10-K

apre-20201231x10k.htm

10-K

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the year ended December 31, 2020

☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period fromto

Commission File Number 001-39069

Aprea Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

Boston, Massachusetts (Zip code)

(Address of principal executive offices)

(617) 463-9385

(Registrant's telephone number, including area code)

Not Applicable

(Former name, former address and former fiscal year, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Name of exchange

Title of each class Trading Symbol on which registered:

Common stock, par value $0.001 per share APRE NASDAQ Global Select Market

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐No ⌧

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No ⌧

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ⌧No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ⌧ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ☐ Accelerated filer ☐

Non-accelerated filer ⌧ Smaller reporting company ⌧

Emerging growth company ⌧

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ⌧

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ◻ No ⌧

The aggregate market value of the voting stock held by non-affiliates of the registrant as of June 30, 2020 was approximately $263.8 million.

There were 21,186,827 shares of the registrant’s common stock, $0.001 par value, outstanding as of March 16, 2021.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive proxy statement for its 2021 Annual Meeting of Stockholders (the “Proxy Statement”), to be filed within 120 days of the registrant’s fiscal year ended December 31, 2020, are incorporated by reference in Part III of this Annual Report on Form 10-K. Except with respect to information specifically incorporated by reference in this Annual Report on Form 10-K, the Proxy Statement is not deemed to be filed as part of this Annual Report on Form 10-K.

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Aprea Therapeutics, Inc.

Annual Report on Form 10-K

For the Year Ended December 31, 2020

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Page

PART I

Item 1. Business 5

Item 1A. Risk Factors 54

Item 1B. Unresolved Staff Comments 115

Item 2. Properties 115

Item 3. Legal Proceedings 115

Item 4. Mine Safety Disclosures 115

PART II

Item 6. [Reserved] 117

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 132

Item 8. Financial Statements and Supplementary Data 133

Item 9A. Controls and Procedures 134

Item 9B. Other Information 134

PART III

Item 10. Directors, Executive Officers and Corporate Governance 135

Item 11. Executive Compensation 135

Item 14. Principal Accounting Fees and Services 135

PART IV

Item 15. Exhibits, Financial Statement Schedules 136

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K includes statements that are, or may be deemed, “forward-looking statements.” In some cases, these forward-looking statements can be identified by the use of forward-looking terminology, including the terms “believes,” “estimates,” “anticipates,” “expects,” “plans,” “intends,” “may,” “designed,” “would,” “could,” “might,” “will,” “should,” “approximately” or, in each case, their negative or other variations thereon or comparable terminology, although not all forward-looking statements contain these words. They appear in a number of places throughout this Annual Report on Form 10-K and include statements regarding our current intentions, beliefs, projections, outlook, analyses or current expectations concerning, among other things, our ongoing and planned development, prospects for commercialization, and market uptake of APR-246, or eprenetapopt, and our other potential product candidates, the strength and breadth of our intellectual property, our ongoing and planned clinical trials, the timing of and our ability to make regulatory filings and obtain and maintain regulatory approvals for our product candidates, the legal and regulatory landscape impacting our business, the degree of clinical utility of our products, particularly in specific patient populations, expectations regarding clinical trial data, our development and validation of manufacturing capabilities, our results of operations, financial condition, liquidity, prospects, growth and strategies, the length of time that we will be able to continue to fund our operating expenses and capital expenditures, our expected financing needs and sources of financing, the industry in which we operate and the trends that may affect the industry or us.

By their nature, forward-looking statements involve risks and uncertainties because they relate to future events, competitive dynamics, and healthcare, regulatory and scientific developments and depend on economic circumstances that may or may not occur in the future or may occur on longer or shorter timelines than anticipated. We caution you that forward-looking statements are not guarantees, or predictive, of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Annual Report on Form 10-K.

Some of the factors that we believe could cause actual results to differ from those anticipated or predicted include:

● our expectations regarding the timing of data from our clinical trials;

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● developments relating to our competitors and our industry;

● our expectations regarding our future costs of goods;

● the impact of government laws and regulations;

● our financial performance; and

Any forward-looking statements that we make in this Annual Report on Form 10-K speak only as of the date of such statement, and we undertake no obligation to update such statements to reflect events or circumstances after the date of this Annual Report on Form 10-K. You should also read carefully the factors described in the “Risk Factors” included in Part I, Item 1A of this Annual Report to better understand significant risks and uncertainties inherent in our business and underlying any forward-looking statements. As a result of these factors, we cannot assure you that the forward-looking statements in this Annual Report on Form 10-K will prove to be accurate. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified timeframe, or at all.

This Annual Report on Form 10-K includes statistical and other industry and market data that we obtained from industry publications and research, surveys and studies conducted by third parties. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. While we believe these industry publications and third-party research, surveys and studies are reliable, we have not independently verified such data.

We qualify all of our forward-looking statements by these cautionary statements. In addition, with respect to all of our forward-looking statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

This Form 10-K may include trademarks, tradenames, and service marks that are the property of other organizations. Solely for convenience, our trademarks and tradenames referred to in this Form 10-K may appear without the ® and TM symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights, or the right of the applicable licensor to these trademarks and tradenames.

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PART I

Item 1. Business

Overview

We are a clinical-stage biopharmaceutical company focused on developing and commercializing novel cancer therapeutics that reactivate mutant p53 tumor suppressor protein. p53 is the protein expressed from the TP53 gene, the most commonly mutated gene in cancer. We believe that mutant p53 is an attractive therapeutic target due to the high incidence of p53 mutations across a range of cancer types and its involvement in key cellular activities such as apoptosis. Cancer patients with mutant p53 face a significantly inferior prognosis even when treated with the current standard of care, and a large unmet need for these patients remains. Our lead product candidate, APR-246, or eprenetapopt, is a small molecule p53 reactivator that is in clinical development for hematologic malignancies, including myelodysplastic syndromes, or MDS, and acute myeloid leukemia, or AML. Eprenetapopt has received Breakthrough Therapy, Orphan Drug and Fast Track designations from the FDA for MDS, Fast Track designation from the FDA for AML, and Orphan Drug designation from the European Commission for MDS, AML and ovarian cancer, and we believe eprenetapopt will be a first-in-class therapy if approved by applicable regulators.

We are conducting multiple trials in hematologic malignancy indications, including a Phase 3 trial of eprenetapopt with azacitidine for frontline treatment of TP53 mutant MDS and which is supported by recently published data from two Phase 1b/2 investigator-initiated trials in the U.S. and France; a Phase 2 trial of eprenetapopt with azacitidine for the post-allogeneic hematopoietic cell transplantation (allo-HCT) maintenance treatment of TP53 mutant MDS/AML; a Phase 1/2 trial of eprenetapopt with venetoclax ± azacitidine for the treatment of frontline and relapsed/refractory AML; and a Phase 1 clinical trial for the treatment of TP53 mutant chronic lymphoid leukemia (CLL) with either eprenetapopt with venetoclax and rituximab, or eprenetapopt with ibrutinib. In addition, we are also testing eprenetapopt with anti-PD-1 therapy in solid tumor patients through a Phase 1/2 clinical trial in advanced gastric, bladder and non-small cell lung cancers. We are also developing an orally-dosed next-generation small molecule p53 reactivator, APR-548, as a potential therapeutic for multiple hematologic and solid tumor indications. We have received authorization from the FDA to initiate Phase 1 clinical trials with APR-548 and anticipate the first patients to be enrolled early in the second quarter of 2021. We have assembled a management team with extensive experience in the discovery, development and commercialization of novel oncology drugs to support our mission of developing p53-reactivating therapies for cancer patients.

Our lead programs are summarized below. We currently retain global development and commercialization rights to all of our product candidates.

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(2) Investigator-initiated trial: Sallman et al, J Clin Oncol, 2021

(3) Investigator-initiated trial: Cluzeau et al, J Clin Oncol, 2021

(4) Azacitidine

(5) Venetoclax

(6) Venetoclax + rituximab

We believe that targeting p53 and thereby reactivating key intrinsic cellular functions has the potential to significantly impact patients’ lives and treatment strategies for a wide variety of cancers. p53 is a tumor suppressor protein that in its normal state functions to sense DNA damage and induce cell cycle arrest, DNA damage repair, senescence and cellular apoptosis. Mutant p53 is an attractive target because it is widely mutated across hematologic and solid tumors and is associated with an aggressive clinical and molecular phenotype. In preclinical studies and clinical trials, mutations in p53 and the apoptotic pathway have been shown to play a key role in cancer genesis, proliferation and resistance to currently marketed therapeutic agents. Many approved and clinical stage oncology drugs are more effective with a functional p53 pathway. Our approach is to restore normal function to p53, thereby re-enabling a cell’s ability to undergo apoptosis. Accordingly, we believe that by targeting p53, our drug candidates may enhance the ability of other anti-cancer therapies to induce cancer cell death. In addition, we believe that our approach may counteract resistance mechanisms that characterize many of the most aggressive cancers. Although we have observed single agent activity in preclinical testing of eprenetapopt, our current clinical program is focused on combination therapy based on the strong additive or synergistic effects we have observed in combination with multiple conventional chemotherapeutic drugs, DNA hypomethylating agents, or HMAs, inhibitors of anti-apoptotic proteins and immuno-oncology checkpoint blockade agents.

Our lead product candidate, eprenetapopt, is a small molecule that has demonstrated reactivation of mutant p53 in clinical trials. Promising clinical data support the application of eprenetapopt across a variety of hematologic malignancies and other oncologic indications. Eprenetapopt is a pro-drug that is administered intravenously and forms the active moiety, 2-methylene-quinuclidin-3-one, or MQ, under physiological conditions. Eprenetapopt has been shown to induce apoptosis in cancer cells with mutant p53 in Phase 1/2 trials. We believe the mechanism of action and current adverse event profile of eprenetapopt may provide the basis for its combination with both conventional and novel therapies, such as targeted therapies, chemotherapy, radiotherapy and immuno-therapy. Eprenetapopt has received

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Breakthrough Therapy, Orphan Drug and Fast Track designations from the FDA for MDS, Fast Track designation from the FDA for AML, and Orphan Drug designation from the European Commission for MDS, AML and ovarian cancer.

We are conducting, supporting and planning multiple clinical trials of eprenetapopt:

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Our second product candidate, APR-548, is a next-generation p53 reactivator with the potential for oral administration. APR-548 is a unique analog of eprenetapopt and therefore a pro-drug of MQ. APR-548 exhibits high oral bioavailability in preclinical testing and is being developed in an oral dosage form. We have planned a Phase 1 dose-escalation clinical trial evaluating safety, tolerability and preliminary efficacy of APR-548 with azacitidine in frontline and relapsed/refractory MDS patients. We anticipate the first patient to be enrolled in the second quarter of 2021.

We have assembled an outstanding team, which includes world-class scientific and clinical oncology leaders, to execute on our mission to create novel p53-reactivating therapies to help patients suffering with cancer. Together with our board of directors, our scientific founders and members of our management team have significant experience in drug discovery and development and finance. Collectively, we believe our team’s strong capabilities position us to build a leading biotech company focused on developing novel cancer therapies to address the significant unmet medical need of patients with p53 mutant malignancies, for whom there are limited effective therapeutic options.

Our strategy

Our mission is to be the leading player in the development and commercialization of p53-targeted cancer therapies. The key elements of our strategy are to:

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Our approach

Background on p53, a key tumor suppressor protein

TP53 is the most widely mutated gene in human cancers. Since its discovery in 1979, p53 has been extensively studied by researchers and the pharmaceutical industry due to its central role in preventing the initiation and progression of liquid and solid tumors. p53 has long been referred to as “the guardian of the genome” because it is the body’s first line of cellular defense against cancers. Among its multiple biologic functions, p53 regulates a variety of tumor suppressive responses including cell cycle arrest, DNA repair, apoptosis, and senescence.

p53 is activated when DNA damage is detected and when oxidative or other cellular stresses exceed thresholds for normal cellular function. The result of p53 activation is to facilitate the repair of the cell or trigger killing of the damaged cell, through a process known as apoptosis, before it can become cancerous and replicate. Given that the mutational status of p53 in a tumor has a strong impact on sensitivity to commonly used anti-cancer drugs and radiotherapy, p53 is important both as clinical marker and as a novel therapeutic target. Importantly, mutations in p53 not only diminish tumor suppression function but also often lead to the acquisition of new pro-tumor functions.

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To date, more than 25,000 unique TP53 mutations have been reported and thus a key challenge in the development of p53-targeted therapies is the vast number of mutations that compromise tumor suppression activity. Incidence of TP53 mutations increases after treatment with chemotherapy or radiation. The most common of these are missense mutations, involving the site-specific exchange of one amino acid for another, and account for 75% of all p53 mutations; however, even the six most frequently mutated “hotspot” missense mutations in p53 collectively represent only ~30% of all missense mutations. Therefore, we believe that a therapeutic agent that targets a small subset of TP53 mutations would be of limited benefit. To circumvent these challenges, previous drug development efforts have primarily focused on gene therapy delivery of wild type p53 or drugs that disrupt interaction with proteins that control p53 activation and abundance. We believe the more effective approach is our direct conformational reactivation of mutant p53 and restoration of wild-type structure and activity, independent of the type of mutation.

Our approach to re-activating p53

One of the most attractive features of apoptosis activation as a cancer therapy is its potential to induce tumor regression rather than to simply stop tumor growth. However, pro-apoptotic agents that cannot discriminate between malignant and normal cells carry a significant risk of side effects. This is an important issue with traditional cancer treatments: radiotherapy and chemotherapy induce apoptosis only as a secondary effect of the cellular damage they induce. These treatments affect most proliferating cells without distinction between malignant or normal cells. Our product candidates, in contrast, are designed to reactivate mutant, non-functional p53 to restore normal apoptotic functions in cancer cells without triggering apoptosis in normal cells, thereby selectively enhancing the effects of other chemotherapy drugs in malignant cancer cells with mutant p53.

Eprenetapopt and MQ, have been extensively studied. MQ-modified mutant p53 protein has been shown to induce significant levels of apoptosis, indicating that covalent binding of MQ activates mutant p53 and induces a p53-dependent apoptotic response. Experiments by our founders looking directly at the conformational state of p53 protein in cells have confirmed that binding of MQ stabilizes mutant p53 in the functional, wild type conformation. Structural biology studies performed by our collaborators have produced the first-ever crystal structures of several single-site missense mutant p53 forms bound to DNA. These structures confirm both the sites of MQ binding to mutant p53 and the stabilization of mutant p53 by MQ in the wild type conformation. Reactivation of mutant p53 via stabilization of the properly folded wild type conformation is the key step in our product candidates’ mechanism of action. The following diagram illustrates this mechanism.

In in vitro and in vivo experiments, our lead p53 re-activating product candidate, eprenetapopt, via MQ, impaired tumor cells’ capacity to respond to oxidative stress. In parallel to binding mutant p53, and as published by Liu et al, Nat Commun, 2017, 14844, MQ depletes intracellular glutathione, or GSH, and induces reactive oxygen species, or ROS. Furthermore, as published in Peng et al, Cell Death Dis, 2013, e881, MQ has been shown to inhibit the reductase activities of the redox enzyme thioredoxin reductase, or TrxR1, and convert the enzyme to a dedicated oxidase, thereby increasing levels of ROS. Additional results reported in Haffo et al, Sci. Reports, 2018, 12671, have demonstrated MQ inhibition of thioredoxin, or Trx1, and glutaredoxin, or Grx1, which further augment oxidative stress, and ribonucleotide reductase, or RNR, which decreases the cell’s ability to repair damaged DNA. These effects on the cellular redox system, illustrated in the following diagram, may contribute to the anticancer activity of eprenetapopt as well as the selectivity for effects on cancer cells versus healthy normal cells. Malignant cells have higher levels of ROS than healthy

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cells and are thus more susceptible to increased stress that can trigger pro-apoptotic responses. MQ-induced oxidative stress is therefore an important secondary feature of the mechanism of action.

Cell fate is a function of the extent and severity of cellular stresses, such as oxidative stress and DNA damage. A network of proteins translates information about cellular stress into biochemical signals and relays this information back to p53, the center of the network. p53 integrates these biochemical signals and becomes activated to initiate cell cycle arrest. When cellular stress and damage are sufficiently high, such as with chemotherapy, p53 initiates apoptosis. MQ restores the ability of a cell to respond to oxidative stress and DNA damage via reactivation of mutant p53 and induces heightened oxidative stress signals to which reactivated p53 can respond. The overlap of these features of the mechanism of action may in turn provide more efficient induction of apoptosis.

Market opportunity for p53 re-activating product candidates

We believe there is a significant market opportunity for therapies targeting mutant p53 because these mutations occur in more than half of all tumors and confer an inferior prognosis relative to patients with wild type p53. Preclinical anti-tumor activity has been observed with eprenetapopt in a wide variety of hematological and solid tumor models and cell lines as reviewed and referenced in Perdrix et al, Cancer 2017, 9, 172. Given the importance of p53 mutations as disease-driver mutations, the sensitivity of hematopoietic cells to oxidative stress and continued unmet medical need, we have initially focused our clinical development in hematological malignancies with TP53 mutations.

Myelodysplastic syndromes—disease background and opportunity

MDS is a collection of bone marrow disorders in which malignant hematopoietic cells prevent production of healthy, mature blood cells. Low blood cell counts, called cytopenias, are a hallmark feature of MDS and are a principal cause of morbidity and mortality from infection and bleeding. MDS can develop de novo or may arise secondary to chemotherapy or radiation treatment for a different, prior malignancy or following an antecedent hematological disorder. Treatment-related MDS is associated with increased complex chromosomal abnormalities and carries a worse prognosis than de novo MDS. As of 2019, there are an estimated 200,000 MDS patients worldwide, with 68,000 of these in the United States and 69,000 MDS patients across the five major markets of the European Union and Japan. Globally, MDS prevalence is expected to increase 2-3% annually in mature markets and 3-4% annually in emerging markets as populations age. MDS predominantly affects older adults, with approximately 75% of patients aged 60 years or older at diagnosis. Around 30% of patients diagnosed with MDS will progress to AML, with the rate being higher for patients with more advanced disease.

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MDS patients are segmented into different risk groups according to the number of cytopenias, bone marrow blast percentage, and cytogenetic abnormalities. The presence of three or more coincident structural genetic abnormalities is classified as a complex karyotype, which correlates with poor prognosis, low response to intensive chemotherapy, high rate of relapse and inferior survival. Mutations in TP53 occur in approximately 20% of patients with de novo MDS and in more than 30% of patients with therapy-related MDS who develop disease secondary to chemotherapy or radiation treatment for other cancers. Sequencing of a panel of commonly mutated genes, including TP53, is standard practice in the diagnosis of MDS.

Historically, treatment response rates in TP53 mutant MDS patients have been poor regardless of therapy. There are no established curative pharmacologic therapies for MDS.Allo-HCT is currently the only recognized therapy believed to increase the likelihood of long-term survival for TP53 mutant MDS patients; however, many patients are not candidates for allo-HCT due to lack of sufficient clinical response to initial therapy, advanced age, comorbidities or lack of a suitable donor. Unfortunately, even for those TP53 mutant MDS patients who receive allo-HCT, the post-transplantation prognosis is poor: TP53 mutations are associated with a 4-fold increased risk of death and 1-year relapse-free survival of only 30% following transplantation.

Given the poor prognosis for patients with TP53 mutant MDS there is a significant need for more effective therapies in this population, particularly if such treatments have a favorable safety profile, a mechanism of action that targets mutant p53 directly, and may be used in combination with existing or future treatment options.

Acute myeloid leukemia—disease background and opportunity

AML is the most common form of adult leukemia, with the highest incidence in patients aged 60 years and older. AML is characterized by proliferation of abnormal immature white blood cells which, like MDS, impairs production of normal blood cells. AML can develop de novo or may arise secondary to progression of other hematologic disorders or from chemotherapy or radiation treatment for a different, prior malignancy; secondary AML carries a worse prognosis than de novo AML. As of 2019, there are an estimated 213,000 AML patients worldwide, with 37,000 of these in the United States and 41,000 across the five major European Union markets and Japan. Globally, AML prevalence is expected to increase approximately 1-2% annually in mature markets and 2-3% in emerging markets.

AML patients are segmented into different risk groups according to cytogenetic abnormalities. The presence of three or more coincident structural genetic abnormalities is classified as a complex karyotype, which correlates with adverse prognosis, low response to intensive chemotherapy, high rate of relapse and inferior survival. Mutations in TP53 occur in approximately 20% of patients with newly diagnosed AML, more than 30% of patients with therapy-related AML and approximately 70-80% of patients with complex karyotype. Sequencing of a panel of commonly mutated genes, including TP53, is standard practice in the diagnosis of AML.

Historically, treatment response rates in TP53 mutant AML patients have been poor regardless of therapy. Similar to MDS, allo-HCT is currently the only recognized therapy believed to increase the likelihood of long-term survival for TP53 mutant AML patients; however, many patients are not candidates for allo-HCT due to lack of sufficient clinical response to therapy, advanced age, comorbidities or lack of a suitable donor. Unfortunately, even for those TP53 mutant AML patients who receive allo-HCT, the post-transplantation prognosis is poor: TP53 mutations areassociated with a 4-fold increased risk of death and 1-year relapse-free survival of only 30% following transplantation.

Given the poor prognosis for patients with TP53 mutant AML there is a significant need for more effective therapies in this population, particularly if such treatments have a favorable safety profile, a mechanism of action that targets mutant p53 directly, and may be used in combination with existing or future treatment options.

Chronic lymphocytic leukemia—disease background and opportunity

Chronic lymphocytic leukemia (CLL) is one of the most common types of B-cell non-Hodgkin lymphoma (NHL), characterized by a progressive accumulation of functionally incompetent monoclonal lymphocytes. As of 2017, the estimated prevalence of CLL was approximately 205,000 in the United States and approximately 180,000 across the five major European Union markets and Japan.

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CLL is associated with a highly heterogeneous disease course that is partly explained by the diverse genetic aberrations identified in CLL patients. Deletions in chromosome 17p [del(17p)] and TP53 mutations belong to the strongest prognostic and predictive markers guiding treatment decisions in CLL. Del(17p) results in loss of one copy of the TP53 gene and is often accompanied by mutation in the remaining TP53 gene copy. TP53 mutation occurs in approximately 25% of CLL and up to approximately 85% of del(17p) CLL. TP53 mutant CLL and del(17p) CLL are associated with markedly decreased survival and impaired response to therapy and many patients will experience disease relapse and progression.

Mantle cell lymphoma—disease background and opportunity

Mantle cell lymphoma (MCL) is an aggressive form of NHL that accounts for approximately 6% of all NHL cases. It is characterized by accumulation of malignant B lymphocytes in the outer edge, or mantle zone, of lymph node follicles. As of 2017, the estimated prevalence of MCL was approximately 16,000 in the United States and approximately 16,000 across the five major European Union markets and Japan.

There are two major variants of MCL, known as classical and leukemic non-nodal (L-NN). Classical nodal MCL, accounting for 80-90% of cases, affects the lymph nodes and extra nodal sites. In contrast, L-NN MCL involves the bone marrow, peripheral blood and spleen. Of these, classical MCL is the more aggressive disease. Like CLL, del(17p) and TP53 mutation are the most frequent findings in MCL. TP53 mutations occur in approximately 20% of cases and are associated with poor prognosis and resistance to first-line and later-line regimens. There is no standard of care therapy for relapsed/refractory MCL but ibrutinib is a preferred treatment option.

Gastric cancer—disease background and opportunity

Gastric cancer includes cancers of the stomach and gastroesophageal junction. It is the fifth most common cancer worldwide and the third leading cause of cancer-related death. In 2020, the estimated prevalence of gastric cancer is approximately 45,000 in the United States, approximately 90,000 in the five major European Union markets and approximately 350,000 in Japan.

Gastric cancer is typically detected at an advanced stage and disease progression after first-line chemotherapy is common. TP53 mutation occurs in approximately 35%-55% of gastric cancers, and up to 90% in high-risk populations. Therapeutic options are limited for patients whose disease progresses after two or more lines of treatment. The humanized anti-PD-1 monoclonal antibody, pembrolizumab, is approved by the US FDA for the treatment of patients with recurrent gastric cancer after two or more prior lines of therapy, including fluoropyrimidine- and platinum-containing chemotherapy and, if appropriate, HER2/new-targeted therapy, and whose tumors express PD-L1.

Bladder cancer—disease background and opportunity

Bladder cancer is a common cancer worldwide and is more common in men than in women. In 2018, the estimated prevalence of bladder cancer was approximately 275,000 in the United States, approximately 370,000 in the five major European Union markets and approximately 120,000 in Japan.

TP53 mutation occurs in approximately 50% of bladder cancer cases. First-line treatment with platinum agents is standard of care; however, few therapeutic options exist for second-line treatment of patients with platinum-refractory bladder cancer. The humanized anti-PD-1 monoclonal antibody, pembrolizumab, is approved by the US FDA for the treatment of locally advanced or metastatic, PD-L1 positive bladder cancer who are not eligible for cisplatin-containing chemotherapy; in patients who are not eligible for any platinum-containing chemotherapy, regardless of PD-L1 status; and in patients who have disease progression during or following platinum-containing chemotherapy.

Non-small cell lung cancer—disease background and opportunity

Lung cancer is the most common cancer worldwide and the leading cause of cancer-related death. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 84% of all lung cancer diagnoses. In 2019, the

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estimated prevalence of NSCLC was approximately 312,000 in the United States, 194,000 in the five major European Union markets and approximately 312,000 in Japan.

TP53 mutation occurs in up to 80% of NSCLC cases. The humanized anti-PD-1 monoclonal antibody, pembrolizumab, is approved by the US FDA as a single agent in NSCLC for the first-line treatment of PD-L1 positive metastatic disease or in patients who have progressive disease during or following platinum-containing chemotherapy. Treatment options are limited for patients whose disease is R/R to prior anti-PD-1 therapy.

Our lead product candidate, eprenetapopt

Our lead product candidate, eprenetapopt, is a small molecule that has demonstrated reactivation of mutant p53 in both clinical trials and preclinical studies. Promising clinical and preclinical data support the application of eprenetapopt across a variety of hematologic malignancies and other oncologic indications. Based on its mechanism of action of p53 reactivation and the complementary increase in oxidative stress, as well as its established synergy with anti-cancer agents as evidenced in preclinical studies, eprenetapopt treatment may be effective in a broad range of clinical settings.

Clinical trials of eprenetapopt in hematologic malignancies

We are currently evaluating eprenetapopt with azacitidine for the treatment of TP53 mutant MDS and/or AML patients, including frontline therapy, relapsed/refractory, or R/R, therapy and post-allo-HCT maintenance therapy; and relapsed/refractory TP53 mutant NHL patients.

The Phase 3 MDS Trial

We are conducting a Phase 3 trial of eprenetapopt with azacitidine in TP53 mutant MDS patients. The trial was fully enrolled with 154 patients randomized 1:1 to either the azacitidine control arm or to the eprenetapopt + azacitidine experimental arm. The primary endpoint of the trial was CR rate. In December 2020 we announced that the Phase 3 trial failed to meet the predefined CR primary endpoint at the primary data cut. In the intention to treat population of 154 patients the CR rate in the eprenetapopt with azacitidine arm was 33.3% (95% CI: 23.1 – 44.9%) compared to 22.4% (95% CI: 13.6 – 33.4%) in the azacitidine alone arm (P = 0.13). Analysis of the primary endpoint at this data cut demonstrated a 53% higher number of patients achieving a CR in the experimental arm receiving eprenetapopt with azacitidine versus the control arm receiving azacitidine alone but did not reach statistical significance.

While analysis of certain secondary endpoints (ORR and duration of responses) appears to favor the experimental arm, the differences are not statistically significant. Additional patients in the study who have not achieved a CR remain on study treatment and the data will be analyzed at future pre-specified timepoints as set forth in the statistical analysis plan.

The combination of eprenetapopt with azacitidine appeared well-tolerated, with an adverse event profile that was similar to that of our other Phase 2 trials. As of March 2, 2021, the most common (≥20%) adverse events in patients in the Phase 3 with MDS who received eprenetapopt with azacitidine were nausea (64%), constipation (63%), vomiting (53%), anemia (47%), neutrophil count decreased (43%), febrile neutropenia (42%), fatigue (41%), white blood cell count decreased (39%), platelet count decreased (33%), headache (33%), dizziness (32%), pyrexia (30%), diarrhea (29%), peripheral edema (25%), cough (24%), thrombocytopenia (24%), hypokalemia (24%), injection site reaction (21%), neutropenia (21%), and decreased appetite (21%). Fatal adverse events occurred in 17% of patients who received eprenetapopt and azacitidine; of these, 3 were reported by an investigator as possibly related to eprenetapopt and azacitidine and 1 as possibly related to eprenetapopt only. The most common (≥5%) serious adverse events in patients who received eprenetapopt with azacitidine were febrile neutropenia (33%), pneumonia (12%), pyrexia (11%), sepsis (9%), muscular weakness (7%) and respiratory failure (5%).

We are continuing our analysis of the data from this Phase 3 clinical trial and subsequent analyses of the trial data, including secondary endpoints, will be conducted as the duration of patient follow-up increases. We intend to provide a further update in the second quarter of 2021 and expect to present additional data from the trial at a future scientific conference.

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The U.S. Phase 1b/2 MDS/AML Trial

We supported an investigator-initiated Phase 1b/2 single-arm, open-label, multi-center trial in the United States of eprenetapopt with azacitidine in HMA-naïve patients with TP53 mutant myeloid neoplasms including MDS and AML. The primary endpoint of the trial was CR rate. Results of the trial were published with open access by Sallman and colleagues in the Journal of Clinical Oncology in January 2021.

The trial included a Phase 1b dose-escalation part that enrolled 12 patients and a Phase 2 part that enrolled 43 patients. Most patients were higher-risk MDS (65%) or AML (20%), with complex karyotype (84%). High risk patients with complex karyotypes and TP53 mutation have been reported to have the poorest prognosis of all MDS and AML patients.

In the intention-to-treat population reported by Sallman et al, the ORR was 71% (95% CI: 57 – 82%) and 44% of patients achieved a CR. In the 40 MDS patients the ORR was 73% (95% CI: 56 – 85%) with 50% achieving a CR. In the 11 AML patients the ORR was 64% (95% CI: 31 – 89%) with 36% achieving a CR. In MDS patients the median duration of response in was 8.4 months (95% CI: 6.5 – 13.2 months) and the median duration of CR was 7.3 months (95% CI: 5.8 months – not estimable). In AML patients the median duration of response was 7.5 months (95% CI: 4.2 months – not estimable) and the median duration of CR was 7.0 months (95% CI: 3.3 months – not estimable). Twenty-one MDS/AML patients discontinued treatment for allo-HCT, as transplant is viewed as a potentially curative option for patients with TP53 mutant MDS and AML. At a median follow-up time of 10.5 months, the median OS in the intention-to-treat population was 10.8 months (95% CI: 8.1 − 13.4 months), which was similar between the MDS (10.4 months; 95% CI: 7.6 – 13.3 months) and AML (10.8 months; 95% CI: 5.1 – 16.5 months) disease cohorts.

The most common (≥20%) adverse events reported by Sallman et al were nausea (64%), vomiting (45%), fatigue (44%), constipation (42%), edema (38%), dizziness (36%), diarrhea (33%), febrile neutropenia (33%), peripheral sensory neuropathy (31%), leukopenia (31%), dyspnea (29%), headache (29%), lung infection (29%), neutropenia (29%), thrombocytopenia (29%), cough (27%), pruritus (25%), anorexia (24%), ataxia (24%), fever (22%), alanine aminotransferase increased (20%), mucositis oral (20%) and tremor (20%). As of March 2, 2021, fatal adverse events occurred in 13% of patients; none were reported by an investigator as possibly related to eprenetapopt or to azacitidine. The most common (≥5%) serious adverse events were febrile neutropenia (33%), pneumonia (25%), sepsis (11%), pyrexia (7%), dehydration (5%), embolism (5%), muscle weakness (5%), respiratory failure (5%) and vomiting (5%).

The French Phase 1b/2 MDS/AML Trial

We are supporting an ongoing investigator-initiated single-arm, open-label Phase 1b/2 trial in France of eprenetapopt with azacitidine in HMA-naïve patients with TP53 mutant MDS and AML. The primary endpoint of the trial was CR rate. Results of the trial were published with open access by Cluzeau and colleagues in the Journal of Clinical Oncology in February 2021.

The trial enrolled 52 patients. Most patients were higher-risk MDS (58%) or AML (35%) with complex karyotype (87%). High risk patients with complex karyotype and TP53 mutation have been reported to have the poorest prognosis of all MDS and AML patients.

In the intention-to-treat population reported by Cluzeau et al, the ORR was 52% with 37% of patients achieving CR. In the 34 MDS patients the ORR was 62% with 47% achieving a CR. In the 18 AML patients the ORR was 33% with 17% achieving a CR. In MDS patients the median duration of response was 10.4 months (95% CI: 2.8 – 16.8 months) and the median duration of CR was 11.4 months (95% CI: 6.5 - 16.8 months). In AML patients the median duration of response was 12.7 months (95% CI: 6.0 – 17.3 months) and the median duration of CR was 14.0 months (95% CI: 11.3 – 17.3 months). At a median follow-up time of 9.7 months, the median OS in the intention-to-treat population was 12.1 months (95% CI: 8.1 – 13.4 months). Median OS was 12.1 months for MDS patients and 10.4 months for AML patients and this difference was not significant (P = 0.92).

The most common (≥20%) adverse events reported by Cluzeau et al were febrile neutropenia (37%) and ataxia (25%). As of March 2, 2021, fatal adverse events occurred in 23% of patients; of these, 4 were reported by an investigator as possibly related to azacitidine and none were reported by an investigator as related to eprenetapopt. The most common

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(≥5%) serious adverse advents were febrile neutropenia (27%), device related infection (12%), pneumonia (8%), sepsis (8%), corona virus infection (6%) and lung disorder (6%).

The Phase 2 MDS/AML Post-transplant Trial

There is a significant unmet medical need for more effective therapies for patients with TP53 mutant AML and MDS following allo-HCT given that the one-year post-transplant relapse-free survival, or RFS, rate is only 30%. In the second quarter of 2019, we opened enrollment to our Phase 2 MDS/AML Post-Transplant Trial to evaluate the adverse event profile and the clinical benefit of eprenetapopt with azacitidine in TP53 mutant MDS and AML patients who have received allo-HCT. The primary endpoint of the trial is the rate of RFS at 1 year. Enrollment is complete with 33 patients included in the trial. We anticipate initial availability of data on the primary endpoint of 1-year RFS in the second quarter of 2021.

As of March 2, 2021, fatal adverse events occurred in one patient and was not reported as related to study treatment. The most common (≥5%) serious adverse events were pyrexia (12%), confusional state (6%), dyspnea (6%) and febrile neutropenia (6%).

The Phase 1/2 AML Trial

We are conducting a Phase 1/2 clinical trial evaluating the adverse event profile and efficacy of treatment with eprenetapopt and venetoclax with or without azacitidine, in frontline and R/R TP53 mutant AML. In preclinical studies, we have observed strong synergy when eprenetapopt and venetoclax are combined in TP53 mutant AML cell lines and believe that this combination may provide meaningful improvements in durable responses for TP53 mutant AML patients with previously untreated and relapsed/refractory AML.

In the AML trial, frontline and R/R TP53 mutant AML patients who have received prior HMA therapy receive treatment with eprenetapopt and venetoclax, and frontline patients who are HMA-naïve receive treatment with eprenetapopt, venetoclax and azacitidine. The primary endpoint is the safety and tolerability of the treatment regimen. The lead-in portion of the trial evaluated the tolerability of eprenetapopt with venetoclax, with or without azacitidine, and no dose-limiting toxicities were observed in 12 patients receiving either regimen. Based on these results, we have expanded the trial to treat 33 additional frontline TP53 mutant AML patients with the combination of eprenetapopt, venetoclax and azacitidine. We also may activate a separate cohort in the trial to evaluate the combination of eprenetapopt with azacitidine in approximately 30 frontline TP53 mutant AML patients.

In addition to the 6 patients enrolled in the lead-in phase, we have enrolled 22 patients into the expansion arm for the eprenetapopt + venetoclax + azacitidine triplet therapy, of whom 13 have undergone repeat bone marrow biopsy and are evaluable for response. As of February 25, 2021, the combined CR + CRi rate in these 19 patients is 63%, including 31% CR. We anticipate completion of enrollment in the triplet regimen expansion cohort during the second quarter of 2021 and availability of preliminary response rate data from the cohort also in the second quarter of 2021. As warranted by adverse event and efficacy data, we may further expand enrollment into this triplet regimen in the Phase 2 part to potentially enable a path to registration in frontline AML.

As of March 2, 2021, fatal adverse events occurred in 6 patients, none of which were reported by an investigator as related to study treatment. The most common (≥5%) serious adverse events were febrile neutropenia (41%), sepsis (15%), pneumonia (12%), muscular weakness (9%), subdural hematoma (9%), blood bilirubin increased (6%), diverticulitis (6%), nausea (6%) and pyrexia (6%).

The Phase 1 NHL Trial

We are currently enrolling a Phase 1 clinical trial evaluating the adverse event profile and preliminary efficacy of eprenetapopt with venetoclax and rituximab, and eprenetapopt with ibrutinib in R/R TP53 mutant CLL. The first patient was enrolled on the first quarter of 2021. We intend to expand the number of patients in individual arms of the trial in a Phase 2 part, as warranted by adverse event and efficacy data. We are also planning to evaluate the combination of eprenetapopt with venetoclax in relapsed/refractory mantle cell lymphoma.

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Clinical development in solid tumors

Phase 1/2 Clinical Trial of Eprenetapopt in R/R Gastric, Bladder and Non-Small Cell Lung Cancers

We are currently enrolling a Phase 1/2 clinical trial evaluating the adverse event profile and preliminary efficacy of eprenetapopt with anti-PD-1 therapy in advanced solid tumors including R/R gastric cancer, bladder cancer and non-small cell lung cancer. In preclinical studies reported by Ghosh and colleagues from Memorial Sloan Kettering Cancer Center at the 2019 AACR annual meeting, we have observed synergy in mouse cancer models when eprenetapopt was combined with immuno-oncology agents, including anti-PD-1. The trial is enrolling both TP53 mutant and TP53 wild-type patients.

Enrollment of the safety lead-in cohort was completed and no dose-limiting toxicities were reported for the 6 patients enrolled. Enrollment of the gastric, bladder and non-small cell lung cancer expansion cohorts is ongoing and we have currently enrolled 8 patients across these expansion arms. Preliminary tolerability and efficacy data is anticipated in the second half of 2021.

As of March 2, 2021, fatal adverse events occurred in one patient and was not reported by investigators as related to study treatment. No serious adverse events, regardless of causality, have been reported in more than one patient.

Phase 1b/2 Clinical Trial of Eprenetapopt in Platinum-Sensitive Ovarian Cancer, or PiSARRO

As part of the early development strategy, eprenetapopt was evaluated in clinical trials in ovarian cancer and this decision was based on the anticipated market size and high prevalence of TP53 mutation of greater than 95% in high-grade serous ovarian cancer, or HGSOC. In March 2014, a Phase 1b trial was initiated as a part of a combined Phase 1b/2 protocol in platinum-sensitive HGSOC to evaluate eprenetapopt with carboplatin and pegylated liposomal doxorubicin, or PLD. All patients had previously been treated with platinum-based antineoplastic agents and all had accumulation of p53, as assessed by immunohistochemistry, or IHC, as a surrogate marker of mutant p53. Archival samples were available for 29 patients, of which 27 had DNA of sufficient quality for sequencing and all 27 were confirmed to be TP53 mutant.

The Phase 1b part of the trial was conducted as a dose-escalation in 35 platinum-sensitive and partially platinum-sensitive patients. The primary trial objectives of the Phase 1b portion were to assess the adverse event profile of eprenetapopt with carboplatin and PLD, to determine a recommended Phase 2 dose level, or RP2D, and to evaluate the pharmacokinetics of eprenetapopt with carboplatin and PLD. Tumor response was a secondary objective.

The most frequently reported eprenetapopt -related AEs were nausea, dizziness, and fatigue, of which most were low-grade. A limited number of eprenetapopt -related grade 3+ AEs were reported, including neutropenia (37%), vomiting (14%), thrombocytopenia (9%), dizziness (6%), anemia (6%), fatigue (3%), headache (3%) and decreased appetite (3%). The most common (>5%) serious adverse events, regardless of causality, were device related infection (17%), vomiting (17%), febrile neutropenia (9%), infection (6%), small intestinal obstruction (6%) and thrombocytopenia (6%).

Although efficacy was not a Phase 1b trial objective, tumor response was evaluated. A 67% ORR was observed in 27 patients who were evaluable for radiological response according to RECIST 1.1, including 11% with complete response and 56% with partial response. In addition, an 84% ORR was observed in 25 patients who were evaluable for CA-125 response according to Gynecologic Cancer InterGroup, or GCIG, criteria. All patients who were evaluable by RECIST 1.1 achieved a best response of stable disease or better, where stable disease indicates lack of objective response but without disease progression. The median time between prior platinum therapy and disease progression prior to enrollment in the trial, known as platinum free interval, or PFI, was 9.4 months, and 40% of patients had received more than one prior line of platinum-based chemotherapy. Two-thirds of patients enrolled in the trial were partially platinum-sensitive, with PFI 6-12 months. The remaining one-third of patients were platinum-sensitive, with PFI greater than 12 months. The median progression-free survival, or PFS, was 10.2 months across all patients and was 10 months and 11.4 months in partially platinum-sensitive and platinum sensitive patients, respectively. The median OS was

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24.3 months. This was the first clinical trial of eprenetapopt with cytotoxic chemotherapy and we believe that the data demonstrated that the agent can be combined with carboplatin and PLD at standard doses.

Data supporting the carboplatin and PLD doublet as a treatment option in platinum-sensitive HGSOC were generated in the CALYPSO trial, a phase 3 clinical trial sponsored by an international consortium of 10 cancer research organizations. The CALYPSO trial enrolled 976 patients, randomized to receive either carboplatin and PLD (48%) or carboplatin and paclitaxel (52%). All patients had received a maximum of two prior lines of chemotherapy; in the carboplatin and PLD arm, 88% had received one prior line and 12% had received two prior lines. The median interval since last chemotherapy, or therapy-free interval, was 15.2 months in the carboplatin and PLD arm, of whom 35% had a therapy-free interval of 6-12 months and 65% had a therapy-free interval in excess of 12 months. The most frequently reported AEs in the carboplatin and PLD arm included neutropenia (80%), nausea (78%), fatigue (78%), anemia (66%), constipation (55%) and vomiting (49%). The most common grade 3+ AEs included neutropenia (35%), thrombocytopenia (16%) and anemia (8%). In the carboplatin and PLD arm PFS was reported as 11.3 months and OS as 30.7 months. Median PFS in the carboplatin and PLD arm was greater than the 9.4 months PFS in the carboplatin and paclitaxel arm (hazard ratio: 0.821, 95% CI, 0.72 – 0.94, P = 0.005). Historically, Phase 3 clinical trials in ovarian cancer, including the CALYPSO trial, have enrolled approximately 500 – 1000 patients to demonstrate statistical significance in PFS.

In the third quarter of 2016, enrollment commenced in the Phase 2 portion of the PiSARRO trial and enrollment was concluded at 211 patients in April 2018. The Phase 2 part was an open-label, randomized, controlled multi-center trial to assess whether patients with platinum-sensitive recurrent HGSOC would benefit from treatment with eprenetapopt in combination with carboplatin/PLD chemotherapy regimen. All patients were required to have accumulation of p53 as assessed by immunohistochemistry. The primary endpoint for the Phase 2 part was PFS, defined as the time from registration to the time of disease progression or relapse or death, or the date of last tumor assessment without any such event.

Patients were randomized in a 1:1 ratio to receive either eprenetapopt with carboplatin and PLD (Arm A) or carboplatin and PLD only (Arm B), with treatment to be repeated every 28 days for up to six cycles. Of 105 patients enrolled in Arm A, 99 received eprenetapopt with carboplatin and PLD and 96 patients were efficacy-evaluable. Of 106 patients enrolled in Arm B, 101 patients received carboplatin and PLD and 97 patients were efficacy-evaluable.

In Arm A, 10 patients (9.5%) achieved CR compared to 3 patients (2.8%) in Arm B; overall response rate (CR+PR) was 49.5% in Arm A (n=52) and 50.0% in Arm B (n=53). Median duration of response by RECIST v1.1 in Arm A was 231 days (95% CI: 198 - 256 days) and 213 days (95% CI: 184 - 265 days) in Arm B (HR 0.92, 95% CI: 0.58-1.45). In the intention-to-treat population, median PFS duration based on RECIST v1.1 adjusting for three stratification factors including platinum-free interval (>6 to12 vs. >12 to<24 months), BRCA status (known positive vs. other) and prior lines of platinum treatment (1 vs. 2) was 283 days (95% CI: 240 days, 314 days) in Arm A patients (n=105) that received APR 246 in combination with carboplatin/PLD therapy, as compared to 295 days (95% CI: 259 days, 335 days) in Arm B patients (n=106) that received carboplatin/PLD therapy alone (HR 1.32, 95% CI: 0.95-1.83, P = 0.10). In Arm A, the median OS duration was 600 days (95% CI: 543 days – not estimable) compared to 620 days in Arm B (95% CI: 504 - 741 days) (HR 0.91, 95% CI: 0.59-1.38, P = 0.64).

Eprenetapopt in combination with carboplatin and PLD was generally well tolerated and adverse events were generally transient and reversible. The most common (≥20%) adverse events in Arm A were nausea (68%), neutropenia (57%), fatigue (48%), vomiting (42%), dizziness (42%), constipation (36%), anemia (31%), thrombocytopenia (23%) and mucosal inflammation (20%). No patients in Arm A died while on-study or within 30 days after last dose. The most common serious adverse events were related to gastrointestinal disorders (13%), and infections and infestations (8%). In Arm A there were no serious adverse events that occurred in ≥5% of patients.

Recruitment to the study was concluded in April 2018 and the final results indicate that a statistically significant difference in the PFS, OS, ORR, and DOR was not observed across the two arms in the limited number of patients enrolled to the study. We believe that the combination of eprenetapopt with carboplatin and PLD was tolerable and that a larger study would be required to determine a difference in the efficacy endpoints of the study, including the rate of CR, which was observed in the study to be substantially higher in the experimental arm. We believe this study further

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supports the clinical development of eprenetapopt as a potential therapy in cancers where TP53 mutations are indicated to be contributing to the prognosis and disease progression.

Phase 2 Clinical Trial of Eprenetapopt in Platinum-Resistant Ovarian Cancer, or PiSARRO-R

In July 2017 we initiated an open-label, multicenter Phase 2 trial, PiSARRO-R, to evaluate the adverse event profile and preliminary efficacy of varying infusion regimens of eprenetapopt with systemic PLD chemotherapy in platinum-resistant HGSOC. The trial enrolled 36 patients and all patients were required to have recurrent disease with PFI between 4 weeks and 6 months, and accumulation of p53 as assessed by immunohistochemistry. A significant majority (69%) of patients had received 2 or more prior lines of chemotherapy. Patients received either a 4500 mg/d fixed dose of eprenetapopt as a 6-hour intravenous infusion (n=28, 78%), or the same or lower fixed dose over 3 or 4 hours (n=8, 22%) for four consecutive days, followed by 40 mg/m2 PLD on Day 4.

Across all patients enrolled in the trial the most common (≥20%) adverse events were nausea (64%), vomiting (53%), constipation (39%), abdominal pain (36%), fatigue (36%), decreased appetite (33%), asthenia (28%), mucosal inflammation (25%), dizziness (25%), anemia (25%), diarrhea (22%), Nine patients died while on-study and 2 patients died within 30 days of last dose; all deaths were due to disease progression. The most common serious adverse events were related to gastrointestinal disorders (25%) and were not increased with shorter duration of infusion. There were no serious adverse events that occurred in ≥5% of patients enrolled in the PiSARRO-R trial. We believe the available adverse event data from the trial demonstrates that reduced duration infusion regimens with eprenetapopt are feasible.

Our second product candidate, APR-548

We are developing a next-generation small molecule mutant p53 reactivator, APR-548, a novel pro-drug of MQ that has the potential to be administered in an oral dosage form. Our initial development of APR-548 is in TP53 mutant hematological malignancies and we intend to explore additional malignancies for future development. We believe that an oral p53-reactivating drug will improve patient convenience and compliance, if approved, including for patients receiving prolonged therapy in the maintenance setting.

In preclinical testing we have observed potency with APR-548 that was superior to that of eprenetapopt in a Saos-2 osteosarcoma cell line expressing an Arg273His mutant p53 and the MIA-PaCa-2 pancreatic cancer cell line harboring an Arg248Trp mutant p53. The half maximal inhibitory concentration, or IC50, in the Saos-2 cell line was calculated to be 5.6 μM ± 1.0 μM (n=3) for APR-548 and 9.5 μM ± 1.2 μM (n=37) for eprenetapopt, representing an approximately 40% reduction in IC50 with APR-548. In the MIA-PaCa-2 cell line, the IC50 for APR-548 was calculated to be 6.0 μM (n=1) versus 19 μM (n=1) for eprenetapopt, representing a nearly 70% reduction in IC50 with APR-548.

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Reduced in vitro IC50(1) of APR-548 in a p53 mutant saos-2 cell line

(1) Half-maximal inhibitory concentration

In studies to evaluate pharmacodynamic effects, the mutant p53 MDS/AML cell line SKM-1 was cultured in the presence of APR-548 and analyzed by flow cytometry for markers of apoptosis (cleaved caspase-3) and cell proliferation (Ki67). Cells treated with APR-548 demonstrated a dose-dependent increase in cleaved caspase-3 and a dose-dependent reduction of Ki67.

Levels of (a) cleaved caspase-3 are increased while (b) Ki67 is reduced in SKM-1 cells treated with APR-548

a) b)

In xenograft studies in which mice were implanted with a mutant TP53 breast adenocarcinoma cell line, MDA-MB-231-luc, we tested the in vivo efficacy of APR-548 when administered as a single agent by twice-daily oral (PO) gavage. In these studies, mice received APR-548 for three cycles where each cycle consisted of 5 consecutive days of dosing followed by 2 days without dosing. Tumor growth inhibition was assessed by measurement of tumor weight at

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post-mortem examination on day 33 post-inoculation. In mice receiving APR-548 via oral administration, we observed reductions in tumor weight relative to untreated control mice. Results from these studies are summarized in the following graph.

Reduction in tumor growth by twice-daily oral administration of APR-548 in mice implanted with mutant TP53 breast adenocarcinoma cell line

In in vivo studies in mouse and dog, we observed high oral bioavailability of APR-548 when dosed as either an aqueous solution or as a solid in capsules. Observed oral bioavailability ranged from 75% to greater than 99%, and with no significant effect of feeding on absorption. Results from these studies are summarized in the following table.

APR-548 dose

Species No. of animals (mg/kg) Route Bioavailability (%)

Mouse (C57Bl/6N) 18 20 PO (solution) 80

Mouse (CD-1) 9 50 PO (solid in capsule) 97

Mouse (CD-1) 9 50 PO (solution) 99

Dog, fed 3 10 PO (solid in capsule) 84

Dog, fasted 3 10 PO (solid in capsule) 83

Dog, fed 3 10 PO (solution) 80

Dog, fasted 3 10 PO (solution) 75

We received authorization to proceed under an IND for APR-548 on October 2, 2020 and have planned a Phase 1 clinical trial of APR-548 with azacitidine in frontline and relapsed/refractory TP53 mutant MDS patients. We anticipate enrollment of the first patient early in the second quarter of 2021.

We have developed a scalable, high-purity process for the manufacture of APR-548 and have completed development of a prototype tablet formulation that provides for rapid dissolution and is well-suited for automated production.

Manufacturing

We currently contract with third parties for the manufacture of our product candidates for certain preclinical trials and clinical trial materials, including raw materials and consumables necessary for their manufacture, consistent with applicable cGMP requirements. We routinely assess both capacity and the current clinical supply chain associated with

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the production of eprenetapopt and are not currently aware of any disruption to our ability to provide supply for our on-going clinical trials. We will continue to monitor and assess the potential impact of the coronavirus pandemic on our clinical trial supply chain. We intend to continue to contract for these materials in the future, including commercial manufacture if our product candidates receive marketing approval. We do not own or operate cGMP manufacturing facilities, nor do we currently plan to build our own cGMP manufacturing capabilities for the production of our product candidates for clinical or commercial use. Although we rely upon contract manufacturers for the manufacture of our product candidates for IND-enabling trials and clinical trials, we have personnel with extensive manufacturing experience who oversee our contract manufacturers. In the future, we may also rely upon collaboration partners, in addition to contract manufacturers, for the manufacture of our product candidates or any products for which we obtain marketing approval.

The active pharmaceutical ingredient, or API, for eprenetapopt is currently manufactured by a single contract manufacturer. Although we may do so in the future, we do not currently have arrangements in place for redundant supply of the API for eprenetapopt. We contract with a different manufacturer for formulation of drug product, sterile fill of vials, labeling and packaging, and the storage and distribution of eprenetapopt to clinical sites. We believe that these third parties have sufficient capacity to meet our current demand and, in the event they fail to meet our demand, we believe that adequate alternative sources for the supply of materials for eprenetapopt exist. We intend to identify and qualify additional manufacturers to provide the API and other services for eprenetapopt prior to seeking marketing approval for eprenetapopt.

We believe that, because eprenetapopt is a small molecule, it can be manufactured through reliable and reproducible synthetic processes from readily available raw materials and then purified and packaged for clinical use. We believe that the chemistry process is amenable to scale-up and requires only customary equipment in the manufacturing process.

We have a manufacturing and supply agreement and quality agreement with Syngene International Private Limited for the manufacture of API. We have a service agreement with Cobra Biopharma for the clinical manufacture, labeling and packaging of formulated drug product. We have a manufacturing and supply agreements and quality agreement with Siegfried Hameln GmbH for the manufacture, supply, labeling and packaging of formulated drug product.

Manufacturing clinical products is subject to extensive regulations that impose various procedural and documentation requirements, which govern record keeping, manufacturing processes and controls, personnel, quality control and quality assurance. Our contract manufacturers are required to comply with current good manufacturing practice regulations, which are regulatory requirements for the production of pharmaceuticals that will be used in humans.

Competition

The pharmaceutical and biotechnology industries generally, and the cancer drug sector specifically, are highly competitive and characterized by rapidly advancing technologies, evolving understanding of disease etiology and a strong emphasis on proprietary drugs. While we believe that our product candidates, development capabilities, experience and scientific knowledge provide us with competitive advantages, we face significant potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

There are a large number of companies developing or marketing treatments for cancer, including the indications for which we may develop product candidates. Many of the companies that we compete against or may compete against in the future have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved drugs than we do. Small or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or that may be necessary for, our programs.

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Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize drugs that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any drugs that we may develop. Our competitors also may obtain FDA or other regulatory approval for their drugs more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market. The key competitive factors affecting the success of all of our product candidates, if approved, are likely to be their efficacy, safety, convenience and price, in guiding the use of related therapeutics, the level of generic competition and the availability of reimbursement from government and other third-party payors.

The most common methods of treating patients with cancer are surgery, radiation and therapy with drugs or biologics. There are a variety of available drug therapies marketed for cancer. In many cases, these drugs are administered in combination to enhance efficacy. Some of the currently-approved drug therapies are branded and subject to patent protection and may be established as standard of care for the treatment of indications for which we may choose to seek regulatory approvals. Many of these approved drugs are well-established therapies and are widely accepted by physicians, patients and third-party payors, and even if our drug candidates were to be approved, there can be no assurance that our drugs would displace existing treatments.

In addition to currently marketed therapies, there are also a number of drugs in late-stage clinical development to treat cancer, including for the treatment of the indications for which we are developing product candidates. These clinical-stage drug candidates may provide efficacy, safety, convenience and other benefits that are not provided by currently-marketed therapies. As a result, they may provide significant competition for any of our product candidates for which we obtain regulatory approval.

We are developing our lead product candidate, eprenetapopt and APR-548, to reactivate p53 for the treatment of various cancers. We are aware of other product candidates that are in clinical development as potential treatments of various cancers through the reactivation of p53. Although there is a subset of drugs that directly target the p53 pathway, there are many cancer drugs that claim to affect the p53 pathway by upstream or complementary pathways. We are aware of molecules in development that also are being explored for p53 upregulation / activation in various stages of clinical development being tested by Actavalon, Inc., CDG Therapeutics, Inc., Cotinga Pharmaceuticals, Inc., Innovation Pharmaceuticals, Inc., MedVax Technologies, Inc., PMV Pharmaceuticals, Inc., and Senhwa Biosciences, Inc., among others. We are also aware of selective small molecule inhibitors that are designed to target the p53-MDM2 interaction in various stages of clinical development being tested by F-Hoffman La Roche Ltd and Hoffman La Roche Inc., or collectively Roche, Amgen Inc., Novartis AG, Kartos Therapeutics, Inc., Aileron Therapeutics and Daiichi Sankyo Co., Ltd. (out licensed worldwide rights to Rain Therapeutics, Inc.), including testing MDM2 inhibitors in combination with a variety of other anti-cancer agents. Finally, we are aware of several small molecules that are designed to inhibit the activity of Bcl-2 and the related protein Mcl-1 and relieve inhibition of the apoptotic cascade. Abbvie Inc.’s venetoclax has been approved in AML and chronic lymphocytic leukemia; companies with Bcl-2 or Mcl-1 inhibitors in various stages of preclinical or clinical development include Amgen Inc., Servier SAS, AstraZeneca Plc, Pfizer Inc. and Zentalis Pharmaceuticals, Inc., among others.

If eprenetapopt were approved for the indications for which we currently have ongoing clinical trials, it would compete with currently-marketed drugs and would likely compete with other drugs that are currently in clinical development, each as discussed below.

MDS / AML

The front-line treatments for patients with higher-risk MDS in the United States are combination chemotherapy or HMAs such as Dacogen (decitabine) or Vidaza (azacitidine). We are aware of several ongoing clinical trials aimed at expanding the use of approved chemotherapy and immunomodulatory agents in higher-risk MDS, as well as several new clinical programs testing novel technologies in this area, including product candidates from Abbvie Inc., argenx, Astex Pharmaceuticals, Inc., Bristol-Myers Squibb Company, CTI BioPharma Corp., Cyclacel Pharmaceuticals, Inc., Eisai Co., Ltd., Gilead Sciences, Inc., ALX Oncology Holdings, Inc., Shattuck Labs, Inc., Trillium Therapeutics, Inc., Karyopharm Therapeutics Inc., Onconova Therapeutics, Inc., and Takeda Pharmaceutical Company Limited.

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CLL

Due to poor responses to traditional chemotherapy agents, CLL patients in the United States with high-risk 17p deletion and/or p53 mutation are typically treated with BCR inhibitors such as ibrutinib, Bcl-2 inhibitors such as venetoclax, and anti-CD20 antibodies such as rituximab. We are aware of several ongoing clinical trials aimed at expanding the use of approved targeted chemotherapy and immunomodulatory agents in high-risk CLL, as well as several new clinical programs testing novel technologies in this area, including product candidates from AbbVie Inc., AstraZeneca Plc, Bayer AG, BeiGene Ltd, Bristol-Myers Squibb Co, F. Hoffman-La Roche Ltd, Gilead Sciences Inc., Incyte Corp, Johnson & Johnson, Juno Therapeutics Inc., Karyopharm Therapeutics Inc., Merck & Co Inc., Novartis AG, Ono Pharmaceutical Co Ltd., Takeda Pharmaceutical Co Ltd, and TG Therapeutics Inc.

MCL

The preferred treatment option for R/R MCL patients in the United States is a BTK inhibitor such as ibrutinib or acalabrutinib. We are aware of several ongoing clinical trials aimed at expanding the use of approved chemotherapy and immunomodulatory agents in MCL, as well as several new clinical programs testing novel technologies in this area, including product candidates from AbbVie Inc., Amgen Inc, AstraZeneca Plc, Bayer AG, BeiGene Ltd, Bristol-Myers Squibb Co, F. Hoffman-La Roche Ltd, Gilead Sciences Inc., Incyte Corp, Johnson & Johnson, Juno Therapeutics Inc., Karyopharm Therapeutics Inc., Merck & Co Inc., and TG Therapeutics Inc.

Gastric cancer

The preferred treatment options for R/R gastric cancer in the United States are dependent on regimens received in first-line therapy as well as patient performance status. Second- and later-line treatments include taxanes, fluoropyrimidines, ramucirumab, irinotecan and pembrolizumab. We are aware of several ongoing clinical trials aimed at expanding the use of approved chemotherapy and immunomodulatory agents in R/R gastric cancer, as well as several new clinical programs testing novel technologies in this area, including product candidates from Altor Bioscience LLC, BeiGene Ltd, Bristol-Myers Squibb Co., Incyte Corp, Merck & Co Inc., Pfizer Inc., and TG Therapeutics Inc.

Bladder cancer

The preferred treatment option for R/R bladder cancer in the United States is the anti-PD-1 antibody, pembrolizumab, Alternative regimens include other anti-PD-1 antibodies, antibodies targeting PD-L1 or CD274, FGFR inhibitors, taxanes, and topoisomerase inhibitors. We are aware of several ongoing clinical trials aimed at expanding the use of approved chemotherapy and immunomodulatory agents in R/R bladder cancer, as well as several new clinical programs testing novel technologies in this area, including product candidates from Altor Bioscience LLC, AstraZeneca Plc, Bristol-Myers Squibb Co., F. Hoffman-La Roche Ltd, and Merck & Co Inc.

NSCLC

The preferred treatment options for R/R NSCLC depend on tumor subtype and the presence of tumor biomarkers such as genetic mutations or PD-L1 expression. Therapeutic agents include pembrolizumab, nivolumab, ipilimumab, platinum agents, taxanes, and topoisomerase inhibitors. We are aware of several ongoing clinical trials aimed at expanding the use of approved chemotherapy and immunomodulatory agents in R/R NSCLC, as well as several new clinical programs testing novel technologies in this area, including product candidates from AbbVie Inc., AstraZeneca Plc., Bayer AG, Bristol-Myers Squibb Co., F. Hoffman-La Roche Ltd, Gilead Sciences Inc., Karyopharm Therapeutics Inc., Milennium Pharmaceuticals Inc., and Pfizer Inc.

Intellectual property

We strive to protect the proprietary technologies that we believe are important to our business, including seeking and maintaining patent protection intended to cover the methods-of-use, formulations, dosing, manufacturing processes, and crystalline solid form of one or more of our product candidates, including eprenetapopt, and composition of matter of our other product candidates, related technology, and other inventions that are important to our business.

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Our success will depend significantly on our ability to obtain and maintain patent and other proprietary protection for commercially important technology, inventions, and know-how related to our business, defend and enforce our patents, preserve the confidentiality of our trade secrets, and operate without infringing the valid and enforceable patents and other proprietary rights of third parties.

A third party may hold intellectual property, including patent rights, which are important or necessary to the development or commercialization of our product candidates. If it becomes necessary for us to use patented or proprietary technology of third parties to develop or commercialize our product candidates, we may need to seek a license from such third parties. Our business could be harmed, possibly materially, if we are unable to obtain such a license on terms that are commercially reasonable, or at all.

We may seek to expand our intellectual property estate by filing patent applications directed to dosage forms, methods of treatment, diagnostics, and additional compounds and their derivatives. Specifically, we have sought and will continue to seek patent protection in the United States and internationally for novel compositions of matter covering the compounds of our product candidates other than eprenetapopt and a crystal form of eprenetapopt, the chemistries and processes for manufacturing these compounds, and the use of these compounds in a variety of therapies. The chemical structure of eprenetapopt is in the public domain. Accordingly, we do not own or license any composition of matter patents claiming the compound of eprenetapopt and will not in the future own or license any composition of matter patents claiming the chemical structure of eprenetapopt as described in the public domain.

The patent positions of biopharmaceutical companies like us are generally uncertain and involve complex legal, scientific and factual questions. In addition, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted after issuance. Consequently, we do not know whether any of our product candidates will be protectable or remain protected by enforceable patents. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Any patents that we hold may be challenged, circumvented or invalidated by third parties.

Because patent applications in the United States and certain other jurisdictions are maintained in secrecy for 18 months, and since publication of discoveries in the scientific or patent literature often lags actual discoveries, we cannot be certain of the priority of inventions covered by pending patent applications. Moreover, we may have to participate in interference proceedings declared by the United States Patent and Trademark Office, or USPTO, to determine priority of invention or in post-grant challenge proceedings at the USPTO or at a foreign patent office, such as inter partes review and post grant review proceedings at the USPTO and opposition proceedings at the European Patent Office, that challenge priority of invention or other features of patentability. Such proceedings could result in substantial cost, even if the eventual outcome is favorable to us. For more information regarding the risks related to our intellectual property, see “Risk Factors—Risks Related to Our Intellectual Property.”

Patent portfolio

As of December 31, 2020, our exclusively owned patent portfolio includes five U.S. issued patents, seven pending U.S. provisional patent applications, one pending U.S. nonprovisional patent application, four pending international (PCT) patent applications, approximately 116 foreign issued patents and approximately 8 pending foreign patent applications. The claims of these owned patents and patent applications are directed toward various aspects of our product candidates and research programs. Specifically, the claims of these patents and patent applications include compositions of matter for product candidates other than eprenetapopt and a crystal form of eprenetapopt, methods-of-use, drug product formulations, dosing, diagnostics and methods of manufacture.

Eprenetapopt Method of Use Family

As of December 31, 2020, we exclusively own a patent family directed to methods-of-uses of eprenetapopt. This patent family includes one U.S. issued patent and approximately 43 patents granted in Europe (validated in Austria, Belgium, Bulgaria, Switzerland-Lichtenstein, Cyprus, Czech Republic, Germany, Denmark, Estonia, Spain, Finland, France, United Kingdom, Greece, Hungary, Ireland, Iceland, Italy, Lithuania, Luxembourg, Monaco, Netherlands, Poland,

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Portugal, Romania, Sweden, Slovenia, Slovakia and Turkey), Australia, Canada, India, and Japan. The issued patents in this family are expected to expire in 2025, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Eprenetapopt Formulation Family

As of December 31, 2020, we exclusively own a patent family directed to formulations of eprenetapopt. This patent family includes one U.S. issued patent and approximately 42 issued patents in Europe (validated in Austria, Belgium, Switzerland-Lichtenstein, Cyprus, Czech Republic, Germany, Denmark, Estonia, Spain, Finland, France, United Kingdom, Greece, Hungary, Ireland, Italy, Lithuania, Luxembourg, Latvia, Monaco, Malta, Netherlands, Norway, Poland, Portugal, Sweden, Slovakia, San Marino and Turkey), Australia, Brazil, Canada, China, India, Israel, Japan, South Korea, Philippines, Russia, Singapore, and South Africa. This patent family also includes approximately 2 pending patent applications in China, Hong Kong, and Thailand. The granted patents and pending applications, if issued, in this family are expected to expire in 2031, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Eprenetapopt Dosing Family

As of December 31, 2020, we exclusively own a pending PCT patent application directed to dosing regimens involving eprenetapopt, which was filed in 2019. This PCT patent application is not eligible to become an issued patent until, among other things, we file a national phase patent application in a PCT contracting state before the expiration of the PCT patent application in that state. If we do not timely file any national phase patent applications, we may lose our priority date with respect to our PCT patent application and any patent protection on the inventions disclosed in our PCT patent application. Any future U.S. patents that may issue from this PCT patent application (assuming the necessary national phase patent applications in U.S. are timely filed and all other applicable requirements are satisfied) are expected to expire in 2039, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Eprenetapopt Process and Solid Form Family

As of December 31, 2020, we exclusively own a pending U.S. nonprovisional patent application directed to improved processes for large scale preparation of eprenetapopt and to a crystalline solid form comprising eprenetapopt, which was filed in 2020. Any future U.S. patents that may issue from this nonprovisional patent application (assuming all applicable requirements are satisfied) are expected to expire in 2040, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Combination Therapy of Eprenetapopt With A Bcl-2 Inhibitor

As of December 31, 2020, we exclusively own a pending PCT application directed to a method of treatment using a combination therapy of eprenetapopt with a Bcl-2 inhibitor which was filed in 2020. This PCT patent application is not eligible to become an issued patent until, among other things, we file a national phase patent application in a PCT contracting state before the expiration of the PCT patent application in that state. If we do not timely file any national phase patent applications, we may lose our priority date with respect to our PCT patent application and any patent protection on the inventions disclosed in our PCT patent application. Any future U.S. patents that may issue from this PCT patent application (assuming all applicable requirements are satisfied) are expected to expire in 2040, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Next-Generation Patent Family/APR-548

As of December 31, 2020, we exclusively own a patent family directed to next-generation p53 reactivators, including APR-548. One pending PCT patent application and one pending national Taiwanese patent application have been filed in 2019 and one European pending patent application has been filed in 2020. In this patent family, the PCT patent

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application is pending with claims directed to compositions of matter and methods-of-use of APR-548. This PCT patent application is not eligible to become an issued patent until, among other things, we file a national phase patent application in a PCT contracting state before the expiration of the PCT patent application in that state. If we do not timely file any national phase patent applications, we may lose our priority date with respect to our PCT patent application and any patent protection on the inventions disclosed in our PCT patent application. Any future patents that may issue from these patent applications (assuming all applicable requirements are satisfied) are expected to expire in 2039 and 2041, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Treatment of Patients after Stem Cell Transplant

As of December 31, 2020, we exclusively own a pending PCT application directed to combination therapy using eprenetapopt with an inhibitor of DNA methyltransferase (e.g., azacitidine) in patients after a stem cell transplant, which was filed in 2020. This PCT patent application is not eligible to become an issued patent until, among other things, we file a national phase patent application in a PCT contracting state before the expiration of the PCT patent application in that state. If we do not timely file any national phase patent applications, we may lose our priority date with respect to our PCT patent application and any patent protection on the inventions disclosed in our PCT patent application. Any future U.S. patents that may issue from this PCT patent application (assuming all applicable requirements are satisfied) are expected to expire in 2040, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Lyophilization

As of December 31, 2020, we exclusively own a pending U.S. provisional patent application directed to preparation of an eprenetapopt solid product by freeze drying (lyophilizing) high-concentration solutions of eprenetapopt, and preparation of hydrochloride salts of eprenetapopt, which was filed in 2020. This provisional patent application is not eligible to become an issued patent until, among other things, we file a non-provisional patent application within 12 months of the filing of our provisional patent application. If we do not timely file any non-provisional patent applications, we may lose our priority date with respect to our provisional patent application and any patent protection on the inventions disclosed in our provisional patent application. Any future U.S. patents that may issue from this provisional patent application (assuming the necessary non-provisional patent applications are timely filed and all other applicable requirements are satisfied) are expected to expire in 2041, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Combination Therapy With A CD-47 Inhibitor

As of December 31, 2020, we exclusively own a pending U.S. provisional patent application directed to methods of treatment using a combination therapy of eprenetapopt with an inhibitor of the CD47 mediated signaling, which was filed in 2020. This provisional patent application is not eligible to become an issued patent until, among other things, we file a non-provisional patent application within 12 months of the filing of our provisional patent application. If we do not timely file any non-provisional patent applications, we may lose our priority date with respect to our provisional patent application and any patent protection on the inventions disclosed in our provisional patent application. Any future U.S. patents that may issue from this provisional patent application (assuming the necessary non-provisional patent applications are timely filed and all other applicable requirements are satisfied) are expected to expire in 2041, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Combination Therapies with Various Therapies

As of December 31, 2020, we exclusively own four pending U.S. provisional patent applications directed to methods of treatment using combination therapies of eprenetapopt with a PD-1-mediated signaling inhibitor, a Bruton’s tyrosine kinase inhibitor, an exportin 1 (XPO1) inhibitor, or a Wee1-like protein kinase (WEE1) inhibitor, which were filed in 2020. These provisional patent applications are not eligible to become an issued patent until, among other things, we

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file one or more non-provisional patent applications within 12 months of the filing of the provisional patent applications. If we do not timely file any non-provisional patent applications, we may lose our priority date with respect to our provisional patent application and any patent protection on the inventions disclosed in our provisional patent application. Any future U.S. patents that may issue from these provisional patent applications (assuming the necessary non-provisional patent applications are timely filed and all other applicable requirements are satisfied) are expected to expire in 2041, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Combination Therapy of APR-548 With Azacitidine

As of December 31, 2020, we exclusively own a pending U.S. provisional patent application directed to methods of treatment using a combination therapy of APR-548 with azacitidine for treating hyperproliferative malignancies, which was filed in 2020. This provisional patent application is not eligible to become an issued patent until, among other things, we file a non-provisional patent application within 12 months of the filing of our provisional patent application. If we do not timely file any non-provisional patent applications, we may lose our priority date with respect to our provisional patent application and any patent protection on the inventions disclosed in our provisional patent application. Any future U.S. patents that may issue from this provisional patent application (assuming the necessary non-provisional patent applications are timely filed and all other applicable requirements are satisfied) are expected to expire in 2041, not giving effect to any potential patent term extensions and patent term adjustments and assuming payment of all appropriate maintenance, renewal, annuity, or other governmental fees.

Intellectual property protection

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional patent application.

In the United States, the Hatch-Waxman Act permits a patent holder to apply for patent term extension of a patent that covers an FDA-approved drug, which, if granted, can extend the patent term of such patent to compensate for part of the patent term lost during the FDA regulatory review process. This extension can be for up to five years beyond the original expiration date of the patent. The length of the patent term extension is related to the length of time the drug is under regulatory review. Patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent applicable to an approved drug may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended.

Similar provisions are available in Europe and other non-United States jurisdictions to extend the term of a patent that covers an approved drug. In the future, if and when our product candidates receive FDA approval, we expect to apply for patent term extensions on patents covering those product candidates. While we intend to seek patent term extensions to any of our patents in any jurisdiction where such extensions are available, there is no guarantee that the applicable authorities, including the FDA and the USPTO in the United States, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

In addition to our reliance on patent protection for our inventions, product candidates and research programs, we also rely on trade secrets and confidentiality agreements to protect our technology, know-how and other aspects our business that are not amenable to, or that we do not consider appropriate for, patent protection. Although we take steps to protect our proprietary information and trade secrets, including through contractual means with our employees and consultants, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual or entity during the course of the party’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or

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research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property. However, such confidentiality agreements and invention assignment agreements can be breached and we may not have adequate remedies for any such breach. For more information regarding the risks related to our intellectual property, see “Risk Factors—Risks Related to Our Intellectual Property.”

Government Regulation

Government regulation and product approvals

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the EU, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of drug products. The processes for obtaining marketing approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

Review and approval of drugs in the United States

In the United States, the FDA approves drug products under the Federal Food, Drug, and Cosmetic Act, or FDCA, and implementing regulations. The failure to comply with applicable requirements under the FDCA and other applicable laws at any time during the product development process, approval process or after approval may subject an applicant and/or sponsor to a variety of administrative or judicial sanctions, including refusal by the FDA to approve pending applications, withdrawal of an approval, debarment, imposition of a clinical hold, issuance of warning letters and other types of letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement of profits, or civil or criminal investigations and penalties brought by the FDA and the Department of Justice or other governmental entities.

An applicant seeking approval to market and distribute a new drug product in the United States must typically undertake the following:

● review by an FDA advisory committee, where appropriate or if applicable;

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● payment of user fees and securing FDA approval of the NDA; and

Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity, and novelty of the product candidate or disease. A clinical hold may occur at any time during the life of an IND and may affect one or more specific trials or all trials conducted under the IND.

Preclinical studies

Before an applicant begins testing a compound with potential therapeutic value in humans, the drug candidate enters the preclinical testing stage. Preclinical studies include laboratory evaluation of product chemistry, toxicity and formulation, as well as in vitro and animal studies to assess the potential safety and activity of the drug for initial testing in humans and to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations. The results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, are submitted to the FDA as part of an IND. Some long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity, may continue after the IND is submitted.

The IND and IRB processes

An IND is an exemption from the FDCA that allows an unapproved drug to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer an investigational drug to humans. Such authorization must be secured prior to interstate shipment and administration of any new drug that is not the subject of an approved NDA. In support of a request for an IND, a sponsor must submit, among other things, a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. The sponsor may be a company seeking to develop the drug or, as in the case of an investigator-initiated trial, the sponsor may be an investigator who is conducting the trial. In addition, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, are submitted to the FDA as part of an IND. The FDA requires a 30-day waiting period after the filing of each IND before clinical trials may begin. This waiting period is designed to allow the FDA to review the IND to determine whether human research subjects will be exposed to unreasonable health risks. At any time during this 30-day period, the FDA may raise concerns or questions about the conduct of the trials as outlined in the IND and impose a clinical hold. In this case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. If the FDA has neither commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin.

Following commencement of a clinical trial under an IND, the FDA may also place a clinical hold or partial clinical hold on that trial. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND. For example, a specific protocol or part of a protocol is not allowed to proceed, while other protocols may do so. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation may only resume after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.

A sponsor may choose, but is not required, to conduct a foreign clinical study under an IND. When a foreign clinical study is conducted under an IND, all IND requirements must be met unless waived. When the foreign clinical study is

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not conducted under an IND, the sponsor must ensure that the study complies with certain FDA regulatory requirements in order to use the study as support for an IND or application for marketing approval. Specifically, FDA has promulgated regulations governing the acceptance of foreign clinical trials not conducted under an IND, establishing that such studies will be accepted as support for an IND or application for marketing approval if the study was conducted in accordance with GCP, including review and approval by an independent ethics committee, or IEC, and use of proper procedures for obtaining informed consent from subjects, and the FDA is able to validate the data from the study through an on-site inspection if FDA deems such inspection necessary. The GCP requirements encompass both ethical and data integrity standards for clinical studies. The FDA’s regulations are intended to help ensure the protection of human subjects enrolled in non-IND foreign clinical trials, as well as the quality and integrity of the resulting data. They further help ensure that non-IND foreign studies are conducted in a manner comparable to that required for IND studies. If a marketing application is based solely on foreign clinical data, the FDA requires that the foreign data be applicable to the U.S. population and U.S. medical practice; the studies must have been performed by clinical investigators of recognized competence; and the FDA must be able to validate the data through an on-site inspection or other appropriate means, if the FDA deems such an inspection to be necessary.

In addition to the foregoing IND requirements, an IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product candidate has been associated with unexpected serious harm to patients.

Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether or not a trial may move forward at designated check points based on access that only the group maintains to available data from the study. Suspension or termination of development during any phase of clinical trials can occur if it is determined that the participants or patients are being exposed to an unacceptable health risk. Other reasons for suspension or termination may be made by us based on evolving business objectives and/or competitive climate.

Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health, or NIH, for public dissemination on its ClinicalTrials.gov website.

Human clinical trials in support of an NDA

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCP requirements, which include, among other things, the requirement that all research subjects provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written study protocols detailing, among other things, the inclusion and exclusion criteria, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated.

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Human clinical trials are typically conducted in the following sequential phases, which may overlap or be combined:

Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently if serious AEs occur. In addition, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions for which there is evidence to suggest a causal relationship between the drug and the AE; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the drug; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted.

Concurrent with clinical trials, companies often complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and, among other things, must develop methods for testing the identity, strength, quality, and purity of the final drug. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the drug candidate does not undergo unacceptable deterioration over its shelf life.

Submission of an NDA to the FDA

Assuming successful completion of required clinical testing and other requirements, the results of the preclinical studies and clinical trials, together with detailed information relating to the product’s chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the drug product for one or more indications. Data can come from company-sponsored clinical trials intended to test the safety and effectiveness of a use of a product, or from several alternative sources, including investigator-initiated trials that are not sponsored by company. Under federal law, the submission of NDAs requiring clinical data is additionally subject to an application user fee, which for federal fiscal year 2021 is $2,875,842. The sponsor of an approved NDA is also subject to annual program fees, which for fiscal year 2021 are $336,432 per eligible product.

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The FDA conducts a preliminary review of an NDA within 60 days of its receipt and informs the sponsor whether the application is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA has agreed to specified performance goals in the review process of NDAs. Most such applications are meant to be reviewed within ten months from the filing date, and most applications for “priority review” products are meant to be reviewed within six months of the filing date. The review process and the Prescription Drug User Fee Act goal date may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant to address an outstanding deficiency identified by the FDA following the original submission.

Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is or will be manufactured. These pre-approval inspections may cover all facilities associated with an NDA submission, including drug component manufacturing (such as APIs), finished drug product manufacturing, and control testing laboratories. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP.

In addition, as a condition of approval, the FDA may require an applicant to develop a REMS. REMS use risk minimization strategies beyond the professional labeling to ensure that the benefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to use the product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential adverse events, and whether the product is a new molecular entity. REMS can include medication guides, physician communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU may include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The FDA may require a REMS before approval or post-approval if it becomes aware of a serious risk associated with use of the product. The requirement for a REMS can materially affect the potential market and profitability of a product.

The FDA is required to refer an application for a novel drug to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Fast track, breakthrough therapy and priority review designations

The FDA is authorized to designate certain products for expedited review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs are referred to as fast track designation, breakthrough therapy designation and priority review designation. In May 2014, the FDA published a final Guidance for Industry titled “Expedited Programs for Serious Conditions-Drugs and Biologics,” which provides guidance on the FDA programs that are intended to facilitate and expedite development and review of new product candidates as well as threshold criteria generally applicable to concluding that a product candidate is a candidate for these expedited development and review programs.

Specifically, the FDA may designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product’s application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. However, the FDA’s time period goal for reviewing a Fast Track application

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does not begin until the last section of the application is submitted. In addition, the Fast Track designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Second, a product may be designated as a Breakthrough Therapy if it is intended, either alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA may take certain actions with respect to Breakthrough Therapies, including holding meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross-disciplinary project lead for the review team; and taking other steps to design the clinical trials in an efficient manner.

Third, the FDA may designate a product for priority review if it is a product that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA determines, on a case-by-case basis, whether the proposed product represents a significant improvement when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-limiting product reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, and evidence of safety and effectiveness in a new subpopulation. A priority designation is intended to direct overall attention and resources to the evaluation of such applications, and to shorten the FDA’s goal for taking action on a marketing application from ten months to six months.

Accelerated approval pathway

The FDA may grant accelerated approval to a drug for a serious or life-threatening condition that provides meaningful therapeutic advantage to patients over existing treatments based upon a determination that the drug has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit. The FDA may also grant accelerated approval for such a condition when the product has an effect on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality, or IMM, and that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. Drugs granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.

For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug, such as an effect on IMM. The FDA has limited experience with accelerated approvals based on intermediate clinical endpoints, but has indicated that such endpoints generally may support accelerated approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a drug.

The accelerated approval pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a drug, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, accelerated approval has been used extensively in the development and approval of drugs for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large trials to demonstrate a clinical or survival benefit.

The accelerated approval pathway is contingent on a sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drug’s clinical benefit. As a result, a drug candidate approved on this basis is subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical trials to confirm the effect on the clinical endpoint. Failure to conduct required post-approval

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studies, or confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the drug from the market on an expedited basis. All promotional materials for drug candidates approved under accelerated regulations are subject to prior review by the FDA.

The FDA’s decision on an NDA

On the basis of the FDA’s evaluation of the NDA and accompanying information, including the results of the inspection of the manufacturing facilities, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the NDA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

If the FDA approves a product, it may limit the approved indications for use for the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess the drug’s safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. After approval, many types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.

Post-approval requirements

Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of adverse experiences with the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing, annual user fee requirements for any marketed products and the establishments at which such products are manufactured, as well as new application fees for supplemental applications with clinical data.

In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and state agencies, and are subject to periodic unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers that the NDA holder may decide to use. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including AEs of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

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● fines, warning letters or holds on post-approval clinical trials;

● injunctions or the imposition of civil or criminal penalties.

The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Drugs may be promoted only for the approved indications and in a manner and for uses consistent with the approved labeling. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability.

In addition, the distribution of prescription drug products is subject to the Prescription Drug Marketing Act, or PDMA, which regulates the distribution of drugs and drug samples at the federal level, and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription drug product samples and impose requirements to ensure accountability in distribution.

Abbreviated new drug applications for generic drugs

In 1984, with passage of the Hatch-Waxman Amendments to the FDCA, Congress established an abbreviated regulatory scheme allowing the FDA to approve generic drugs that are shown to contain the same active ingredients as, and to be bioequivalent to, drugs previously approved by the FDA pursuant to NDAs. To obtain approval of a generic drug, an applicant must submit an abbreviated new drug application, or ANDA, to the agency. An ANDA is a comprehensive submission that contains, among other things, data and information pertaining to the API, bioequivalence, drug product formulation, specifications and stability of the generic drug, as well as analytical methods, manufacturing process validation data and quality control procedures. ANDAs are “abbreviated” because they generally do not include preclinical and clinical data to demonstrate safety and effectiveness. Instead, in support of such applications, a generic manufacturer may rely on the preclinical and clinical testing previously conducted for a drug product previously approved under an NDA, known as the reference-listed drug, or RLD.

Specifically, in order for an ANDA to be approved, the FDA must find that the generic version is identical to the RLD with respect to the active ingredients, the route of administration, the dosage form, and the strength of the drug. An applicant may submit an ANDA suitability petition to request the FDA’s prior permission to submit an abbreviated application for a drug that differs from the RLD in route of administration, dosage form, or strength, or for a drug that has one different active ingredient in a fixed-combination drug product (i.e., a drug product with multiple active ingredients). At the same time, the FDA must also determine that the generic drug is “bioequivalent” to the innovator drug. Under the statute, a generic drug is bioequivalent to a RLD if “the rate and extent of absorption of the drug do not show a significant difference from the rate and extent of absorption of the listed drug.” Upon approval of an ANDA, the FDA indicates whether the generic product is “therapeutically equivalent” to the RLD in its publication “Approved Drug Products with Therapeutic Equivalence Evaluations,” also referred to as the “Orange Book.” Physicians and pharmacists may consider a therapeutic equivalent generic drug to be fully substitutable for the RLD. In addition, by operation of certain state laws and numerous health insurance programs, the FDA’s designation of therapeutic equivalence often results in substitution of the generic drug without the knowledge or consent of either the prescribing physician or patient.

Under the Hatch-Waxman Amendments, the FDA may not approve an ANDA until any applicable period of non-patent exclusivity for the RLD has expired. The FDCA provides a period of five years of non-patent data exclusivity for a new drug containing a new chemical entity. For the purposes of this provision, an NCE is a drug that contains no active moiety that has previously been approved by the FDA in any other NDA. An active moiety is the molecule or ion responsible for the physiological or pharmacological action of the drug substance. In cases where such NCE exclusivity has been granted, an ANDA may not be filed with the FDA until the expiration of five years from the date the NDA is approved, unless the submission is accompanied by a Paragraph IV certification that a listed patent for the RLD is

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invalid or will not be infringed by the drug that is the subject of the ANDA, in which case the applicant may submit its application four years following the original product approval.

The FDCA also provides for a period of three years of exclusivity if the NDA includes reports of one or more new clinical investigations, other than bioavailability or bioequivalence studies, that were conducted by or for the applicant and are essential to the approval of the application. This three-year exclusivity period often protects changes to a previously approved drug product, such as a new dosage form, route of administration, combination or indication. Three-year exclusivity would only be available for a drug product that contains a previously approved active moiety, provided the statutory requirement for a new clinical investigation is satisfied. Unlike five-year NCE exclusivity, an award of three-year exclusivity does not block the FDA from accepting ANDAs seeking approval for generic versions of the drug as of the date of approval of the original drug product; it does, however, block the FDA from approving ANDAs during the period of exclusivity. The FDA typically makes decisions about awards of data exclusivity shortly before a product is approved.

505(b)(2) NDAs

As an alternative path to FDA approval for modifications to formulations or uses of products previously approved by the FDA pursuant to an NDA, an applicant may submit an NDA under Section 505(b)(2) of the FDCA. Section 505(b)(2) was enacted as part of the Hatch-Waxman Amendments and permits the filing of an NDA where at least some of the information required for approval comes from studies not conducted by, or for, the applicant, and for which the applicant has not obtained a right of reference. If the 505(b)(2) applicant can establish that reliance on FDA’s previous findings of safety and effectiveness is scientifically and legally appropriate, it may eliminate the need to conduct certain preclinical studies or clinical trials of the new product. The FDA may also require companies to perform additional bridging studies or measurements, including clinical trials, to support the change from the previously approved reference drug. The FDA may then approve the new product candidate for all, or some, of the label indications for which the reference drug has been approved, as well as for any new indication sought by the 505(b)(2) applicant. An RLD’s unexpired non-patent exclusivities would also block FDA from accepting or approving 505(b)(2) NDAs in the same way as they apply to ANDAs.

Hatch-Waxman patent certification and the 30-Month Stay

Upon approval of an NDA or a supplement thereto, NDA sponsors are required to list with the FDA each patent with claims that cover the applicant’s product or an approved method of using the product. Each of the patents listed by the NDA sponsor is published in the Orange Book. When an ANDA applicant files its application with the FDA, the applicant is required to certify to the FDA concerning any patents listed for the reference product in the Orange Book, except for patents covering methods-of-use for which the ANDA applicant is not seeking approval. To the extent that the Section 505(b)(2) applicant is relying on studies conducted for an already approved product, the applicant is required to certify to the FDA concerning any patents listed for the approved product in the Orange Book to the same extent that an ANDA applicant would.

Specifically, the applicant must certify with respect to each patent that:

● the required patent information has not been filed;

● the listed patent has expired;

A certification that the new product will not infringe the already approved product’s listed patents or that such patents are invalid or unenforceable is called a Paragraph IV certification. If the applicant does not challenge the listed patents or indicates that it is not seeking approval of a patented method of use, the application will not be approved until all the

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listed patents claiming the referenced product have expired (other than method of use patents involving indications for which the applicant is not seeking approval).

If the ANDA or 505(b)(2) applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA or 505(b)(2) application has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days after the receipt of a Paragraph IV certification automatically prevents the FDA from granting final approval of the application until the earlier of 30 months after the receipt of the Paragraph IV notice, expiration of the patent, or a decision in the infringement case that is favorable to the applicant. The ANDA or 505(b)(2) application also will not be approved until any applicable non-patent exclusivity listed in the Orange Book for the branded reference drug has expired.

Pediatric studies and exclusivity

Under the Pediatric Research Equity Act of 2003, an NDA or supplement thereto must contain data that are adequate to assess the safety and effectiveness of the drug product for the claimed indications in all relevant pediatric subpopulations, and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. With enactment of the Food and Drug Administration Safety and Innovation Act of 2012, sponsors must also submit pediatric study plans prior to the assessment data.

Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests, and other information required by regulation. The applicant, the FDA, and the FDA’s internal review committee must then review the information submitted, consult with each other, and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or partial waivers from the pediatric data requirements. Additional requirements and procedures relating to deferral requests and requests for extension of deferrals are contained in FDASIA. Unless otherwise required by regulation, the pediatric data requirements do not apply to products with orphan designation.

Pediatric exclusivity is another type of non-patent marketing exclusivity in the United States and, if granted, provides for the attachment of an additional six months of marketing protection to the term of any existing regulatory exclusivity, including the non-patent and orphan exclusivity. This six-month exclusivity may be granted if an NDA sponsor submits pediatric data that fairly respond to a written request from the FDA for such data. The data do not need to show the product to be effective in the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDA’s request, the additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA within the statutory time limits, whatever statutory or regulatory periods of exclusivity or patent protection cover the product are extended by six months. This is not a patent term extension, but it effectively extends the regulatory period during which the FDA cannot approve another application. FDA may only grant pediatric exclusivity if existing patent or exclusivity protections for the drug would otherwise expire at least 9 months after the grant of the pediatric exclusivity; FDA has 180 days to make a pediatric exclusivity determination once the NDA sponsor submits study reports required under the written request.

Orphan drug designation and exclusivity

Under the Orphan Drug Act, the FDA may designate a drug product as an “orphan drug” if it is intended to treat a rare disease or condition (generally meaning that it affects fewer than 200,000 individuals in the United States, or more in cases in which there is no reasonable expectation that the cost of developing and making a drug product available in the United States for treatment of the disease or condition will be recovered from sales of the product). A company must request orphan product designation before submitting an NDA. If the request is granted, the FDA will disclose the identity of the therapeutic agent and its potential use. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process. Among the other benefits of orphan drug designation

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are tax credits for certain research and an exemption from the NDA or BLA application fee. The FDA may revoke orphan drug designation, and if it does, it will publicize that the drug is no longer designated as an orphan drug.

If the sponsor of a product with orphan designation receives the first FDA approval for that drug for the disease or condition for which it has such designation or for a select indication or use within the rare disease or condition for which it was designated, the product generally will receive orphan product exclusivity. Orphan product exclusivity means that the FDA may not approve any other applications for the same product for the same indication for seven years, except in certain limited circumstances. If a drug or drug product designated as an orphan product ultimately receives marketing approval for an indication broader than what was designated in its orphan product application, it may not be entitled to exclusivity. Orphan drug exclusivity, however, could also block the approval of one of our therapeutic candidates for seven years if a competitor obtains orphan drug designation and FDA approval of the same therapeutic candidate for the same condition or disease as our orphan-designated drug.

Orphan exclusivity will not bar approval of another product under certain circumstances, including if a subsequent product with the same active ingredient for the same indication is shown to be clinically superior to the approved product on the basis of greater efficacy or safety, or providing a major contribution to patient care, or if the company with orphan drug exclusivity is not able to meet market demand. Further, the FDA may approve more than one product for the same orphan indication or disease as long as the products contain different active ingredients. Moreover, competitors may receive approval of different products for the indication for which the orphan product has exclusivity or obtain approval for the same product but for a different indication for which the orphan product has exclusivity.

In addition, as the FDA has interpreted the Orphan Drug Act, even if a previously approved same drug does not have unexpired orphan exclusivity, a demonstration of clinical superiority is required for a subsequent marketing application for the same orphan-designated drug for the same disease or condition to be awarded a 7-year period of orphan exclusivity upon marketing approval. In recent years, there have been multiple legal challenges to this FDA interpretation, and in August 2017, Congress amended the orphan drug provisions of the FDCA through enactment of the FDA Reauthorization Act of 2017 to codify FDA’s longstanding interpretation. Section 527 of the FDCA now expressly provides that if a sponsor of an orphan-designated drug that is otherwise the same as an already approved drug for the same rare disease or condition is seeking orphan exclusivity, FDA shall require such sponsor, to demonstrate that such drug is clinically superior to any already approved or licensed drug that is the same drug in order to obtain orphan drug exclusivity.

Patent term restoration and extension

A patent claiming a new drug product may be eligible for a limited patent term extension under the Hatch-Waxman Act, which permits a patent restoration of up to five years for patent term lost during product development and the FDA regulatory review. The restoration period granted is typically one-half the time between the effective date of an IND and the submission date of an NDA less any time the applicant did not act with due diligence during the period, plus the time between the submission date of an NDA and the ultimate approval date less any time the applicant did not act with due diligence during the period. Patent term restoration cannot be used to extend the remaining term of a patent past a total of 14 years from the product’s approval date. Only one patent applicable to an approved drug product is eligible for the extension, only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended, and the application for the extension must be submitted prior to the expiration of the patent in question. A patent that covers multiple drugs for which approval is sought can only be extended in connection with one of the approvals. The USPTO reviews and approves the application for any patent term extension or restoration in consultation with the FDA. Similar provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an approved drug. In the future, if and when our products receive FDA approval, we expect to apply for patent term extensions on patents covering those products. We plan to seek patent term extensions to any of our issued patents in any jurisdiction where these are available, however there is no guarantee that the applicable authorities, including the FDA in the United States, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions. For more information regarding the risks related to our intellectual property, see “Risk Factors—Risks Related to Our Intellectual Property.”

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FDA approval and regulation of companion diagnostics

A therapeutic product may rely upon an in vitro companion diagnostic for use in selecting the patients that will be more likely to respond to that therapy. If safe and effective use of a therapeutic depends on an in vitro diagnostic, then the FDA generally will require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time that the FDA approves the therapeutic product. In August 2014, the FDA issued final guidance clarifying the requirements that will apply to approval of therapeutic products and in vitro companion diagnostics. According to the guidance, for novel drugs, a companion diagnostic device and its corresponding therapeutic should be approved or cleared contemporaneously by the FDA for the use indicated in the therapeutic product’s labeling. In July 2016, the FDA issued a draft guidance intended to assist sponsors of the drug therapeutic and in vitro companion diagnostic device on issues related to co-development of the products.

If FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, FDA generally will not approve the therapeutic product or new therapeutic product indication if the companion diagnostic device is not approved or cleared for that indication. Approval or clearance of the companion diagnostic device will ensure that the device has been adequately evaluated and has adequate performance characteristics in the intended population. The review of in vitro companion diagnostics in conjunction with the review of our therapeutic treatments for cancer will, therefore, likely involve coordination of review by the FDA’s Center for Drug Evaluation and Research and the FDA’s Center for Devices and Radiological Health Office of In Vitro Diagnostics Device Evaluation and Safety.

Under the FDCA, in vitro diagnostics, including companion diagnostics, are regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, preclinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance, and premarket approval, or PMA. The FDA has generally required in vitro companion diagnostics intended to select the patients who will respond to cancer treatment to obtain a PMA for that diagnostic simultaneously with approval of the drug. We expect that any companion diagnostic developed for use with eprenetapopt will utilize the PMA pathway.

The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are subject to an application fee of $365,657 for most PMAs for FY 2021. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, a PMA application typically requires data regarding analytical and clinical validation studies. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation, or QSR, which imposes elaborate testing, control, documentation and other quality assurance requirements.

APRE US Equity

APRE · 10-K · period ended 2020-12-31

Item 1. Business

APRE US Equity☆

APRE · 10-K · period ended 2020-12-31

Item 1. Business

APRE US Equity