Actinium Pharmaceuticals, Inc. 10-Q

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATION FORWARD-LOOKING STATEMENT NOTICE This Form 10-Q contains certain forward-looking statements. For this purpose, any statements contained in this Form 10-Q that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, words such as “may,” “will,” “expect,” “believe,” “anticipate,” “estimate” or “continue” or comparable terminology are intended to identify forward-looking statements. These statements by their nature involve substantial risks and uncertainties, and actual results may differ materially depending on a variety of factors, many of which are not within our control. These factors include but are not limited to economic conditions generally and in the industries in which we may participate; competition within our chosen industry, including competition from much larger competitors; technological advances and failure to successfully develop business relationships. Description of Business Actinium Pharmaceuticals, Inc. is a clinical-stage, biopharmaceutical company applying its proprietary platform technology and deep understanding of radiobiology to the development of novel targeted therapies known as Antibody Radiation-Conjugates (“ARCs”). ARCs combine the cell-killing ability of radiation via a radioisotope payload with a targeting agent, such as a monoclonal antibody, to deliver radiation in a precise manner inside the body to specific, targeted cells, to potentially achieve greater efficacy with lower toxicity than with external beam radiation. ARCs enable a broader usage of radiation than external beam radiation as they can be used in the treatment of both solid tumors and blood cancers. Blood or hematologic cancers are known to be highly sensitive to radiation. Our clinical pipeline is focused on ARCs targeting the antigens CD45 and CD33, both of which are expressed in multiple hematologic cancers. Our clinical programs are focused on two primary areas: (1) targeted conditioning prior to a bone marrow transplant (“BMT”), adoptive cell therapy (“ACT”) such as CAR-T or gene therapy and (2) ARC therapeutic combinations with other agents. Our product development strategy is actively informed by clinical data with our ARCs in over 500 patients, including our ongoing Pivotal Phase 3 SIERRA trial. Our clinical pipeline has emanated from our Antibody Warhead Enabling (“AWE”) technology platform, which is protected by over 160 issued and pending patents, trade secrets and know-how and is being utilized in a collaborative research partnership with Astellas Pharma, Inc. (“Astellas”). We are also utilizing our AWE technology platform to advance our research objectives focused on developing next-generation targeted radiotherapies. To accelerate development efforts we are undertaking an expansion of our R&D organization and research laboratories to enable us to more effectively leverage our drug development experience to advance candidates to clinical trials. Targeted Conditioning To the best of our knowledge, we are advancing the only multi-target, multi-indication, clinical-stage pipeline for targeted conditioning and the only ARC-based targeted conditioning regimens in development. Our ARCs for targeted conditioning are intended to potentially enable improved access and outcomes to cell-based therapies with curative potential, including BMT, ACT, and gene therapy Conditioning in the context of BMT, ACT or gene therapy is the act of depleting certain blood and immune-forming cells, including bone marrow stem cells and, in some cases, cancer cells prior to transplanting new cells into a patient. Currently, conditioning is accomplished using a combination of cytotoxic chemotherapeutic agents and external radiation. These non-targeted conditioning regimens are highly toxic and may prevent a patient from receiving a potentially curative therapy and hinder outcomes. ARCs have the potential to increase patient access and outcomes by way of their ability to selectively deplete targeted cells while sparing normal healthy cells, resulting in potentially lower systemic and off-target toxicities. We use our ARCs both at high isotope dose levels to achieve myeloablation, which fully depletes bone marrow stem cells and at lower isotope dose levels to achieve lymphodepletion, which spares bone marrow stem cells from depletion. In addition, dosing may be titrated downward from myeloablative doses to achieve partial myeloablation, which may be appropriate for certain gene therapy programs. 15 CD45 Targeted Conditioning Program Our CD45 ARC is comprised of the anti-CD45 monoclonal antibody known as apamistamab (formerly BC8) and the radioisotope Iodine-131 (“I-131”). CD45 is an antigen expressed on leukemia, lymphoma and myeloma cancer cells, as well as nucleated immune cells including bone marrow stem cells, but is not expressed outside of the hematopoietic, or blood forming, system. This unique expression on blood cancer and immune cells enables simultaneous depletion of both cell types, making CD45 an optimal antigen for targeted conditioning applications. CD45 is a cell surface antigen with an average expression of 200,000 copies per cell, however, it only internalizes at a rate of 10-15%. We believe our ARC approach is the most effective method to target CD45 positive cells, as the radioisotope payload linear energy transfer can readily ablate a targeted cell without requiring payload internalization like an antibody drug conjugate or without relying on biological effector function processes like a naked antibody. Furthermore, since CD45 expression level varies from low to high antigen density as the immune cells become more terminally differentiated, we can selectively condition depending on the therapeutic application, from full myeloablation to transient lymphodepletion, by adjusting the dose or intensity of the I-131 isotope payload. Full myeloablation can be achieved with high doses of I-131, as its energy pathlength and crossfire effect can penetrate into bone marrow niches to target and deplete blood and immune system forming bone marrow stem cells. Myeloablation is applicable to autologous or allogeneic BMT and to autologous gene-edited or modified therapies that can reconstitute a patient’s blood and immune systems. Alternatively, low doses of I-131 can be transiently lymphodepleting and spare a patient’s bone marrow stem cells, which we believe is ideal for ACT applications such as CAR-T. We intend to develop our CD45 targeted conditioning program for BMT, ACT and gene therapy applications for malignant and non-malignant diseases and believe that multiple radioisotopes beyond I-131 may be utilized including alpha and beta emitters. Our lead CD45 targeted conditioning product candidate is Iomab-B, which uses high doses of I-131 to achieve myeloablative conditioning prior to a BMT. Iomab-B is currently being studied in the pivotal Phase 3 Study of Iomab-B in Elderly Relapsed or Refractory AML (“SIERRA”), clinical trial for targeted conditioning prior to an allogeneic BMT for patients with active, relapsed or refractory (“r/r”) Acute Myeloid Leukemia, (“AML”), who are age 55 or older. Patients with active, r/r AML are not normally considered eligible for BMT and the SIERRA trial is the only randomized Phase 3 trial to offer BMT as a treatment option for this patient population. The SIERRA trial compares outcomes of patients randomized to receive Iomab-B and a BMT (the “study arm”) to those patients randomized to receive physician’s choice of salvage therapy (the “control arm”). The control arm is also defined as conventional care, as no standard of care exists for this patient population and includes over 20 agents that may be used as single agents or in combination including venetoclax, a targeted Bcl-2 inhibitor, Midostaurin and Sorafenib, targeted FLT3 inhibitors, hypomethylating agents and cytotoxic chemotherapies. Patients who fail to achieve a Complete Remission (“CR”) on the control arm are ineligible to proceed to a BMT, but the trial design permits these patients to “cross over” to receive the study arm treatment if they meet the eligibility criteria. The primary endpoint of the SIERRA trial is durable Complete Remission (“dCR”) of 180 days and the secondary endpoint is Overall Survival (“OS”). When the crossover patients receive Iomab-B and BMT, they have not achieved remission with their salvage therapy and are considered to be failures for the primary endpoint of the study. The SIERRA trial is currently active at 24 sites in the United States and Canada, which includes many of the leading BMT sites based on volume. We expect to complete enrollment of the SIERRA trial and have topline data that we believe will support the submission of a Biologics License Application (“BLA”) with the U.S. Food and Drug Administration (“FDA”). If approved, we expect our initial commercial launch would target the leading 50-100 BMT and medical centers that perform the vast majority of BMT’s in the United States. In the European Union (“EU”), we received favorable feedback from the European Medicines Agency (“EMA”) via their scientific advice program that the trial design, primary endpoint and planned statistical analysis from the SIERRA trial are acceptable as the basis for a Marketing Authorization Application, or MAA. Additionally, the EMA commented that it does not anticipate the need for further standalone preclinical toxicology or safety studies. Overall, transplant procedures in the EU are approximately fifty percent higher than in the United States with a similar market dynamic, with a majority of BMT volume being conducted in a concentrated number of leading medical centers. Currently we intend to secure a partner for Iomab-B in the EU. 16 The SIERRA trial is powered to show a two-times difference in the primary endpoint of dCR of at least 180 days at complete enrollment of the planned 150 patients. The SIERRA trial design allowed for up to two interim analyses of the primary endpoint, exercisable at our discretion and triggered by an enrollment range of 70 to 110 patients. In April 2020, we exercised a single ad hoc analysis on a number of patients representing less than two thirds of full trial enrollment of 150 patients, which required a higher success threshold compared to the two-time difference in dCR rate at full trial enrollment. In December 2020, we announced that the independent Data Monitoring Committee (“DMC”) completed the single ad hoc interim analysis. Based on the DMC’s review of unblinded data, including the study’s primary endpoint of dCR of at least 180 days, it was recommended that the study continue as planned to full enrollment of 150 patients. We did not receive the unblinded primary and secondary endpoint efficacy data from SIERRA. By exercising only a single interim analysis, there was a minimal alpha spend resulting in a p-value threshold of 0.046 for the primary endpoint evaluation at full enrollment of 150 patients. The SIERRA trial reached 75% enrollment, representing 113 patients, in the third quarter of 2020. Data from the first 113 patients enrolled in the SIERRA trial, which represents 75% of the total of 150 patients to be enrolled in the trial, was presented in oral presentations at the American Society of Hematology (“ASH”) Annual Meeting in December 2020 and at the Transplantation & Cellular Therapy (“TCT”) Meetings of the American Society for Transplantation and Cellular Therapy (“ASTCT”) and Center for International Bone & Marrow Transplant Research (“CIBMTR”) in February 2021. It was reported that 100% of patients (49/49) on the study arm that received a therapeutic dose of Iomab-B received a BMT, with a median time to BMT of 30 days, and all patients achieved neutrophil and platelet engraftment in a median time of 18 days despite a high median blast count of 29%. On the control arm, only 18% of patients (10/57) achieved remission after salvage therapy, and then received a BMT with a median time to BMT of 67 days and median blast count of 20%. Of the 82% of patients failing to achieve a CR with conventional care (47/57), 30 patients were eligible to cross over to receive Iomab-B followed by transplant. These patients are considered as having failed the primary endpoint of the study. All crossover patients who received the therapeutic dose of Iomab-B (30/30) received a BMT, with a median time to BMT of 24 days and they achieved engraftment in a median time of 19 days despite high median blast count of 22% at time of crossover. It was also reported that 100-day non-relapse transplant-related mortality (100-day TRM) of the study or Iomab-B arm was only 4% (2/45) of patients that received a BMT compared to 20% of patients (2/10) who received a BMT after salvage therapy on the control arm. The universal engraftment rate and low 100-day TRM rate of the Iomab-B arm resulted in 43 patients potentially evaluable for the primary endpoint compared to 8 patients in the control arm, a greater than five times difference. Our Iomab-ACT program is intended for targeted conditioning prior to ACT or gene therapy and uses the same I-131-apamistamab ARC construct as Iomab-B at varying doses. At lower doses of one-eighth to one-sixth of the myeloablative dose, it is applicable for lymphodepletion prior to CAR-T or certain gene therapy applications where stem cell myeloablation is not necessary. At higher doses it is applicable for gene therapy applications where stem cell myeloablation is necessary. We believe our Iomab-ACT program is highly differentiated when compared to Fludarabine and Cyclophosphamide (“Flu/Cy”) or other chemotherapy-based regimens that are used as the standard of practice today for lymphodepletion prior to CAR-T. CD45 is an antigen expressed on certain immune cell types that are relevant to the mechanism of CAR-T therapies including lymphocytes, regulatory T-cells and macrophages that have been associated with clinical responses that may limit the safety, efficacy and durability of response of these CAR-T therapies including cytokine release syndrome (“CRS”) and neurotoxicity. Some of these limitations may be attributable to the chemotherapy-based conditioning agents that are being used prior to CAR-T therapies. Preclinical data supporting the rational for our Iomab-ACT program was presented at multiple medical conferences in 2019. Unlike chemotherapy, Iomab-ACT is targeted in nature and, due to this CD45-directed targeting, we expect we can improve CAR-T cell expansion, potentially resulting in responses that are more durable, but also resulting in reduced CAR-T related toxicities. Importantly, we expect the Iomab-ACT program construct to enable lymphodepletion through a single-dose, outpatient administration versus Flu/Cy or other chemotherapy-based lymphodepletion regimens that can require multiple infusion cycles over several days. Because of this potentially superior profile, the Iomab-ACT construct could result in improved access to CAR-T therapy and better outcomes. 17 We are studying Iomab-ACT in a clinical collaboration with Memorial Sloan Kettering Cancer Center (“MSKCC”) for targeted conditioning prior to administration of MSKCC’s 19-28z CD19 targeting CAR-T in patients with relapsed or refractory B-cell acute lymphoblastic leukemia (“ALL”) or diffuse large B-cell lymphoma (“DLBCL”). We received grant funding from the National Institute of Health (“NIH”) to fund this trial with MSKCC being a co-recipient on this grant. This is a first of its kind study to use an ARC-based conditioning regimen with CAR-T therapy. The hypothesized rationale for this study is that Iomab-ACT will exert an anti-tumor effect on the chemotherapy-refractory B-ALL cells that are sensitive to radiation resulting in reduced disease burden and simultaneously deplete CD45 expressing immune cells implicated in CAR-T related toxicities, resulting in an optimal homeostatic environment for the CAR-T cells. Results with MSKCC’s 19-28z CD-19 CAR-T in 53 patients with r/r B-ALL published in the New England Journal of Medicine reported complete remissions in 83% (44/53) of patients, which compares favorably to standard chemotherapy regimens that have complete remission rates of 18% - 45% in this patient population. Median event-free survival (EFS) was 6.1 months and median overall survival (OS) was 12.9 months at a median follow up period of 29 months (range 1 – 65 months). There was a 26% (14/53) rate of Grade 3 or greater CRS and a 42% rate of Grade 3 or 4 neurotoxicity reported. The study will evaluate the feasibility of using an ARC-based conditioning regimen with CAR-T therapy and will evaluate safety measures including incidence of CRS and neurotoxicity and efficacy measures including responses and survival outcomes. In March 2021, we announced that patient enrollment was initiated, and the first patient was administered Iomab-ACT followed by their 19-28z CAR-T therapy. We expect proof of concept data from this study in the second half of 2021. In addition, we are working in collaboration with University of California Davis to utilize Iomab-ACT conditioning in an ongoing Phase 1/2 trial with a novel anti-HIV autologous stem cell gene therapy for patients with HIV-related lymphoma. We believe this would be the first gene therapy trial to use an ARC-based conditioning regimen. I-131-Apamistamab has clinical proof of concept as a targeted conditioning regimen for patients with high-risk, relapsed or refractory lymphoma prior to an autologous stem cell transplant from a previous study, where a favorable safety profile with no dose-limiting toxicities and minimal non-hematologic toxicities were observed and promising efficacy with median overall survival not reached (range: 29 months to not reached) and 31% of patients in prolonged remission at a median of 36 months follow up (range: 25 – 41 months). In this study, Iomab-ACT is intended to replace the chemotherapy-based condition regimen known as BEAM (BCNU/carmustine, etoposide, cytarabine, and melphalan) to simultaneously kill the patient’s lymphoma cells and deplete the patient’s stem cells to make room for the transplant. Upon engraftment, the transplanted gene-modified autologous stem cells containing three anti-HIV genes are intended to equip the patient with a new immune system that is resistant to the HIV virus. We continue to identify additional gene therapies for which Iomab-ACT can be used for targeted conditioning with the goal of collaborating with multiple academic or industry developers to establish Iomab-ACT as a non-chemotherapy universal targeted conditioning solution. We are also exploring an Ac-225-based CD45 ARC, as a potential next-generation targeted conditioning agent. Dosimetry results with this Ac-225-based alpha emitting ARC showed selective accumulation in immune cell target organs such as bone marrow, spleen, and liver with the potential for lower exposure to non-target tissues from longer path length beta emitter radioisotopes like Iodine-131 and Lutetium-177. Preclinical data demonstrated that conditioning with this Ac-225-based CD45-targeting agent result in depletion of peripheral immune cells and hematopoietic progenitor cells, thereby enabling engraftment of donor cells. A dose dependent response was observed with low doses depleting white blood cells without affecting hematopoietic progenitor cells, representing a lymphodepletive dose that is relevant for adoptive cell therapies such as CAR-T, while higher doses eliminated peripheral immune cells and hematopoietic progenitor cells, which is applicable to ex vivo gene therapies and BMT. CD33 Program: Targeted Conditioning, Combinations and Therapeutics Our CD33 program is evaluating the clinical utility of Actimab-A, an ARC comprised of the anti-CD33 mAb lintuzumab linked to the potent alpha-emitting radioisotope Actinium-225 (“Ac-225”). CD33 is expressed in the majority of patients with AML and myelodysplastic syndrome (“MDS”) as well as approximately one-third of patients with multiple myeloma. Ac-225 emits four alpha particles and can kill a cell with one alpha-particle hit, making it one of the most powerful cell-killing agents with no know resistance mechanism to the double strand DNA breaks it can cause. We source Ac-225 from the Department of Energy’s Oak Ridge National Laboratory through an annual supply agreement, which we expect to renew annually. 18 Our CD33 development program is driven by data obtained from nearly one hundred fifty treated patients, including results from a Phase 1/2 trial that was conducted in 58 patients with newly diagnosed AML, which was completed in 2018. This clinical data, as well as our experience with Iomab-B, is shaping a two-pronged approach with our CD33 program, where at high doses we are exploring its use for targeted conditioning and at low doses we are exploring its use for therapeutic combinations with other treatment modalities. We believe that radiation via an ARC can be synergistic when used in combination with chemotherapy, targeted agents and immunotherapy based on mechanistic rationales supported by our own clinical data, preclinical research and scientific and clinical evidence in the literature. We have prioritized our efforts and resources in favor of combination trials for our CD33 program development strategy rather than single agent trials at this time. Our CD33 ARC development program encompasses the following ongoing trials: Combination Trials : ● Phase 1 investigator initiated Actimab-A + CLAG-M combination trial with the salvage chemotherapy regimen CLAG-M (cladribine, cytarabine, filgrastim and mitoxantrone) for fit patients age 18 and above with relapsed or refractory AML at the Medical College of Wisconsin (“MCW”). The combination of Actimab-A + CLAG-M is supported by mechanistic rationale for combining inhibitors of DNA replication and/or repair processes such as mitoxantrone, a topoisomerase-II inhibitor, and radiation, as imparted by tumor-targeting of Ac-225 with Actimab-A. Thus far, we have reported preliminary data from dose cohorts one, two and the third and planned final dose cohort of 0.75 µCi/kg of Actimab-A. At the 2020 American Society of Hematology Annual Meeting, it was reported that 100% of patients (3/3) receiving 0.75 µCi/kg of Actimab-A, and CLAG-M achieved a complete remission, which is nearly 85% greater than the 55% remission rate observed in a study of CLAG-M alone conducted at MCW in the same r/r AML patient population. Complete Remission or Complete Remission with Incomplete blood count recovery (“CRi”) were observed in all dose cohorts (0.25, 0.50 and 0.75 µCi/kg) with 67% of patients (10/15) achieving CR or CRi. The 0.25 and 0.50 µCi/kg doses of Actimab-A have been shown to be subtherapeutic as a single agent. Of the 10 patients achieving CR or Cri, 70% achieved negative minimal residual disease (“MRD”) status with no detectable disease via flow cytometry, indicating that these are deep remissions. No dose-limiting toxicities (“DLTs”) were reported in the third dose cohort of 0.75 µCi/kg and therefore maximum tolerable dose (“MTD”) was not reached. As a result, MCW amended the study protocol to allow for continued dose escalation and the trial is now enrolling patients at a dose of 1.0 µCi/kg. Upon completion of this Phase 1 trial, we will work to develop a regulatory and development pathway that can potentially support a registration for the Actimab-A + CLAG-M combination. In addition, the Actimab-A + CLAG-M combination study has provided proof of principle that the addition of subtherapeutic doses of Actimab-A to other AML therapies can lead to well-tolerated regimens with improved responses. ● Phase 1/2 Actimab-A + Ven combination trial with the BCL-2 inhibitor Venetoclax (“ven”) for fit and unfit patients age 18 and above with relapsed or refractory AML. This multi-center trial is being led by UCLA Medical Center. This combination is supported by mechanistic evidence in preclinical studies using ven-resistant AML tumor cell lines. In these models, we have demonstrated that Actimab-A can deplete Mcl-1 and Bcl-XL, two proteins implicated in mediating resistance to venetoclax, in addition to causing potentially lethal double-stranded DNA breaks in these CD33 expressing cells. Furthermore, in vivo studies in animal models of ven-resistant AML demonstrated robust tumor regression and improved survival in cohorts receiving the Actimab-A ven combination compared to ven alone. The rationale for this clinical study is that the addition of Actimab-A will; 1) have a direct anti-tumor effect via double-stranded DNA breaks and 2) deplete Mcl-1 and BCL-XL making the AML cells more susceptible to ven. At the 2020 ASH annual meeting, data from the first dose cohort of 0.50 µCi/kg Actimab-A in combination with ven were presented. There was a 67% overall response rate (2/3 patients), including one CR and one partial response (“PR”) with blast count reduction of 50%. All 3 patients were poor risk with adverse cytogenetics and each patient had an additional high-risk marker (FLT3-ITD+, antecedent JAK2+ myelofibrosis, or TP53 mutation). The patient achieving a CR was in second relapse and a TP53 mutation as well as multiple other high-risk markers. The trial is now active and recruiting at 4 trial sites in dose escalation cohorts. We expect to have Phase 1 safety and preliminary proof of concept clinical data from this combination study in 2021. In addition to these active trials, we are working to identify additional modalities and agents that can be the basis for Actimab-A therapeutic combinations. 19 Antibody Warhead Enabling Technology Platform Our proprietary AWE technology platform is supported by intellectual property, know-how and trade secrets that cover the generation, development, methods of use and manufacture of ARCs and certain of their components. Our AWE technology patent portfolio presently includes 35 patent families comprised of 160 issued patents and pending patent applications, of which 9 are issued and 25 are pending in the United States, and 126 are issued or pending internationally. The effective life of the patents in our portfolio range from expirations between 2021 and 2040. Our technology enables the direct labeling, or conjugation and labeling, of a biomolecular targeting agent to a radionuclide warhead and its development and use as a therapeutic regimen for the treatment of diseases such as cancer. Our AWE intellectual property covers various methods of use for ARCs in multiple diseases, including indication, dose and scheduling, radionuclide warhead, and therapeutic combinations. We have particular expertise in the area of ARCs utilizing the alpha emitting isotope Ac-225 including clinical experience in treating approximately 150 patients with our alpha-emitter ARCs, “gold standard” linker technology and 5 issued patents in the United States and 49 patents internationally related to the manufacturing or Ac-225 in a cyclotron, which we believe has the potential to produce higher quantities of Ac-225 than currently utilized methods. We have enhanced our research and development capabilities around AWE by securing and staffing research facilities. Our research laboratories are focused on applying our AWE technology platform to the development of radiation conjugates and to execute on research collaborations. Our R&D efforts employ a multidisciplinary approach leveraging our team’s knowledge and experience in cancer cell biology, radiochemistry, radiation sciences, immunology and oncology drug development. We intend to focus on generating ARCs using our existing intellectual property, evaluating assets for in-licensing to complement our existing clinical pipeline and securing collaborations and partnerships with biopharmaceutical companies. By adding research and development capabilities to our clinical development and clinical supply chain capabilities, we seek to enable the rapid translation of radiotherapies. We have formed a wholly owned research subsidiary for the purposes of advancing certain of our R&D objectives. Our AWE technology platform is being utilized in our ongoing research collaboration with Astellas to arm select targeting agents owned by Astellas with alpha-emitting AC-225 for the development of theranostics for solid tumor indications, which combine the ability of radioisotopes to be used for both diagnostic and therapeutic purposes. Recent Developments Impact of COVID–19 Pandemic The global health crisis caused by the novel coronavirus COVID-19 pandemic and its resurgences has and may continue to negatively impact global economic activity, which, despite progress in vaccination efforts, remains uncertain and cannot be predicted with confidence. In addition, a new Delta variant of COVID-19, which appears to be the most transmissible variant to date, has begun to spread globally. The impact of the Delta variant cannot be predicted at this time, and could depend on numerous factors, including vaccination rates among the population, the effectiveness of COVID-19 vaccines against the Delta variant and the response by governmental bodies and regulators. Given the ongoing and dynamic nature of the circumstances, it is difficult to predict the impact of the COVID-19 pandemic on our business. Many countries around the world have continued to impose quarantines and restrictions on travel and mass gatherings to slow the spread of the virus. Accordingly, our ability to continue to operate our business may also be limited. Such events may result in a period of business, supply and drug product manufacturing disruption, and in reduced operations, any of which could materially affect our business, financial condition and results of operations. In response to COVID-19, we implemented remote working and thus far have not experienced a significant disruption or delay in our operations as it relates to the clinical development of our drug candidates. Such government-imposed precautionary measures may have been relaxed in certain countries or states, but there is no assurance that more strict measures will be put in place again due to a resurgence in COVID-19 cases, including those involving new variants of the coronavirus, which may be more contagious and deadly than prior strains. Therefore, the COVID-19 pandemic may continue to affect our operation, may further divert the attention and efforts of the medical community to coping with COVID-19 and disrupt the marketplace in which we operate and may have a material adverse effect on our operations. 20 A continuation or worsening of the levels of market disruption and volatility seen in the recent past could have an adverse effect on our ability to access capital, which could in the future negatively affect our liquidity. In addition, a recession or market correction resulting from the spread of COVID-19 could materially affect our business and the value of our common stock. Currently, the Phase 3 SIERRA trial for our lead program, Iomab-B, remains active at a majority of our clinical trial sites, with investigators providing feedback that recruitment and enrollment will remain active because of the acute nature of the disease, the high unmet needs of patients with relapsed or refractory AML, the potentially curative nature of BMT and the differentiated profile of Iomab-B. Certain sites that had not been actively enrolling due to COVID-19 at the initial outbreak of the pandemic resumed recruitment and enrollment in mid-2020, and we currently do not have any sites that are not recruiting and enrolling patients due to COVID-19. We also believe our earlier stage CD33 clinical trials will continue to recruit and enroll patients given the acute nature of relapsed or refractory AML. The continuation of the pandemic could adversely affect our planned clinical trial operations, including our ability to conduct the trials on the expected timelines and recruit and retain patients and principal investigators and site staff who, as healthcare providers, may have heightened exposure to COVID-19 if their geography is impacted by the pandemic. Further, the continuation and/or resurgence of the COVID-19 pandemic could result in delays in our clinical trials due to prioritization of hospital resources toward the pandemic, restrictions in travel, potential unwillingness of patients to enroll in trials at this time, or the inability of patients to comply with clinical trial protocols if quarantines or travel restrictions impede patient movement or interrupt healthcare services. In addition, we rely on independent clinical investigators, contract research organizations and other third-party service providers to assist us in managing, monitoring and otherwise carrying out our preclinical studies and clinical trials, and the pandemic may affect their ability to devote sufficient time and resources to our programs or to travel to sites to perform work for us. Additionally, COVID-19 may result in delays in receiving approvals from local and foreign regulatory authorities, delays in necessary interactions with IRB’s or Institutional Review Boards, local and foreign regulators, ethics committees and other important agencies and contractors due to limitations in employee resources or forced furlough of government employees. To date, COVID-19 has not had a financial impact on our company. We continue to monitor the impacts of COVID-19 on the global economy and on our business operations. Although we expect that vaccinations for COVID-19 will continue to improve conditions, the ultimate impact from COVID-19 on our business operations and financial results during 2021 will depend on, among other things, the ultimate severity and scope of the pandemic, including the new variants of the virus, the pace at which governmental and private travel restrictions and public concerns about public gatherings will ease, the rate at which historically large increases in unemployment rates will decrease, if at all, and whether, and the speed with which the economy recovers. We are not able to fully quantify the impact that these factors will have on our financial results during 2021 and beyond, but developments related to COVID-19 may materially affect us in 2021. 21 Results of Operations – Three Months Ended June 30, 2021 Compared to Three Months Ended June 30, 2020 The following table sets forth, for the periods indicated, data derived from our statements of operations: For the Three Months Ended June 30, (in thousands) 2021 2020 Revenue: Revenue $ - $ - Other revenue 266 - Total revenue 266 - Operating expenses: Research and development, net of reimbursements 3,631 3,508 General and administrative 1,710 1,154 Total operating expenses 5,341 4,662 Other income: Interest income – net 54 37 Total other income 54 37 Net loss $ (5,021 ) $ (4,625 ) Revenue We recorded no commercial revenue for the three months ended June 30, 2021 and June 30, 2020. Other revenue We determined that certain collaborations with a third-party are within the scope of ASC 606. The collaboration agreement is made up of multiple modules related to various research activities. While the third party has the option to terminate the agreement at the conclusion of any module, we identified a single performance obligation to provide research services within each module for which we receive monetary consideration. The consideration is recognized to revenue over each module and revenue recognized during the three months ended June 30, 2021 was $0.3 million. Research and development expense Research and development expenses increased $0.1 million to $3.6 million for the three months ended June 30, 2021 compared to $3.5 million for the three months ended June 30, 2020. The increase was primarily due to higher compensation expense resulting from the hiring of additional employees and expenses related to our new laboratory space, mostly offset by lower expenses on our CD45 program. General and administrative expense General and administrative expenses of $1.7 million for the three months ended June 30, 2021 increased $0.5 million compared to $1.2 million for the three months ended June 30, 2020, primarily attributable to higher professional fees. Other income Other income is comprised of net interest income in both reporting periods. The amount for the three months ended June 30, 2021 of $54 thousand increased from $37 thousand for the three months ended June 30, 2020, as a higher average balance of cash and cash equivalents offset a lower average interest rate. 22 Net loss Net loss of $5.0 million for the three months ended June 30, 2021 increased by $0.4 million from $4.6 million for the three months ended June 30, 2020, primarily due to higher research and development expenses and higher general and administrative expenses, partially offset by other revenue. Results of Operations – Six Months Ended June 30, 2021 Compared to Six Months Ended June 30, 2020 The following table sets forth, for the periods indicated, data derived from our statements of operations: For the Six Months Ended June 30, (in thousands) 2021 2020 Revenue: Revenue $ - $ - Other revenue 888 - Total revenue 888 - Operating expenses: Research and development, net of reimbursements 7,907 7,659 General and administrative 3,428 2,686 Total operating expenses 11,335 10,345 Other income: Interest income – net 106 50 Total other income 106 50 Net loss $ (10,341 ) $ (10,295 ) Revenue We recorded no commercial revenue for the six months ended June 30, 2021 and June 30, 2020. Other revenue We determined that certain collaborations with a third-party are within the scope of ASC 606. The collaboration agreement is made up of multiple modules related to various research activities. While the third party has the option to terminate the agreement at the conclusion of any module, we identified a single performance obligation to provide research services within each module for which we receive monetary consideration. We recognized revenue during the six months ended June 30, 2021 of $0.9 million from certain collaborations with a third-party. Research and development expense Research and development expenses increased $0.2 million to $7.9 million for the six months ended June 30, 2021 compared to $7.7 million for the six months ended June 30, 2020. The increase was primarily due to higher compensation expense resulting from the hiring of additional employees and expenses related to our new laboratory space, mostly offset by lower expenses on our CD45 program. General and administrative expense General and administrative expenses of $3.4 million for the six months ended June 30, 2021 increased $0.7 million compared to $2.7 million for the six months ended June 30, 2020, primarily attributable to higher professional fees. Other income Other income is comprised of net interest income in both reporting periods. The amount for the six months ended June 30, 2021 of $106 thousand increased from $50 thousand for the six months ended June 30, 2020, as a higher average balance of cash and cash equivalents offset a lower average interest rate. 23 Net loss Net loss of $10.3 million for the six months ended June 30, 2021 was unchanged from the prior-year comparison period, primarily due to higher research and development expenses and higher general and administrative expenses being offset by other revenue. Liquidity and Capital Resources We have financed our operations primarily through sales of shares of our common stock and warrants. The following tables sets forth selected cash flow information for the periods indicated: For the Six Months Ended June 30, (in thousands) 2021 2020 Cash used in operating activities $ (10,226 ) $ (10,365 ) Cash used in investing activities (65 ) - Cash provided by financing activities 28,644 54,577 Net change in cash, cash equivalents and restricted cash $ 18,353 $ 44,212 Net cash used in operating activities for the six months ended June 30, 2021 of $10.2 million decreased by $0.2 million from $10.4 million in the prior-year period, primarily due to the increase in other revenue. Net cash used in investing activities for the six months ended June 30, 2021 of $65 thousand was primarily due to the purchase of equipment for our new laboratory space. Net cash provided by financing activities for the six months ended June 30, 2021 was $28.6 million, primarily from the sale of shares of our common stock. In August 2020 we entered into the Capital on Demand™ Sales Agreement with JonesTrading Institutional Services LLC, or JonesTrading, pursuant to which we may sell, from time to time, through or to JonesTrading, up to an aggregate of $200 million of our common stock. Shares of common stock are offered pursuant to our shelf registration statement on Form S-3 filed with the United States Securities and Exchange Commission, or SEC, on August 7, 2020. As of December 31, 2020, we had sold 2.1 million shares of common stock, resulting in gross proceeds of $22.6 million and net proceeds of $21.7 million. For the six months ended June 30, 2021, we sold 3.5 million shares of common stock, resulting in gross proceeds of $29.6 million and net proceeds of $28.7 million. During the six months ended June 30, 2020, net cash provided by financing activities was $54.6 million, including sale of shares of our common stock and pre-funded warrants. On April 24, 2020, we issued and sold 4.3 million shares of common stock and pre-funded warrants to purchase 2.8 million shares of common stock. The price to the public for each share of common stock sold in the offering was $4.50, and the price to the public for each pre-funded warrant sold in the offering was $4.497. The pre-funded warrants were exercisable at an exercise price of $0.003 per share. Gross proceeds from this offering were $31.6 million, before deducting underwriting discounts and commissions and other offering expenses payable by us. Net proceeds from the offering were approximately $29.1 million. In June 2020, holders of 1.2 million pre-funded April 2020 warrants exercised their warrants and received 1.2 million shares of common stock. On June 19, 2020, we issued and sold 1.9 million shares of common stock and pre-funded warrants to purchase 0.7 million shares of common stock. The price to the public in this offering for each share of common stock was $9.75 and for each pre-funded warrant was $9.747. Each pre-funded warrant had an exercise price of $0.003 per share. Gross proceeds from this offering to us were $25.0 million, before deducting underwriting discounts and commissions and other offering expenses payable us. Net proceeds from this offering were approximately $23.0 million. Off-Balance Sheet Arrangements We do not have any off-balance sheet arrangements that have, or are reasonably likely to have a current or future effect on our financial condition, changes in financial condition, revenue or expenses, results of operations, liquidity, capital expenditures or capital resources that is material to investors. 24 Critical Accounting Policies and Use of Estimates Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements during the reporting periods. These items are monitored and analyzed by us for changes in facts and circumstances, and material changes in these estimates could occur in the future. We base our estimates on historical experience, known trends and events, 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. Changes in estimates are reflected in reported results for the period in which they become known. Actual results may differ materially from these estimates under different assumptions or conditions. Our significant accounting policies are described in detail in the notes to our consolidated financial statements appearing in our Annual Report filed on Form 10-K for the year ended December 31, 2020. Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants. A fair value hierarchy has been established for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. Revenue Recognition We recognize revenue in accordance with ASC 606. Under ASC 606, we recognize revenue when our customer obtains control of promised goods or services, in an amount that reflects the consideration that we expect to receive in exchange for those goods or services. To determine revenue recognition for arrangements within the scope of ASC 606, we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue as we satisfy a performance obligation. We only apply the five-step model to contracts when it is probable that we will collect the consideration to which we are entitled in exchange for the goods or services we transfer to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, we assess whether the promised goods or services promised within each contract are distinct and, therefore, represent a separate performance obligation. Goods and services that are determined not to be distinct are combined with other promised goods and services until a distinct bundle is identified. In determining whether goods or services are distinct, we evaluate certain criteria, including whether (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (capable of being distinct) and (ii) the good or service is separately identifiable from other goods or services in the contract (distinct in the context of the contract). ASC 606 requires us to allocate the arrangement consideration on a relative standalone selling price basis for each performance obligation after determining the transaction price of the contract and identifying the performance obligations to which that amount should be allocated. The relative standalone selling price is defined in the new revenue standard as the price at which an entity would sell a promised good or service separately to a customer. We then recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation as each performance obligation is satisfied, either at a point in time or over time, and if over time, recognition is based on the use of an output or input method. Collaborative Arrangements We follow the accounting guidance for collaboration agreements, which requires that certain transactions between us and collaborators be recorded in our consolidated statements of operations and comprehensive loss on either a gross basis or net basis, depending on the characteristics of the collaborative relationship, and requires enhanced disclosure of collaborative relationships. We evaluate our collaboration agreements for proper classification in our consolidated statements of operations and comprehensive loss based on the nature of the underlying activity. When we conclude that we have a customer relationship with one of our collaborators, we follow the guidance of ASC 606 . 25 Research and Development Costs Research and development costs are expensed as incurred. These costs include the costs of manufacturing drug product, the costs of clinical trials, costs of employees and associated overhead, and depreciation and amortization costs related to facilities and equipment. Research and development reimbursements are recorded by us as a reduction of research and development costs. Share-Based Payments We estimate the fair value of each stock option award at the grant date by using the Black-Scholes option pricing model. The fair value determined represents the cost for the award and is recognized over the vesting period during which an employee is required to provide service in exchange for the award. We account for forfeitures of stock options as they occur. Accounting Standards Recently Adopted In August 2020, FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity , which, among other things, provides guidance on how to account for contracts on an entity’s own equity. This ASU simplifies the accounting for certain financial instruments with characteristics of liabilities and equity. Specifically, the ASU eliminated the need for us to assess whether a contract on our own equity (1) permits settlement in unregistered shares, (2) whether counterparty rights rank higher than shareholder’s rights, and (3) whether collateral is required. In addition, the ASU requires incremental disclosure related to contracts on our own equity and clarifies the treatment of certain financial instruments accounted for under this ASU on earnings per share. This ASU may be applied on a full retrospective of modified retrospective basis. This ASU is effective January 1, 2022 and interim periods presented, although early adoption of this ASU was permitted effective January 1, 2021. We early adopted this standard effective January 1, 2021 and the standard did not have a significant impact on our financial statements. Accounting Standards Recently Issued In May 2021, FASB issued ASU 2021-04, Earnings Per Share (topic 260), Debt — Modifications and Extinguishments (Subtopic 470-50), Compensation – Stock Compensation (Topic 718) and Derivatives and Hedging – Contracts in an Entity’s Own Equity (Subtopic 815-40) – Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options , which provides guidance of a modification or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange as (1) an adjustment to equity and, if so, the related earnings per share (EPS) effects, if any, or (2) an expense and, if so, the manner and pattern of recognition. The amendments in this ASU are effective January 1, 2022, including interim periods. Early adoption is permitted. We will apply the amendments prospectively to modifications or exchanges occurring on or after January 1, 2022. We will evaluate the impact of ASU 2017-09 on any future changes to the terms and conditions of its warrants. Subsequent Event Since June 30, 2021, we have sold 0.2 million shares of common stock under its Capital on Demand™ Sales Agreement with JonesTrading, resulting in net proceeds of $1.8 million.