of NTM disease has more than doubled since 1997 and unfortunately, infections caused by NTM are often undiagnosed, masquerading as another respiratory condition such as COPD or asthma. By comparison, the prevalence of TB in North America has declined. There are currently no oral FDA-approved therapeutics specifically approved for use to treat NTM pulmonary disease. Given the unmet medical need, there are regulatory incentives available to encourage drug development to address NTM disease. These include orphan drug designation, potential for breakthrough therapy status and QIDP designation. Treatment of NTM disease requires prolonged therapy (continuing for approximately 12 to 24 months) with a combination regimen and is frequently complicated by tolerability and/or toxicity issues. Treatment failure is common and is often due to poor compliance or inability to tolerate the regimen. Many patients experience progressive lung disease and mortality is high. We believe there is a need for new, potent, orally available therapies for NTM disease. While there are competitive compounds in development for NTM disease, these therapies are not effective in all patients and are not orally available. We believe that our intellectual property portfolio for SPR720, which includes multiple issued patents and patent applications pending, will provide SPR720 protection globally, including in the United States and Europe, through 2033. 11 Our SPR720 Development Plan Our strategy is to develop SPR720 to become the first oral treatment FDA-indicated for NTM disease, and ultimately provide a treatment option to NTM patients to reduce their disease burden and improve their quality of life. In March 2020, the FDA granted orphan drug designation for SPR720, a designation that is given to drugs intended to treat a rare disease or condition that affects fewer than 200,000 persons in the United States. An orphan drug designation can provide specific benefits including up to seven years of market exclusivity in the United States upon regulatory approval. In February 2019, we received QIDP designation for SPR720 for the treatment of lung infections caused by nontuberculous mycobacteria and for the treatment of lung infections caused by Mycobacterium tuberculosis. QIDP designation entitles a future marketing application for SPR720 for this indication to priority review by the FDA. Neither the QIDP nor orphan drug designation, however, guarantee a faster development process or ensure FDA approval. In September 2020, SPR720 was awarded Fast Track Designation by the FDA for treatment of adult patients with NTM pulmonary disease. In December 2020, we initiated a Phase 2a dose-ranging clinical trial of SPR720 in patients with nontuberculous mycobacterial pulmonary disease following the acceptance of our investigational new drug, or IND, application for SPR720 in August 2020. The Phase 2a clinical trial is designed as a multi-center, partially blinded, placebo-controlled proof-of-concept clinical trial of SPR720 that is expected to enroll approximately 90 treatment-inexperienced patients with NTM-PD due to MAC. Patients are randomized to receive either 500 mg or 1,000 mg of oral SPR720 once daily, placebo, or standard- of-care, or SOC, consisting of a macrolide and ethambutol, plus the option of adding a rifamycin. The objectives of the trial are to evaluate the plasma pharmacokinetics, safety, tolerability, and microbiological response of SPR720 compared with placebo and SOC over 28 days of treatment, with the inclusion of the SOC arm to assess and ensure assay sensitivity for the trial design. The doses selected for the Phase 2a trial of SPR720 are supported by pharmacokinetic analyses as well as data from the Phase 1 clinical trial of SPR720. The Phase 1 trial reported in December 2019 was designed as a double-blind, placebo-controlled, ascending dose, multi-cohort study in healthy subjects. Data from this Phase 1 trial was presented at ID Week 2020 and indicated that SPR720 is generally well-tolerated, and predicted therapeutic exposures could be attained with a 500 – 1,000 mg once daily oral dose . The Phase 1 clinical trial of SPR720 evaluated the safety, tolerability and PK of orally administered SPR720 at single doses ranging from 100 mg to 2000 mg and repeat total daily doses ranging from 500 mg to 1500 mg for up to 7 to 14 days. Across seven single ascending dose, or SAD, and five multiple ascending dose, or MAD, cohorts, a total of 96 healthy volunteers (including a cohort of healthy elderly (age ≥ 65 years) volunteers) were randomized to receive SPR720 or placebo. There were no serious adverse events reported and all participants completed the trial. An analysis of preliminary blinded data indicates that SPR720 was generally well-tolerated at doses up to 1000 mg over the maximum studied duration of 14 days. Preliminary analyses of PK data across the cohorts show no significant impact of either advanced age or administration with food on PK variables. At doses of 500 mg or higher, the mean plasma drug exposures of SPR719, the active metabolite of SPR720, are consistent with those suggested by in vivo models of SPR720 to be necessary for clinical efficacy against target NTM pathogens. Update on Phase 2a Clinical Trial On February 5, 2021, we announced that the FDA informed us that a clinical hold had been placed on our Phase 2a clinical trial of SPR720, following our notification to the FDA of our decision to pause dosing in our ongoing Phase 2a clinical trial of SPR720 as a precautionary measure related to events in our ongoing animal toxicology study of SPR720. The decision to implement the pause was made based on a recommendation from the Company’s Safety Review Board, or SRB, following review of data from an ongoing toxicology study of SPR720 in adult non-human primates in which mortalities with inconclusive causality to treatment were observed. The animal study is being conducted to assess the potential toxicity of SPR720. A concurrent study of SPR720 in rats is proceeding uneventfully. These studies are meant to support longer-term treatment with SPR720 beyond the 28 days currently supported by IND-enabling toxicology studies. No serious adverse events have been observed in any human study participants. Subsequent to receiving verbal notification from the FDA of the clinical hold, we received a formal clinical hold letter in which the FDA has requested additional information from the non-human primate trial, including a study report. We have decided to discontinue the Phase 2a clinical trial at this time to best facilitate future potential adjustments to the protocol based on FDA feedback and to avoid incurring costs associated with the trial while on clinical hold. We are continuing to work with the FDA to evaluate the findings and determine the further development pathway for the SPR720 clinical program. 12 IV Potentiator Product Candidate SPR206: Our IV-administered product candidate being developed as an innovative option to treat multi-drug resistant (MDR) Gram-negative bacterial infections in the Hospital Setting. SPR206 is an IV-administered product candidate being developed as an innovative option to treat MDR Gram-negative bacterial infections in the Hospital Setting. Gram-negative bacteria represent a subset of bacterial organisms distinguished by the presence of an outer cell membrane. SPR206 is designed to treat MDR Gram-negative bacterial infections through interactions with the bacteria’s outer cell membrane as a monotherapy. SPR206 is a direct acting IV-administered agent that has demonstrated single-agent antibacterial activity in preclinical studies against Gram-negative bacteria, including organisms identified by the CDC and the WHO as urgent and serious threats to human health, including Acinetobacter baumannii and Pseudomonas aeruginosa . In January 2020 we reported results from a Phase 1 clinical trial designed as a double-blind, placebo-controlled, ascending dose, multi-cohort study in healthy subjects. In the Phase 1 clinical trial SPR206 was well-tolerated at doses that are likely to be within a therapeutic range for target MDR Gram-negative bacterial infections and has a safety profile that we believe supports the further development of SPR206. The Phase 1 clinical trial of SPR206 was designed as a double-blind, placebo-controlled, ascending dose, multi-cohort study in healthy subjects. In this SAD and MAD Phase 1 clinical trial, a total of 96 healthy volunteers were randomized to receive SPR206 or placebo. All reported adverse events were mild to moderate and there were no reported severe or serious adverse events. No evidence of nephrotoxicity was observed and there were no subjects with clinically significant changes in laboratory tests during the study. SPR206 was well-tolerated at doses up to 100 mg administered three-times a day, a total of 300 mg daily, for 14 consecutive days. Pharmacokinetic data across the cohorts indicate dose linearity and dose proportionality as well as mean plasma drug exposures of SPR206 that are concordant with preclinical models predictive for clinical efficacy against target Gram-negative pathogens. We have conducted a preclinical toxicology study of SPR206 in accordance with good laboratory practice, or GLP, requirements as well as conducted nonclinical studies in which SPR206 demonstrated activity as a single agent against MDR and extensively drug resistant, or XDR, bacterial strains, including isolates of Pseudomonas aeruginosa , Acinetobacter baumannii and carbapenem-resistant Enterobacteriaceae , in both in vitro and in vivo models of infection. We expect to initiate a Phase 1 bronchoalveolar lavage, or BAL, clinical trial to assess the penetration of SPR206 into the pulmonary compartment in the first half of 2021 and to initiate a renal impairment study of SPR206 in 2021. SPR206 has been granted QIDP designation by the FDA for the treatment of cUTI and hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP). We have multiple patent applications pending for SPR206 that we believe will provide SPR206 protection globally, including in the United States and Europe, through 2039. Following an evaluation of the IV Potentiator product candidates, we discontinued development of SPR741, effective January 1, 2020. We believe that the collective data from the recent Phase 1 and preclinical studies of SPR206 suggest a potency and safety profile that may be superior to SPR741. Further, we believe SPR206 may have a potentially faster path to pivotal clinical trials when compared with SPR741 because SPR206 is being developed as a single agent. As a result of this decision, we terminated our license agreement with Northern Antibiotics Oy (Ltd.) relating to SPR741. Effective January 1, 2020, the intellectual property rights associated with SPR741 reverted to Northern Antibiotics and we no longer have any rights with respect thereto and we no longer have any obligations for the cost of maintaining such intellectual property. SPR206 Advantages We believe that with the following key attributes, SPR206, an IV Potentiator, has the potential to become a safe and effective treatment for serious Gram-negative infections: • Potential to Expand the Potency of Standard-of-Care Antibiotics . SPR206 is designed to expand the potency of SOC antibiotics by restoring and expanding their Gram-negative activity. We believe that this novel mechanism could provide a new option for patients with resistant Gram-negative infections, thereby improving therapeutic outcomes, decreasing physicians’ reliance on older poorly tolerated and ineffective drugs. 13 • SPR206 appears to be a safe and potent IV-administered direct-acting agent . SPR206 is designed to interact with LPS to disrupt the outer membrane. SPR206 is also designed to have direct antibiotic activity, while retaining Potentiator activity, including activity against Pseudomonas aeruginosa and Acinetobacter baumannii . Data from SPR206 in vitro and in vivo GLP safety pharmacology and absorption, distribution, metabolism, and excretion, or ADME, studies and 14-day, two-species GLP toxicology studies provide support for an acceptable safety profile, which led to SPR206’s designation as a clinical candidate and the initiation of a Phase 1 clinical trial in December 2018. Phase 1 data demonstrate s that SPR206 is well-tolerated at doses that are likely to be within a therapeutic range for target MDR Gram-negative bacterial infections and has a safety profile that we believe supports the further development of SPR206. We are developing SPR206 as a treatment for high-risk patients with suspected or known Gram-negative infections such as carbapenem-resistant Enterobacteriaceae , or CRE, carbapenem resistant Acinetobacter baumannii , or CRAB, and MDR Pseudomonas aeruginosa , or MDR PA, to prevent mortality and reduce the length of stay in the hospital setting. SPR206—Development Plan Advancing SPR206 into Two Phase 1 Clinical Trials in 2021 We plan to advance SPR206 into a Phase 1 BAL clinical trial to assess the penetration of SPR206 into the pulmonary compartment in the first half of 2021 and to initiate a renal impairment study of SPR206 in 2021. Its advancement is supported by the Phase 1 SAD and MAD that we reported data for in January 2020. The Phase 1 trial was designed as a double-blind, placebo-controlled, ascending dose, multi-cohort study in healthy subjects. In the Phase 1 clinical trial, SPR206 was well-tolerated at doses that are likely to be within a therapeutic range for target MDR Gram-negative bacterial infections and had a safety profile that we believe supports the further development of SPR206. The Phase 1 clinical trial of SPR206 was designed as a double-blind, placebo-controlled, ascending dose, multi-cohort study in healthy subjects. In this SAD and MAD Phase 1 clinical trial, a total of 96 healthy volunteers were randomized to receive SPR206 or placebo. All reported adverse events were mild to moderate and there were no reported severe or serious adverse events. No evidence of nephrotoxicity was observed and there were no subjects with clinically significant changes in laboratory tests during the study. SPR206 was well-tolerated at doses up to 100 mg administered three-times a day, a total of 300 mg daily, for 14 consecutive days. Pharmacokinetic data across the cohorts indicate dose linearity and dose proportionality as well as mean plasma drug exposures of SPR206 that are concordant with preclinical models predictive for clinical efficacy against target Gram-negative pathogens. In Vitro Activity of SPR206 against MDR Gram-Negative Bacteria Results from multiple susceptibility studies against contemporary clinical isolates suggest that SPR206 possesses potent activity against MDR Enterobacteriaceae, carbapenem resistant Pseudomonas aeruginosa and carbapenem resistant Acinetobacter baumannii . 14 Our Strategy Our goal is to identify, develop and commercialize novel treatments for MDR bacterial infections, focusing on areas of high unmet medical need for safe and effective antibiotic treatments. Key elements of our strategy are as follows: • Advance our lead product candidate tebipenem HBr to regulatory approval. In September 2020, Spero announced positive data from the ADAPT-PO Phase 3 trial evaluating an all oral regimen of tebipenem HBr head-to-head versus an all IV regimen of ertapenem for the treatment of adults with cUTI, including AP. The ADAPT-PO trial achieved its primary objective, demonstrating that oral tebipenem HBr was statistically non-inferior to intravenous ertapenem in the treatment of patients with cUTI and patients with AP with respect to the primary endpoint of overall response at the TOC visit in the micro-ITT population. Overall response (combined clinical cure plus microbiological eradication) rates at TOC were 58.8% for oral tebipenem versus 61.6% for IV ertapenem (treatment difference, -3.3%; 95% confidence interval [CI]: -9.7, 3.2; -12.5% NI margin). Comparative safety and tolerability data from 1,372 hospitalized adult patients enrolled in the study were similar between the tebipenem HBr and ertapenem treatment groups. We intend to make an NDA submission to the FDA for tebipenem HBr in the second half of 2021. In addition to cUTI, we believe that tebipenem HBr has the potential to treat other serious and life-threatening infections, including CABP. In December 2020, we initiated a Phase 1 bronchoalveolar lavage, or BAL, clinical trial to assess the penetration of tebipenem HBr into the pulmonary compartment and we expect to report data from the trial in second half of 2021. In addition, our tebipenem HBr collaboration with BARDA, which is further described elsewhere in this “Business” section of our Annual Report on Form 10-K, provides funding for a clinical trial in pneumonia patients. • Establish global commercialization and marketing capabilities . We have global commercialization rights to all of our product candidates, with the exception of tebipenem HBr and SPR206 in certain contractually specified Asian countries. Additionally, the Bill & Melinda Gates Medical Research Institute, or Gates MRI, holds rights to develop SPR720 for the treatment of lung infections caused by Mycobacterium tuberculosis in certain countries. Our management team has significant expertise in the commercialization of infectious disease treatments. Prior to joining us, members of our management team have collectively played leading roles in the approval and launch of 11 infectious disease products. We intend to build a targeted sales force and directly commercialize our product candidates in the United States in both hospital and community settings. Outside the United States, we intend to enter into collaborations with third parties to develop and market our product candidates in targeted geographical markets. By collaborating with companies that have an existing commercial presence and experience in such markets, we believe we can efficiently maximize the commercial potential of our product candidates. • Diversify into rare orphan infectious disease markets such as NTM disease. We believe there is a significant opportunity to develop products for underserved “orphan” infectious disease areas, such as NTM disease. These markets offer the attributes of fewer branded or generic competitors as well as chronic therapy. We believe our drug candidate SPR720 has the potential to be the first oral antibiotic approved for the treatment of nontuberculous mycobacterial pulmonary disease. We may seek to acquire other product candidates for other underserved, debilitating orphan infectious diseases. We will evaluate our ability to continue to advance SPR720 through clinical development. In December 2020, we initiated a Phase 2a clinical trial of SPR720 in treatment inexperienced patients with NTM pulmonary disease due to MAC. On February 5, 2021, we announced that the FDA informed us that a clinical hold had been placed on our Phase 2a clinical trial of SPR720, which is further described elsewhere in this “Business” section of our Annual Report on Form 10-K under the heading “Update on Phase 2a Clinical Trial.” In December 2019, we reported Phase 1 data for SPR720 showing that SPR720 was generally well-tolerated, with a pharmacokinetic profile that we believe supports further development of the compound as an oral agent for the treatment of NTM disease. In June 2019, SPR720 was the focus of an equity investment by the Novo REPAIR Impact Fund for $10 million as well as a collaboration with Bill & Melinda Gates Medical Research Institute, or Gates MRI, to further the development of SPR720 for TB. In March 2020, the FDA granted orphan drug designation for SPR720 for the treatment of NTM infection, a designation available to drugs intended to treat a rare disease or condition that affects fewer than 200,000 persons in the United States. An orphan drug designation can provide specific benefits such as seven years of market exclusivity in the United States upon regulatory approval. In September 2020, SPR720 was awarded Fast Track Designation by the FDA for treatment of adult patients with NTM pulmonary disease . • Maximize the value of our pipeline through collaborations with other pharmaceutical companies. We may elect to pursue strategic collaborations with other pharmaceutical companies to leverage our pipeline. We believe it may be beneficial to develop and commercialize one or more of our product candidates through partnering opportunities. Such collaborations may include regional collaborations to advance our pipeline products, or product-specific deals pairing our product candidates with collaborators’ antibiotics, whether generic or novel, with the intention of enhancing those antibiotics’ performance and efficacy. • Continue to pursue collaborations with non-commercial organizations for scientific expertise and funding support. We have received funding support from BARDA, the United States National Institute of Allergy and Infectious Diseases, or NIAID, the United States Department of Defense, or DoD, and the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator, or CARB-X, a public-private partnership funded by BARDA within the United States Department of Health and Human Services. We intend to continue to collaborate with government agencies and non-profit foundations to support the development of our product candidates. 15 • Expand our portfolio of product candidates for the treatment of MDR infections. Since our inception, we have focused on identifying and developing antibiotics to treat MDR infections, and we are using our expertise to aggressively build and expand a portfolio of product candidates for the treatment of such infections where unmet need exists and no viable generic alternatives are available. Our management team has deep-rooted relationships in the academic, medical and corporate infectious disease community, which provide us visibility into new and innovative therapies under development. Our focus in assessing product candidates relies on three principles: 1) broad spectrum of activity, 2) convenient for patients and 3) novel mechanism to overcome resistance. We believe the greatest unmet medical needs for safe and effective antibiotic treatments lie among infections due to MDR bacteria, as patients with these infections often have limited or inadequate therapeutic options, leading to high rates of mortality. The increasing prevalence of drug resistance and MDR bacteria, and the limitations of existing therapies and traditional drug development approaches, highlight the critical need for novel therapies capable of overcoming resistance, particularly orally administrable agents. Collaboration, License and Service Agreements In addition to our own patents and patent applications, we have acquired or licensed patents, patent applications and know-how from various third parties to access intellectual property covering product candidates that we are developing. We have certain obligations under these acquisitions or licensing agreements, including diligence obligations and payments, which are contingent upon achieving various development, regulatory and commercial milestones. Also, pursuant to the terms of some of these license agreements, when and if commercial sales of a product commence, we may be obligated to pay royalties to such third parties on net sales of the respective products. Some of our license agreements include sublicenses of rights owned by third-party head licensors. In addition, we have entered into a license agreement (described below) pursuant to which we have granted certain development, manufacturing and commercialization rights with respect to our Potentiator product candidates. Meiji Agreements To support our development of tebipenem HBr, in June 2017 we entered into an exclusive License Agreement with Meiji Seika Pharma Co., Ltd., or the Meiji License. Pursuant to the Meiji License, we obtained know-how, data and regulatory documents that will support the development of tebipenem HBr. We retain exclusive rights to commercialize tebipenem HBr throughout the world, except in Japan, Bangladesh, Brunei, Cambodia, China, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, South Korea, Taiwan, Thailand and Vietnam, where Meiji will have exclusive rights to commercialize tebipenem HBr. With Meiji, we have established a joint development committee for the management of the development of tebipenem HBr, including any joint, cross-territory studies that may be undertaken by the parties, if any. In addition, the parties will establish a joint commercialization committee to coordinate information sharing relative to commercialization of the new formulation. Meiji and we have granted each other exclusive cross licenses to our respective tebipenem intellectual property, including know-how and regulatory documentation. The license granted to us by Meiji includes certain know-how that Meiji received from Global Pharma, as described below. As such, our rights to the Global Pharma know-how component are non-exclusive. Under the Meiji License, we have paid Meiji a one-time nonrefundable upfront fee of $0.6 million and are obligated to pay Meiji future clinical and regulatory milestone payments up to an aggregate of $2.0 million and royalties of a low single-digit percentage based on net sales of tebipenem HBr. In October 2017, we paid a $1.0 million milestone payment to Meiji upon the enrollment of the first patient in our Phase 1 clinical trial of tebipenem HBr. Additionally, we are obligated to pay Meiji a percentage of certain amounts received from any sublicensees, up to an aggregate of $7.5 million. Some of the know-how that we received under the Meiji License to support tebipenem HBr development was originally obtained by Meiji through a license from Global Pharma, which we refer to as the head license. Prior to entering into the Meiji License with us, Meiji received written approval from Global Pharma permitting Meiji to enter into the Meiji License with us. Specifically, in a letter agreement between Global Pharma and Meiji entered into in January 2017, Global Pharma consented to Meiji assisting us with the transfer or license of the Global Pharma know-how and Meiji know-how on a non-exclusive basis outside of those Asian countries identified above, as well as certain related matters. This letter agreement does not contemplate us having any right to sublicense the Global Pharma know-how. Global Pharma retains rights to its know-how outside of those Asian countries identified above. The Meiji License continues in effect until the expiration of all payment obligations thereunder (including royalty payments and licensee revenue) on a product-by-product and country-by-country basis, unless earlier terminated by the parties. Pursuant to the terms of the Meiji License, in addition to each party’s right to terminate the agreement upon the other party’s material breach (if not cured within a specified period after receipt of notice) or insolvency, we also have unilateral termination rights (i) in the event that we abandon the development and commercialization of tebipenem HBr for efficacy, safety, legal or business factors, and (ii) under certain circumstances arising out of the head license with Global Pharma. 16 IV Potentiator Product Agreements Northern License Agreement In January 2020, we terminated our license agreement with Northern Antibiotics Oy (Ltd.) relating to SPR741. Effective January 1, 2020, the intellectual property rights associated with SPR741 have entirely reverted to Northern Antibiotics and we no longer have any rights with respect thereto and we no longer have any obligations for the cost of maintaining such intellectual property. Cantab Agreements In June 2016, we entered into a stock purchase agreement, or the Cantab Agreement, with Pro Bono Bio PLC, a corporation organized under the laws of England, and its affiliates, including PBB Distributions Limited, or PBB, Cantab Anti-Infectives Ltd., or CAI and New Pharma License Holdings Limited, or NPLH, in order to acquire NPLH and its intellectual property rights and assets relating to our Potentiator products, and our next-generation potentiating agents in particular. The intellectual property portfolio we acquired includes patents which cover SPR206 as well as other novel potentiating agents, polymyxin derivatives and other LPS or outer-membrane bacterial disrupting agents. In exchange for the acquisition of NPLH, we paid PBB upfront consideration in the amount of $0.3 million and also agreed to make milestone payments of up to $5.8 million upon the achievement of specified clinical and regulatory milestones and a payment of £5.0 million ($6.8 million as of December 31, 2020) upon the achievement of a specified commercial milestone. We also agreed to pay royalties of a low single-digit percentage based on net sales of products licensed under the agreement. In addition, Spero Cantab issued an equity interest in Spero Cantab and entered into a subscription agreement and shareholders agreement with PBB. In July 2017, we repurchased PBB’s minority equity interest in Spero Cantab in exchange for a one-time nonrefundable upfront fee of approximately $0.2 million and we also amended the Cantab Agreement to increase the contingent milestone payments to PBB by an aggregate of $0.1 million. The Cantab Agreement continues indefinitely, with royalty payment obligations thereunder continuing on a product-by-product and country-by-country basis until the later of ten years after the first commercial sale of such product in such country or the expiration in such country of the last to expire valid claim of any of the applicable patents. In addition, we hold a NIAID contract that partially funded the next-generation potentiating agent development program. That contract was novated from CAI to us in December 2017. Under the contract we were obligated to pay PBB a percentage of funds received from NIAID up to a maximum of $1.3 million, which was fulfilled as of December 31, 2020. Everest Medicines License Agreement On January 4, 2019, we, through NPLH, entered into a license agreement, or the Original Everest License Agreement, with Everest, which Original Everest License Agreement also included an option granted by our wholly owned subsidiary, Spero Potentiator, Inc., a Delaware corporation, or Potentiator. Under the terms of the Original Everest License Agreement, we granted Everest an exclusive license to develop, manufacture and commercialize SPR206 or products that contain SPR206, or Licensed Products, in Greater China (which includes Mainland China, Hong Kong and Macau), South Korea and certain Southeast Asian countries, collectively referred to as the Territory. We retained development, manufacturing and commercialization rights with respect to SPR206 and Licensed Products in the rest of the world and also retained the right to develop or manufacture SPR206 and Licensed Products in the Territory for use outside the Territory. In addition to the license grant to SPR206, we granted Everest a 12-month exclusive option to negotiate with us for an exclusive license to develop, manufacture and commercialize SPR741 in the Territory. For the reasons discussed above, following an evaluation of the Potentiator product candidates, we discontinued the development of SPR741, effective January 1, 2020, and decided to move forward with SPR206 as our lead Potentiator product candidate. In addition, on October 29, 2019, Everest notified us that it did not intend to exercise its option with respect to SPR741 under the Original Everest License Agreement. Accordingly, effective January 1, 2020, we no longer have any intellectual property rights with respect to SPR741 and we no longer have any obligations for the cost of maintaining such intellectual property. Under the terms of the Original Everest License Agreement, we received an upfront payment of $3.0 million. We also received a milestone payment of $2.0 million in the fourth quarter of 2020 upon completion and delivery of the results of a clinical study. 17 In January 2021, we entered into an amended and restated license agreement, or the Amended Everest License Agreement, with Everest and Potentiator, which amended and restated in its entirety the Original Everest License Agreement. The Amended Everest License Agreement modified the dates and values of certain milestone events related to development and commercialization of SPR206. Everest will now be making more significant investments in the development of SPR206 beyond what was contemplated at the time of the Original Everest License Agreement. The Original Everest License Agreement provided that we could receive up to $59.5 million upon achievement of certain milestones. The Amended Everest License Agreement provides that we may receive up to $38.0 million upon achievement of certain milestones, of which $2.0 million has been received to date. In addition, under the Amended Everest License Agreement, the Company assigned patents in the Territory to Everest, rather than licensing such patents to Everest, and the option related to SPR741 and related provisions have been removed. We are also entitled to receive high single-digit to low double-digit royalties on net sales, if any, of Licensed Products in the Territory following regulatory approval of SPR206. Everest has the right to sublicense to affiliates and third parties in the Territory. Everest is responsible for all costs related to developing, obtaining regulatory approval of and commercializing SPR206 and Licensed Products in the Territory, and is obligated to use commercially reasonable efforts to develop, manufacture and commercialize Licensed Products, including to achieve certain specified diligence milestones within agreed-upon periods. A joint development committee will be established between us and Everest to coordinate and review the development, manufacturing and commercialization plans with respect to Licensed Products in the Territory. Unless earlier terminated due to certain material breaches of the contract, or otherwise, the Amended Everest License Agreement will expire on a jurisdiction-by-jurisdiction and Licensed Product-by-Licensed Product basis until the latest to occur of expiration of the last valid claim under a licensed patent in such jurisdiction, the expiration of regulatory exclusivity in such jurisdiction or ten years after the first commercial sale of such Licensed Product in such jurisdiction. The Amended Everest License Agreement may be terminated in its entirety by Everest upon 90 or 180 days’ prior written notice, depending on the stage of development of the initial Licensed Product. Other License, Collaboration and Service Agreements Gates MRI Collaboration In June 2019, we entered into a collaboration with Gates MRI, a nonprofit research institution wholly owned by the Bill and Melinda Gates Foundation, to develop SPR720 for the treatment of lung infections caused by Mycobacterium tuberculosis, or Mtb. In furtherance of the Gates MRI’s charitable purposes, we also granted the Gates MRI a no cost, exclusive license to develop, manufacture and commercialize SPR720 for the treatment of TB in low- and middle- income countries. Gates MRI will conduct and fund preclinical and clinical studies for the development of SPR720 against TB as well as certain collaborative research activities performed by us. Vertex Assignment and License Agreement In May 2016, we entered into an agreement with Vertex Pharmaceuticals Incorporated, or Vertex, pursuant to which Vertex assigned to us rights to patents relating to SPR720 and SPR719 (an active metabolite). The acquired patent portfolio includes protection for composition of matter, method of use, and specific key intermediates used in the manufacture of SPR719 and SPR720. We also obtained certain know-how and a license to research, develop, manufacture and sell products for a proprietary compound, as well as a transfer of materials as part of the transaction. In return, we granted Vertex an exclusive license to the assigned patents and know-how for use outside of the diagnosis, treatment or prevention of bacterial infections. In exchange for the assigned patents, we paid Vertex an upfront, one-time, non-refundable, non-creditable fee of $0.5 million, which was recognized as research and development expense, and we also agreed to pay Vertex future clinical, regulatory and commercial milestones up to $81.3 million in the aggregate and a royalty on the net sales of licensed products ranging from mid-single digits to low double digits. During the year ended December 31, 2020, we paid and recorded $0.9 million in expense related to the achievement of regulatory milestones for SPR720. The agreement continues in effect until the expiration of all payment obligations thereunder, with royalty payment obligations continuing on a product-by-product and country-by-country basis until the later of ten years after the first commercial sale of such product in such country or the date of expiration in such country of the last to expire applicable patent. Further, Vertex has the right to terminate the agreement if provided with notification from us of our intent to cease all development or if no material development or commercialization efforts occur for a period of 12 consecutive months. 18 Savior Service Agreement In November 2018, we entered into a service agreement with Savior Lifetec Corporation, or Savior, to perform technology transfer, process development, analytical method development and testing and formulation development for tebipenem HBr. Per the terms of the agreement, we paid Savior a non-refundable supervision fee of approximately $2.0 million to manage the buildout of a commercial manufacturing facility. The supervision fee is classified as a prepaid asset on our balance sheet and is being amortized over a service period of approximately 34 months. We have paid Savior an additional $5.1 million for facility build out costs, which is classified as a long-term asset on our balance sheet as of December 31, 2020. Government Awards Through December 31, 2020, we have committed funding support of up to an aggregate of $49.7 million in non-dilutive funding from BARDA, NIAID, the DoD and concluded awards from CARB-X, SBIR and the DoD, with the potential to receive a total of up to $63.0 million (inclusive of amounts we have already received) if certain options are exercised. The awards are subject to termination for convenience at any time by the granting government agency, and the granting government agency is not obligated to provide funding to us beyond the base period amounts from Congressionally approved annual appropriations. These awards are structured in the following manner: • BARDA award to support the further clinical development of tebipenem HBr. The BARDA award provides total reimbursement to us of up to $46.8 million for qualified expenses for tebipenem HBr development over a five-year period. The award initially committed funding of $15.7 million over a three-year base period from July 2018 to June 30, 2021 for cUTI development activities. In May 2019, the contract was modified to include additional funding of approximately $2.5 million for tebipenem HBr, increasing the amount of initial committed funding from $15.7 million to approximately $18.2 million. In January 2020, BARDA exercised its first option under the contract, committing $15.9 million for tebipenem HBr through November 2021. Total committed funding under the BARDA award to date is $34.1 million, including the first option exercised in 2020. There is a second option exercisable by BARDA for the remaining $12.7 million of funding, subject to specified milestones being achieved under the award agreement. As part of our tebipenem HBr collaboration with BARDA described above, there will be studies assessing the efficacy of tebipenem HBr in treatment of infections caused by biodefense threats such as anthrax, plague, and melioidosis, including a clinical trial in pneumonia patients. The Defense Threat Reduction Agency, or DTRA, will provide up to $10.0 million in addition to the total potential $46.8 million from BARDA, to cover the cost of the nonclinical biodefense aspects of the collaboration program. While such funding would be for the purpose of developing tebipenem HBr in these areas, we will not receive any funds directly from DTRA. Upon these achievements, BARDA may exercise its second option to fund a clinical trial in pneumonia patients to demonstrate safety and data suggestive of efficacy. • NIAID funding for SPR206. The NIAID contract for SPR206 provides for total development funding of up to $6.5 million over a base period and three option periods. To date, funding for the base period and the first two option periods, totaling $5.9 million, have been committed through March 2021. • NIAID award under its Small Business Innovation Research program, or SBIR, for SPR720. This award provided up to $1.0 million of support for our SPR720 program. The scope of the program included in vitro and in vivo assessments of SPR720 against TB as well as nonclinical and manufacturing activities in support of both TB and NTM indications. The NIAID SBIR award was structured as a base period followed by a single option. For the base period of March 1, 2017 through February 28, 2018, NIAID committed funding of approximately $0.6 million for the SPR720 program. In February 2018 NIAID exercised the approximately $0.4 million option, with a period of performance from March 1, 2018 through February 28, 2019. In January 2019, the period of performance for this award was extended through February 28, 2020. This award has been closed out as of December 31, 2020. • DoD funding for SPR206. In July 2019 we were awarded a $5.9 million award from the DoD Congressionally Directed Medical Research Programs, or CDMRP, Joint Warfighter Medical Research Program, which will support, over a four-year period into July 2023, the development of SPR206. The funding will cover the costs of select Phase 1 pharmacology studies, a 28-day GLP non-human primate toxicology study, and microbiological surveillance studies that would be required for a potential NDA submission with the FDA for SPR206. This award was preceded by a DoD cooperative agreement award made to Spero in September 2016 that funded our potentiator product candidates to develop anti-infective agents to combat Gram-negative bacteria. It was structured as a single, two-year $1.5 million award with a period of performance through September 2019. That award has now been closed out. 19 Intellectual Property We strive to protect the proprietary technology that we believe is important to our business, including seeking and maintaining patents intended to cover our product candidates and compositions, their methods of use and processes for their manufacture and any other inventions that are commercially important to the development of our business. We also rely on trade secrets to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. Our success will significantly depend on our ability to obtain and maintain patent and other proprietary protection for commercially important technology and inventions and know-how related to our business, defend and enforce our patents, preserve the confidentiality of our trade secrets and operate without infringing the valid and enforceable patents and proprietary rights of third parties. We also rely on know-how and continuing technological innovation to develop and maintain our proprietary position. Spero-Owned Intellectual Property Relating to Tebipenem HBr and Other Compounds Under Development We have patent applications directed to the composition of matter, formulation and/or use of tebipenem HBr, SPR206 and SPR720 pending in the United States, Europe, Japan and other countries. Tebipenem HBr Oral Carbapenem (Tebipenem Pivoxil Hydrobromide) Our tebipenem HBr program contains two pending United States provisional patent applications, one issued and two pending United States patent applications, and four issued and 37 pending foreign patent applications covering novel preparations of tebipenem pivoxil hydrobromide as of December 31, 2020, all wholly owned by us. The provisional patent application must be converted to PCT applications within one year of their May 2020 and November 2020 filing dates. The issued foreign patents are issued in Australia (2), Brazil, and South Africa. Foreign patent applications are pending in Australia, Brazil, Canada, China, Colombia, the Eurasian Patent Office, the European Patent Office, Egypt, Indonesia, Israel, India, Japan, South Korea, Mexico, New Zealand, the Philippines, Singapore, Thailand, Vietnam, and South Africa. United States and foreign patents covering our tebipenem pivoxil hydrobromide preparations will have statutory expiration dates of December 2037, February 2038, May 2040, and November 2040. Patent term adjustments or patent term extensions could result in later expiration dates. In January 2021, the United States Patent and Trademark Office, or USPTO, issued U.S. Patent No, 10,889,587, which is directed to the crystalline formulation of tebipenem HBr, Spero’s oral carbapenem in development for the treatment of cUTI and AP. This patent covers a crystalline form of tebipenem pivoxil HBr, pharmaceutical compositions of tebipenem pivoxil HBr and methods of use. The patent expires in February 2038. Next-Generation Potentiator Product (SPR206) The intellectual property portfolio for our next-generation polymyxin program contains patent applications and issued patents directed to composition of matter for polymyxin-like compounds with different structural features, pharmaceutical compositions comprising the same, and methods of use for these novel compounds and compositions. As of December 31, 2020, we owned one United States patent and three pending United States patent applications, ten foreign patents, and 46 pending foreign patent applications in a number of jurisdictions including Argentina, Australia, Brazil, Canada, China, Colombia, the Eurasian Patent Office, the European Patent Office, Hong Kong, India, Israel, Japan, South Korea, Malaysia, Mexico, New Zealand, the Philippines, Russia, Singapore, South Africa, Taiwan, Thailand, Ukraine, Venezuela and Vietnam. Issued United States or foreign patents and any patents issuing from pending United States or foreign applications covering our next-generation polymyxin program will have a statutory expiration date of May 2034, March 2035, November 2035, or June 2039. Patent term adjustments or patent term extensions could result in later expiration dates. In 2019 Spero entered into an agreement with Everest, by which Everest would develop, manufacture, and commercialize SPR206 in China, South Korea, and certain Southeast Asian countries. Spero’s agreement with Everest has since been amended to include an obligation by Spero to assign its SPR206 patent rights to Everest in these countries. NTM Disease Program (SPR720) Our intellectual property portfolio for our DNA Gyrase Inhibitor program includes issued patents and pending patent applications directed to composition of matter for SPR720, and its close analogs and prodrugs, novel solid forms of SPR720 and its prodrugs, methods of manufacture, and methods of treatment using SPR720 alone and in combination with other antibiotic compounds. All patents and patent applications in the portfolio are wholly owned by us. As of December 31, 2020, we owned 11 issued United States patents, 91 issued foreign patents, and seven pending foreign patent applications. The issued and foreign patents are in a number of jurisdictions including the European Union and its member states, Argentina, Australia, Brazil, Canada, China, Hong Kong, Indonesia, Israel, India, Japan, South Korea, Mexico, New Zealand, the Philippines, Russia, Singapore, South Africa, and Taiwan. Issued United States and foreign patents, and patents issuing from pending United States and foreign applications, will have statutory expiration dates of January 2032, June 2032 and July 2033. Patent term adjustments or patent term extensions could result in later expiration dates. 20 Patent Term and Patent Term Extensions The term of individual patents depends upon the legal term for patents in the countries in which they are obtained. In most countries, including the United States, the patent term is 20 years from the earliest filing date of a non-provisional patent application. In the United States, a patent’s term may be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the USPTO in examining and granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier filed patent. The term of a patent that covers a drug, biological product or medical device approved pursuant to a pre-market approval may also be eligible for patent term extension when FDA approval is granted, provided statutory and regulatory requirements are met. The length of the patent term extension is related to the length of time the drug is under regulatory review while the patent is in force. The Hatch-Waxman Act permits a patent term extension of up to five years beyond the expiration date set for the patent. Patent extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent applicable to each regulatory review period may be granted an extension and only those claims reading on the approved drug are extended. Similar provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an approved drug. Trade Secrets We rely, in some circumstances, on trade secrets to protect our unpatented technology. However, trade secrets can be difficult to protect. We seek to protect our trade secrets and proprietary technology and processes, in part, by confidentiality agreements with our employees, consultants, scientific advisors and contractors. We also seek to preserve the integrity and confidentiality of our data and trade secrets by maintaining physical security of our premises and physical and electronic security of our information technology systems. While we have confidence in these individuals, organizations and systems, agreements or security measures may be breached. We may not have adequate remedies for any breach and could lose our trade secrets through such a breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our consultants, contractors or collaborators use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting trade secrets, know-how and inventions. Competition The biopharmaceutical industry is characterized by intense competition and rapid innovation. Our potential competitors include large pharmaceutical and biotechnology companies, specialty pharmaceutical companies and generic drug companies. Many of our potential competitors have greater financial, technical, and human resources than we do, as well as greater experience in the discovery and development of product candidates, obtaining FDA and other regulatory approvals of products and the commercialization of those products. Accordingly, our potential competitors may be more successful than us in obtaining FDA approval of drugs and achieving widespread market acceptance. We anticipate that we will face intense and increasing competition as new drugs enter the market and advanced technologies become available. Finally, the development of new treatment methods for the diseases we are targeting could render our product candidates non-competitive or obsolete. We believe the key competitive factors that will affect the development and commercial success of our most advanced product candidate, tebipenem HBr, if approved, will be efficacy, coverage of drug-resistant strains of bacteria, safety and tolerability profile, reliability, convenience of oral dosing, price, availability of reimbursement from governmental and other third-party payers and susceptibility to drug resistance. We are developing tebipenem HBr as an oral antibiotic for use as a monotherapy for the treatment of resistant and MDR infections. If approved, tebipenem HBr would compete with several antibiotics currently in clinical development for urinary tract infection, including sulopenem from Iterum Therapeutics Limited, ARX-1796 from Pfizer, Gepotidacin from GSK and Pivmecillinam from Utilility Therapeutics. We also expect that tebipenem HBr, if approved, would compete with future and current generic versions of marketed antibiotics. If approved, we believe that tebipenem HBr would compete effectively against these compounds on the basis of tebipenem HBr’s potential: • broad range of activity against a wide variety of resistant and MDR Gram-negative bacteria; • low probability of drug resistance; • a favorable safety and tolerability profile supported by years of post-marketing experience in Japan; • a convenient oral dosing regimen and opportunity to step-down from IV-administered therapy; and • as a monotherapy treatment for MDR Gram-negative infections. We are also developing SPR206 as an innovative IV-administered agent for Gram-negative infections in the hospital. If approved, SPR206 would compete with several IV-administered products marketed for the treatment of Gram-negative infections, including ceftazidime-avibactam (Avycaz) from Allergan plc and Pfizer Inc., ceftolozane-tazobactam (Zerbaxa) from Merck & Co., plazomicin (Zemdri) from Cipla Therapeutics, Inc., eravacycline (Xerava) from Tetraphase Pharmaceuticals, Inc., and meropenem-vaborbactam (Vabomere) from Melinta Therapeutics, Inc. There are also a number of IV-administered product candidates in late-stage clinical development that are intended to treat resistant Gram-negative infections, including cefiderocol from Shionogi & Co. Ltd., and imipenem-relebactam from Merck & Co. Each of these products and product candidates employs a mechanism of action that differs from the mechanism of action employed by SPR206. 21 We are developing SPR720 to be the first approved oral treatment for NTM disease. There are currently no oral agents approved to treat NTM disease. Only one drug is approved to treat NTM infection that would potentially compete with SPR720 called Arikayce from Insmed, an inhaled version of a commonly used drug in the hospital setting called amikacin. It should be noted that combination therapy is recommended for treating this condition. Government Regulation and Product Approval Government authorities in the United States, at the federal, state and local level, and in other countries, extensively regulate, among other things, the research, development, clinical trials, testing, manufacture, including any manufacturing changes, authorization, pharmacovigilance, adverse event reporting, recalls, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, import and export of pharmaceutical products and product candidates such as those we are developing. The processes for obtaining regulatory approvals in the United States and in foreign countries, along with subsequent compliance with applicable statutes and regulations, require the expenditure of substantial time and financial resources. United States Government Regulation In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or FDCA, and implementing regulations. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable United States requirements at any time during the product development process, approval process or after approval, may subject an applicant to a variety of administrative or judicial sanctions, such as the FDA’s refusal to approve pending NDAs, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement or civil and/or criminal penalties. The process required by the FDA before a drug may be marketed in the United States generally involves the following: • completion of preclinical laboratory tests, animal studies and formulation studies in compliance with GLPs and other applicable regulations; • submission to the FDA of an IND which must become effective before human clinical trials may begin; • approval by an independent institutional review board, or IRB, at each clinical site before each trial may be initiated; • performance of adequate and well-controlled human clinical trials in accordance with GCPs to establish the safety and efficacy of the proposed drug product for each indication; • submission to the FDA of an NDA and payment of user fees; • satisfactory completion of an FDA advisory committee review, if applicable; • satisfactory completion of an FDA pre-approval inspection of the manufacturing facility or facilities at which the product is produced to assess compliance with current good manufacturing practices, or cGMPs, and to assure that the facilities, methods and controls are adequate to preserve the drug’s identity, strength, quality and purity; • satisfactory completion of audits of clinical trial sites conducted by FDA to assure compliance with GCPs and the integrity of clinical data; and • FDA review and approval of the NDA. Preclinical Studies Preclinical studies include laboratory evaluation of product chemistry, toxicity and formulation, as well as animal studies to assess potential safety and efficacy. Preclinical tests intended for submission to the FDA to support the safety of a product candidate must be conducted in compliance with GLP regulations and the United States Department of Agriculture’s Animal Welfare Act. A drug sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data and any available clinical data or literature, among other things, to the FDA as part of an IND. Some nonclinical testing may continue even after the IND is submitted. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions related to one or more proposed clinical trials and places the clinical trial on a clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an IND may not result in the FDA allowing clinical trials to commence. A clinical hold may occur at any time during the life of an IND and may affect one or more specific studies or all studies conducted under the IND. 22 Clinical Trials Clinical trials involve the administration of the investigational new drug to human subjects under the supervision of qualified investigators in accordance with GCP requirements, which include the requirement that all research subjects provide their informed consent in writing for their participation in any clinical trial along with the requirement to ensure that the data and results reported from the clinical trials are credible and accurate. Clinical trials are conducted under protocols detailing, among other things, the objectives of the trial, the criteria for determining subject eligibility, the dosing plan, the parameters to be used in monitoring safety, the procedure for timely reporting of adverse events, and the effectiveness criteria to be evaluated. A protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, an IRB at each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution. Information about certain clinical trials and clinical trial results must be submitted within specific timeframes to the National Institutes of Health, or NIH, for public dissemination on its www.clinicaltrials.gov website. Human clinical trials are typically conducted in three sequential phases, which may overlap or be combined: Phase 1 : The drug is initially introduced into healthy human subjects or patients with the target disease or condition and tested for safety, dosage tolerance, absorption, metabolism, distribution, excretion and, if possible, to gain an early indication of its effectiveness. During Phase 1 clinical trials, sufficient information about the investigational drug’s pharmacokinetics and pharmacological effects may be obtained to permit the design of well-controlled and scientifically valid Phase 2 clinical trials. Phase 2 : The drug is administered to a larger, but still limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted indications and to determine dosage tolerance and optimal dosage. Phase 2 clinical trials are typically well-controlled and closely monitored. Phase 3 : The drug is administered to an expanded patient population, generally at geographically dispersed clinical trial sites, in well-controlled clinical trials to generate enough data to statistically evaluate the efficacy and safety of the product for approval, to establish the overall risk-benefit profile of the product, and to provide adequate information for the labeling of the product. Phase 3 clinical trials usually involve a larger number of participants than a Phase 2 clinical trial. Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently if serious adverse events occur. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Results from one trial may not be predictive of results from subsequent trials. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. Marketing Approval Assuming successful completion of the required clinical testing, the results of the nonclinical studies and clinical trials, together with detailed information relating to the product’s chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the product for one or more indications. Under the Prescription Drug User Fee Act, or PDUFA, as amended, each NDA must be accompanied by a significant user fee. The FDA adjusts the PDUFA user fees on an annual basis. PDUFA also imposes an annual program fee for prescription drug products. Fee waivers or reductions are available in certain circumstances, such as where a waiver is necessary to protect the public health, where the fee would present a significant barrier to innovation, or where the applicant is a small business submitting its first human therapeutic application for review. Under the performance goals and policies agreed to by the FDA under PDUFA, the FDA has a goal of ten months from the date of “filing” of a standard NDA for a new molecular entity to review and act on the submission, and six months from the filing date for an application with priority review. This review typically takes 12 months from the date the NDA is submitted to FDA (eight months for priority applications) because the FDA has approximately two months to make a “filing” decision. Furthermore, the FDA is not required to complete its review within the established ten-month timeframe (or six months for priority applications) and may extend the review process by issuing requests for additional information or clarification. The FDA conducts a preliminary review of all NDAs within the first 60 days after submission, before accepting them for filing, to determine whether they are sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA reviews an NDA to determine, among other things, whether the drug is safe and effective and whether the facilities in which it is manufactured, processed, packaged or held meet standards designed to assure the product’s continued safety, quality and purity. 23 In addition, under the Pediatric Research Equity Act of 2003, as amended and reauthorized, certain NDAs or supplements to an NDA must contain data that are adequate to assess the safety and effectiveness of the drug for the claimed indications in all relevant pediatric subpopulations, and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults or full or partial waivers from the pediatric data requirements. Unless otherwise required by regulation, the pediatric data requirements do not apply to products with orphan designation. During the review and approval process, the FDA likely will re-analyze the clinical trial data, which could result in extensive discussions between the FDA and the applicant during the review process. The FDA also may require submission of a risk evaluation and mitigation strategy, or REMS, plan if it determines that a REMS is necessary to ensure that the benefits of the drug outweigh its risks and to assure the safe use of the drug. The REMS plan could include medication guides, physician communication plans, assessment plans, and elements to assure safe use, such as restricted distribution methods, patient registries, or other risk minimization tools. The FDA may refer an application for a novel drug or a drug that presents difficult questions of safety or efficacy to an advisory committee. An advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical trial sites to assure that the clinical trials were conducted in compliance with IND regulations and GCP requirements and to assure the integrity of the clinical data submitted to the FDA. The FDA generally accepts data from foreign clinical trials in support of an NDA if the trials were conducted under an IND. If a foreign clinical trial is not conducted under an IND, the FDA nevertheless may accept the data in support of an NDA if the study was conducted in accordance with GCPs and the FDA is able to validate the data through an on-site inspection, if deemed necessary. Although the FDA generally requests that marketing applications be supported by some data from domestic clinical trials, the FDA may accept foreign data as the sole basis for marketing approval if (1) the foreign data are applicable to the United States population and United States medical practice, (2) the studies were performed by clinical investigators with recognized competence, and (3) the data may be considered valid without the need for an on-site inspection or, if the FDA considers the inspection to be necessary, the FDA is able to validate the data through an on-site inspection or other appropriate means. The testing and approval process for a new drug product requires substantial time, effort and financial resources, and each may take several years to complete. Data obtained from preclinical and clinical testing are not always conclusive and may be susceptible to varying interpretations, which could delay, limit or prevent regulatory approval. The FDA may not grant approval on a timely basis, or at all. After evaluating the NDA and all related information, including the advisory committee recommendation, if any, and inspection reports regarding the manufacturing facilities and clinical trial sites, the FDA may issue an approval letter, or, in some cases, a complete response letter. An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications. A complete response letter, or CRL, describes all of the specific deficiencies in the NDA identified by the agency. A CRL indicates that the review cycle of the application is complete and the application will not be approved in its present form. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. Additionally, the CRL may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the NDA, addressing all of the deficiencies identified in the letter, or withdraw the application. If and when those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the NDA, the FDA will issue an approval letter to the applicant. The FDA has committed to reviewing such resubmissions in response to an issued CRL in either two or six months depending on the type of information included. Even with submission of this additional information, however, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval. Even if the FDA approves a product, it may limit the approved indications for use of the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess a drug’s safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution and use restrictions or other risk management mechanisms under a REMS plan, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-marketing studies or surveillance programs. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes, and additional labeling claims, are subject to further testing requirements and FDA review and approval. 24 Special FDA Expedited Review The FDA is authorized to designate certain products for expedited development or review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs include fast track designation, breakthrough therapy designation, QIDP designation, and priority review designation. The purpose of these programs is to provide important new drugs to patients earlier than under standard FDA review procedures. To be eligible for a fast track designation, the FDA must determine, based on the request of a sponsor, that a product is intended to treat a serious or life threatening disease or condition and demonstrates the potential to address an unmet medical need, or if the drug qualifies as a QIDP under the GAIN Act. The FDA will determine that a product will fill an unmet medical need if it will provide a therapy where none exists or provide a therapy that may be potentially superior to existing therapy based on efficacy or safety factors. Fast track designation provides additional opportunities for interaction with the FDA’s review team and may allow for rolling review of NDA components before the completed application is submitted, if the sponsor provides a schedule for the submission of the sections of the NDA, the FDA agrees to accept sections of the NDA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the NDA. In addition, fast track designation may be withdrawn by the sponsor or rescinded by the FDA if the designation is no longer supported by data emerging in the clinical trial process. Tebipenem HBr has been granted fast track designation by the FDA for the treatment of cUTI and AP, and in September 2020, SPR720 received fast track designation for treatment of adult patients with NTM pulmonary disease. In addition, with the enactment of the FDA Safety and Innovation Act, or FDASIA, in 2012, Congress created a new regulatory program for therapeutic candidates designated by FDA as “breakthrough therapies” upon a request made by the IND sponsors. A breakthrough therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA must take certain actions with respect to breakthrough therapies, such as holding timely meetings with and providing advice to the product sponsor, intended to expedite the development and review of an application for approval of a breakthrough therapy. FDASIA also included the Generating Antibiotics Incentives Now Act, or the GAIN Act, which directed the FDA to implement the qualified infectious disease product, or QIDP, designation program. The GAIN Act created incentives for the development of antibacterial and antifungal drug products for the treatment of serious or life-threatening infections. A therapeutic candidate designated as a QIDP is eligible for fast track designation, and the first marketing application submitted for a specific drug product and indication for which QIDP designation was granted will be granted priority review. A subsequent application from the same sponsor for the same product and indication will receive priority review designation only if it otherwise meets the criteria for priority review. As discussed further below under “Qualified Infectious Disease Product Exclusivity,” the GAIN Act also provides the possibility of a five-year exclusivity extension that is added to any other marketing exclusivity for which a QIDP-designated drug qualifies upon FDA approval. Finally, the FDA may designate a product for priority review if it is a drug or biologic that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA determines at the time that the marketing application is submitted, on a case-by-case basis, whether the proposed drug represents a significant improvement in treatment, prevention or diagnosis of disease when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-limiting drug reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, or evidence of safety and effectiveness in a new subpopulation. A priority review designation is intended to direct overall attention and resources to the evaluation of such applications, and to shorten the FDA’s goal for taking action on a marketing application from ten months to six months for an NDA for a new molecular entity from the date of filing. Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened. Furthermore, fast track designation, breakthrough therapy designation and priority review do not change the standards for approval and may not ultimately expedite the development or approval process. Accelerated Approval Pathway In addition, a product studied for its safety and effectiveness in treating serious or life-threatening illnesses and that provide meaningful therapeutic benefit over existing treatments may receive accelerated approval, meaning that it may be approved on (i) the basis of adequate and well-controlled clinical trials establishing that the drug product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or (ii) on an intermediate clinical endpoint that can be measured earlier than irreversible morbidity or mortality, or IMM, and that is reasonably likely to predict an effect on IMM or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. As a condition of approval, the FDA may require a sponsor of a drug receiving accelerated approval to perform post-marketing studies to verify and describe the predicted effect on IMM or other clinical endpoint, and the drug may be subject to expedited withdrawal procedures. Drugs granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval. 25 The accelerated approval pathway is usually contingent on a sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drug’s clinical benefit. As a result, a therapeutic candidate approved on this basis is subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical trials to confirm the effect on the clinical endpoint. Failure to conduct required post-approval studies, or to confirm the predicted clinical benefit of the product during post-marketing studies, would allow the FDA to withdraw approval of the drug. All promotional materials for drug products being considered and approved under the accelerated approval program are subject to prior review by the FDA. Limited Population Antibacterial Drug Pathway On December 13, 2016, former President Obama signed into law the Cures Act, which is intended to accelerate medical product development. Section 3042 of the Cures Act established the limited population pathway for certain antibacterial or antifungal drugs intended to treat targeted groups of patients suffering from serious or life-threatening infections where unmet need exists. Approvals of these limited population drugs are expected to rely on data from smaller clinical trials than would ordinarily be required by the FDA. For drugs approved through this pathway, the statement “Limited Population” will appear prominently next to the drug’s name in labeling, which is intended to provide notice to healthcare providers that the drug is indicated for use in a limited and specific population of patients. To date, the FDA has approved two products under this pathway, and in August 2020 it published a final guidance for industry entitled “Limited Population Pathway for Antibacterial and Antifungal Drugs” that describes the criteria, processes, and other general considerations for demonstrating the safety and effectiveness of limited population antibacterial and antifungal drugs, or LPADs, and is intended to assist sponsors in their development of certain new products for approval under the LPAD pathway. Post-Approval Requirements Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of adverse experiences with the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. Certain modifications to the product, including changes in indications or manufacturing processes or facilities, may require the applicant to develop additional data or conduct additional preclinical studies and clinical trials to support the submission to FDA. There also are continuing, annual user fee requirements for any marketed products, as well as new application fees for supplemental applications with clinical data. The FDA may impose a number of post-approval requirements as a condition of approval of an NDA. For example, the FDA may require post-marketing testing, including Phase 4 clinical trials, and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization. In addition, FDA regulations require that products be manufactured in specific approved facilities and in accordance with cGMPs. The cGMP regulations include requirements relating to organization of personnel, buildings and facilities, equipment, control of components and drug product containers and closures, production and process controls, packaging and labeling controls, holding and distribution, laboratory controls, records and reports and returned or salvaged products. Drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and some state agencies, and are subject to periodic unannounced inspections by the FDA for compliance with cGMP requirements and other laws. Changes to the manufacturing process are strictly regulated and, depending on the significance of the change, may require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of quality control and quality assurance. The FDA strictly regulates the marketing, labeling, advertising and promotion of drug products that are placed on the market. A product cannot be commercially promoted before it is approved, and approved drugs may generally be promoted only for their approved indications and for use in patient populations described in the product’s approved labeling. Promotional claims must also be consistent with the product’s FDA-approved label, including claims related to safety and effectiveness. The government also closely scrutinizes the promotion of prescription drugs in specific contexts such as direct-to-consumer advertising, industry-sponsored scientific and educational activities, and promotional activities involving the Internet and social media. Although physicians may prescribe legally available products for off-label uses, manufacturers may not market or promote such uses. After an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. 26 Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in mandatory revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences of regulatory non-compliance include, among other things: • restrictions on, or suspensions of, the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls; • interruption of production processes, including the shutdown of manufacturing facilities or production lines or the imposition of new manufacturing requirements; • fines, warning letters or other enforcement letters or clinical holds on post-approval clinical trials; • mandated modification of promotional materials and labeling and the issuance of corrective information; • refusal of the FDA to approve pending NDAs or supplements to approved NDAs, or suspension or revocation of product approvals; • product seizure or detention, or refusal to permit the import or export of products; • injunctions or the imposition of civil or criminal penalties; or • consent decrees, corporate integrity agreements, debarment, or exclusion from federal health care programs. In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act, or PDMA, which regulates the distribution of drugs and drug samples at the federal level, and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription pharmaceutical product samples and impose requirements to ensure accountability in distribution. Most recently, the Drug Supply Chain Security Act, or the DSCSA, was enacted with the aim of building an electronic system to identify and trace certain prescription drugs distributed in the United States. The DSCSA mandates phased-in and resource-intensive obligations for pharmaceutical manufacturers, wholesale distributors, and dispensers over a 10‑year period that is expected to culminate in November 2023. Regulatory Exclusivity and Approval of Follow-on Products Hatch-Waxman Exclusivity In 1984, with passage of the Hatch-Waxman Amendments to the FDCA, Congress enacted Section 505(b)(2) of the FDCA and also established an abbreviated regulatory scheme authorizing the FDA to approve generic drugs that are shown to contain the same active ingredients as, and to be bioequivalent to, drugs previously approved by the FDA pursuant to NDAs. To obtain approval of a generic drug, an applicant must submit an abbreviated new drug application, or ANDA, to the agency. An ANDA is a comprehensive submission that contains, among other things, data and information pertaining to the active pharmaceutical ingredient, bioequivalence, drug product formulation, specifications and stability of the generic drug, as well as analytical methods, manufacturing process validation data and quality control procedures. ANDAs are “abbreviated” because they cannot include preclinical and clinical data to demonstrate safety and effectiveness. Instead, in support of such applications, a generic manufacturer must rely on the preclinical and clinical testing previously conducted for a drug product previously approved under an NDA, known as the reference-listed drug, or RLD. Specifically, in order for an ANDA to be approved, the FDA must find that the generic version is identical to the RLD with respect to the active ingredients, the route of administration, the dosage form, the strength of the drug and the conditions of use of the drug. At the same time, the FDA must also determine that the generic drug is “bioequivalent” to the innovator drug. Under the statute, a generic drug is bioequivalent to a RLD if “the rate and extent of absorption of the drug do not show a significant difference from the rate and extent of absorption of the listed drug.” Upon approval of an ANDA, the FDA indicates whether the generic product is “therapeutically equivalent” to the RLD in its publication “Approved Drug Products with Therapeutic Equivalence Evaluations,” also referred to as the “Orange Book.” Physicians and pharmacists consider a therapeutic equivalent generic drug to be fully substitutable for the RLD. In addition, by operation of certain state laws and numerous health insurance programs, the FDA’s designation of therapeutic equivalence often results in substitution of the generic drug without the knowledge or consent of either the prescribing physician or patient. 27 In contrast, Section 505(b)(2) permits the filing of an NDA where at least some of the information required for approval comes from studies not conducted by or for the applicant and for which the applicant has not obtained a right of reference. A Section 505(b)(2) applicant may eliminate the need to conduct certain preclinical or clinical studies if it can establish that reliance on studies conducted for a previously-approved product is scientifically appropriate. Unlike the ANDA pathway used by developers of bioequivalent versions of innovator drugs, which does not allow applicants to submit new clinical data other than bioavailability or bioequivalence data, the 505(b)(2) regulatory pathway does not preclude the possibility that a follow-on applicant would need to conduct additional clinical trials or nonclinical studies; for example, it may be seeking approval to market a previously approved drug for new indications or for a new patient population that would require new clinical data to demonstrate safety or effectiveness. As part of the NDA review and approval process, applicants are required to list with the FDA each patent that has claims that cover the applicant’s product or method of therapeutic use. Upon approval of a new drug, each of the patents listed in the application for the drug is then published in the Orange Book. Drugs listed in the Orange Book can, in turn, be cited by potential follow-on competitors in support of approval of an ANDA or 505(b)(2) NDA. When an ANDA applicant submits its application to the FDA, it is required to certify to the FDA concerning any patents listed for the reference product in the FDA’s Orange Book. Specifically, the applicant must certify that: (i) the required patent information has not been filed; (ii) the listed patent has expired; (iii) the listed patent has not expired, but will expire on a particular date and approval is sought after patent expiration; or (iv) the listed patent is invalid or will not be infringed by the new product. Moreover, to the extent that the Section 505(b)(2) NDA applicant is relying on studies conducted for an already approved product, the applicant also is required to certify to the FDA concerning any patents listed for the NDA-approved product in the Orange Book to the same extent that an ANDA applicant would. If the follow-on applicant does not challenge the innovator’s listed patents, the FDA will not approve the ANDA or 505(b)(2) application until all the listed patents claiming the referenced product have expired. A certification that the new product will not infringe the already approved product’s listed patents, or that such patents are invalid, is called a Paragraph IV certification. If the follow-on applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days of the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA or 505(b)(2) NDA until the earlier of 30 months, expiration of the patent, settlement of the lawsuit, or a decision in the infringement case that is favorable to the ANDA/505(b)(2) applicant. An ANDA or 505(b)(2) application also will not be approved until any applicable non-patent exclusivities listed in the Orange Book for the referenced product have expired. The Hatch-Waxman Amendments to the FDCA provided a five-year period of non-patent data exclusivity within the United States to the first applicant to gain approval of an NDA for a new chemical entity, or NCE. For the purposes of this provision, an NCE is a drug that contains no active moiety that has previously been approved by the FDA in any other NDA. An active moiety is the molecule or ion responsible for the physiological or pharmacological action of the drug substance. In cases where such NCE exclusivity has been granted, an ANDA or 505(b)(2) NDA may not be filed with the FDA until the expiration of five years unless the submission is accompanied by a Paragraph IV certification, in which case the applicant may submit its application four years following the original product approval. The FDCA also provides for a period of three years of data exclusivity if an NDA or NDA supplement includes reports of one or more new clinical investigations, other than bioavailability or bioequivalence studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application. This three-year exclusivity period often protects changes to a previously approved drug product, such as new indications, dosage forms, route of administration or combination of ingredients. Three-year exclusivity would be available for a drug product that contains a previously approved active moiety, provided the statutory requirement for a new clinical investigation is satisfied. Unlike five-year NCE exclusivity, an award of three-year exclusivity does not block the FDA from accepting ANDAs or 505(b)(2) NDAs seeking approval for generic versions of the drug as of the date of approval of the original drug product; rather, this three-year exclusivity covers only the conditions of use associated with the new clinical investigations and, as a general matter, does not prohibit the FDA from approving follow-on applications for drugs containing the original active ingredient. Five-year and three-year exclusivity also will not delay the submission or approval of a traditional NDA filed under Section 505(b)(1) of the FDCA; however, an applicant submitting a traditional NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness. For drug products that contain an “antibiotic” ingredient approved prior to 1997, the statute imposes certain limitations on the award of non-patent exclusivity. However, we do not believe these limitations would apply to tebipenem HBr or any of our other investigational antibiotics currently in preclinical and clinical development. 28 Qualified Infectious Disease Product Exclusivity Under the GAIN Act, the FDA may designate a product as a QIDP. In order to qualify for designation as a QIDP, the drug product candidate must be an antibiotic or antifungal drug for human use intended to treat serious or life-threatening infections, including those caused by either (i) an antibiotic or antifungal resistant pathogen, including novel or emerging infectious pathogens, or (ii) a so-called “qualifying pathogen” found on a list of potentially dangerous, drug-resistant organisms to be established and maintained by the FDA. We obtained a QIDP designation for the oral formulation of tebipenem HBr for cUTI in November 2016 and CABP and DFI in April 2017. We were granted QIDP designation by the FDA for SPR206 in October 2018 for the treatment of cUTI and hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP). In February 2019, we were granted QIDP designation for SPR720 capsule for oral use for the treatment of lung infections caused by nontuberculous mycobacteria and for the treatment of lung infections caused by Mycobacterium tuberculosis . In addition to the expedited review benefits for which a QIDP-designated drug candidate may be eligible, such a drug that is approved for the use for which the QIDP designation was granted will receive a five-year extension to any non-patent marketing exclusivity period for which the drug qualified upon approval, such as five-year NCE exclusivity, three-year new clinical data exclusivity, seven-year orphan exclusivity, or six-month pediatric exclusivity. This so-called GAIN exclusivity extension is not available to a QIDP-designated drug that has previously received the five-year extension period, such as when an applicant is seeking approval for a new indication or new strength. Orphan Drug Designation and Exclusivity In March 2020, the FDA granted orphan drug designation for SPR720 for the treatment of NTM infection. Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug intended to treat a rare disease or condition, which is generally a disease or condition that affects either (i) fewer than 200,000 individuals in the United States, or (ii) more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making available in the United States a drug for this type of disease or condition will be recovered from sales in the United States for that drug. Legislative proposals are currently being considered that would revise or revoke the second option available for a drug candidate to receive an orphan designation, the so-called “cost recovery” pathway. Orphan drug designation must be requested before submitting an NDA. After the FDA grants orphan drug designation, the identity of the therapeutic agent and its potential orphan use will be disclosed publicly by the FDA; the posting will also indicate whether a drug is no longer designated as an orphan drug. More than one product candidate may receive an orphan drug designation for the same indication, and the same product candidate can be designated for more than one qualified orphan indication. The benefits of orphan drug designation include research and development tax credits and exemption from FDA prescription drug user fees. Orphan drug designation does not convey any advantage in or shorten the duration of the regulatory review and approval process if or when an NDA for the drug candidate is filed. If a product that has orphan drug designation subsequently receives the first FDA approval for the indication for which it has such designation, the product is entitled to orphan product exclusivity, which means that for seven years, the FDA may not approve any other marketing applications for the same drug for the same indication, except under limited circumstances described further below. Orphan exclusivity does not block the approval of a different drug for the same rare disease or condition, nor does it block the approval of the same drug for different conditions. As a result, even if one of our product candidates receives orphan drug exclusivity, the FDA can still approve different drugs for use in treating the same indication or disease, which could create a more competitive market for our drug products, if approved for marketing in the future. Additionally, if a drug designated as an orphan product receives marketing approval for an indication broader than what was designated, it may not be entitled to orphan drug exclusivity. Orphan exclusivity will not bar approval of another product with the same drug for the same condition under certain circumstances, including if a subsequent product with the same drug for the same condition is shown to be clinically superior to the approved product on the basis of greater efficacy or safety or a major contribution to patient care, or if the company with orphan drug exclusivity cannot assure the availability of sufficient quantities of the drug to meet the needs of persons with the disease or condition for which the drug was designated. Following amendments made to the statute as part the FDA Reauthorization Act of 2017, the FDA is required to publish a summary of the clinical superiority findings when a drug is eligible for orphan product exclusivity on the basis of a demonstration of clinical superiority. In addition, the FDA finalized guidance in 2018 indicating that it does not expect to grant any additional orphan drug designation to products for pediatric subpopulations of common diseases. Nevertheless, FDA intends to still grant orphan drug designation to a drug that otherwise meets all other criteria for designation when it prevents, diagnoses or treats either (i) a rare disease that includes a rare pediatric subpopulation, (ii) a pediatric subpopulation that constitutes a valid orphan subset, or (iii) a rare disease that is in fact a different disease in the pediatric population as compared to the adult population. 29 Pediatric Exclusivity Pediatric exclusivity is another type of non-patent marketing exclusivity available in the United States and, if granted, it provides for the attachment of an additional six months of marketing protection to the term of any existing regulatory exclusivity or listed patents. Under the Best Pharmaceuticals for Children Act, or BPCA, certain therapeutic candidates may obtain an additional six months of exclusivity if the sponsor submits information requested in writing by the FDA, referred to as a Written Request, relating to the use of the active moiety of the product candidate in children. The data do not need to show the product to be effective in the pediatric population studied; rather, the additional protection is granted if the pediatric clinical trial is deemed to have fairly responded to the FDA’s Written Request. Although the FDA may issue a Written Request for studies on either approved or unapproved indications, it may only do so where it determines that information relating to that use of a product candidate in a pediatric population, or part of the pediatric population, may produce health benefits in that population. The issuance of a Written Request does not require the sponsor to undertake the described trials. This is not a patent term extension, but it effectively extends the regulatory period during which the FDA cannot approve another application. Foreign Regulation In addition to regulations in the United States, we will be subject to a variety of foreign regulations governing clinical trials and commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we must obtain approval by the comparable regulatory authorities of foreign countries or economic areas, such as the European Union, or EU, and Australia, before we may commence clinical trials or market products in those countries or areas. The approval process and requirements governing the conduct of clinical trials, product authorization, pricing and reimbursement vary greatly from place to place, and the time may be longer or shorter than that required for FDA approval. Before clinical trials may be conducted in any EU Member State, a sponsor must submit a clinical trial authorization application, or CTA, which must be approved in each country in which the sponsor intends to perform a clinical trial. The procedure for submitting a CTA was set forth in an existing EU Clinical Trial Directive. However, the way clinical trials are conducted in the EU underwent a major change when the Clinical Trial Regulation became effective, which initially had been scheduled to occur in 2019 but has been delayed. The Regulation harmonizes the assessment and supervision processes for clinical trials throughout the EU, via an EU portal and database. The European Medicines Agency, or the EMA, will set up and maintain the portal and database, in collaboration with the EU Member States and the European Commission. In June 2016, the electorate in the United Kingdom. voted in favor of leaving the EU (commonly referred to as “Brexit”). Thereafter, in March 2017, the country formally notified the EU of its intention to withdraw pursuant to Article 50 of the Lisbon Treaty, and the United Kingdom formally left the EU on January 31, 2020. A transition period began on February 1, 2020, during which EU pharmaceutical law remained applicable to the United Kingdom. This transition period ended on December 31, 2020. Since the regulatory framework in the United Kingdom covering the quality, safety and efficacy of pharmaceutical products, clinical trials, marketing authorization, commercial sales and distribution of medicinal products is derived from EU Directives and Regulations, Brexit could materially impact the future regulatory regime which applies to products and the approval of product candidates in the United Kingdom, as United Kingdom legislation now has the potential to diverge from EU legislation. It remains to be seen how Brexit will impact the regulatory regime in the United Kingdom in the long-term. The Medicines and Healthcare products Regulatory Agency has recently published detailed guidance for industry and organizations to follow from January 1, 2021 now the transition period is over, which will be updated as the United Kingdom’s regulatory position on medicinal products evolves over time. The goal of Clinical Trial Regulation is to create an environment that is favorable to conducting clinical trials in the EU, with the highest standards of safety for participants and increased transparency of trial information. The Regulation will require consistent rules for conducting clinical trials throughout the EU and information on the authorization, conduct and results of each clinical trial carried out in the EU to be publicly available. When the Regulation becomes applicable, it will replace the existing EU Clinical Trial Directive and national legislation that was put in place to implement the Directive. It will also apply to trials authorized under the previous legislation if they are still ongoing three years after the Regulation becomes effective. The authorization and oversight of clinical trials will remain the responsibility of EU Member States, with EMA managing the database and supervising content publication on the public website. 30 Under EU regulatory systems, a company may submit marketing authorization applications either under a centralized or decentralized procedure. The centralized procedure is compulsory for medicinal products produced by biotechnology or those medicinal products containing new active substances for specific indications such as the treatment of AIDS, cancer, neurodegenerative disorders, diabetes, viral diseases and designated orphan medicines, and optional for other medicines which are highly innovative. Under the centralized procedure, a marketing application is submitted to the EMA where it will be evaluated by the Committee for Medicinal Products for Human Use and a favorable opinion typically results in the grant by the European Commission of a single marketing authorization that is valid for all EU M ember S tates within 67 days of receipt of the opinion. The initial marketing authorization is valid for five years, but once renewed is usually valid for an unlimited period. The decentralized procedure provides for approval by one or more “concerned” member states based on an assessment of an application performed by one member state, known as the “reference” member state. Under the decentralized approval procedure, an applicant submits an application, or dossier, and related materials to the reference member state and concerned member states. The reference member state prepares a draft assessment and drafts of the related materials within 120 days after receipt of a valid application. Within 90 days of receiving the reference member state’s assessment report, each concerned member state must decide whether to approve the assessment report and related materials. If a member state does not recognize the marketing authorization, the disputed points are eventually referred to the European Commission, whose decision is binding on all member states. Pharmaceutical Coverage, Pricing and Reimbursement Sales of our products, if approved for marketing, will depend, in part, on the availability and extent of coverage and reimbursement by third-party payors, such as government health programs, including Medicare and Medicaid, commercial insurance and managed healthcare organizations. These third-party payors are increasingly challenging the price and limiting the coverage and reimbursement amounts for medical products and services. There may be significant delays in obtaining coverage and reimbursement for approved products, and coverage may be more limited than the purposes for which the product is approved by the FDA or regulatory authorities in other countries. It is time consuming and expensive to seek reimbursement from third-party payors. Moreover, eligibility for reimbursement does not imply that any product will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim payments for new products, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Payment rates may vary according to the use of the product and the clinical setting in which it is used, may be based on payments allowed for lower cost products that are already reimbursed and may be incorporated into existing payments for other services. Net prices for products may be reduced by mandatory discounts or rebates required by third-party payors and by any future relaxation of laws that presently restrict imports of products from countries where they may be sold at lower prices than in the United States. In the United States, third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies, but they also have their own methods and approval process apart from Medicare coverage and reimbursement determinations. Accordingly, one third-party payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product. In addition, the containment of healthcare costs has become a priority for federal and state governments, and the prices of drugs have been a focus in this effort. The United States government, state legislatures and foreign governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on coverage and reimbursement, and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit our net revenue and results. Decreases in third-party reimbursement for our product candidates or a decision by a third-party payor to not cover our product candidates could reduce physician usage of the product candidate and have a material adverse effect on our sales, results of operations and financial condition. Moreover, there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. Individual states in the United States have also increasingly passed legislation and implemented regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In December 2020, the U.S. Supreme Court held unanimously that federal law does not preempt the states’ ability to regulate pharmaceutical benefit managers, or PBMs, and other members of the health care and pharmaceutical supply chain, an important decision that may lead to further and more aggressive efforts by states in this area. In the United States, the federal government provides health insurance for people who are 65 years or older, and certain people with disabilities or certain conditions irrespective of their age, through the Medicare program, which is administered by the Centers for Medicare & Medicaid Services, or CMS. Coverage and reimbursement for products and services under Medicare are determined in accordance with the Social Security Act and pursuant to regulations promulgated by CMS, as well as the agency’s coverage and reimbursement guidance and determinations. Drugs and other products that are utilized within the hospital in-patient setting are typically reimbursed under a prospective payment system, or a predetermined payment amount that is based on diagnosis related groups, or DRGs for Medicare patients and under a bundled payment for commercially insured patients. These payment amounts differ by type of diagnoses, procedures performed and the severity of the patient’s condition, among other things. A drug that is used in a treatment or procedure under a specific DRG or bundled payment is generally not eligible for any separate payment. For catastrophic cases where costs greatly exceed the bundled payment amount, the hospital may be eligible for an outlier payment that is intended to cover part of the expense above the standard payment. 31 Medicaid is a health insurance program for low-income children, families, pregnant women, and people with disabilities that is jointly funded by the federal and state governments, but administered by the states. In general, state Medicaid programs are required to cover drugs and biologicals of manufacturers that have entered into a Medicaid Drug Rebate Agreement, although such drugs and biologicals may be subject to prior authorization or other utilization controls. The United States Congress and state legislatures from time to time propose and adopt initiatives aimed at cost containment, which could impact our ability to sell our products profitably. For example, the federal Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, known collectively as the ACA, among other things, contains provisions that may reduce the profitability of drug products through increased rebates for drugs reimbursed by Medicaid programs, extension of Medicaid rebates to Medicaid managed care plans, mandatory discounts for certain Medicare Part D beneficiaries and annual fees based on pharmaceutical companies’ share of sales to federal health care programs. Adoption of general controls and measures, coupled with the tightening of restrictive policies in jurisdictions with existing controls and measures, could limit payments for pharmaceutical drugs. The Medicaid Drug Rebate Program requires pharmaceutical manufacturers to enter into and have in effect a national rebate agreement with the Secretary of the Department of Health and Human Services, or DHHS, as a condition for states to receive federal matching funds for manufacturers’ outpatient drugs furnished to Medicaid patients. The ACA also expanded the universe of Medicaid utilization subject to drug rebates by requiring pharmaceutical manufacturers to pay rebates on Medicaid managed care utilization and by enlarging the population potentially eligible for Medicaid drug benefits. As another example, the 2021 Consolidated Appropriations Act signed into law on December 27, 2020 incorporated extensive healthcare provisions and amendments to existing laws, including a requirement that all manufacturers of drug products covered under Medicare Part B report the product’s average sales price, or ASP, to DHHS beginning on January 1, 2022, subject to enforcement via civil money penalties. Since its enactment, there have been judicial and Congressional challenges to certain aspects of the ACA and as a result certain sections of the ACA have not been fully implemented or effectively repealed. Members of Congress have indicated that they may continue to seek to modify, repeal or otherwise invalidate all, or certain provisions of, the ACA. For example, the Tax Cuts and Jobs Act, or TCJA, was enacted in 2017 and, among other things, removed penalties, starting January 1, 2019, for not complying with the ACA’s individual mandate to carry health insurance, commonly referred to as the “individual mandate.” In December 2018, a U.S. District Court Judge in the Northern District of Texas ruled that the individual mandate was a critical and inseverable feature of the ACA, and therefore, because it was repealed as part of the TCJA, the remaining provisions of the ACA were invalid and the law in its entirety was unconstitutional. In December 2019, the U.S. Court of Appeals for the Fifth Circuit upheld the District Court ruling that the individual mandate was unconstitutional but remanded the case back to the District Court to determine whether other reforms enacted as part of the ACA but not specifically related to the individual mandate or health insurance could be severed from the rest of the ACA so as not to be declared invalid as well. On March 2, 2020, the United States Supreme Court granted the petitions for writs of certiorari to review this case and allocated one hour for oral arguments, which occurred on November 10, 2020. A decision from the Supreme Court is expected to be issued in mid-2021. The uncertainty around the future of the ACA, and in particular the impact to reimbursement levels, may lead to uncertainty or delay in the purchasing decisions of our customers, which may in turn negatively impact our product sales. If there are not adequate reimbursement levels, our business and results of operations could be adversely affected. In addition, in some foreign countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing vary widely from country to country. For example, in the EU, the sole legal instrument at the EU level governing the pricing and reimbursement of medicinal products is Council Directive 89/105/EEC, or the Price Transparency Directive. The aim of this Directive is to ensure that pricing and reimbursement mechanisms established in the EU Member States are transparent and objective, do not hinder the free movement of and trade in medicinal products in the EU, and do not hinder, prevent or distort competition on the market. The Price Transparency Directive does not provide any guidance concerning the specific criteria on the basis of which pricing and reimbursement decisions are to be made in individual EU Member States, nor does it have any direct consequence for pricing or reimbursement levels in individual EU Member States. The EU Member States are free to restrict the range of medicinal products for which their national health insurance systems provide reimbursement, and to control the prices and/or reimbursement levels of medicinal products for human use. An EU Member State may approve a specific price or level of reimbursement for the medicinal product, or alternatively adopt a system of direct or indirect controls on the profitability of the company responsible for placing the medicinal product on the market, including volume-based arrangements, caps and reference pricing mechanisms. Health Technology Assessment, or HTA, of medicinal products is becoming an increasingly common part of the pricing and reimbursement procedures in some EU Member States, including France, Germany, Ireland, Italy and Sweden. The HTA process in the EU Member States is governed by the national laws of these countries. HTA is the procedure according to which the assessment of the public health impact, therapeutic impact, and the economic and societal impact of use of a given medicinal product in the national healthcare systems of the individual country is conducted. HTA generally focuses on the clinical efficacy and effectiveness, safety, cost, and cost-effectiveness of individual medicinal products as well as their potential implications for the healthcare system. Those elements of medicinal products are compared with other treatment options available on the market. The outcome of HTA regarding specific medicinal products will often influence the pricing and reimbursement status granted to these medicinal products by the 32 competent authorities of individual EU Member States. The extent to which pricing and reimbursement decisions are influenced by the HTA of the specific medicinal product vary between EU Member States. A negative HTA of one of our products by a leading and recognized HTA body could not only undermine our ability to obtain reimbursement for such product in the EU Member State in which such negative assessment was issued, but also in other EU Member States. For example, EU Member States that have not yet developed HTA mechanisms could rely to some extent on the HTA performed in countries with a developed HTA framework when adopting decisions concerning the pricing and reimbursement of a specific medicinal product. Other Healthcare Laws Our current and future business operations are subject to healthcare regulation and enforcement by the federal government and the state and foreign governments where we research, and, if approved, market, sell and distribute our therapeutic candidates. These laws include, without limitation, state and federal anti-kickback, fraud and abuse, false claims, privacy and security, physician sunshine and drug pricing transparency laws and regulations such as: • The federal Anti-Kickback Statute prohibits, among other things, any person from knowingly and willfully offering, soliciting, receiving or providing remuneration, directly or indirectly, to induce either the referral of an individual, for an item or service or the purchasing or ordering of a good or service, for which payment may be made under federal healthcare programs such as the Medicare and Medicaid programs. The federal Anti-Kickback Statute is subject to evolving interpretations. In the past, the government has enforced the federal Anti-Kickback Statute to reach large settlements with healthcare companies based on sham consulting and other financial arrangements with physicians. A person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the civil False Claims Act; • The federal civil and criminal false claims laws, including the civil False Claims Act, and civil monetary penalty laws, prohibit, among other things, knowingly presenting or causing the presentation of a false, fictitious or fraudulent claim for payment to the U.S. government, knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the U.S. government, or from knowingly making a false statement to avoid, decrease or conceal an obligation to pay money to the U.S. government. Actions under these laws may be brought by the Attorney General or as a qui tam action by a private individual in the name of the government. The federal government uses these laws, and the accompanying threat of significant liability, in its investigation and prosecution of pharmaceutical and biotechnology companies throughout the U.S., for example, in connection with the promotion of products for unapproved uses and other allegedly unlawful sales and marketing practices; • The U.S. federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created new federal, civil and criminal statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation; • The Physician Payments Sunshine Act, enacted as part of the ACA, among other things, imposes reporting requirements on manufacturers of FDA-approved drugs, devices, biologics and medical supplies covered by Medicare or Medicaid to report, on an annual basis, to DHHS information related to payments and other transfers of value to physicians (defined to include doctors, dentists, optometrists, podiatrists, chiropractors and, beginning in 2022 for payments and other transfers of value provided in the previous year, certain advanced non-physician health care practitioners), teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members; • HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and their respective implementing regulations impose specified requirements relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly applicable to “business associates,” defined as independent contractors or agents of covered entities, which include certain healthcare providers, health plans, and healthcare clearinghouses, that create, receive, maintain or transmit protected health information in connection with providing a service for or on behalf of a covered entity. HITECH also increased the civil and criminal penalties that may be imposed against covered entities, business associates and possibly other persons, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce HIPAA and seek attorney’s fees and costs associated with pursuing federal civil actions; and 33 • Analogous state laws and regulations, such as state anti-kickback and false claims laws which may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; state laws which require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug and therapeutic biologics manufacturers to report information related to payments to physicians and other healthcare providers or marketing expenditures and pricing information; state and local laws which require the registration of pharmaceutical sales representatives; and state laws and non-United States laws and regulations that govern the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways, thus complicating compliance efforts. Healthcare Reform In the United States and some foreign jurisdictions, there have been, and continue to be, several legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of product candidates, restrict or regulate post-approval activities, and affect the ability to profitably sell product candidates that obtain marketing approval. The FDA’s and other regulatory authorities’ policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our current or future product candidates. For example, in August 2017, the FDA Reauthorization Act was signed into law, which reauthorized the FDA’s user fee programs and included additional drug and device amendments to the FDCA, and in December 2019, former President Trump signed into law the Creating and Restoring Equal Access to Equivalent Samples Act or the “CREATES Act,” which aims to address the concern articulated by both the FDA and others in the industry that some reference product manufacturers have improperly restricted the distribution of their products, including by invoking the existence of a REMS for certain products, to deny generic product developers access to samples of brand products. The CREATES Act established a private cause of action that permits a generic product developer to sue the reference product manufacturer to compel it to furnish the necessary samples on “commercially reasonable, market-based terms.” Whether and how generic product developers will use this new pathway, as well as the likely outcome of any legal challenges to provisions of the CREATES Act, remain highly uncertain and its potential effects on our future commercial products are unknown. As another example, in November 2020 the Trump Administration finalized regulations aimed at implementing a system whereby state governmental entities could lawfully import and distribute prescription drugs sourced from Canada, with the stated goal of lowering drug prices domestically. However, the impact of such future programs is uncertain, in part because lawsuits have been filed challenging the government’s authority to promulgate these regulations, but also because they may be vulnerable to being overturned by a joint resolution of disapproval from Congress under the procedures set forth in the Congressional Review Act, which could be applied to regulatory actions taken by the Trump Administration on or after August 21, 2020 ( i.e. , in the last 60 days of legislative session of the 116th Congress). Other regulatory actions that were initiated or finalized during the final months of the Trump Administration are also subject to uncertainty following the January 20, 2021 transition to a new Democrat-led presidential administration. Following his inauguration, President Biden took immediate steps to order a regulatory freeze on all pending substantive executive actions in order to permit incoming department and agency heads to review whether questions of fact, policy, and law may be implicated and to determine how to proceed. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we otherwise may have obtained and we may not achieve or sustain profitability, which would adversely affect our business, prospects, financial condition and results of operations. Moreover, among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access. Manufacturing We do not own or operate manufacturing facilities for the production of any of our product candidates, nor do we have plans to develop our own manufacturing operations in the foreseeable future. We currently rely on a limited number of third-party contract manufacturers for all of our required raw materials, drug substance, and finished drug product for our preclinical research and clinical trials. We currently employ internal resources to manage our manufacturing. We intend to have two suppliers for tebipenem HBr’s active pharmaceutical ingredient. Each supplier would be capable of producing kilogram quantities for commercial scale and would be able to produce over 10kg of active pharmaceutical ingredient under cGMP conditions. 34 Human Capital As of December 31, 2020, we had 89 full-time employees, including a total of 20 employees with M.D. or Ph.D. degrees. Of these employees, 55 employees were primarily engaged in research and development activities, and 34 provide administrative, business and operations support. All of these employees were based in the United States. None of our employees are represented by labor unions or covered by collective bargaining agreements. We consider our employee relations to be good. We hire and maintain an experienced, committed, diverse, inclusive and highly motivated workforce. Effective attraction, development, and retention of human resource talent, or human capital, is vital to the success of our mission-driven growth strategy. We face intense competition for qualified individuals from numerous pharmaceutical and biotechnology companies, universities, governmental entities and other research institutions, and we believe that our future success will depend in large part on our continued ability to attract and retain highly skilled employees. To attract qualified applicants to our company and retain our employees, we offer a competitive rewards package consisting of base salary and cash target bonus, a comprehensive benefit package and equity compensation. We want our employees to learn, grow and look for ways to help develop skills through industry, company and functional training, as well as mentoring opportunities. We offer a robust set of career-enhancing learning experiences and initiatives to all employees, aligned with our mission, vision, and values. Our Corporate Information We were formed as Spero Therapeutics, LLC in December 2013 under the laws of the State of Delaware. On June 30, 2017, through a series of transactions, Spero Therapeutics, LLC merged with and into Spero Therapeutics, Inc. (formerly known as Spero OpCo, Inc.), a Delaware corporation. Our principal executive offices are located at 675 Massachusetts Avenue, Cambridge, Massachusetts 02139, and our telephone number is (857) 242-1600. Our website address is www.sperotherapeutics.com. Available Information Financial and other information about us is available on our website. We make available on our website, free of charge, copies of our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the United States Securities and Exchange Commission, or the SEC. The information contained in our website is not intended to be a part of this filing.