Protagonist Therapeutics, Inc 10-Q

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS You should read the following discussion and analysis of our financial condition and results of operations together with our Unaudited Condensed Consolidated Financial Statements and related notes included in Part I, Item 1 of this quarterly report (this “Quarterly Report”) on Form 10-Q and with our Audited Consolidated Financial Statements and related notes thereto for the year ended December 31, 2020, included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 10, 2021. Forward-Looking Statements This Quarterly Report contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “intends,” “may,” “plans,” “potential,” “predicts,” “projects,” “should,” “targets,” “will,” “would,” and similar expressions intended to identify forward-looking statements. Forward-looking statements reflect our current views with respect to future events, are based on assumptions, and are subject to risks, uncertainties and other important factors. In particular, statements, whether expressed or implied, concerning, among other things, the potential for our programs, the timing of our clinical trials, the potential for eventual regulatory approval and commercialization of our product candidates and our potential receipt of milestone payments and royalties under our collaboration agreements, the timing and amount of potential payments that we may be required to make to collaboration partners; future operating results or the ability to generate sales, income or cash flow, and the impact of the ongoing COVID-19 pandemic are forward-looking statements. They involve risks, uncertainties and assumptions that are beyond our ability to control or predict, including those discussed in Part II, Item 1A, of this Quarterly Report. While we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Given these risks, uncertainties and other important factors, you should not place undue reliance on these forward-looking statements. Also, forward-looking statements represent our estimates and assumptions only as of the date of this Quarterly Report. Except as required by law, we assume no obligation to update any forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in any forward-looking statements, even if new information becomes available in the future. “Protagonist,” the Protagonist logo and other trademarks, service marks and trade names of Protagonist are registered and unregistered marks of Protagonist Therapeutics, Inc. in the United States and other jurisdictions. ​ ​ 28 Table of Contents Overview We are a biopharmaceutical company with multiple peptide-based investigational new chemical entities in different stages of development, all derived from the Company's proprietary discovery technology platform. Our clinical programs fall into two broad categories of diseases; (i) hematology and blood disorders, and (ii) inflammatory and immunomodulatory diseases. Our Product Pipeline Our most advanced clinical asset, rusfertide (generic name for PTG-300) is an injectable hepcidin mimetic in development for the potential treatment of erythrocytosis, iron overload and other blood disorders. Hepcidin is a key hormone in regulating iron equilibrium and is critical to the proper development of red blood cells. Rusfertide mimics the effect of the natural hormone hepcidin, but with greater potency, solubility and stability. We initiated Phase 2 proof of concept (“POC”) studies in the blood disorders polycythemia vera (“PV”) in the third quarter of 2019 and hereditary hemochromatosis (“HH”) in January 2020. In December 2020, we presented four posters and one oral presentation relating to rusfertide at the American Society for Hematology’s virtual annual meeting, including updated interim Phase 2 results for rusfertide in PV. In June 2021, we presented updated Phase 2 data supporting the long-term efficacy of rusfertide in PV during an oral presentation at the European Hematology Association (“EHA”) 2021 Virtual Congress. We believe these interim results provide evidence regarding the potential of rusfertide for managing hematocrit, reducing thrombotic risk and improving iron deficiency symptoms. Rusfertide has a unique mechanism of action in the potential treatment of PV, which may enable it to decrease and maintain hematocrit levels within the range of recommended clinical guidelines without causing the iron deficiency that may occur with frequent phlebotomy. ​ We completed patient enrollment in the ongoing pivotal Phase 2 clinical trial of rusfertide in PV in April 2021. Based on end of Phase 2 feedback provided by the FDA’s Division of Nonmalignant Hematology and written comments from the European Medicines Agency (“EMA”) received during the first quarter of 2021, we expect to initiate a global Phase 3 clinical trial of rusfertide in PV in early 2022. During the first quarter of 2021, we initiated another Phase 2 study for rusfertide in up to 20 patients diagnosed with PV and with routinely elevated hematocrit levels (>48%). In addition, we completed enrollment for our Phase 2 POC study in HH, our second indication, in April 2021 and expect to disclose preliminary data from this study in the fourth quarter of 2021. ​ 29 Table of Contents To date we have received the following designations for rusfertide in PV: ​ ● The U.S. Food and Drug Administration (“FDA”) granted orphan drug designation for rusfertide for the treatment of PV in June 2020; ● The European Medicines Agency granted orphan drug designation for rusfertide for the treatment of PV in October 2020; ● The FDA granted Fast Track designation for rusfertide for the treatment of PV in December 2020; and ● The FDA granted Breakthrough Therapy Designation for rusfertide for the treatment of PV in June 2021. ​ Our alpha-4-beta-7 (“α4β7”) antagonist PN-943 and our Interleukin-23 receptor (“IL-23R”) antagonist compounds, including PTG-200, PN-235 and PN-232, are orally delivered investigational drugs that are designed to block biological pathways currently targeted by marketed injectable antibody drugs. Our orally stable peptide approach may offer targeted delivery to the GI tissue compartment. We believe that, compared to antibody drugs, these product candidates have the potential to provide improved safety due to minimal exposure in the blood, increased convenience and compliance due to oral delivery, and the opportunity for the earlier introduction of targeted oral therapy. PN-943 is an investigational, orally delivered, gut-restricted α4β7 specific integrin antagonist for IBD. We submitted a U.S. Investigational New Drug application with the FDA for PN-943 in December 2019, which took effect in January 2020. During the second quarter of 2020 we initiated a 150-patient Phase 2 study evaluating the safety, tolerability and efficacy of PN-943 in patients with moderate to severe UC. This ongoing study is expected to be completed in the second quarter of 2022, subject to delays related to the COVID-19 pandemic. In May 2017, we entered into a worldwide license and collaboration agreement with Janssen Biotech, Inc. (“Janssen”), a Johnson & Johnson company, to co-develop and co-detail our IL-23R antagonist compounds, including PTG-200 and certain related compounds for all indications, including IBD. PTG-200 (also referenced as JNJ-67864238) is an investigational, orally delivered, IL-23R antagonist for the treatment of IBD. The agreement with Janssen was amended in May 2019 to expand the collaboration by supporting efforts towards second-generation IL- 23R antagonists. In January 2020, as part of the expanded research collaboration, we announced the identification and nomination of an orally delivered IL-23R antagonist peptide as a second-generation development candidate, triggering a $5.0 million milestone payment to us. Janssen initiated a global Phase 2 POC clinical study for PTG-200 in moderate-to-severe CD in the fourth quarter of 2019, and the study is currently in progress. In October 2020, we announced the selection of two second-generation IL-R antagonists for advancement into clinical development, PN-235 (also referenced as JNJ-77242113) and PN-232 (also referenced as JNJ-75105186). A Phase 1 study was initiated for PN-235 in December 2020 and is expected to be completed in the fourth quarter of 2021. A Phase 1 study was initiated for PN-232 in May 2021 and is expected to be completed in the second quarter of 2022. The current development plan contemplates parallel development of multiple collaboration compounds against multiple indications in the IL-23 pathway. Our clinical assets are all derived from our proprietary discovery platform. Our platform enables us to engineer novel, structurally constrained peptides that are designed to retain key advantages of both orally delivered small molecules and injectable antibody drugs in an effort to overcome many of their limitations as therapeutic agents. Importantly, constrained peptides can be designed to potentially alleviate the fundamental instability inherent in traditional peptides to allow different delivery forms, such as oral, subcutaneous, intravenous, and rectal. We continue to use our peptide technology platform to discover product candidates against targets in disease areas with significant unmet medical needs. COVID-19 Business Impact ​ We are subject to risks and uncertainties as a result of the ongoing COVID-19 pandemic. We are continuing to closely monitor the impact of the COVID-19 pandemic on our business and have taken and continue to take proactive efforts to protect the health and safety of our patients, study investigators, clinical research staff and employees, and to maintain business continuity. The extent of the impact of the COVID-19 pandemic on our activities is uncertain and difficult to predict, as the pandemic and the response to the pandemic continue to evolve. Capital markets and economies worldwide have been significantly impacted by the COVID-19 pandemic, and the pandemic has contributed 30 Table of Contents to a global economic recession. Such economic disruption could have a material adverse effect on our business. Policymakers around the globe have responded with fiscal policy actions to support the healthcare industry and economy as a whole. The magnitude and overall effectiveness of these actions remains uncertain. The severity of the impact of the COVID-19 pandemic on our activities will depend on a number of factors, including, but not limited to, the duration and severity of the pandemic, including the severity of any additional periods of increases or spikes in the number of cases in the areas we, our suppliers and our manufacturers operate and areas where our clinical trial sites are located; the development and spread of COVID-19 variants; the timing, extent, effectiveness and durability of vaccine programs or other treatments; and new or continuing travel and other restrictions and public health measures, such as social distancing, business closures or disruptions. Accordingly, the extent and severity of the impact on our existing and planned clinical trials, manufacturing, collaboration activities and operations is uncertain and cannot be fully predicted. We have experienced delays in our existing and planned clinical trials due to the worldwide impacts of the pandemic. Our future results of operations and liquidity could be adversely impacted by further delays in existing and planned clinical trials and collaboration activities, continued difficulty in recruiting patients for these clinical trials, delays in manufacturing and collaboration activities, supply chain disruptions, the ongoing impact on operating activities and employees, and the ongoing impact of any initiatives or programs that we may undertake to address financial and operational challenges. As of the date of issuance of this Quarterly Report on Form 10-Q, the extent to which the COVID-19 pandemic may materially impact our future financial condition, liquidity or results of operations is uncertain. Operations We have incurred net losses in each year since inception and we do not anticipate achieving sustained profitability in the foreseeable future. Our net loss was $30.8 million and $54.8 million for the three and six months ended June 30, 2021, respectively. Our net loss was $19.4 million and $39.5 million for the three and six months ended June 30, 2020, respectively. As of June 30, 2021, we had an accumulated deficit of $338.7 million. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant research, development, commercialization and other expenses related to our ongoing operations and product development, including clinical development activities under our worldwide license and collaboration agreement with Janssen, and, as a result, we expect to continue to incur losses in the future as we continue our development of, and seek regulatory approval for, our product candidates. Janssen License and Collaboration Agreement On May 26, 2017, we and Janssen, one of the Janssen Pharmaceutical Companies of Johnson & Johnson, entered into an exclusive license and collaboration agreement for the clinical development, manufacture and potential commercialization of PTG-200 worldwide for the treatment of CD and UC (the “Janssen License and Collaboration Agreement”), which was subsequently amended effective May 7, 2019 (the “First Amendment”). The First Amendment expanded the scope of the Janssen License and Collaboration Agreement by supporting efforts toward identifying and developing second-generation compounds. Janssen is a related party to us as Johnson & Johnson Innovation - JJDC, Inc., a significant stockholder of ours, and Janssen are both subsidiaries of Johnson & Johnson. During the third quarter of 2017, we received a non-refundable, upfront cash payment of $50.0 million from Janssen. During the second quarter of 2019, we received a non-refundable cash payment of $25.0 million upon execution of the First Amendment. During the first quarter of 2020, we received a cash payment of $5.0 million upon the successful nomination of a second-generation development candidate. See Note 3 and Note 17 to the condensed consolidated financial statements included elsewhere in this report for additional information. Critical Accounting Polices and Estimates Our management’s discussion and analysis of our financial condition and results of operations is based on our unaudited condensed consolidated financial statements, which have been prepared in accordance with United States generally accepted accounting principles. The preparation of these unaudited condensed consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and 31 Table of Contents the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, as well as the reported revenue generated and expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. In making estimates and judgments, management employs critical accounting policies. Use of Estimates Due to the ongoing COVID-19 pandemic, there has been uncertainty and disruption in the global economy and financial markets. We have taken into consideration any known COVID-19 impacts in our accounting estimates to date and are not aware of any additional specific events or circumstances that would require any additional updates to our estimates or judgments or a revision of the carrying value of our assets or liabilities as of the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. Stock-Based Compensation We recognize compensation costs related to stock options accounted for under Accounting Standards Codification Topic 718 – “ Stock Compensation” based on the estimated fair value of the awards on the date of grant. We estimate the fair value, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The estimated fair value of the stock-based awards is generally recognized over the requisite service period, which is generally the vesting period of the respective awards. The Black-Scholes option-pricing model requires the use of subjective assumptions which determine the fair value of stock-based awards. Expected volatility generally requires significant judgement to determine. For the year ended December 31, 2020, our expected volatility was estimated based upon a mix of 75% of the average volatility for comparable publicly traded biopharmaceutical companies over a period equal to the expected term of the stock option grants and 25% of the volatility of our own stock price since our initial public offering in August 2016. Beginning January 1, 2021, our expected volatility is estimated based upon a mix of 50% of the average volatility for comparable publicly traded biopharmaceutical companies over a period equal to the expected term of the stock option grants and 50% of the volatility of our own stock price since our initial public offering in August 2016. These comparable companies are chosen based on their similar size, stage in the life cycle, or area of specialty. We will continue to apply this process until a longer period of historical information regarding the volatility of our own stock price becomes available. In February 2021, we granted performance share units (“PSUs) to certain of our executives. Stock-based compensation expense associated with PSUs is based on the fair value of our common stock on the grant date, which equals the closing price of our common stock on the grant date. We recognize compensation expense over the vesting period of the awards that are ultimately expected to vest when the achievement of the related performance obligation becomes probable. The total fair value of the PSUs granted in February 2021 was $2.6 million. There have been no other material changes in our critical accounting policies during the three and six months ended June 30, 2021, as compared to those disclosed in “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates” in our Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 10, 2021. Components of Our Results of Operations License and Collaboration Revenue Our license and collaboration revenue is derived from payments we receive under the Janssen License and Collaboration Agreement. See Note 3 to the condensed consolidated financial statements included elsewhere in this report for additional information. 32 Table of Contents Research and Development Expenses Research and development expenses represent costs incurred to conduct research, such as the discovery and development of our product candidates. We recognize all research and development costs as they are incurred, unless there is an alternative future use in other research and development projects or otherwise. Non-refundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when payment has been made. In instances where we enter into agreements with third parties to provide research and development services to us, costs are expensed as services are performed. Amounts due under such arrangements may be either fixed fee or fee for service and may include upfront payments, monthly payments, and payments upon the completion of milestones or the receipt of deliverables. Research and development expenses consist primarily of the following: ● expenses incurred under agreements with clinical study sites that conduct research and development activities on our behalf; ● employee-related expenses, which include salaries, benefits and stock-based compensation; ● laboratory vendor expenses related to the preparation and conduct of pre-clinical, non-clinical, and clinical studies; ● costs related to production of clinical supplies and non-clinical materials, including fees paid to contract manufacturers; ● license fees and milestone payments under license and collaboration agreements; and ● facilities and other allocated expenses, which include expenses for rent and maintenance of facilities, information technology, depreciation and amortization expense and other supplies. We recognize the funds from grants under government programs as a reduction of research and development expenses when the related research costs are incurred. In addition, we recognize the funds related to our Australian research and development refundable cash tax incentive that are not subject to refund provisions as a reduction of research and development expenses. The research and development tax incentives are recognized when there is reasonable assurance that the incentives will be received, the relevant expenditure has been incurred and the amount of the consideration can be reliably measured. We evaluate our eligibility under the tax incentive program as of each balance sheet date and make accruals and related adjustments based on the most current and relevant data available. We may alternatively be eligible for a taxable credit in the form of a non-cash tax incentive. We allocate direct costs and indirect costs incurred to product candidates when they enter clinical development. For product candidates in clinical development, direct costs consist primarily of clinical, pre-clinical, and drug discovery costs, costs of supplying drug substance and drug product for use in clinical and pre-clinical studies, including clinical manufacturing costs, contract research organization fees, and other contracted services pertaining to specific clinical and pre-clinical studies. Indirect costs allocated to our product candidates on a program specific basis include research and development employee salaries, benefits, and stock-based compensation, and indirect overhead and other administrative support costs. Program-specific costs are unallocated when the clinical expenses are incurred for our early-stage research and drug discovery projects, our internal resources, employees and infrastructure are not tied to any one research or drug discovery project and are typically deployed across multiple projects. As such, we do not provide financial information regarding the costs incurred for early-stage pre-clinical and drug discovery programs on a program-specific basis prior to the clinical development stage. 33 Table of Contents The following table summarizes our research and development expenses incurred during the periods indicated: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ 2021 2020 2021 2020 ​ ​ (Dollars in thousands) Clinical and development expense — rusfertide (PTG-300) ​ $ 12,168 ​ $ 7,753 ​ $ 22,247 ​ $ 14,559 Clinical and development expense — PN-943 ​ ​ 7,751 ​ ​ 7,002 ​ ​ 15,475 ​ ​ 14,020 Clinical and development expense — PN-235 ​ ​ 1,433 ​ ​ — ​ ​ 3,232 ​ ​ — Clinical and development expense — PN-232 ​ ​ 39 ​ ​ — ​ ​ 39 ​ ​ — Clinical and development expense — PTG-200 ​ ​ 1 ​ ​ 40 ​ ​ 2 ​ ​ 925 Clinical and development expense — PTG-100 ​ ​ 141 ​ ​ 12 ​ ​ 250 ​ ​ 193 Preclinical and drug discovery research expense ​ ​ 5,884 ​ ​ 5,633 ​ ​ 11,245 ​ ​ 9,916 Grants and tax incentives expense reimbursement, net ​ (985) ​ (183) ​ (1,813) ​ (588) Total research and development expenses ​ $ 26,432 ​ $ 20,257 ​ $ 50,677 ​ $ 39,025 ​ We expect our research and development expenses will increase as we progress our product candidates into later stage clinical trials, expand the number of ongoing clinical trials, advance development activities under the Janssen License and Collaboration Agreement, advance our discovery research projects into the pre-clinical stage and continue our early-stage research. The process of conducting research, identifying potential product candidates and conducting pre-clinical and clinical trials necessary to obtain regulatory approval is costly and time intensive. We may never succeed in achieving marketing approval for our product candidates regardless of our costs and efforts. The probability of success of our product candidates may be affected by numerous factors, including pre-clinical data, clinical data, competition, manufacturing capability, our ability to receive, and the timing of, regulatory approvals, market conditions, and our ability to successfully commercialize our products if they are approved for marketing. As a result, we are unable to determine the duration and completion costs of our research and development projects or when and to what extent we will generate revenue from the commercialization and sale of any of our product candidates. Our research and development programs are subject to change from time to time as we evaluate our priorities and available resources. General and Administrative Expenses General and administrative expenses consist of personnel costs, allocated facilities costs and other expenses for outside professional services, including legal, human resources, audit and accounting services, and pre-commercial selling and marketing costs. Personnel costs consist of salaries, benefits and stock-based compensation. Allocated expenses consist of expenses for rent and maintenance of facilities, information technology, depreciation and amortization expense and other supplies. We expect to continue to incur expenses to support our continued operations, including expenses related to existing and future compliance with rules and regulations of the SEC and those of the national securities exchange on which our securities are traded, insurance expenses, investor relations, professional services and general overhead and administrative costs. Interest Income Interest income consists of interest earned on our cash, cash equivalents and marketable securities, which is comprised of contractual interest, premium amortization and discount accretion. Interest Expense Interest expense consists of interest recognized on borrowings under our term loan facility, which is comprised of contractual interest, amortization of origination fees and other issuance costs, and accretion of final payment fees. 34 Table of Contents Loss on Early Repayment of Debt Loss on early repayment of debt consists of prepayment and final payment fees paid upon the early repayment of our long-term debt. Other Expense (Income), Net Other (expense) income, net consists primarily of amounts related to foreign exchange gains and losses and related items. Results of Operations Comparison of the Three Months Ended June 30, 2021 and 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ ​ ​ ​ June 30, ​ Dollar ​ % ​ 2021 2020 Change Change ​ ​ (Dollars in thousands) ​ ​ License and collaboration revenue - related party ​ $ 2,265 ​ $ 6,217 ​ $ (3,952) ​ (64) Operating expenses: ​ ​ ​ Research and development (1) ​ ​ 26,432 ​ ​ 20,257 ​ ​ 6,175 30 General and administrative (2) ​ 6,715 ​ 4,177 ​ 2,538 61 Total operating expenses ​ 33,147 ​ 24,434 ​ 8,713 36 Loss from operations ​ (30,882) ​ (18,217) ​ (12,665) 70 Interest income ​ 97 ​ 207 ​ (110) (53) Interest expense ​ ​ — ​ ​ (209) ​ ​ 209 ​ (100) Loss on early repayment of debt ​ ​ — ​ ​ (585) ​ ​ 585 ​ (100) Other (expense) income, net ​ ​ (57) ​ ​ 512 ​ ​ (569) ​ (111) Loss before income tax expense ​ ​ (30,842) ​ ​ (18,292) ​ ​ (12,550) ​ 69 Income tax expense ​ ​ — ​ ​ (1,129) ​ ​ 1,129 ​ (100) Net loss ​ $ (30,842) ​ $ (19,421) ​ $ (11,421) 59 (1) Includes $2.2 million and $1.0 million of non-cash stock-based compensation expense for the three months ended June 30, 2021 and 2020, respectively. (2) Includes $1.8 million and $1.0 million of non-cash stock-based compensation expense for the three months ended June 30, 2021 and 2020, respectively. License and Collaboration Revenue License and collaboration revenue decreased $4.0 million, or 64%, from $6.2 million for the three months ended June 30, 2020 to $2.3 million for the three months ended June 30, 2021, which was primarily related to a decrease in services provided under the Janssen License and Collaboration Agreement recognized based on proportional performance. The level of services has decreased as the Company nears completion of its performance obligations delivered pursuant to the collaboration, including the anticipated completion of its ongoing PN-235 Phase 1 trial in the fourth quarter of 2021 and its ongoing PN-232 Phase 1 trial in the first half of 2022. We have determined that the transaction price of the initial performance obligation under the Janssen License and Collaboration Agreement was $95.8 million as of June 30, 2021, a decrease of $0.5 million from the transaction price of $96.3 million as of March 31, 2021. In order to determine the transaction price, we evaluated all payments expected to be received during the duration of the contract, net of development costs reimbursement expected to be payable to Janssen. We determined that the transaction price includes the $50.0 million upfront payment, the $25.0 million payment received upon the effectiveness of the First Amendment, the $5.0 million payment triggered by the successful nomination of a second-generation compound, $17.9 million of reimbursement from Janssen for services performed for PTG-200 Phase 2 and for second-generation compound research costs and other services, and estimated 35 Table of Contents variable consideration consisting of a $7.5 million milestone payment subject to the completion of a Phase 1 study for a second-generation compound, offset by $9.6 million of net cost reimbursement to Janssen for services performed. The decrease in transaction price from March 31, 2021 to June 30, 2021 was due primarily to a decrease in the forecast of cost reimbursements to Janssen for services performed. We re-evaluate the transaction price each reporting period and as uncertain events are resolved or other changes in circumstances occur. Research and Development Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ ​ ​ ​ ​ June 30, ​ Dollar ​ % ​ 2021 ​ 2020 ​ Change ​ Change ​ ​ (Dollars in thousands) ​ ​ Clinical and development expense — rusfertide (PTG-300) ​ $ 12,168 ​ $ 7,753 ​ $ 4,415 ​ 57 Clinical and development expense — PN-943 ​ ​ 7,751 ​ ​ 7,002 ​ ​ 749 ​ 11 Clinical and development expense — PN-235 ​ ​ 1,433 ​ ​ — ​ ​ 1,433 ​ * Clinical and development expense — PN-232 ​ ​ 39 ​ ​ — ​ ​ 39 ​ * Clinical and development expense — PTG-200 ​ ​ 1 ​ ​ 40 ​ ​ (39) ​ (98) Clinical and development expense — PTG-100 ​ ​ 141 ​ ​ 12 ​ ​ 129 ​ * Preclinical and drug discovery research expense ​ ​ 5,884 ​ ​ 5,633 ​ ​ 251 ​ 4 Grants and tax incentives expense reimbursement, net ​ (985) ​ (183) ​ (802) ​ 438 Total research and development expenses ​ $ 26,432 ​ $ 20,257 ​ $ 6,175 ​ 30 *Percentage not meaningful ​ Research and development expenses increased $6.2 million, or 30%, from $20.3 million for the three months ended June 30, 2020 to $26.4 million for the three months ended June 30, 2021. The increase was primarily due to an increase of $4.4 million in rusfertide clinical trial and development costs, including the ongoing Phase 2 trials in PV, which began in December 2019, and HH, which began in early 2020, and clinical and contract manufacturing activities in preparation for a planned global Phase 3 clinical trial of rusfertide in PV; $1.4 million of Phase 1 clinical trial and development costs for PN-235; an increase of $0.7 million in PN-943 clinical trial and development costs following the initiation of the Phase 2 trial in UC in 2020, and an increase of $0.3 million in preclinical and drug discovery research expenses. These increases were partially offset by a decrease of $0.8 million increase in grant and accrued refundable cash tax incentives. ​ We had 81 and 52 full-time equivalent research and development employees as of June 30, 2021 and 2020, respectively. ​ General and Administrative Expenses ​ General and administrative expenses increased $2.5 million, or 61%, from $4.2 million for the three months ended June 30, 2020 to $6.7 million for the three months ended June 30, 2021 primarily due to an increase of $1.5 million in personnel expenses, a $0.4 million increase in market research expenses, and a $0.3 million increase in consulting fees to support the growth of our business, and a $0.2 million increase in legal fees. The increase in personnel expenses was primarily due to increases of $0.8 million in stock-based compensation expense and $0.6 million in wages and benefits. ​ We had 20 and 17 full-time equivalent general and administrative employees as of June 30, 2021 and 2020, respectively. ​ Interest Income Interest income decreased $0.1 million, or 53%, from $0.2 million for the three months ended June 30, 2020 to $0.1 million for the three months ended June 30, 2021. This decrease was due primarily to the recent record low interest 36 Table of Contents rate environment and a change in the mix of marketable securities compared to the prior year period, despite higher interest-earning asset balances. Interest Expense Interest expense decreased $0.2 million, or 100%, from $0.2 million for the three months ended June 30, 2020 to zero for the three months ended June 30, 2021. The decrease in interest expense was due to the prepayment of our outstanding long-term debt under our term credit facility during the second quarter of 2020. We had no debt outstanding under our term loan facility during the three months ended June 30, 2021. Loss on Early Repayment of Debt Loss on early repayment of debt of $0.6 million for the three months ended June 30, 2020 reflects prepayment and final payment fees in connection with the early repayment of our term loan in June 2020. We had no debt outstanding during the three months ended June 30, 2021. Other (Expense) Income, Net Other expense, net was $0.1 million for the three months ended June 30, 2021 compared to other income, net of $0.5 million for the three months ended June 30, 2020. The change was due primarily to a $0.5 million foreign currency revaluation gain recorded for the three months ended June 30, 2020. Income Tax Expense Income tax expense decreased $1.1 million, or 100%, from $1.1 million for the three months ended June 30, 2020 to zero for the three months ended June 30, 2021. Our effective income tax rate was 0% for the three months ended June 30, 2021 as compared to 6.2% for the three months ended June 30, 2020. During the second quarter of 2020, our Australia subsidiary sold beneficial rights to discovery intellectual property to our U.S. entity, and the U.S. entity reimbursed the Australia subsidiary for certain direct development costs. Upon completion of the sale, we analyzed tax planning strategies and future income and concluded that a valuation allowance is necessary for our Australia subsidiary. Income tax expense for the three months ended June 30, 2020 reflects this sale of intellectual property rights, cost reimbursements and related adjustments to the deferred tax asset, establishing a valuation allowance and certain uncertain tax position liabilities. We maintained a full valuation allowance on our tax position as of June 30, 2021. Comparison of the Six Months Ended June 30, 2021 and 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ ​ ​ ​ ​ June 30, ​ Dollar ​ % ​ 2021 2020 Change Change ​ ​ (Dollars in thousands) ​ ​ License and collaboration revenue - related party ​ $ 8,454 ​ $ 9,864 ​ $ (1,410) ​ (14) Operating expenses: ​ ​ ​ Research and development (1) ​ ​ 50,677 ​ ​ 39,025 ​ ​ 11,652 30 General and administrative (2) ​ 12,680 ​ 8,753 ​ 3,927 45 Total operating expenses ​ 63,357 ​ 47,778 ​ 15,579 33 Loss from operations ​ (54,903) ​ (37,914) ​ (16,989) 45 Interest income ​ 199 ​ ​ 733 ​ (534) (73) Interest expense ​ ​ — ​ ​ (452) ​ ​ 452 (100) Loss on early repayment of debt ​ ​ — ​ ​ (585) ​ ​ 585 (100) Other (expense) income, net ​ ​ (136) ​ ​ 22 ​ ​ (158) ​ (718) Loss before income tax expense ​ ​ (54,840) ​ ​ (38,196) ​ ​ (16,644) ​ 44 Income tax expense ​ ​ — ​ ​ (1,305) ​ ​ 1,305 ​ (100) Net loss ​ $ (54,840) ​ $ (39,501) ​ $ (15,339) 39 37 Table of Contents (1) Includes $3.6 million and $2.1 million of non-cash stock-based compensation expense for the six months ended June 30, 2021 and 2020, respectively. (2) Includes $3.0 million and $2.0 million of non-cash stock-based compensation expense for the six months ended June 30, 2021 and 2020, respectively. ​ License and Collaboration Revenue License and collaboration revenue decreased $1.4 million, or 14%, from $9.9 million for the six months ended June 30, 2020 to $8.5 million for the six months ended June 30, 2021, which was primarily related to a decrease in services provided under the Janssen License and Collaboration Agreement recognized based on proportional performance. The level of services has decreased as the Company nears completion of its performance obligations delivered pursuant to the collaboration, including the anticipated completion of its ongoing PN-235 Phase 1 trial in the fourth quarter of 2021 and its ongoing PN-232 Phase 1 trial in the first half of 2022. We have determined that the transaction price of the initial performance obligation under the Janssen License and Collaboration Agreement was $95.8 million as of June 30, 2021, a decrease of $2.8 million from the transaction price of $98.6 million as of December 31, 2020. In order to determine the transaction price, we evaluated all payments expected to be received during the duration of the contract, net of development costs reimbursement expected to be payable to Janssen. We determined that the transaction price includes the $50.0 million upfront payment, the $25.0 million payment received upon the effectiveness of the First Amendment, the $5.0 million payment triggered by the successful nomination of a second-generation compound, $17.9 million of reimbursement from Janssen for services performed for PTG-200 Phase 2 and for second-generation compound research costs and other services, and estimated variable consideration consisting of a $7.5 million milestone payment subject to the completion of a Phase 1 study for a second-generation compound, offset by $9.6 million of net cost reimbursement to Janssen for services performed. The decrease in transaction price from December 31, 2020 to June 30, 2021 was due primarily to a decrease in the forecast of remaining services to be provided under the initial performance obligation and an increase in the forecast for cost reimbursements to Janssen for services performed. We re-evaluate the transaction price each reporting period and as uncertain events are resolved or other changes in circumstances occur. Research and Development Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ ​ ​ ​ ​ June 30, ​ Dollar ​ % ​ 2021 ​ 2020 ​ Change ​ Change ​ ​ (Dollars in thousands) ​ ​ Clinical and development expense — rusfertide (PTG-300) ​ $ 22,247 ​ $ 14,559 ​ $ 7,688 ​ 53 Clinical and development expense — PN-943 ​ ​ 15,475 ​ ​ 14,020 ​ ​ 1,455 ​ 10 Clinical and development expense — PN-235 ​ ​ 3,232 ​ ​ — ​ ​ 3,232 ​ * Clinical and development expense — PN-232 ​ ​ 39 ​ ​ — ​ ​ 39 ​ * Clinical and development expense — PTG-200 ​ ​ 2 ​ ​ 925 ​ ​ (923) ​ (100) Clinical and development expense — PTG-100 ​ ​ 250 ​ ​ 193 ​ ​ 57 ​ 30 Preclinical and discovery research expense ​ ​ 11,245 ​ ​ 9,916 ​ ​ 1,329 ​ 13 Grants and tax incentives expense reimbursement, net ​ (1,813) ​ (588) ​ (1,225) ​ 208 Total research and development expenses ​ $ 50,677 ​ $ 39,025 ​ $ 11,652 ​ 30 *Percentage not meaningful ​ Research and development expenses increased $11.7 million, or 30%, from $39.0 million for the six months ended June 30, 2020 to $50.7 million for the six months ended June 30, 2021. The increase was primarily due to an increase of $7.7 million in rusfertide clinical trial and development costs, including the ongoing Phase 2 trials in PV, which began in December 2019, and HH, which began in early 2020, and clinical and contract manufacturing activities incurred in 2021 in preparation for a planned global Phase 3 clinical trial of rusfertide in PV; $3.2 million of Phase 1 clinical trial and development costs for PN-235 beginning in December 2020; an increase of $1.5 million in PN-943 38 Table of Contents clinical trial and development costs following the initiation of the Phase 2 trial in UC during the second quarter of 2020; and an increase of $1.3 million in preclinical and drug discovery research expenses, including pre-clinical costs related to our research collaboration efforts with Janssen which were completed during the second quarter of 2021. These increases were partially offset by a $1.2 million increase in grant and accrued refundable cash tax incentives and a decrease of $0.9 million in PTG-200 clinical trial and development expenses under the Janssen License and Collaboration Agreement due to our delivery of substantially all agreed-upon services for the PTG-200 Phase 2 clinical trial. ​ We had 81 and 52 full-time equivalent research and development employees as of June 30, 2021 and 2020, respectively. ​ General and Administrative Expenses General and administrative expenses increased $3.9 million, or 45%, from $8.8 million for the six months ended June 30, 2020 to $12.7 million for the six months ended June 30, 2021 primarily due to an increase of $2.0 million in personnel expenses, $0.6 million in market research expenses, $0.4 million in consulting expenses, and $0.3 million in recruiting expenses to support the growth of our operations, and a $0.6 million increase in legal fees due primarily to an arbitration matter with a former research and collaboration partner. The increase in personnel expenses was primarily due to increases of $1.0 million in stock-based compensation expense and $0.9 million in wages and salaries. ​ We had 20 and 17 full-time equivalent general and administrative employees as of June 30, 2021 and 2020, respectively. ​ Interest Income ​ Interest income decreased $0.5 million, or 73%, from $0.7 million for the six months ended June 30, 2020 to $0.2 million for the six months ended June 30, 2021. This decrease was due primarily to the recent record low interest rate environment and a change in the mix of marketable securities compared to the prior year period, despite higher interest-earning asset balances. ​ Interest Expense Interest expense decreased $0.5 million, or 100%, from $0.5 million for the six months ended June 30, 2020 to zero for the six months ended June 30, 2021. The decrease in interest expense was due to the prepayment of our outstanding long-term debt under our term credit facility during the second quarter of 2020. We had no debt outstanding under our term loan facility during the six months ended June 30, 2021. Loss on Early Repayment of Debt Loss on early repayment of debt of $0.6 million for the six months ended June 30, 2020 reflects prepayment and final payment fees paid in connection with the early repayment of our term loan in June 2020. We had no debt outstanding during the six months ended June 30, 2021. Other (Expense) Income, Net Other expense, net was $0.1 million for the six months ended June 30, 2021 compared to zero for the six months ended June 30, 2020. The change was due primarily to an increase in foreign exchange losses. Income Tax Expense Income tax expense decreased $1.3 million, or 100%, from $1.3 million for the six months ended June 30, 2020 to zero for the six months ended June 30, 2021. Our effective income tax rate was 0% for the six months ended June 30, 2021 as compared to 3.4% for the six months ended June 30, 2020. During the second quarter of 2020, our 39 Table of Contents Australia subsidiary sold beneficial rights to discovery intellectual property to our U.S. entity, and the U.S. entity reimbursed the Australia subsidiary for certain direct development costs. Upon completion of the sale, we analyzed tax planning strategies and future income and concluded that a valuation allowance is necessary for our Australia subsidiary. Income tax expense for the six months ended June 30, 2020 reflects this sale of intellectual property rights, cost reimbursements and related adjustments to the deferred tax asset, establishing a valuation allowance and certain uncertain tax position liabilities. We maintained a full valuation allowance on our tax position as of June 30, 2021. Liquidity and Capital Resources Sources of Liquidity Historically, we have funded our operations primarily from net proceeds from the sale of shares of our common stock and payments under collaboration agreements. In December 2020, we filed an automatic registration statement on Form S-3ASR and an accompanying prospectus (Registration Statement No. 333-251254), pursuant to which we completed an underwritten public offering of 4,761,904 shares of common stock at a public offering price of $21.00 per share and issued an additional 714,285 shares of our common stock at a price of $21.00 per share following the underwriters’ exercise of their option to purchase additional shares. Net proceeds, after deducting underwriting commissions and offering costs paid by us, were $107.6 million. In June 2021, pursuant to Registration Statement No. 333-251254, we completed an underwritten public offering of 3,046,358 shares of common stock at a public offering price of $37.75 per share and issued an additional 456,953 shares of common stock at a public offering price of $37.75 per share following the underwriters’ exercise of their option to purchase additional shares. Net proceeds, after deducting underwriting commission and offering costs paid by us, were $123.8 million. This Form S-3ASR expires in December 2023. ​ In October 2019, we filed a registration statement on Form S-3 (File no. 333-234414) that was declared effective as of November 22, 2019 and permits the offering, issuance, and sale by us of up to a maximum aggregate offering price of $250.0 million of our common stock, preferred stock, debt securities and warrants (the “2019 Form S-3”). Up to a maximum of $75.0 million of the maximum aggregate offering price of $250.0 million may be issued and sold pursuant to an ATM financing facility under a sales agreement we entered into on November 27, 2019 (the “2019 Sales Agreement”). In May 2020, we completed an underwritten public offering of 7,000,000 shares of common stock at a public offering price of $14.00 per share, and we issued an additional 1,050,000 shares of our common stock at a price of $14.00 per share following the underwriters’ exercise of their option to purchase additional shares. Net proceeds, after deducting underwriting commissions and offering costs paid by us, were $105.3 million. During the year ended December 31, 2020, we issued 2,483,719 shares under our ATM facility for net proceeds of $41.9 million. No shares were issued under the ATM facility during the three and six months ended June 30, 2021. As of June 30, 2021, a total of $94.2 million of common stock remained available for sale under the 2019 Form S-3, $31.9 million of which remained available for sale under the ATM financing facility. This Form S-3 expires in October 2022. We have received $80.0 million in non-refundable payments from Janssen since the inception of the Janssen License and Collaboration Agreement in 2017 through June 30, 2021, as follows: ​ ● Upon effectiveness of the agreement, we received a non-refundable, upfront cash payment of $50.0 million from Janssen; ● Upon effectiveness of the First Amendment, we became eligible to receive a $25.0 million payment from Janssen, which was received during the second quarter of 2019; and ● In December 2019, we became eligible to receive a $5.0 million payment triggered by the successful nomination of a second-generation development compound, which was received during the first quarter of 2020. We also receive payments for services provided under the collaboration agreement and in-kind reimburses Janssen for certain costs they have incurred based on the cost sharing terms of the agreement. 40 Table of Contents Pursuant to the amended and restated License and Collaboration Agreement with Janssen executed July 27, 2021 (the “Restated Agreement”), we will be eligible to receive clinical development, regulatory and sales milestones, if and as achieved. Upcoming potential development milestones for second-generation products include: ● $7.5 million for completion of the first Phase 1 clinical trial of a second-generation product; ● $25.0 million for dosing of the third patient in the first Phase 2 clinical trial for any second-generation product for any indication; and ● $10.0 million for dosing of the third patient in the first Phase 2 clinical trial for any second-generation product for a second indication (i.e. an indication different than the indication which triggered the $25.0 million milestone described directly above). The next potential development milestone for initial product PTG-200 is $50.0 million for dosing of the third patient in a Phase 2b clinical trial for CD. In October 2019, we entered into a credit and security agreement pursuant to which the lenders party thereto agreed to make term loans available to us for working capital and general business purposes, in a principal amount of up to $50.0 million, at our option, until September 30, 2021. $20.0 million remains available under this term loan facility through September 30, 2021 subject to the satisfaction of certain conditions, including the achievement of certain clinical development milestones. We had no outstanding debt balance as of June 30, 2021. Additional information about this credit facility is presented in Note 9 to the condensed consolidated financial statements included elsewhere in this report. Capital Requirements ​ As of June 30, 2021, we had $380.4 million of cash, cash equivalents and marketable securities and an accumulated deficit of $338.6 million. Our capital expenditures for six months ended June 30, 2021 were $0.6 million. Our capital expenditures for the years ended December 31, 2020 and 2019 were $0.5 million and $1.0 million, respectively. Our primary uses of cash are to fund operating expenses, primarily our research and development expenditures, general and administrative costs and pre-commercialization costs. Cash used to fund operating expenses is impacted by the timing of when we pay these expenses. We believe, based on our current operating plan and expected expenditures, that our existing cash, cash equivalents and marketable securities and access to our term loan facility will be sufficient to meet our anticipated operating and capital expenditure requirements for at least the next 12 months from the date of this filing. We have based this estimate on assumptions that may prove to be wrong. We could utilize our available capital resources sooner than we currently expect if our planned pre-clinical and clinical trials are successful, our product candidates enter new and more advanced stages of clinical development or our newer product clinical trials or advance beyond the discovery stage. We expect to require additional financing to advance our product candidates through clinical development and toward potential regulatory approval and to develop, acquire or in-license other potential product candidates. Such additional funding may come from raising additional capital, seeking access to additional debt, and additional collaborative or other arrangements with corporate sources, but such funding may not be available at terms acceptable to us, if at all. We anticipate that we will need to raise substantial additional funding, the requirements of which will depend on many factors, including: ​ ● the progress, timing, scope, results and costs of advancing our clinical trials and pre-clinical studies for our product candidates, including the ability to enroll patients in a timely manner for our clinical trials; ● the costs of and ability to obtain clinical and commercial supplies and any other product candidates we may identify and develop; ● our ability to successfully commercialize the product candidates we may identify and develop; 41 Table of Contents ● the selling and marketing costs associated with our current product candidates and any other product candidates we may identify and develop, including the cost and timing of expanding our sales and marketing capabilities; ● the achievement of development, regulatory and sales milestones resulting in payments to us from Janssen under the Janssen License and Collaboration Agreement or other such arrangements that we may enter into, and the timing of receipt of such payments, if any; ● the timing, receipt and amount of royalties under the Janssen License and Collaboration Agreement on worldwide net sales of PTG-200, including any second-generation compounds, upon regulatory approval or clearance, if any; ● the amount and timing of sales and other revenues from our current product candidates and any other product candidates we may identify and develop, including the sales price and the availability of adequate third-party reimbursement; ● the cash requirements of any future acquisitions or discovery of product candidates; ● the time and cost necessary to respond to technological and market developments; ● the extent to which we may acquire or in-license other product candidates and technologies; ● costs necessary to attract, hire and retain qualified personnel; ● the costs of maintaining, expanding and protecting our intellectual property portfolio; and ● the costs of ongoing general and administrative activities to support the growth or our business. Adequate additional funding may not be available to us on acceptable terms, or at all. Any failure to raise capital as and when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. Further, our operating plans may change, and we may need additional funds to meet operational needs and capital requirements for clinical trials, other research and development activities and pre-commercialization costs. If we do raise additional capital through public or private equity offerings or convertible debt securities, the ownership interest of our existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect our stockholders’ rights. If we raise additional capital through debt financing, we may be subject to covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Because of the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to fully estimate the amounts of increased capital outlays and operating expenditures associated with our current and anticipated product development programs. 42 Table of Contents The following table summarizes our cash flows for the periods indicated (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ 2021 2020 Cash used in operating activities ​ $ (52,456) ​ $ (37,330) Cash provided by investing activities ​ 980 ​ 37,559 Cash provided by financing activities ​ 126,369 ​ 112,976 Cash Flows from Operating Activities Cash used in operating activities for the six months ended June 30, 2021 was $52.5 million, consisting of our net loss of $54.8 million and a net change of $6.3 million in net operating assets and liabilities, partially offset by $8.7 million in non-cash charges. Non-cash charges were primarily comprised of $6.6 million of stock-based compensation, $0.9 million of operating lease right-of-use asset amortization, $0.8 million of net amortization of discount on marketable securities, and $0.4 million of depreciation and amortization. The change in net operating assets and liabilities was primarily due to a decrease of $12.5 million in deferred revenue related to the Janssen License and Collaboration Agreement, an increase of $4.7 million in receivable from collaboration partner, an increase of $1.7 million in research and development tax incentive receivable, an increase in prepaid expenses and other assets of $1.4 million, and a decrease of $1.0 million in operating lease liability, partially offset by an increase of $8.7 million in payable to collaboration partner, an increase of $4.9 million in accounts payable and an increase of $1.4 million in accrued expenses and other payables. Cash used in operating activities for the six months ended June 30, 2020 was $37.3 million, consisting of our net loss of $39.5 million and a net change of $5.0 million in net operating assets, partially offset by $7.1 million in non-cash charges. Non-cash charges were primarily comprised of $4.0 million of stock-based compensation, a $1.4 million change in net deferred tax asset, $0.9 million of operating lease right-of-use asset amortization, a $0.6 million loss on early prepayment of long-term debt and $0.4 million of depreciation and amortization., partially offset by $0.2 million of net accretion of discount on marketable securities. The change in net operating assets and liabilities was primarily due to a decrease of $7.5 million in deferred revenue related to the Janssen License and Collaboration Agreement, a $1.0 million decrease in operating lease liability, a $0.3 million increase in Australia research and development incentive receivable, a $0.3 million decrease in payable to collaboration partner and a $0.3 million increase in prepaid expenses and other assets, partially offset by a decrease of $3.8 million in receivable from collaboration partner and an increase of $0.4 million in accrued expenses and other payables. Cash Flows from Investing Activities Cash provided by investing activities for the six months ended June 30, 2021 was $1.0 million, consisting of proceeds from maturities of marketable securities of $165.1 million, offset by purchases of marketable securities of $163.5 million and purchases of property and equipment of $0.6 million. Cash provided by investing activities for the six months ended June 30, 2020 was $37.6 million, consisting of proceeds from maturities of marketable securities of $104.6 million, partially offset by purchases of marketable securities of $66.8 million and purchases of property and equipment of $0.3 million. Cash Flows from Financing Activities Cash provided by financing activities for the six months ended June 30, 2021 was $126.4 million, consisting of $124.0 million of cash proceeds from our public offering of common stock and $2.6 million from the issuance of common stock upon exercise of stock options and purchases of common stock under our employee stock purchase plan, partially offset by $0.2 million of tax withholding payments related to net settlement of restricted stock units. Cash provided by financing activities for the six months ended June 30, 2020 was $113.0 million, consisting primarily of cash proceeds from our public offering of common stock of $105.7 million, cash proceeds from ATM sales 43 Table of Contents of $16.8 million, and proceeds from the issuance of common stock upon exercise of stock options and purchases of common stock under our employee stock purchase plan of $1.0 million, partially offset by early repayment of long-term debt of $10.5 million. Contractual Obligations and Other Commitments During the three and six months ended June 30, 2021, there were no material changes to our contractual obligations and commitments described under Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 10, 2021.