arvn-10k_20201231.htm

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2020

Commission File Number: 001-38672

ARVINAS, INC.

(Exact name of registrant as specified in its Charter)

5 Science Park 395 Winchester Ave. New Haven, Connecticut 06511

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (203) 535-1456

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

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

None

(Title of class)

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 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☒

As of June 30, 2020, the last business day of the registrant’s most recently completed second fiscal quarter, the aggregate market value of the Common Stock held by non-affiliates of the registrant was approximately $1,347.5 million, based on the closing price of the registrant’s Common Stock on such date. The number of shares of registrant’s Common Stock, $0.001 par value per share, outstanding as of February 24, 2021 was 48,874,027.

DOCUMENTS INCORPORATED BY REFERENCE

Part III of this Annual Report incorporates by reference information from the definitive Proxy Statement for the registrant’s 2021 Annual Meeting of Stockholders, which is expected to be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2020.

Table of Contents

Page

PART I

Item 1. Business 5

Item 1A. Risk Factors 54

Item 1B. Unresolved Staff Comments 91

Item 2. Properties 91

Item 3. Legal Proceedings 91

Item 4. Mine Safety Disclosures 91

PART II

Item 6. Selected Financial Data 93

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 106

Item 8. Financial Statements and Supplementary Data 106

Item 9A. Controls and Procedures 107

Item 9B. Other Information 108

PART III

Item 10. Directors, Executive Officers and Corporate Governance 109

Item 11. Executive Compensation 109

Item 14. Principal Accounting Fees and Services 109

PART IV

Item 15. Exhibits, Financial Statement Schedules 110

FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this Annual Report on Form 10-K, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. The words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “predict,” “project,” “target,” “potential,” “goals,” “will,” “would,” “could,” “should,” “continue” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

The forward-looking statements in this Annual Report on Form 10-K include, among other things, statements about:

• our plans to pursue research and development of other product candidates;

• the potential receipt of revenue from future sales of our product candidates;

• our sales, marketing and distribution capabilities and strategy;

• our ability to enter into additional collaborations with third parties;

• our intellectual property position;

• the impact of COVID-19 on our business and operations;

• the impact of government laws and regulations; and

• our competitive position.

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this Annual Report on Form 10-K, particularly in the “Risk Factors” section, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.

You should read this Annual Report on Form 10-K and the documents that we have filed as exhibits to this Annual Report on Form 10-K completely and with the understanding that our actual future results may be materially different from what we expect. We do not assume any obligation to update any forward-looking statements except as required by applicable law.

Throughout this Annual Report on Form 10-K, the “Company,” “Arvinas,” “we,” “us,” and “our,” except where the context requires otherwise, refer to Arvinas, Inc. and its consolidated subsidiaries, or any one or more of them as the context may require, and “our board of directors” refers to the board of directors of Arvinas, Inc.

We use Arvinas, the Arvinas logo, and other marks as trademarks in the United States and other countries. This Annual Report on Form 10-K contains references to our trademarks and service marks and to those belonging to other entities. Solely for convenience, trademarks and trade names referred to in this Annual Report on Form 10-K, including logos, artwork and other visual displays, may appear without the ® or TM symbols, but such 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 rights of the applicable licensor to these trademarks and trade names. We do not intend our use or display of other entities’ trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other entity.

Risk Factor Summary

Our business is subject to a number of risks that if realized could materially affect our business, prospects, operating results and financial condition. These risks are discussed more fully in the “Risk Factors” section of this Annual Report on Form 10-K. These risks include the following:

PART I

Item 1. Business.

Overview

We are a clinical-stage biopharmaceutical company dedicated to improving the lives of patients suffering from debilitating and life-threatening diseases through the discovery, development and commercialization of therapies to degrade disease-causing proteins. We use our PROTAC Discovery Engine, our proprietary technology platform to engineer proteolysis targeting chimeras, or PROTAC targeted protein degraders, that are designed to harness the body’s own natural protein disposal system to selectively remove disease-causing proteins. We believe that our targeted protein degradation approach is a therapeutic modality that may provide distinct advantages over existing modalities, including traditional small molecule therapies and gene-based medicines. Our small-molecule PROTAC technology has the potential to address a broad range of intracellular disease targets, including those representing the up to 80% of proteins that cannot be addressed by existing small molecule therapies, commonly referred to as “undruggable” targets. We are using our PROTAC Discovery Engine to build an extensive pipeline of protein degradation product candidates to target diseases in oncology (including immuno-oncology), neuroscience, and other therapeutic areas.

We have designed and optimized our PROTAC Discovery Engine for the discovery of PROTAC therapeutics to address diseases caused by abnormal proteins or aberrant protein expression. We engineer our PROTAC targeted protein degraders to tag a target protein for degradation through the ubiquitin proteasome system, one of the cell’s natural protein disposal systems, and then to iteratively degrade additional target protein molecules. The PROTAC Discovery Engine includes advanced screening capabilities, including in-house high-throughput and DNA-encoded library screening abilities that are tailored to the needs of incorporation into PROTAC protein degraders and to optimize their drug-like properties. Following selection and identification, we use tools including predictive computational modeling and privileged linkers that allow the potential for increased potency and selectivity. Finally, we have utilized our own proprietary PROTAC-specific optimization strategies, which we refer to as the Arvinas Rules, to create PROTAC degraders that, for example, are capable of being delivered through multiple routes of administration, including oral delivery, as well as PROTAC targeted protein degraders that are able to penetrate the blood brain barrier.

Our two lead product candidates are ARV-110 and ARV-471. We are developing ARV-110, a PROTAC protein degrader targeting the androgen receptor protein, or AR, for the treatment of men with metastatic castration-resistant prostate cancer, or mCRPC. We initiated a Phase 1 clinical trial of ARV-110 in March 2019. This Phase 1 trial is designed to assess the safety, tolerability and pharmacokinetics of ARV-110 and also includes measures of anti-tumor activity as secondary endpoints, including reduction in prostate specific antigen, or PSA, a well-recognized biomarker of prostate cancer progression. We received Fast Track designation for ARV-110 for mCRPC in May 2019. In October 2020, we initiated ARDENT, the Phase 2 expansion portion of the ARV-110 clinical trial.

We are also developing ARV-471, a PROTAC protein degrader targeting the estrogen receptor protein, or ER, for the treatment of patients with locally advanced or metastatic ER positive / HER2 negative breast cancer. We initiated a Phase 1 clinical trial of ARV-471 in August 2019. This Phase 1 trial is designed to assess the safety, tolerability and pharmacokinetics of ARV-471 and also includes measures of anti-tumor activity as secondary endpoints. We amended the protocol for our Phase 1 clinical trial for ARV-471 in the first quarter of 2020 to include the Phase 2 expansion cohort and in the fourth quarter of 2020 to include a Phase 1b cohort expansion of ARV-471 in combination with Ibrance® (palbociclib). In February 2021, we initiated VERITAC, the Phase 2 expansion portion of the ARV-471 clinical trial.

In our preclinical studies, these lead product candidates have demonstrated potent and selective protein degradation. We believe favorable clinical trial results in these initial oncology programs would provide validation of our platform as a new therapeutic modality for the potential treatment of diseases caused by dysregulated intracellular proteins regardless of therapeutic area.

We expect to file an investigational new drug, or IND, application and initiate a Phase 1 trial in the first half of 2021 for ARV-766, an AR degrader developed to target and degrade wild-type and mutated AR including at least one additional, clinically relevant AR point mutation as compared to ARV-110.

In addition to our clinical product candidates, we are expanding our pipeline by utilizing our platform to potentially address currently undruggable targets. Unlike existing small molecule inhibitor therapies, our PROTAC targeted protein degraders can degrade proteins using any available binding site, including low-affinity active binding sites or non-functional binding sites, bringing biological utility to ligands that would otherwise be ineffective. While some gene-based medicines are also seeking to address undruggable targets, our PROTAC targeted protein degraders confer the advantages of traditional small molecule therapies, such as broad tissue distribution, multiple routes of administration, including oral delivery, a well-established development pathway and relative ease of manufacturing.

We are further diversifying our pipeline by developing new PROTAC targeted protein degradersagainst targets for which we believe protein degradation offers advantages to existing therapeutic modalities. For example, we are pursuing targets for the treatment of neurodegenerative diseases, including tauopathies, which are diseases associated with an aggregation of tau proteins in the brain, such as Alzheimer’s disease. We have engineered PROTAC targeted protein degradersthat, in preclinical studies, have successfully achieved blood brain barrier penetration, a key step in developing drugs with the potential to treat neurodegenerative targets. We believe there are many other indications for which our PROTAC technology may be advantageous.In an effort to realize the full potential of our PROTAC technology, our ongoing strategic collaborations with Pfizer Inc., or Pfizer, Genentech, Inc. and F. Hoffman-La Roche Ltd, collectively referred to as Genentech, and Bayer AG, or Bayer, address targets across multiple therapeutic areas.

We have been a leader in the field of directed protein degradation using chimeric small molecules since our founding in 2013. Our PROTAC technology platform has its origins in work performed at Yale University, or Yale, by our scientific founder and Chief Scientific Advisor, Professor Craig Crews, a leading researcher in the field of protein degradation. We have assembled a scientific team with extensive know-how and translational medicine expertise to develop PROTAC targeted protein degraders with features not previously disclosed in published third-party studies. Our management team draws on extensive experience in all phases of drug discovery and development gained at large pharmaceutical and biotechnology companies to continue to advance our product pipeline and expand the capabilities of our platform.

Our Strategy

Our goal is to discover, develop, and commercialize therapies that improve the lives of patients suffering from cancer, neurological disorders and other serious diseases. We engineer PROTAC protein degraders that are designed to selectively remove disease-causing proteins, and we believe that our proprietary PROTAC technology is a new therapeutic modality with the potential to provide distinct advantages over existing therapies and to address a broad range of targets, including undruggable proteins. The key elements of our strategy are to:

Our Product Pipeline

Our platform has generated several promising degradation product candidates that may be capable of targeting diseases in a wide range of organ systems and tissues. We and our collaborators have initiated programs across multiple therapeutic areas with the goal of developing and delivering life-changing therapies to patients in need. Our lead therapeutic programs, for which we retain full worldwide development and commercialization rights, are summarized in the table below.

IND dates referenced in the table above are anticipated; ER+/HER2-, estrogen receptor+/human epidermal growth factor receptor 2-; NSCLC, non-small-cell lung carcinoma; CRC, colorectal cancer; FTLD-tau, frontotemporal lobar degeneration-tau; PSP, progressive supranuclear palsy; AD, Alzheimer’s disease, MSA, multiple systems atrophy.

We classify our programs as in the exploratory stage of development when we are synthesizing and testing PROTAC protein degraders to evaluate degradation of the selected target, differential biology compared to inhibitors, and proof of concept pharmacodynamics and efficacy in vivo. A program advances to the research stage when we have identified a lead PROTAC protein degrader that demonstrates promising activity in in vitro and in vivo biological models relative to defined criteria. In the research stage, we are working to optimize the PROTAC protein degraders for a desired profile, including degradation potency, selectivity, drug metabolism and pharmacokinetics, pharmacodynamic activity and in vivo efficacy, and we have begun characterizing preclinical tolerability and toxicology. A program enters the IND-enabling stage once we are performing studies intended to support the submission of an IND application, including expanded toxicology, drug product optimization and IND documentation preparation.

In addition to the programs above and our early-stage development collaborations with Bayer, Genentech, and Pfizer, we are conducting exploratory research and development work on multiple other undisclosed targets.

Our Focus

The Role of Proteins in Disease

Human cells produce tens of thousands of different proteins, the entirety of which is referred to as the proteome. Proteins are responsible for many structural, functional and regulatory processes in cells.

Proteins are large, complex biomolecules made through a series of steps based on instructions carried from deoxyribonucleic acid, or DNA, the genetic “blueprint” within the cell. Generally, sequences of DNA are converted into messenger ribonucleic acid, or mRNA, during a process called transcription. mRNA provides the template that specifies the assembly of a particular sequence of amino acids into proteins during a process known as translation. The amino acid sequence dictates, among other things, the conformation, or 3-D shape, of the resulting protein. Proteins can have complex shapes, with multiple chains of amino acids folding together in some cases to reach a final form. The final form of the protein, as well as the timing, location and concentration of its expression within the cell, is essential to the protein’s intended function.

In healthy cells, the transcription and translation processes contribute to producing properly folded proteins in the right amounts and at the correct times to ensure normal cell health and function. This balance can be disrupted by a variety of events and factors, such as cellular stress, genetic mutations and transcriptional or translational errors, which can then lead to cellular overexpression, abnormal production rates, misfolding or mutations of proteins. When proteins are overexpressed or mutated, a wide variety of diseases can result. For example, it is well documented that overexpression of androgen receptor, a nuclear hormone receptor, is implicated in prostate cancer. Similarly, overexpression of estrogen receptor is known to be associated with breast cancer. In neurodegenerative diseases, abnormal deposition of misfolded or aggregated proteins in the brain, including the intraneuronal aggregation of the microtubule-associated protein tau, are associated with Alzheimer’s disease. Recent genomic advances continue to implicate the role of specific proteins in many disease states.

There are multiple therapeutic approaches, both approved and in development, to treat diseases caused by abnormal proteins or aberrant protein expression. Each operates at a different point in the lifecycle of the protein, as illustrated in the following graphic:

Small Molecule Inhibitors, Gene Therapy and Gene Editing

Traditional small molecules seek to block or inhibit the expression or function of an errant protein. While there are numerous examples of safe and effective small molecule therapies, their efficacy can be limited by weak or incomplete binding of the therapeutic molecule to the relevant binding site on the protein, the cell’s ability to counteract the inhibitory effect of the drug by producing more of the protein, mutation of the target, or evolution of the cell to rely on alternate pathways. These cellular responses often result in a need for higher dosing levels, which can in turn introduce safety challenges from off-target and toxic effects, or drug resistance.

Gene therapy approaches act by augmenting the errant protein with normal protein by using viral vectors to introduce DNA from an exogenous source that codes for a functional protein. While there have been promising advances in this field, the fundamental approach is limited by delivery, expression efficacy, pre-treatment conditioning, durability and manufacturing challenges that curtail the practical utility of gene therapy.

Gene editing or gene silencing approaches such as CRISPR/Cas9, RNA interference and antisense act by either correcting or inactivating, or knocking out, the gene that would otherwise be transcribed and translated to express the errant protein. By correcting or knocking out the gene, the errant protein is never made, preventing its downstream negative effects. In the case of CRISPR/Cas9, the resulting modification of the gene occurs at the DNA level and is believed to be irreversible. While there are examples of approved therapies in this field that have the potential to correct specific genetic defects, gene editing and gene silencing approaches generally face delivery, stability, biodistribution, specificity and selectivity challenges, in addition to significant manufacturing hurdles.

Protein Degradation

When proteins become old, mutated, misfolded or simply have served their purpose, they are naturally degraded by the body through the ubiquitin proteasome system in which cells mark or tag a particular protein for disposal by attaching several molecules of the small regulatory protein ubiquitin to the protein to be disposed. This process generally proceeds along the following steps in rapid sequence:

• The E1 enzyme activates ubiquitin, which is then transferred to an E2 enzyme.

Several therapeutic approaches work at the protein level by modulating the ubiquitin proteasome system to harness the cell’s natural protein disposal system to degrade and remove a protein. Degradation can be induced by inhibiting chaperone molecules such as HSP90, which are known to facilitate correct protein folding, resulting in tagging misfolded proteins for degradation. HSP90 inhibitors, however, have shown limited efficacy in the clinic to date.

Some degraders use an approach that causes a conformational change in a specifically targeted protein, resulting in a misfolded protein, which triggers the cell’s innate protein degradation system to dispose of the misfolded protein. Although these compounds have shown efficacy, they only induce the degradation of those proteins able to adopt a non-native state, leaving a wide array of protein targets unaddressed. The only currently marketed protein degrader utilizing this mechanism, the breast cancer therapy fulvestrant, requires intramuscular administration, further limiting its convenience and pharmacokinetic profile.

Chimeric small molecules use a different protein degradation approach. Instead of causing improper folding or inhibiting molecules that facilitate proper folding of the target protein, chimeric small molecules directly recruit an E3 ligase to tag specifically targeted proteins with ubiquitin, signaling the proteasome to degrade the targeted protein. Our PROTAC targeted protein degraders take this approach to protein degradation.

PROTAC Targeted Protein Degraders —Our Approach to Protein Degradation

We have engineered our PROTAC targeted protein degraders to utilize the cell’s naturally occurring protein disposal system, directing the proteasome to recognize and degrade specific proteins associated with disease. Our PROTAC targeted protein degraders are chimeric small molecules with two operative ends—one, a ligand that binds to the protein targeted for degradation, and the other, a ligand that binds to an E3 ligase. These two ligands are connected by a chemical chain linker. Our PROTAC targeted protein degraders bring the targeted protein and the E3 ligase together into a three-component grouping known as a trimer complex to facilitate the transfer of ubiquitin to the target protein. Once four ubiquitins are attached in a chain to the target protein, the proteasome recognizes and degrades the protein. The entire cycle from the formation of the trimer complex, which can occur in a period of nanoseconds, to degradation of the target protein by the proteasome happens over a period of minutes. After our PROTAC targeted protein degrader facilitates the tagging of a target protein molecule with ubiquitin through formation of the trimer complex, it can move on to another target protein molecule to conduct the degradation process again, potentially completing this cycle hundreds of times before eventually being metabolized or eliminated from the cell. We refer to this recycling as our PROTAC targeted protein degraders’ iterative mechanism of action.

The figure below depicts our PROTAC-induced cycle from E3 ligase binding and target protein recruitment, to trimer formation and ubiquitin transfer, to degradation of the target protein by the proteasome, to the release of ubiquitin and PROTAC targeted protein degrader for further degradation cycles.

Our Discovery Platform—PROTAC Discovery Engine

We have designed and optimized our PROTAC Discovery Engine for the discovery of PROTAC targeted protein degrader therapeutics to address diseases caused by abnormal proteins or aberrant protein expression. The PROTAC Discovery Engine includes advanced screening capabilities, including in-house high-throughput and DNA-encoded library screening abilities that are tailored to the needs of incorporation into PROTAC protein degraders and to optimize their drug-like properties. Following selection and identification, we use tools including predictive computational modeling and privileged linkers that allow the potential for increased potency and selectivity. Finally, we have utilized our own proprietary Arvinas Rules to create PROTAC degraders that, for example, are capable of being delivered through multiple routes of administration, including oral delivery, as well as PROTAC targeted protein degraders that are able to penetrate the blood brain barrier.

Design and Optimization of our PROTAC Targeted Protein Degraders

As genomic knowledge and advances in genome mapping have increased, the understanding of proteins implicated in diseases has similarly increased. We undertake a rigorous evaluation process to prioritize protein targets for which we believe our PROTAC approach can achieve differentiated clinical outcomes for patients over existing modalities. Our PROTAC Discovery Engine is built from nearly 20 years of experience, know-how, and intellectual property and comprises three stages:

Ligase Selection and Ligand Identification

Rapid PROTAC Design

Turning Degraders into Drugs

Key Features of Our PROTAC Targeted Protein Degraders

In the design, optimization and development of our PROTAC targeted protein degraders, we focus on the following key features that we believe are critical to successfully engineering PROTAC targeted protein degrader therapeutics with potentially robust application across multiple indications and therapeutic areas: potency, selectivity, and deliverability and versatility. We have harnessed these features to successfully target and degrade a wide range of protein classes, including nuclear proteins, transcription factors, epigenetic modulators, membrane proteins, cytosolic proteins and high molecular weight neuroprotein aggregates.

Potency

The potency of our PROTAC technology is driven by two key characteristics: the iterative mechanism of our PROTAC targeted protein degraders and the ability to turn weak binders into potent degraders.

Iterative Mechanism

Our PROTAC targeted protein degraders behave iteratively to repeatedly induce the ubiquitination and subsequent degradation of proteins. As a result, protein degradation may be observed with PROTAC targeted protein degrader concentrations much lower than those required for typical small molecule inhibition, even operating at picomolar concentrations. We expect that the high cellular potency of PROTAC targeted protein degrader could provide the possibility of removal of proteins at levels equivalent to the knock out effect intended by gene-based medicines currently being explored. Our PROTAC targeted protein degraders offer potentially significant therapeutic advantages, including low doses, low drug exposures and practical dosing intervals, potentially mitigating toxicity and tolerability risks.

The iterative mechanism of our PROTAC targeted protein degraders potentially leads to more complete and lasting inactivation of downstream signaling in cells. In oncology, this translates into improved inhibition of tumor cell growth and reduces the likelihood of cell compensation through activation of alternative proteins, a common risk associated with small molecule inhibitors. This enables PROTAC targeted protein degraders to operate in a broad therapeutic space between desired degradation-induced pharmacology and unwanted inhibition-induced effects.

Once the pre-existing reservoir of the targeted protein is depleted, our PROTAC targeted protein degraders only need to degrade newly resynthesized protein to maintain their effect. Depending on the resynthesis rate of the protein, this may be achievable with low tissue concentrations of PROTAC targeted protein degrader, which could lead to safety benefits and opportunities for flexible dosing regimens.

Weak Binders Become Potent Degraders

Using our platform and know-how, we are able to engineer potent PROTAC targeted protein degraders that do not require a high degree of binding strength to their targets. This contrasts with small molecule inhibitors, which require strong binding to a target protein and function by continually occupying the protein’s active site. The potency of our PROTAC targeted protein degraders is determined by a number of kinetic factors: formation of the trimer complex, rapid ubiquitination, trafficking of the ubiquitinated target to the proteasome and release of the PROTAC targeted protein degrader to enter another iterative cycle of degradation. As a result, a PROTAC targeted protein degrader with a low level of target protein occupancy can maintain a deep and prolonged suppression of protein levels, leading to the desired pharmacological effect. This provides opportunities to use our PROTAC technology to repurpose small molecules that only weakly bind to their target to create potent degraders as PROTAC targeted protein degraders.

For example, we have published experiments where we built PROTAC targeted protein degraders from the known protein kinase inhibitor foretinib, which is a relatively weak binder to the protein p38α, a protein implicated in immune disorders and heart disease. We constructed a foretinib-based PROTAC targeted protein degrader we refer to as PROTAC 1, which happened to further weaken the binding affinity to p38α. Binding affinity is measured by KD, or equilibrium dissociation constant. In this case, we observed that PROTAC 1 exhibited a tenfold reduction in binding affinity relative to foretinib, decreasing from 1 micromolar, or μM, to 11 μM. Despite the significantly weaker binding affinity, PROTAC 1 achieved potent degradation of p38α with a DC50, a concentration that results in half maximal degradation, of 210 nanomolar, or nM, which means that its degradation potency is approximately 50-fold better than its binding strength. The figure below shows a western blot of cells treated with increasing concentrations (left to right) of foretinib, the PROTAC 1, and an inactivated (non-degrading) version of PROTAC 1. The decreasing presence of the p38α protein is depicted by a lighter shade of the p38α band in the western blot as the doses of the PROTAC 1 increase. This demonstrates our ability to use a weak binder to create a potent PROTAC targeted protein degrader. Based on our experience, we believe that with additional medicinal chemistry effort, the degradation potency of this weak-binding PROTAC targeted protein degrader could be further increased.

Selectivity

When a ligand is incorporated into a PROTAC targeted protein degrader, the trimer complex initiated by the PROTAC targeted protein degrader often causes the ligand’s selectivity to increase, meaning that the degradation profile of a PROTAC targeted protein degrader can be even more selective than the binding profile of the ligand alone. By minimizing the binding of a ligand to off-target proteins and maximizing selectivity for a target protein, our PROTAC targeted protein degraders may reduce the potential for incidental degradation of normal, healthy proteins and unwanted drug effects and toxicity.

We published experiments in which a ligand binding to 133 kinases degraded fewer than ten proteins when incorporated into a PROTAC targeted protein degrader with limited additional modification. The figure below on the left depicts foretinib binding to 133 protein kinases as measured by a competitive binding assay. The figure on the right depicts cells treated with a foretinib-based PROTAC targeted protein degrader degrading only a small subset of cellular proteins (lower left quadrant of the graph) as shown by mass spectrometry analysis.

With further modification, and based on our experience, we believe it is possible to engineer promiscuous binders such as this into more selective protein degraders, and when starting with less promiscuous, yet still unselective, binders, identify very selective PROTAC target protein degraders.

This selectivity allows for engineering of PROTAC targeted protein degraders that degrade only the mutated and unwanted protein, while sparing the normal, or wild-type, protein that may be necessary for healthy function. For example, we have demonstrated degradation of abnormal, but not wild-type, forms of the BRAF protein using a PROTAC targeted protein degrader. Wild-type BRAF helps transmit chemical signals from outside the cell to the cell’s nucleus and is part of a pathway that regulates cell proliferation, differentiation, migration and apoptosis. Mutations of BRAF, however, have been associated with a number of different cancers. As shown in the figure below, our PROTAC targeted protein degrader degraded BRAF mutants, as depicted by a lighter shade in the columns labeled 300 nM, representative of each of the three classes of BRAF mutations, while not degrading the wild-type BRAF, as depicted by an unchanging shade in each of the columns shown on the western blot.

1hMito is a protein this particular PROTAC targeted protein degrader is not targeted to degrade, and is

included as a control to ensure total protein is equivalent in each lane.

Deliverability and Versatility

Our PROTAC targeted protein degraders have the potential for delivery through multiple routes of administration to reach target proteins, and certain of our PROTAC targeted protein degraders are capable of penetrating the blood brain barrier. In addition, the broad expression of the E3 ligases we target and the potential to turn weak binding ligands into potent degraders allows the application of our PROTAC technology to develop treatments for diseases associated with proteins that cannot be addressed by existing small molecule therapies.

Deliverability

We have developed PROTAC targeted protein degraders that are capable of being delivered orally, intravenously, subcutaneously and intrathecally, among other routes of administration, as well as PROTAC targeted protein degraders that are able to penetrate the blood brain barrier. The multiple routes of delivery for our PROTAC targeted protein degraders potentially provide many attractive clinical dosing options. For example, oral delivery can offer a differentiating, competitive and commercial advantage over other therapeutic approaches such as gene-based medicines that allows for more convenient treatment. Further, oral administration avoids risks of adverse events associated with intravenous or intramuscular administration, such as the potential for infection and blood clots at the infusion site.

Versatility

We believe our PROTAC targeted protein degraders may have potential application in a wide range of therapeutic areas because the E3 ligases we currently target are expressed widely across tissue types. Ligands that bind to some proteins may be of only weak affinity. However, we believe that our PROTAC technology will allow the degradation of proteins through such low affinity active binding sites or non-functional binding sites. Our ability to design weak binding PROTAC targeted protein degraders that nonetheless initiate rapid ubiquitination and subsequent degradation of targeted proteins has the potential to expand the number of disease-causing proteins targeted for drug development to include the up to 80% of proteins that cannot be addressed by existing small molecule therapies and are currently considered undruggable. We believe that rendering these targets druggable for the first time represents the true breadth and potential of our PROTAC Discovery Engine.

We conducted an experiment designed to demonstrate that non-functional binding sites, analogous to those that may be present on proteins considered undruggable, can be used to target proteins for degradation by PROTAC targeted protein degraders. The figure below depicts a structural model of the Abl tyrosine kinase. This protein kinase possesses an enzymatic active site that is inhibited by the marketed small molecule, imatinib. The Abl kinase also has a second, non-functional active site, called an allosteric site, in its structure that can bind a different small molecule, named GNF-2, which despite binding allosterically (with a relatively weak KD of 500 nM), inhibits only the wild type protein (C-Abl), but not BCR-Abl-a mutated form of Abl implicated in chronic myelogenous leukemia.

When GNF-2 is converted into a PROTAC targeted protein degrader and used to treat cells, both BCR-Abl and C-Abl are effectively degraded. The figure below shows western blots of cells treated by increasing concentrations of our PROTAC targeted protein degrader and shows decreasing presence of each of BCR-Abl and C-Abl protein (depicted by a lighter shade of the BCR/Abl and C-Abl band in the western blot). Downstream signaling, as denoted by reduction of phosphorylated Stat5 (pStat5), is subsequently inhibited.

1Tubulin is a protein the GNF-2 PROTAC targeted protein degrader is not targeted to degrade, and is included

as a control to ensure total protein is equivalent in each lane.

PROTAC-induced degradation may offer a solution for undruggable proteins because only binders, not functional inhibitors, are needed to facilitate E3 ligase recruitment and initiation of the degradation process. The probability of finding a suitable ligand using binding-site-agnostic screening is increased because the function of the ligand itself is not required. As a result, there is the potential for PROTAC targeted protein degraders to generate therapeutics from poorly selective ligands, weak-affinity ligands, or ligands that may not be intrinsically biologically active.

Our Programs

ARV-110 for the Treatment of Men with Metastatic Castration-Resistant Prostate Cancer

We are developing ARV-110, an orally bioavailable, AR degrading PROTAC targeted protein degrader, for the treatment of men with metastatic castration-resistant prostate cancer, or mCRPC. We have chosen AR degradation as our initial therapeutic focus due to the well-documented biology of AR signaling as the principal driver of this cancer. ARV-110 has demonstrated activity in preclinical models of AR overexpression and AR mutations, both common mechanisms of resistance to current standard-of-care agents in men with prostate cancer. We believe that the differentiated PROTAC pharmacology of ARV-110, including its iterative activity, has the potential to translate into significantly improved clinical outcomes over current standard-of-care agents.

Prostate Cancer

In the United States, prostate cancer is both the second most prevalent cancer in men and the second leading cause of cancer death in men. Current estimates predict that one in nine men will be diagnosed with prostate cancer in his lifetime. The American Cancer Society estimates that in 2021 there will be over 248,000 new cases of prostate cancer in the United States and approximately 34,000 deaths from the disease. Men with mCRPC have a poor prognosis and a predicted survival rate of fewer than two years from the initial time of progression.

Treatment options for prostate cancer depend on many different factors, including the stage of the cancer. Castration-resistant prostate cancer is defined by disease progression despite androgen deprivation therapy, or ADT, and is often indicated by rising levels of prostate-specific antigen, or PSA. In making treatment evaluations, physicians monitor disease burdens in several ways, including changes in PSA levels. Increased PSA blood levels are considered by many physicians as indicative of cancer progression, and alternative treatment options may be considered. Current standard of care for men with castration-resistant prostate cancer provides that patients should initially receive a combination of ADT and either abiraterone, which works by decreasing androgen levels, or enzalutamide, which works by blocking androgen binding to AR. If the disease progresses despite these second-generation hormonal therapies, chemotherapy is considered the next treatment option. Treatment with chemotherapy is generally postponed for as long as possible due to the potential for severe side effects including neuropathies, nausea, diarrhea, decreased mental capacity and increased risk of infections.

Androgen receptor remains the principal driver of castration-resistant prostate cancer progression during the transition from localized to metastatic disease, with AR gene amplification occurring in 40% to 60% of patients, amplification of a transcription regulatory region upstream of the AR gene occurring in 70% to 87% of patients, and AR point mutations occurring in approximately 15% of patients. Between 15% to 25% of patients do not respond to either abiraterone or enzalutamide and the vast majority of the responsive patients will ultimately become resistant, resulting in limited survival. There remains meaningful unmet medical need in the treatment paradigm of mCRPC, including a significant underserved set of patients who are or become resistant to current therapies. Based on our preclinical data, we believe our PROTAC targeted protein degraders may overcome these known resistance mechanisms and create meaningful clinical benefit for patients.

Preclinical Development

We have conducted a comprehensive preclinical program to study ARV-110 as a potential treatment for men with mCRPC and initiated a Phase 1 clinical trial in March 2019 and the Phase 2 expansion cohort of that clinical trial in October 2020.

In in vitro models, ARV-110 degraded 95% to 98% of AR in multiple cell lines typically used in prostate cancer research.

ARV-110 is also highly selective for AR. A proteomic analysis of VCaP cells treated in vitro with ARV-110 at a 10 nM concentration for eight hours demonstrated that only AR was degraded from the nearly 4,000 measured proteins.

Importantly, in addition to AR degradation and selectivity, we have observed in preclinical studies the ability of ARV-110 to potently inhibit prostate cancer cell growth and reduce PSA levels. In addition to guiding treatment decisions, reduction in PSA is often an indicator of the effectiveness of treatment in clinical trials, although it is not recognized as a surrogate endpoint for purposes of regulatory approval. For example, ARV-110 demonstrated equivalent reduction in PSA to enzalutamide at ten-fold lower concentration levels in an in vitro inhibition study of PSA synthesis in Lymph Node Cancer of the Prostate cells, which are androgen-sensitive human prostate adenocarcinoma cells, that have been engineered to overexpress AR.

In in vivo mouse models, ARV-110 has inhibited AR-dependent tumor growth, in a statistically significant manner. ARV-110 exhibited superior tumor growth inhibition compared to enzalutamide in both castrated and intact (non-castrated) xenograft models derived from VCaP cell lines.

To assess the ability of ARV-110 to treat enzalutamide-resistant cancers, we conducted in vivo studies of ARV-110 in an enzalutamide-resistant VCaP xenograft model. These VCaP tumors acquired resistance to enzalutamide after being continuously propagated in castrated, enzalutamide treated mice for approximately three years. This resistance can be seen in the figure below, as tumors in mice dosed with enzalutamide grew at nearly the same rate as tumors in mice dosed only with the drug vehicle-a control similar to dosing a placebo. Orally delivered ARV-110 significantly inhibited tumor growth, described as tumor growth inhibition, or TGI, in these enzalutamide-resistant VCaP tumors.

We have also conducted preclinical studies of ARV-110 for enzalutamide-insensitive cancers. We conducted an in vivo study using a tumor line derived directly from a patient, referred to as a patient derived xenograft, or PDX, model. This model is derived from a tumor from a patient not treated with enzalutamide but that is insensitive to enzalutamide. This insensitivity can be seen in the figure below, as tumors in mice dosed with enzalutamide grew at only a slightly slower rate than tumors in mice dosed only with the drug vehicle. In contrast, orally delivered ARV-110 significantly inhibited tumor growth in these enzalutamide-insensitive tumors, achieving a TGI value of 100%. Further, PSA levels in the plasma of mice following 20 days of ARV-110 dosing significantly decreased in comparison to those dosed with only the drug vehicle or enzalutamide.

We believe the activity of ARV-110 in the above VCaP and PDX models may closely reflect enzalutamide resistance or insensitivity in the clinic and shows the potential for treatment of patients whose tumors have become resistant to, or demonstrate intrinsic resistance to, a current standard-of-care agent.

ARV-110 has also reduced the levels of PSA in plasma comparable to levels achieved with enzalutamide in a different VCaP xenograft mouse model but at a lower dosing level.

We conducted IND-enabling Good Laboratory Practice, or GLP, toxicology studies with ARV-110 in rats and dogs to support advancement of ARV-110 into clinical development. Both study designs called for animals to be treated once daily, orally for 28 days, followed by a 14-day recovery period for high dose animals. We believe both studies provide favorable safety margins of approximately five to ten times higher than the anticipated therapeutic doses.

In the rat study, a no observed adverse effect level, or NOAEL, of 40 milligrams per kilogram, or mpk, the mid-dose, in female animals and 120 mpk, the high dose, in male animals was identified. All findings observed in male high-dose animals were considered reversible by the study director. Atrophy of the prostate and seminal vesicles was noted in male animals at all dose levels and we believe is attributable to the pharmacologic activity of ARV-110.

In the dog study, the NOAEL was 10 mpk per day, the mid-dose. The high dose of 30 mpk per day exceeded the maximum tolerated dose, and dosing in this group was stopped prior to the planned completion to allow for collection of reversibility data. Elevations in liver function enzymes noted in some mid- and high-dose animals were considered reversible by the study director, and non-adverse as they were without microscopic correlates. In addition, at all dose levels, including animals receiving vehicle only, gastrointestinal alteration such as loose and abnormally colored stools were noted. Decreased prostate weights were noted in all male animals and we believe are attributable to the pharmacologic activity of ARV-110.

Our Phase 1/2 Clinical Trial

In March 2019, we initiated dosing in a Phase 1 clinical trial of ARV-110. Our Phase 1 trial is designed as an open label, dose-escalation study of ARV-110 in approximately 28 to 60 men with mCRPC whose disease has progressed on at least two prior systemic therapies, one of which must have been enzalutamide or abiraterone. The Phase 1 trial is designed to primarily investigate the safety and tolerability of ARV-110. Secondary endpoints include characterization of ARV-110’s pharmacokinetic profile and preliminary assessment of biochemical and clinical activity based on evaluation of PSA levels, and radiographic measurement of evaluable lesions. The anti-tumor effects of ARV-110 in measurable lesions will be assessed using Response Evaluation Criteria in Solid Tumors, or RECIST, a standardized set of rules for response assessment based on tumor shrinkage which is widely used in oncology clinical trials. We also will evaluate exploratory markers of disease burden, such as circulating tumor cell enumeration, as exploratory endpoints of the trial. The dose escalation portion of the trial is enrolling patients at four study centers in the United States. The protocol provided for a starting dose of 35 mg/day, administered orally. Up to a total of 20 patients (inclusive of patients previously enrolled at a given dose level) may be added to a previously studied dose escalation cohort once that dose has been deemed safe for further development. Eligible patients include those who have received at least two prior approved therapies for castrate-resistant prostate cancer (at least one of which must be abiraterone or enzalutamide).

In October 2019, we shared preliminary data from the first three dose-escalation cohorts (35 mg, 3 patients; 70 mg, 4 patients; and 140 mg, 3 patients). ARV-110 (35 mg, 70 mg, and 140 mg) was well tolerated, with no dose-limiting toxicities and no grade 2, 3, or 4 treatment-related adverse events observed. The data presented showed dose proportionality for ARV-110 and that average plasma exposures of ARV-110 in the third (140 mg) cohort had reached levels associated with tumor growth inhibition in preclinical studies.

In May 2020, we announced updated data from the Phase 1/2 clinical trial for ARV-110. The data showed evidence of in-tumor AR reduction. As of the April 20, 2020 data cut-off, 20 patients were evaluable for prostate-specific antigen, or PSA, response, including 12 patients treated at 140 mg or higher. These 12 patients exclude one patient who received two weeks of therapy prior to discontinuing due to a rosuvastatin-related dose limiting toxicity.

Of the 12 patients treated at 140 mg and above, circulating tumor DNA analysis of five patients showed AR forms (L702H point mutations and AR-V7 splice variants) not degradable by ARV-110 in preclinical studies. In the group of seven remaining patients who had degradable forms of AR (other AR point mutations, AR amplification and wildtype AR), two patients achieved confirmed PSA responses that remained ongoing, as of the cut-off.

One of these patients had a 74% decline from baseline in PSA and remained without progression after 30 weeks, as of the data cut-off. This patient did not have measurable disease at baseline for assessment by RECIST. The second patient had both a deep PSA response (97% decline from baseline) and a confirmed partial RECIST response (80% decrease from baseline in tumor mass) and remained without progression after 18 weeks, as of the data cut-off. Both responses, which were in patients at the 140 mg dose, were achieved by ARV-110 despite prior treatment with enzalutamide, abiraterone, chemotherapy and other therapies. Tumors from both patients have H875Y and T878A point mutations in AR, which are known to drive resistance to current standard of care treatments and have been degraded by ARV-110 in preclinical studies. In addition to these two patients, PSA reductions were observed in other patients but did not meet a 50% reduction in PSA threshold at data cutoff, and four patients remained on ARV-110 without radiographic progression for at least 20 weeks.

A potential drug-drug interaction between ARV-110 and rosuvastatin, or ROS, was identified during the trial. Of the 22 patients enrolled, two had concurrent use of ROS. One patient receiving 280 mg ARV-110 experienced a Grade 4 dose-limiting toxicity of elevated aspartate transaminase/alanine transaminase, or AST/ALT, liver enzymes followed by acute renal failure. The second patient, receiving 70 mg ARV-110, experienced a Grade 3 AST/ALT elevation, which resolved after the removal of ROS, and the patient was retreated with ARV-110. Follow-up exploratory findings indicate that ROS concentrations, but not ARV-110 concentrations, were elevated in both patients who had liver function test increases. Subsequent in vitro transport pump studies indicated that ARV-110 inhibited breast cancer resistant pump transporter, of which ROS is a substrate. Following the initial data that supported a potential interaction with ROS, concomitant use of ROS was precluded, and as of the cut-off date no other ARV-110 related Grade 3 or 4 adverse events had been reported. Six other patients had, as of the data cut-off date, received concomitant non-ROS statins without AST/ALT adverse events.

In the first and third quarters of 2020, we amended the protocol for our Phase 1 clinical trial for ARV-110. These amendments included the addition of a Phase 2 expansion cohort.

In December 2020, we announced updated interim data from the dose escalation portion of our clinical trial.

We reported that ARV-110 exposures have risen dose proportionally, and at 420 mg oral daily dosing, exposures in nearly all patients have surpassed a threshold we associated with tumor growth inhibition with ARV-110 in enzalutamide-resistant preclinical models of prostate cancer.

In the dose escalation portion of the trial, 76% of patients had been treated with prior chemotherapy, and 82% previously received both abiraterone and enzalutamide. Patients had a median of five prior lines of therapy. Multiple lines of therapy in nonmetastatic and metastatic castrate resistant prostate cancer are associated with a decreased responsiveness to AR-directed therapies and an increase in tumor heterogeneity, including in genetic mutations, which reduce the tumor’s dependence on the AR signaling axis. Analysis of trial patient tumor DNA showed that 84% of patients in the trial had at least one and often several non-AR gene mutations. As such, these patients would not be expected to respond to AR-directed agents such as ARV-110. In addition, we found that rates of certain AR mutations have been found to be higher than we anticipated based on previously published studies of men with mCRPC.

We have identified a molecularly defined, late-line population with a particularly strong response to ARV-110. Two of five patients (40%) with multiple AR mutations, including T878 and/or H875, had PSA reductions equal to or greater than 50%, or PSA50 response, and one patient had a tumor size reduction of 80%.

In addition, two of 15 patients (13%) with wild-type AR also had a PSA50 response, representing activity in a broader patient population. In the full group of patients with exposures above the minimum threshold we predicted to be efficacious by preclinical studies, four of 28 (14%) had PSA reductions greater than 50%. We believe that this PSA50 response rate is substantially higher than would be expected from approved AR-directed therapies in such late line patients. Specifically, PSA50 response rates from standard-of-care AR-directed therapies generally decrease to 8%-15% in mCRPC patients with fewer prior therapies.

The dual signals of ARV-110 activity in a molecularly defined population (T878/H875) and in AR wild-type patients support our two-pronged strategy for ARV-110 development and suggest a robust opportunity to address unmet need in patients with mCRPC.

In October 2020, we initiated the ARDENT Phase 2 expansion portion of the trial comprising patient subgroups at a dose of 420 mg daily and with the possibility of adding a further dose or schedule. T878/H875 patients will be enriched in a subgroup to ensure sufficient patient numbers in an effort to confirm the potential for accelerated regulatory approval for ARV-110 in this population. A separate subgroup will enrich for less-pretreated patients (i.e., no prior chemotherapy and with only one previous second-generation AR-directed therapy, such as enzalutamide or abiraterone), to ensure sufficient numbers of patients whose tumors are expected to be more AR-dependent, less genetically complex, and potentially more responsive to ARV-110.

We expect to provide complete data from the dose escalation portion of the Phase 1/2 trial in 2021 and provide interim data from the ARDENT Phase 2 expansion portion of the Phase 1/2 trial in the second half of 2021, with full data following in 2022. In 2021, we also expect to begin at least one Phase 1b combination trial with a standard-of-care prostate cancer therapy and provide data in 2022.

ARV-766 for the Treatment of Men with Metastatic Castration-Resistant Prostate Cancer

We are developing ARV-766 to target and degrade wild-type and mutated AR including at least one additional, clinically relevant AR point mutation, the L702H point mutation, which ARV-110 does not degrade. The L702H point mutation in the ligand-binding domain of AR results in activation of the AR by glucocorticoids and can cause resistance to a standard of care regimen. Recent studies have reported that between approximately 2-9% of patients with mCRPC had an L702H point mutation. We expect to file an IND application for ARV-766 and initiate a Phase 1 dose escalation clinical trial in the first half of 2021, and if ARV-766 progresses as planned, we expect to provide data from the Phase 1 clinical trial and transition to Phase 2 in 2022.

Next Generation AR Degraders

We are developing additional PROTAC targeted protein degraders capable of degrading certain AR splice variants. We expect that results from our Phase 1/2 clinical trials of ARV-110 and ARV-766 will provide further data on the role of androgen receptor splice variant-7, or AR-V7, in prostate cancer. ARV-110 and ARV-766 bind to full-length AR at its ligand-binding domain. AR-V7 is a truncated form of AR that lacks the ligand-binding domain necessary to bind with ARV-110 and ARV-766 and which ARV-110 and ARV-766 therefore do not degrade. AR functions as a dimer, a complex made up of two individual AR proteins. AR-V7 can form a dimer with a full-length AR, and such non-identical protein dimers are called heterodimers. We believe that ARV-110 and ARV-766, by degrading the full-length AR component of the heterodimer, could successfully inactivate AR-V7-directed signaling. Although shown to form a heterodimer preclinically, there is uncertainty as to whether AR-V7 and AR form a heterodimer in patients’ tumors. It is also possible that AR-V7 signals through V7-only dimers, which would be unaffected by ARV-110 and ARV-766. Although the presence of AR-V7 has been shown to correlate with a lack of response to enzalutamide and abiraterone, a published study demonstrated that approximately 40% of patients with AR-V7 expressing circulating tumor cells show a PSA response to enzalutamide. Given the evolving potential role of AR-V7 in prostate cancer, as a follow-on to ARV-110 and ARV-766, we are exploring the identification and development of a PROTAC targeted protein degrader that can degrade AR-V7 directly, as well as other AR splice variants.

ARV-471 for the Treatment of Patients with Locally Advanced or Metastatic ER Positive / HER2 Negative Breast Cancer

We are developing ARV-471, an orally bioavailable ER degrading PROTAC targeted protein degrader, as an alternative to, and potentially more potent degrader than, the intramuscular injection fulvestrant and other selective ER degraders currently in development for the treatment of patients with locally advanced or metastatic ER positive / HER2 negative breast cancer. Similar to our AR program, we have chosen ER degradation as a therapeutic focus given the well-documented biology of ER signaling as a principal driver in a high percentage of breast cancers. ARV-471 has demonstrated activity in ER positive breast cancer preclinical models. We are clinically investigating ARV-471 for use as a single agent and in combination with cyclin-dependent kinase (CDK) 4/6 inhibitors such as palbociclib. We believe ARV-471 has the potential to improve clinical outcomes over current standards of care for patients with locally advanced or metastatic ER positive / HER2 negative breast cancer.

Breast Cancer

In the United States, breast cancer is the second most common cancer and the second leading cause of cancer death in women. The American Cancer Society estimates that in 2021 there will be approximately 281,000 women diagnosed with invasive breast cancer in the United States. Metastatic breast cancer accounts for approximately 6% of newly diagnosed cases. Approximately 80% of newly diagnosed breast cancers are ER+, with many patients developing resistance to current treatment options over time.

Treatment options for breast cancer depend on many different factors, including the stage of the cancer and whether the cancer cells contain hormone receptors. Patients with locally advanced or metastatic breast cancer are treated with systemic therapy, including hormone therapy, chemotherapy and targeted therapy, either as single-agents or in combination. Patients with locally advanced or metastatic ER positive / HER2 negative breast cancer are often treated with hormone therapy, such as tamoxifen or an aromatase inhibitor, sometimes in combination with targeted drugs such as CDK 4/6 inhibitors. In patients with aggressive disease or whose disease continues to progress with a hormonal treatment regimen, chemotherapy may be prescribed. Treatment with chemotherapy is generally postponed for as long as possible due to the potential for severe side effects including neuropathies, nausea, diarrhea, decreased mental capacity and increased risk of infections.

A current standard of care for patients with ER positive / HER2 negative locally advanced or metastatic breast cancer is fulvestrant, an ER degrader administered as a monthly intramuscular injection, either as a single-agent or in combination with another targeted therapy. While fulvestrant has validated the importance of ER degradation as a therapeutic intervention, up to 50% of ER can remain when compared to baseline levels after six months of treatment with fulvestrant, providing an opportunity for more potent ER degraders, such as ARV-471, our PROTAC targeted protein degrader.

Preclinical Development

We have conducted a comprehensive preclinical program to study ARV-471 as a potential treatment for patients with locally advanced or metastatic ER positive / HER2 negative breast cancer. In our preclinical studies, ARV-471 was a superior degrader of ER compared to fulvestrant. ARV-471 has also shown superior tumor growth inhibition when combined with a CDK4/6 inhibitor compared to fulvestrant and the same combination partner.

In in vitro models, ARV-471 has induced ER degradation in multiple cell lines typically used in breast cancer research.

In in vivo experiments ARV-471 has achieved superior tumor growth inhibition and degradation compared to fulvestrant. We have tested ARV-471 for tumor growth inhibitory activity using an industry-standard MCF-7 xenograft mouse model. MCF-7 is a well-characterized estradiol-dependent ER positive / HER2 negative cell line that forms tumors when implanted in the mammary fat pad of female mice. As shown in the figure below, ARV-471 resulted in very high tumor growth inhibition when dosed daily orally at 10 mpk and more than 80% tumor shrinkage when dosed daily orally at 30 mpk for 28 days. At both doses, ARV-471 demonstrated superior activity compared to a clinically relevant dose of fulvestrant, which is 200 mpk twice per week for two weeks and then once per week for two weeks.

After 28 days of dosing in this efficacy study, the MCF-7 tumors were removed from the mice and processed for western blots to observe the level of ER degradation induced by oral dosing of ARV-471. ARV-471 reduced ER by 85%, on average, at 10 mpk as compared to the control tumors and by 89%, on average, at 30 mpk as compared to the control tumors.

We have also conducted preclinical studies to test ARV-471 in a PDX model. This model is derived from a tumor with an ESR1 mutation (Y537S), which is a mutation in the ER that occurs in patients who have been treated with standard-of-care agents such as tamoxifen or an aromatase inhibitor, such as letrozole, and has been cited as a mechanism of resistance to those drugs. These studies included a comparison with fulvestrant. In this 28-day dosing study, oral ARV-471 inhibited tumor growth by 99% at the 10 mpk dosing level and by 106% at the 30 mpk dosing level which was observed to be superior at both dosing levels to a clinically relevant dose of 200 mpk of fulvestrant. Further, ARV-471 was shown to reduce ER by 79% and 88% at the 10 mpk and 30 mpk dosing levels, respectively, compared with 63% at the 200 mpk of fulvestrant dosing level.

We have also conducted studies of ARV-471 in combination with palbociclib, a CDK4/6 inhibitor that is standard of care when used together with fulvestrant. In these studies, we have achieved significant tumor shrinkage with ARV-471 in ER positive / HER2 negative MCF-7 xenograft models. As shown in the figure below, in a 28-day dosing study in MCF-7 xenografts, ARV-471 at 30 mpk daily in combination with palbociclib was superior in shrinking tumors, as compared to either palbociclib as a single agent at 60 mpk daily, or the standard-of-care combination of palbociclib at 60 mpk daily plus fulvestrant at 200 mpk twice per week for two weeks and then once per week for two weeks.

We believe that ARV-471 may also show compelling activity in combination with other targeted agents currently used or in clinical trials for locally advanced or metastatic breast cancer including PI3K and mTOR inhibitors and plan to test these combinations in preclinical models.

We conducted IND-enabling GLP toxicology studies with ARV-471 in rats and dogs to support advancement of ARV-471 into clinical development. The designs for these studies called for animals to be treated once daily, orally for 28 days, followed by a 28-day recovery period at each dose level in the rat study and for the high dose animals only in the dog study.

In the rat study, animals were treated at doses of 0 (vehicle control), 3, 10, 30 and 100 mpk/day. The NOAEL was 100 mpk, the high dose. All findings observed were considered reversible by the study director. Evidence of pharmacologic activity was noted in the reproductive organs of rats at the 3 mpk dose level and higher. In the dog study, animals received 0 (vehicle control), 15, 45 or 90 mpk/day. The NOAEL was 90 mpk, the high dose. All findings observed in high-dose animals were considered reversible by the study director.

Our Phase 1/2 Clinical Trial

In August 2019, we initiated dosing in a Phase 1 clinical trial for ARV-471. The trial is an open-label dose-escalation study in which we expect to dose approximately 28 to 36 patients with locally advanced or metastatic ER positive / HER2 negative breast cancer who have progressed on at least two prior endocrine therapy regimens and a CDK4/6 inhibitor. Eligible patients may have also received up to three prior regimens of cytotoxic chemotherapy. The protocol provides for a starting dose of 30 mg/day, administered orally.

In the first and fourth quarters of 2020, we amended the protocol for our Phase 1 clinical trial for ARV-471, to include the Phase 2 expansion cohort and a Phase 1b cohort expansion of ARV-471 in combination with Ibrance® (palbociclib), respectively.

The Phase 1/2 trial is designed to primarily investigate the safety and tolerability of ARV-471 and characterize its pharmacokinetic profile. ER degradation by comparing ER levels in pre-treatment and post-treatment tumor biopsies in patients with appropriate lesions will also be evaluated as a secondary endpoint. Other secondary endpoints include the evaluation of anti-tumor response in patients with measurable disease using RECIST.

In October 2019, we shared preliminary data from three patients enrolled in the first dose escalation cohort (30 mg). At that dose ARV-471 was well tolerated, with no dose-limiting toxicities and no treatment-related adverse events observed. The data presented showed that average plasma exposures of ARV-471 in the 30 mg dose cohort reached levels associated with tumor growth inhibition in preclinical studies.

In December 2020, we announced updated interim data from the dose escalation portion of our ongoing Phase 1/2 clinical trial of ARV-471 in patients with locally advanced or metastatic ER+/HER2- breast cancer.

As of the data cut-off date of November 11, 2020, 21 adult patients with locally advanced or metastatic ER+/HER2- breast cancer were dosed with ARV-471 (orally, once-daily) in the Phase 1 clinical trial. 100% of these patients were previously treated with a CDK 4/6 inhibitor, 71% of patients also received prior fulvestrant, and 23% of patients were also pretreated with investigational selective estrogen receptor degraders or SERDs. Overall, patients had a median of five prior therapies.

One patient in the ARV-471 trial had a confirmed partial response, with a 51% reduction in target lesion size as assessed by RECIST. In addition to the confirmed partial response, two additional patients had unconfirmed partial responses and one additional patient demonstrated stable disease with greater than 50% target lesion shrinkage. For a clinical benefit rate, or CBR, evaluation, 12 patients had sufficient follow-up to be included. Five of 12 patients (42%) achieved CBR. CBR is defined to include partial responses, complete responses and stable disease at 6 months. Three of these five patients had previously received fulvestrant, and another was treated with two investigational SERDs.

ARV-471 was well tolerated at all dose levels, as of the data cut-off date. The most common treatment-related Grade 1-2 adverse events were nausea (24%), arthralgia (19%), fatigue (19%), and decreased appetite (14%). None of these led to discontinuation or dose reduction of ARV-471. No patients reported treatment-related Grade 3 or 4 adverse events, and no dose-limiting toxicities have been reported. A maximum tolerated dose has not been reached and dose escalation continues.

The plasma exposures of ARV-471 have been dose proportional up to and including 360 mg orally once daily and have substantially exceeded our predicted thresholds of efficacy based on preclinical studies. The estimated half-life of ARV-471 is 28 hours, supporting a once-daily schedule of administration. Analysis of five paired tumor biopsies at doses up to 120 mg provide compelling proof of mechanism for ARV-471. At those doses, we have observed ER degradation up to 90% (average of 62%).

We believe that the interim data from our ongoing clinical trial compares favorably to previously reported Phase 1 clinical trial results of other SERDs with respect to tolerability, ER degradation and efficacy signals.

We expect to complete the dose escalation portion of the Phase 1/2 clinical trial of ARV-471 in the first half of 2021. In February 2021, we initiated the VERITAC Phase 2 expansion portion of the trial at 200 mg daily with the possibility of adding a second dose level. We anticipate sharing interim data from the VERITAC dose expansion portion in 2022.

We initiated a Phase 1b cohort expansion of ARV-471 in combination with Ibrance® (palbociclib) in December 2020. This trial will evaluate the safety and tolerability of ARV-471 in combination with palbociclib and seek to identify a recommended combination dose.

We expect to begin two additional studies of ARV-471 in the second half of 2021: a combination trial of ARV-471 with another targeted therapy in second and/or third line metastatic breast cancer, and a window of opportunity study in early breast cancer.

The combined data from these studies will inform our global development strategy and path forward toward the goal for ARV-471 to become the leading endocrine therapy in ER+/HER2- breast cancer.

Our Exploratory and Research Programs

Neurodegenerative Diseases

Neurodegenerative diseases are generally progressive in nature and result in the degeneration and often death of neurons in the brain, leading to cognitive decline, functional impairment and eventually death. These diseases affect a rapidly growing patient population and represent one of the largest unmet medical needs of our time. Alzheimer’s and Parkinson’s diseases encompass the largest patient populations among the neurodegenerative diseases. The Alzheimer’s Association estimated that more than 5 million Americans aged 65 and older were living with Alzheimer’s dementia in 2020, and the Parkinson’s Foundation estimated that nearly one million Americans are living with Parkinson’s disease. Alzheimer’s disease is marked by the progressive accumulation of aggregated tau protein, while aggregation of alpha-synuclein is thought to cause Parkinson’s disease.

Inhibitor-based therapies targeting the proteins thought to be the cause of these neurodegenerative diseases have failed to show clinically meaningful benefit to date. While some existing products provide symptomatic relief to Alzheimer’s and Parkinson’s patients, they have significant side effect risks and over time gradually lose their effectiveness in treating the symptoms of the disease. Further, there are no approved disease-modifying treatments for Alzheimer’s or Parkinson’s.

Developing PROTAC Targeted Protein Degraders that Cross the Blood Brain Barrier

Engineering products that cross the blood brain barrier is a highly desirable characteristic in developing effective therapeutics for patients with neurodegenerative diseases as compared with therapies delivered directly into the central nervous system, or CNS. Any product candidates for neurodegenerative disease must reach their intended targets in the brain at exposure levels that will provide a therapeutic effect, while having an acceptable safety profile.

Importantly, we have achieved brain penetration in preclinical models following parenteral administration of PROTAC degrader molecules designed to specifically target pathologic oligomers of tau and α-synuclein, for the treatment of Alzheimer’s disease and other tauopathies and Parkinson’s disease and other synucleinopathies, respectively. These PROTAC degrader molecules achieved concentrations in the brain sufficient to induce degradation of the aggregated proteins, widespread penetration into different parts of the brain, and brain/plasma ratios of 0.5 to 5.0, which are comparable to approved therapeutics with CNS activity.

Developing PROTAC Targeted Protein Degraders that Degrade Proteins Associated with Neurodegenerative Diseases

We have conducted preclinical studies to establish the potential of our PROTAC Discovery Engine in the CNS for the treatment of neurodegenerative diseases, including tauopathies, the largest of which is Alzheimer’s disease. We have demonstrated that tau PROTAC protein degrader molecules could be dosed peripherally and degrade pathogenic tau in the brain of a mouse tauopathy model. The figure below shows a greater than 95% reduction in pathologic tau in the cortex of the brain of the Tg2508 mouse model 24 hours following a single parenteral administration of two different tau targeting PROTAC degraders, PROTAC-A at 15 mg per kg and PROTAC-B at 30 mg per kg. We anticipate filing an IND application for our tau program in 2022.

2 AUC, or area under the curve, for pathologic tau was measured from the cortex region of the brain by WESTM capillary electrophoresis.

**** Tukey's multiple comparisons test p-value < 0.0001

Alpha-synuclein is an abundant neuronal protein that localizes predominantly to presynaptic terminals within the brain. While the normal function of this protein is not fully understood, the pathologic aggregation of alpha-synuclein is implicated in synucleinopathies; the most common of which is Parkinson’s disease.

In preclinical studies, we have demonstrated that alpha-synuclein PROTAC degraders can specifically degrade aggregated forms of the protein. We have conducted in vitro experiments in cells expressing the A53T mutant form of alpha-synuclein, a mutation that causes aggregation of alpha-synuclein and early-onset Parkinson’s diseases in patients. We treated these cells with alpha-synuclein targeting PROTAC degraders at 1 μM for 48 hours. The table below shows that three different PROTAC molecules, P-3, P-5, and P-6, each degraded aggregated forms of alpha-synuclein in a statistically significant manner, as measured by an alpha-synuclein oligomer based enzyme-linked immunosorbent assay.

In addition to our tau and alpha-synuclein programs, our neuroscience programs include a program directed to mutant huntingtin (mHTT), a key protein target for Huntington’s disease.

Other Oncology, Immuno-Oncology and Undruggable Targets

We have active exploratory and research programs to evaluate additional established targets in oncology and immuno-oncology, as well as other currently undruggable targets. In line with our strategy, we assess potential exploratory programs on a target-by-target basis to decide whether our PROTAC targeted protein degraders provide a compelling differentiated approach over standard-of-care or other, existing or potential competing mechanisms of action directed against a specific target. In the case of currently undruggable targets, we assess whether the features of our PROTAC targeted protein degraders, including their potential to degrade proteins via sites other than enzymatic active sites and the ability to initiate the degradation process using only weak binders, offer us opportunities to degrade those targets.

Our exploratory and research activity in oncology and immuno-oncology includes programs directed to the B-cell lymphoma 6 protein (BCL6), a transcription factor implicated in B cell lymphomas; Kirsten rat sarcoma (KRAS), an oncogenic cell growth regulator; Myc, an oncogenic transcription factor driving tumor cell proliferation; and hematopoietic progenitor kinase 1 (HPK1), a suppressor of T cell activation. We anticipate filing an IND application for our BCL6 program as well as an additional oncology-associated program in 2022.

Intellectual Property

Our commercial success depends in part upon our ability to secure and maintain patent and other proprietary protection for our platform protein degradation technologies, including our PROTAC targeted protein degrader programs, product candidates, and know-how related to our business, defend and enforce our intellectual property rights, in particular our patent rights, preserve the confidentiality of our trade secrets, and operate without infringing valid and enforceable intellectual property rights of others.

The patent positions for biopharmaceutical companies like us are generally uncertain and can involve complex legal, scientific and factual issues. In addition, the coverage claimed in a patent application can be significantly reduced before a patent is issued, and its scope can be reinterpreted and even challenged after issuance. As a result, we cannot guarantee that any of our product candidates will be protected or remain protectable 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.

As of February 1, 2021, our patent estate that we own, co-own and in-license includes 20 issued U.S. patents, 36 foreign granted patents, and 344 pending patent applications.

PROTAC Patents and Patent Applications

Our PROTAC patent portfolio is generally organized into two categories: PROTAC platform patent filings, and PROTAC product candidate or protein target-specific patent filings.

PROTAC Platform

As of February 1, 2021, our PROTAC platform patent estate that we own, co-own, and in-license, and that covers our various E3 ubiquitin ligase constructs, includes two issued U.S. patents, 9 granted foreign patents, 9 pending U.S. patent applications and 80 pending foreign patent applications. This patent estate covers constructs that have ligands for the Von Hippel Lindau, or VHL, E3 ubiquitin ligase, the cereblon, or CRBN, E3 ubiquitin ligase, the inhibitor apoptosis protein, or IAP, E3 ubiquitin ligase, and the human mouse double minute homolog, or MDM2, E3 ubiquitin ligase.

We exclusively license from Yale University a portfolio of patents and patent applications describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds comprised of ligands for the VHL E3 ubiquitin ligase, as well as claims to associated methods of use. Patents have been granted in Australia, Mexico, the United States, and Russia, and patent applications are pending in the United States, Brazil, Canada, China, Europe, Hong Kong, India, Japan and South Korea. If all appropriate maintenance fees are paid, each granted patent will expire in 2033 without taking potential patent term extensions into account. We also co-own with Yale patent applications describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds comprised of ligands for the VHL E3 ligase. A patent has issued in the United States, and patent applications are pending in the United States, Australia, Canada, China, Europe, Hong Kong, India, Japan, South Korea, Mexico and Russia. Our rights to this patent and these patent applications are governed by the Yale License Agreement described below.

We own three patent families with three pending U.S. patent applications describing composition-of-matter claims covering the CRBN E3 ubiquitin ligase ligand generically, the chemical linker group generically, and a small molecule or peptide ligand that binds to a target protein generically. We own granted patents in Australia, Japan, Europe, and Russia. Patent applications are pending in the United States, Australia, Brazil, Canada, China, Europe, Hong Kong, India, Japan, Korea, Mexico, and Russia. If all appropriate maintenance fees are paid, each granted patent in these families will expire in 2035 without taking potential patent term extensions into account.

We own a patent family describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds comprised of ligands for the IAP E3 ubiquitin ligase as well as claims to associated methods of use. Patent applications in this family are pending in the United States, Australia, Brazil, Canada, Europe, Hong Kong, India, Korea, Mexico and Russia. If granted, and all appropriate maintenance fees are paid, the expiration of these patents would be in 2036 without taking potential patent term extensions into account.

We own a patent family describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds comprised of ligands for the MDM2 E3 ubiquitin ligase as well as claims to associated methods of use. Patent applications in this family are pending in the United States, Australia, Brazil, Canada, China, Europe, Hong Kong, India, Japan, Korea, Mexico, and Russia. If granted, and all appropriate maintenance fees are paid, the expiration of these patents would be in 2036, without taking potential patent term extensions into account.

PROTAC Product Candidates

Our product or protein-specific patent applications were created to pursue more focused patent exclusivity around PROTAC targeted protein degrader compounds designed to target specific proteins. As of February 1, 2021, our PROTAC product patent portfolio that we own, co-own and in-license includes 15 U.S. issued patents, 26 issued foreign patents, 54 pending U.S. patent applications, and 193 pending foreign patent applications.

We own seven patent families describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds addressing AR and associated methods of treating cancer. The first patent family has two issued U.S. patents, two granted foreign patents, three pending U.S. applications and 22 pending foreign patent applications describing composition-of-matter and method of use claims covering ARV-110. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2037 without taking potential patent term extension into account. The second patent family has four pending applications in the U.S., three granted foreign patents, and 26 foreign applications describing alternative composition-of-matter claims. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2036 without taking potential patent term extension into account. The third patent family has three pending U.S. applications and one pending Patent Cooperation Treaty, or PCT, application

describing claims directed to additional methods of treating cancer using ARV-110. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2040 without taking potential patent term extension into account. The fourth patent family has three pending U.S. applications, one pending PCT application, and one pending foreign application describing composition-of-matter claims directed to ARV-766. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2040 without taking potential patent term extension into account. The fifth patent family has a pending U.S. application describing claims directed to additional methods of treating cancer using ARV-110. Any patent granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2041 without taking potential patent term extension into account. The sixth patent family has a pending U.S. application describing claims directed to methods of manufacture, crystalline and ultrapure forms, and dosage forms of ARV-110. Any patent granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2041 without taking potential patent term extension into account. The seventh patent family has two pending U.S. applications describing claims directed to methods of treating cancer with ARV-110 in patients with specific AR mutations. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2041 without taking potential patent term extension into account.

We own six patent families describing composition-of-matter claims encompassing PROTAC targeted protein degrader compounds addressing ER and associated methods of treating cancer. The first patent family has two issued U.S. patents, two pending U.S. applications, two granted foreign patents, and 20 pending foreign patent applications describing composition-of-matter and method of use claims covering ARV-471. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2037 without taking potential patent term extension into account. The second patent family has two pending U.S. applications and one pending PCT application describing claims directed to methods of treating cancer using ARV-471 as a monotherapy, and also combined with an additional anti-cancer agent. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2040 without taking potential patent term extension into account. The third patent family has a pending U.S. application describing claims directed to crystalline forms of ARV-471. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2041 without taking potential patent term extension into account. The fourth patent family has a pending U.S. application describing claims directed to methods of treating cancer with ARV-471 in patients with specific ER mutations. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2041 without taking potential patent term extension into account. The fifth patent family has one issued U.S. patent, one pending U.S. patent application, and two pending foreign applications describing alternative ER-based PROTAC compounds and methods of use to treat cancer. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2039 without taking potential patent term extension into account. The sixth patent family has one issued U.S. patent, one pending U.S. patent application, and 13 pending foreign applications describing alternative ER-based PROTAC compounds and methods of use to treat cancer. Any patents granted in this family, assuming all appropriate maintenance fees are paid, will expire in 2038 without taking potential patent term extension into account.

We and Yale co-own nine patent families describing composition of matter claims of PROTAC targeted protein degrader compounds addressing certain discovery and other potential protein targets, and associated methods of use. Patent applications for each of these are pending in the United States. In addition, patent applications are pending at the international stage of the PCT for six of the families and with the European Patent Office for one of the families. Our rights to these patent applications are governed by the Yale License Agreement described below.

We also co-own with Genentech two pending U.S. patent applications, and 27 foreign patent applications directed to PROTAC targeted protein degrader compounds addressing a specific protein. Our rights to these patent applications are governed by the Genentech License Agreement described below.

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 term of a patent covering a drug approved by the U.S. Food and Drug Administration, or FDA, may be eligible for a patent term extension under the Hatch-Waxman Act as compensation for the loss of patent term during the FDA regulatory review process. The period of extension may be up to five years beyond the expiration of the patent but cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval. Only one patent among those eligible for an extension may be extended. Similar provisions are available in Europe and in certain other jurisdictions to extend the term of a patent that covers an approved drug. It is possible that issued U.S. patents covering ARV-110 and ARV-471 may be entitled to patent term extensions. If our product candidates receive FDA approval, we intend to apply for patent term extensions, if available, to extend the term of patents that cover the approved product candidates. We also intend to seek patent term extensions in any jurisdiction where they are available; however, there is no guarantee that the applicable authorities, including the FDA, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions.

The United States also offers Patent Term Adjustment,or PTA, whereby a particular patent’s term is automatically extended beyond the 20-year term if the United States Patent and Trademark Office caused delays during the underlying patent application’s examination. However, potentially available PTA will be reduced by any amount of delay caused by the applicant.

Trade Secrets

We also rely on trade secrets, technical know-how and continuing innovation to develop and maintain our competitive advantage. Our policy requires inventors who are identified on any company-owned patent applications to assign rights to us. We also rely on confidentiality agreements with our employees, consultants and other advisors to protect our proprietary information. Our policy is to require third parties that receive material confidential information to enter into confidentiality agreements with us.

Trademarks

We own a U.S. service mark registration for PROTAC for pharmaceutical products development of new small molecules aimed at degrading disease-causing cellular proteins for treatment in the field of oncology, immunology, inflammatory diseases, and central nervous system disorders. We also own a U.S. trademark registration for the mark PROTAC for small molecule products aimed at degrading disease-causing cellular proteins for treatment in the fields of oncology, immunology, inflammatory diseases, and central nervous system disorders.

We also own U.S. and Chinese service mark registrations for ARVINAS in word and logo form for pharmaceutical products development of new small molecules aimed at degrading disease-causing cellular proteins for treatment in the fields of oncology, immunology, inflammatory diseases, and central nervous system disorders.

We also own U.S. service mark registrations for our “degrading dots” logo mark in both black and white and color form for pharmaceutical products development of new small molecules aimed at degrading disease-causing cellular proteins for treatment in the fields of oncology, immunology, inflammatory diseases, and central nervous system disorders.

Licenses and Strategic Collaborations

Yale University License Agreement

In July 2013, we entered into a license agreement with Yale pursuant to which Yale granted us an exclusive, worldwide license under specified intellectual property rights for the treatment or prevention of any human or animal disease in which a product mediates degradation of one or more target proteins, which we refer to as the Field, subject to certain exceptions. These licensed intellectual property rights arose from the research conducted by Dr. Craig Crews at Yale. During the period in which Professor Crews serves as a member of our board of directors or scientific advisory board or has a similar advisory arrangement, has a consulting arrangement with us, or his laboratory is performing sponsored research for us, and so long as he is an employee or faculty member (including emeritus faculty member) at Yale, Yale will notify us of any inventions in the Field invented in Professor Crews’ laboratory and such invention will be included in the licensed intellectual property, subject to the rights of any non-profit sponsor of the research to use such invention solely for non-profit purposes. In addition, the laboratory of Professor Crews is restricted from conducting any sponsored research, collaboration or other similar arrangement in the Field with a for-profit company while Professor Crews is engaged with us, except where such arrangement allows Yale to grant us licenses of any inventions developed in the laboratory of Professor Crews in the Field in the licensed territory.

We are obligated to use commercially reasonable efforts to implement a written plan we agreed to with Yale setting forth a description of any research and development, testing, governmental approval and commercialization activities relating to licensed products and our financing plans. We must update this plan on an annual basis to indicate progress to date on the plan and a schedule of major events required to commercialize licensed products.

Pursuant to the license agreement we paid to Yale an upfront payment of $149,511. We are responsible for paying Yale an annual license maintenance fee in varying amounts (ranging from the low tens-thousands of dollars to the mid to high tens-thousands of dollars) until the first sale to a third party of any licensed product, which is creditable against our royalty obligations for the given year. As of December 31, 2020, we have paid a total of $435,000 in license maintenance fees to Yale. We are required to pay Yale, subject to the achievement of specified development and regulatory milestones, payments aggregating up to approximately $3.0 million for the first licensed product and up to approximately

$1.5 million for the second licensed product. We are not required to make any milestone payments for any licensed products beyond the first two. While the agreement remains in effect, we are required to pay Yale low single-digit royalties on aggregate worldwide net sales of certain licensed products, which may be subject to reductions. Yale is guaranteed a minimum royalty payment amount (ranging from $200,000 to $500,000) for each year after the first sale of a licensed product that results in net sales. The agreement requires that we must also pay Yale a mid-single digit to mid-double digit percentageof certainconsideration we receive from a sublicensee for the first licensed product we sublicense. We are also responsible for costs relating to the prosecution and maintenance of the licensed patents. Finally, subject to certain conditions, all payments made by us to Yale (except patent costs) will be tripled during the pendency of any patent challenge made by us against Yale.

We have also agreed to pay for PROTAC targeted protein degrader research support from Yale pursuant to a sponsored research agreement that we entered into with Yale in July 2016 and amended in April 2018. Under the sponsored research agreement, as amended, we agreed to pay Yale an aggregate of $3.7 million over five years, ending in April 2021, and as of December 31, 2020, we had paid Yale an aggregate of approximately $3.5 million. The research is performed by and under the supervision and direction of Professor Crews for so long as he is employed by Yale.

The license agreement remains in effect until (a) for certain products, the date on which the last claim of the licensed patents expires; and (b) for certain products, 10 years after the sale of such products. The expiration of the last to expire patent right licensed from Yale, if it issues as a patent and all appropriate maintenance fees are paid, is currently expected be in 2038. We could also obtain rights to additional patents, including through the issuance of pending patent applications, with later expiration dates, through our rights to any inventions in the Field invented in Professor Crews’ laboratory, which could extend the term of the Yale Agreement. Either we or Yale may terminate the agreement for the other party’s uncured material breach of certain provisions, we may terminate the agreement for convenience upon six months’ prior notice, and Yale may terminate the agreement if we fail to make a payment when due, fail to obtain or maintain adequate insurance coverage or fail to achieve specified financing or regulatory milestone events. The agreement will automatically terminate if we become insolvent.

Genentech License Agreement

In September 2015, we entered into an Option and License Agreement with Genentech, Inc. and F. Hoffmann-La Roche Ltd, collectively referred to as Genentech, focused on PROTAC targeted protein degrader discovery and research for target proteins, or Targets, based on our proprietary platform technology, other than excluded Targets as described below. This collaboration was expanded in November 2017 through an Amended and Restated Option, License and Collaboration Agreement, which we refer to as the Restated Genentech Agreement.

The collaboration is managed by a joint research committee and a joint project team, each of which is comprised of representatives from us and Genentech. Decisions of the joint research committee and joint project team are made by consensus, with each party having one vote. If the joint research committee is unable to agree, and the parties’ executives are not able to resolve the dispute, then Genentech has final decision-making authority, subject to specified limitations.

Under the Restated Genentech Agreement, Genentech has the right to designate up to ten Targets for further discovery and research utilizing our PROTAC platform technology. Genentech may designate as a Target any protein to which a PROTAC targeted protein degrader, by design, binds, to achieve its mechanism of action, subject to certain exclusions. Genentech also has the right to remove a Target from the collaboration and substitute a different Target that is not an excluded Target at any time prior to us commencing research on such Target or in certain circumstances following commencement of research by us.

Once a Target becomes subject to the collaboration, we are obligated to use diligent efforts to undertake a research program in accordance with a research plan agreed to by the parties for such Target. We are responsible for funding our activities under the research program for each Target up to the amount set forth in the budget for such Target agreed upon by the parties in the research plan. For costs incurred in excess of the budgeted amount, Genentech has the option of either having us continue the work on the Target and reimbursing us for our costs in doing so or terminating the work on such Target.

The research program for each Target contemplates that the discovery and research work will occur in two stages: Stage 1, in which our objective will be to identify a PROTAC targeted protein degrader that demonstrates in vitro protein degradation of the Target; and Stage 2, in which our objective will be to demonstrate certain in vitro and in vivo research and development activity, but not to complete toxicology studies or other necessary IND-enabling studies. For each Target, at the conclusion of Stage 1, Genentech has the opportunity to continue the research program for such Target or terminate all activities on such Target. At the conclusion of each stage, we are obligated to provide certain deliverables to Genentech, including a data package at the end of Stage 2. Genentech has an option to obtain an exclusive worldwide

license to the applicable PROTAC targeted protein degraders directed against the applicable Target, which we refer to as Licensed PROTACs. Each such option must be exercised within a specified time after we deliver the data package for such Licensed PROTAC to Genentech. Once Genentech exercises an option, it is responsible, at its cost, to use diligent efforts to develop and commercialize the Licensed PROTAC through first commercial sale in the United States, the European Union and Japan.

During the term of the Restated Genentech Agreement, we and our affiliates are not permitted, either directly or indirectly, to conduct any activities in the design, identification or discovery of any small molecule pharmacologically active agent directed against a Target included in the collaboration, including certain PROTAC targeted protein degraders whose intended primary mechanism of action is, by design, through induction of proteasomal degradation of such Target.

Under the terms of the Restated Genentech Agreement, we received $11.0 million in 2015 and an additional $34.5 million in 2017 in upfront payments and expansion target payments. We are eligible to receive up to an aggregate of $27.5 million in additional expansion target payments if Genentech exercises its options for all remaining Targets. We are also eligible to receive payments aggregating up to $44.0 million per Target subject to the achievement of specified development milestones; payments aggregating up to $52.5 million per Target (assuming approval of two indications) subject to the achievement of specified regulatory milestones; and payments aggregating up to $60 million per Licensed PROTAC subject to the achievement of specified sales milestones. These milestone payments are subject to reduction if we do not have a valid patent claim covering the Licensed PROTAC at the time the milestone is achieved. We are also eligible to receive, on net sales of Licensed PROTACs, mid-single digit royalties, which may be subject to reductions.

Unless earlier terminated, the Restated Genentech Agreement will expire upon the expiration of all royalty periods for any Licensed PROTACs. The royalty period for each Licensed PROTAC expires on a country-by-country basis upon either (1) the expiration of the last-to-expire valid patent claim covering such Licensed PROTAC or (2) ten years after the first commercial sale with respect to such Licensed PROTAC, depending on whether the sale of the Licensed PROTAC is covered by an applicable valid claim. The expiration of the last to expire patent right licensed to Genentech, if it issues as a patent and all appropriate maintenance fees are paid, is currently expected be in 2038. We could also obtain rights to additional patents, including through the issuance of pending patent applications, with later expiration dates, or new Licensed PROTACs could be added to the agreement that are subject to additional royalty terms with later expiration dates, which in either case could extend the term of the Restated Genentech Agreement. Genentech has the right to terminate the Restated Genentech Agreement for convenience in its entirety or with respect to a specific Target on 60 days’ prior notice. Either we or Genentech may terminate the agreement, in its entirety or with respect to a specific Target, if the other party is in material breach and such breach is not cured within the specified cure period. In addition, either we or Genentech may terminate the agreement in the event of specified insolvency events involving the other party. If Genentech terminates the agreement for convenience or if we terminate the agreement as a result of Genentech’s uncured material breach or Genentech’s insolvency, all licenses we granted to Genentech terminate (either in its entirety or with respect to a specific Target, as applicable based on the nature of the termination). If Genentech terminates the agreement as a result of our uncured material breach or our insolvency, all licenses that we granted to Genentech terminate (either in its entirety or with respect to a specific Target, as applicable based on the nature of the termination), except that Genentech has the right to elect to retain its licenses, in which case it would no longer be obligated to use diligent efforts to develop and commercialize the applicable Licensed PROTACs and its payment obligations to us would be reduced.

Pfizer License Agreement

In December 2017, we entered into a Research Collaboration and License Agreement with Pfizer, Inc., or Pfizer, setting forth our collaboration to identify or optimize PROTAC targeted protein degraders that mediate for degradation of Targets using our proprietary platform technology that are identified in the agreement or subsequently selected by Pfizer, subject to certain exclusions. We refer to this agreement as the Pfizer Collaboration Agreement.

Under the Pfizer Collaboration Agreement, Pfizer has designated a number of initial Targets. For each identified Target, we and Pfizer will conduct a separate research program pursuant to a research plan. Pfizer may make substitutions for any of the initial Target candidates, which substitutions are limited subject to the stage of research for such Target.

We and Pfizer are obligated to use commercially reasonable efforts to complete our respective activities set forth in a research plan, including, in our case, the obligation to provide certain deliverables at the end of each stage. Under the research plan, we are required to provide compound formulation and conduct pharmacokinetic/pharmacodynamic and drug safety research and development activities in support of screening and other activities conducted by Pfizer relating to a Target. Following the provision of the deliverables by us for a stage, we will suspend the conduct of any further activities until Pfizer has exercised its right to proceed. If Pfizer does not exercise such right within the applicable time period, we will cease activities for such Target and such Target will no longer be part of the collaboration. Each party will bear its own costs in the conduct of such activities, except that any additional work that we agree with Pfizer to perform outside of the research plan will be paid for by Pfizer.

Pfizer has the right to exercise an option to obtain an exclusive worldwide license with respect to each Target for a specified period of time after receipt of the applicable deliverables for such Target. If Pfizer does not exercise its option for a Target, such Target is no longer subject to the Pfizer Collaboration Agreement. If Pfizer exercises such option, Pfizer will have an exclusive license to develop and commercialize compounds directed against such Target, subject to certain diligence obligations.

During the term of the Pfizer Collaboration Agreement, we and our affiliates are not permitted, either directly or indirectly, to develop or commercialize any pharmacologically-active agent whose primary mechanism of action is, by design, directed to a Target, or grant any license, covenant not to sue or other right to any third party for the conduct of such activities. There are no restrictions on Pfizer from developing, manufacturing or commercializing products, programs, technologies or processes that are similar to or may compete with any covered by the Pfizer Collaboration Agreement, subject to certain limitations on Pfizer’s right to use our confidential information or know-how.

Under the terms of the Pfizer Collaboration Agreement, we received an upfront non-refundable payment and certain additional payments totaling $28.0 million in 2018 in exchange for use of the Company’s technology license and to fund Pfizer-related research as defined within the agreement. We are also eligible to receive up to an additional $37.5 million in non-refundable option payments if Pfizer exercises its options for all targets under the agreement. Pfizer has exercised options for $4.9 million as of December 31, 2020. The options are recognized as revenue over the estimated period of performance. We are also entitled to receive up to $225 million in development milestone payments and up to $550 million in sales-based milestone payments for all designated targets. In addition, we are eligible to receive, on net sales of PROTAC targeted protein degrader-related products, mid- to high-single digit tiered royalties, which may be subject to reductions. Pfizer paid us $1.2 million in December 2019 and $3.0 million in 2020 relating to adding additional targets into the collaboration.

Unless earlier terminated, the Pfizer Collaboration Agreement will expire upon the expiration of all royalty obligations thereunder. The royalty period for each product developed under the Pfizer Collaboration Agreement will expire on a country-by-country basis upon the later of (1) the expiration of the last-to-expire valid patent claim that claims or covers the composition of matter of a compound contained within such product or (2) ten years after the first commercial sale with respect to such product. Pfizer has the right to terminate the Pfizer Collaboration Agreement for convenience in its entirety or with respect to a specific target on 60 days’ prior notice. Either we or Pfizer may terminate the Pfizer Collaboration Agreement, in its entirety or with respect to a specific target, if the other party is in material breach and such breach is not cured within the specified cure period. In addition, either we or Pfizer may terminate the Pfizer Collaboration Agreement in the event of specified insolvency events involving the other party. If Pfizer terminates the agreement in its entirety or as a result of our uncured material breach or our insolvency, Pfizer retains its license with respect to Targets for which it has exercised an option (unless Pfizer elects otherwise), subject to reduced payment obligations.

Bayer Collaboration Agreement

In June 2019, we entered into a Collaboration and License Agreement with Bayer AG, or Bayer, setting forth our collaboration to identify or optimize PROTAC targeted protein degraders, that mediate for degradation of Targets using our proprietary platform technology, which Targets will be selected by Bayer, subject to certain exclusions and limitations. We refer to this agreement as the Bayer Collaboration Agreement. The Bayer Collaboration Agreement became effective in July 2019.

For the identified Targets, we and Bayer will conduct a research program pursuant to separate research plans tailored to each Target selected by Bayer. Bayer may make substitutions for any such initial Target candidates, subject to certain conditions and based on the stage of research for such Target.

We and Bayer are obligated to use commercially reasonable efforts to complete our respective activities set forth in each research plan, including, in our case, the obligation to provide certain deliverables at certain stages of the research plans. The joint steering committee established under the collaboration shall determine whether the research program with respect to a given Target has been completed. In the absence of any such determination by the joint steering committee, and unless otherwise agreed by the parties in writing, for each Target for which research program activities have commenced, if no research funding is allocated to such Target for the 12 month period commencing on July 1, 2019 or any anniversary thereof, and we refer to each as a Research Program Year, the research program with respect to the relevant Target shall be deemed completed as of the end of the last Research Program Year for which funding was allocated to such Target. Bayer shall pay to the Company research funding payments of $3.0 million dollars per year in each of the first four Research Program Years. If the Company’s costs for its research activities under the research plans exceed the research funding provided by Bayer for any Research Program Year before completion of all relevant research program activities in such Research Program Year, and the Company has complied with its reporting obligations to Bayer with respect to research program costs, the Company shall not be obligated to carry out further research program activities for the given Research Program Year unless Bayer has agreed in writing to fund such additional activities.

During the term of the Bayer Collaboration Agreement, weand our affiliates are not permitted, either directly or indirectly, to design, identify, discover or develop any small molecule pharmacologically-active agent whose primary mechanism of action is, by design, directed to the inhibition or degradation of any Target selected or reserved by Bayer, or grant any license, covenant not to sue or other right to any third party in the field of human disease under the licensed intellectual property for the conduct of such activities. There are no restrictions on Bayer from developing, manufacturing or commercializing products, programs, technologies or processes that are similar to or may compete with any covered by the Bayer Collaboration Agreement, subject to certain limitations on Bayer’s right to use the Arvinas’ confidential information or know-how.

Under the terms of the Bayer Collaboration Agreement, we received an aggregate upfront payment of $17.5 million in August 2019. We are entitled to receive up to an additional $12.0 million in research funding payments, subject to increases, as described above. We are also eligible to receive up to $197.5 million in development milestones and up to $490.0 million in sales-based milestones for all designated Targets. In addition, we are eligible to receive, on net sales of PROTAC targeted protein degrader-related products, mid-single digit to low-double digit tiered royalties, which may be subject to reductions.

Unless earlier terminated, the Bayer Collaboration Agreement will expire upon the expiration of all royalty obligations thereunder. The royalty period for each product developed under the Bayer Collaboration Agreement will expire on a country-by-country basis upon the later of (1) the expiration of the last-to-expire valid patent claim that covers the manufacture, use or sale of such product or (2) ten years after the first commercial sale with respect to such product. Bayer has the right to terminate the Bayer Collaboration Agreement for convenience in its entirety or with respect to a specific target on 60 days’ prior written notice. Either the Company or Bayer may terminate the Bayer Collaboration Agreement, in its entirety or with respect to a specific target, if the other party is in material breach and such breach is not cured within the specified cure period. In addition, either we or Bayer may terminate the Bayer Collaboration Agreement in the event of specified insolvency events involving the other party. If Bayer terminates the agreement in its entirety as a result of our uncured material breach or the Company’s insolvency, Bayer may elect in writing to retain its license with respect to any Targets previously identified and delivered to Bayer, subject to reduced payment obligations.

Bayer Joint Venture

In June 2019, we, Bayer and Bayer CropScience LP, or BCS, also committed to the formation of a joint venture, conditioned on terms set forth in a commitment agreement, or Commitment Agreement, among us, BCS and a newly formed Delaware limited liability company, or Oerth. In July 2019, following the expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, we consummated the formation of the joint venture in which we and BCS each received an ownership interest in Oerth initially representing 50% of the ownership interests. Oerth was formed for the purpose of researching, developing and commercializing PROTAC targeted protein degraders, or PROTAC Products, for applications in the field of agriculture. A 15% ownership interest of Oerth was reserved for the future grant of incentive units to service providers of Oerth.

In exchange for their ownership interests in Oerth, we made an in-kind intellectual property contribution to Oerth and BCS made an in-kind intellectual property contribution to Oerth. In addition, BCS made a $56.0 million total cash commitment to Oerth, or the Total Cash Commitment, $16.0 million of which BCS contributed to Oerth in connection with the JV closing.

Our and BCS’s ownership interest in Oerth, and the accompanying rights and obligations as members of Oerth, are governed by an amended and restated limited liability company agreement, or LLC Agreement, by and among us, BCS and Oerth. Oerth is generally governed by a board of managers, or the JV Board, which is comprised of four voting members, two of which have been designated by us and two of which have been designated by BCS. JV Board decisions will generally be made by majority vote of the managers, with each manager having one vote. Certain matters will require the consent of both BCS and the Company or both of their designated managers on the JV Board.

We, Oerth and BCS also entered into an option agreement, or the Option Agreement, pursuant to which the parties will agree to certain procedures for, and preferential rights relating to, the possible transfer to BCS of PROTAC Product candidates researched, developed and commercialized by Oerth under the joint venture. BCS will have a right of first negotiation, and last matching rights under certain circumstances, to enter into a license with Oerth for the exclusive right to research, develop, manufacture, use and commercialize the applicable PROTAC Product candidate in the field of agriculture for which it was developed. In addition, Oerth is allowed to receive and consider unsolicited third-party offers or seek third-party offers for the exclusive license to the applicable PROTAC Product candidate. The Option Agreement sets forth the procedures the JV Board will follow when considering and voting on any offers as well as the considerations on how to value any offer.

We and BCS also entered into separate service agreements, or the Services Agreements. We and BCS will provide services to Oerth as agreed from time to time by us and BCS, as applicable, and set forth in statements of work to be delivered under the applicable Services Agreement.

We and BCS each also entered into respective intellectual property contribution agreements, each, an IP Contribution Agreement, with Oerth. Pursuant to the IP Contribution Agreement by and between us and Oerth, or Company IP Contribution Agreement, in addition to certain non-exclusive licenses, we granted to Oerth an exclusive, worldwide, fully paid-up, royalty-free license, including certain rights to sublicense, to use certain of our PROTAC technology to research, develop, manufacture, use and commercialize and sell PROTAC Products in the field of agriculture.

Pursuant to the IP Contribution Agreement by and between BCS and Oerth, or the BCS IP Contribution Agreement, in addition to certain non-exclusive licenses, BCS and certain of its affiliates granted to Oerth an exclusive, worldwide, fully paid-up, royalty-free license, including certain rights to sublicense, to use certain of BCS’ or its affiliates’ intellectual property that covers ubiquitin ligases or moieties that bind ubiquitin ligase complexes, and linkers that attach ubiquitin ligase binding moieties to moieties that bind to a target, to research, develop, manufacture, use and commercialize and sell PROTAC Products in the field of agriculture.

The Company IP Contribution Agreement and the BCS IP Contribution Agreement also contain a non-exclusive, worldwide, fully paid-up, royalty-free license grant from Oerth to each of us and BCS, respectively, under various forms of intellectual property developed by Oerth to research, develop, manufacture, use and commercialize products outside of the field of agriculture, in each case excluding intellectual property licensed by the other contributing party to Oerth.

During the term of the joint venture and, in certain limited cases as described below, for one year following the end of the term of the joint venture, neither we, Bayer nor any of our respective affiliates may research, develop, manufacture, use or commercialize in the field of agriculture any PROTAC Products whose primary mechanism of action by design is the binding to and degradation of any Target, subject to certain exclusions for early stage research activities and minority investments. In addition, in the event either BCS or a third party licenses a PROTAC Product candidate from Oerth pursuant to the Option Agreement, the non-licensing party or parties to the Commitment Agreement will be prohibited from developing, commercializing or otherwise exploiting any product utilizing PROTAC technology to target the same Target as that of the licensed product candidate in the field of agriculture.

The term of the joint venture will end upon the termination of the Commitment Agreement. We and BCS can terminate the Commitment Agreement upon mutual written consent. Either we or BCS may terminate the Commitment Agreement in the event of specified uncured breaches by the other party or in the event the other party becomes subject to specified bankruptcy, winding up or similar circumstances. Either party may also terminate upon a change of control of the other party, as defined in the Commitment Agreement. Either party may also terminate the Commitment Agreement in the event that Oerth runs out of funds.

Upon a termination by either party for specified “bad actor” breaches of the other party, the defaulting party will remain subject to the exclusivity provisions described above for a period of one year following such termination.

In the event of a termination of the Commitment Agreement, all rights licensed to Oerth pursuant to the Company IP Contribution Agreement will terminate, except for any rights licensed to BCS or third parties pursuant to license agreements entered into by Oerth prior to termination or, in certain termination events, to BCS to continue the research, development and commercialization of PROTAC Products that have reached field candidate status. Similarly, all rights licensed to Oerth pursuant to the BCS IP Contribution Agreement will terminate, except for any rights licensed to third parties pursuant to license agreements entered into by Oerth prior to termination.

All intellectual property owned by Oerth will, as of the date of termination, be assigned to be owned jointly and undividedly by the Company and BCS (with the Company’s interest to be exclusively licensed to BCS to continue the research, development and commercialization of PROTAC Products that have reached field candidate status in certain specified termination events) unless the Company or BCS terminates the Commitment Agreement for a specified bad actor breach of the other party, in which case the intellectual property owned by Oerth will thereafter be owned solely and exclusively by the non-breaching party.

Competition

The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on intellectual property and proprietary products. While we believe that our technology, expertise, scientific knowledge and intellectual property estate provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions that conduct research, seek patent protection, and establish collaborative arrangements for research, development, manufacturing, and commercialization. Not only must we compete with other companies that are focused on protein degradation, but any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future. Moreover, our industry is characterized by the existence of large numbers of patents and frequent allegations of patent infringement.

Our platform and product focus is the discovery and development of protein degradation therapies using our small molecule PROTAC targeted protein degraders. Other companies researching chimeric small molecules for protein degradation include C4 Therapeutics, Inc., Cullgen Inc., Kymera Therapeutics, Inc. and Nurix Therapeutics, Inc. Further, several large pharmaceutical companies have disclosed preclinical or clinical investments in this field, including AbbVie, Amgen, AstraZeneca plc, Boehringer Ingelheim, Bristol Myers Squibb Company, GlaxoSmithKline plc, Genentech, Novartis International AG and Sanofi SA. In addition to competition from other protein degradation therapies, any products that we develop may also face competition from other types of therapies, such as small molecule, antibody, or gene therapies.

Our lead product candidates target oncologic indications. The most common methods of treating patients in oncologic indications are surgery, radiation and drug therapy, including chemotherapy, hormone therapy and targeted drug therapy. There are a variety of available drug therapies marketed for cancer, including prostate cancer and breast 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 others are available on a generic basis. Many of these approved drugs are well established therapies and are widely accepted by physicians, patients and third-party payors. In general, although there has been considerable progress over the past few decades in the treatment of cancer and the currently marketed therapies provide benefits to many patients, these therapies all are limited to some extent in their efficacy and frequency of adverse events, and none of them are successful in treating all patients. As a result, the level of morbidity and mortality from cancer remains high.

In addition to currently marketed drugs, there are also several product candidates in late stage clinical development for the treatment of oncologic indications, including for mCRPC and metastatic ER positive / HER2 negative breast cancer. These products in development include, in the case of metastatic ER positive / HER2 negative breast cancer, selective estrogen receptor degraders and 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 market approval.

If any of our product candidates are approved for the indications for which we expect to conduct clinical trials, they will compete with the foregoing therapies and the currently marketed drugs and potentially any drugs in development. It is also possible that we will face competition from other biologic or pharmaceutical approaches as well as from other types of therapies.

Many of our current or potential competitors, either alone or with their collaboration partners, have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. 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 necessary for, our programs. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller 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 necessary for, our programs. Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain FDA or other regulatory approval for their products 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. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic products. There are generic products currently on the market for certain of the indications that we are pursuing, and additional products are expected to become available on a generic basis over the coming years. If our product candidates are approved, we expect that they will be priced at a significant premium over competitive generic products.

The key competitive factors affecting the success of all our programs, if approved, are likely to be their efficacy, safety, convenience, price, level of generic competition and availability of reimbursement.

Commercialization Plans

We have not yet established our own commercial organization or distribution capabilities because our product candidates are still in preclinical and clinical development. Other than our discovery collaboration agreements, we have retained commercialization rights for all of our development programs. If any of our product candidates receive marketing approval, we will need to develop a plan to commercialize them in the United States and other key markets. We currently expect that we would build our own focused, specialized sales and marketing organization to support the commercialization in the United States of product candidates for which we receive marketing approval and that can be commercialized with such capabilities. We expect to utilize a variety of types of collaboration, co-promotion, distribution and other marketing arrangements with one or more third parties to commercialize our product candidates in markets outside the United States or for situations in which a larger sales and marketing organization is required.

As product candidates advance through our pipeline, our commercial plans may change. In particular, some of our research programs target potentially larger indications. Data, the size of the development programs, the size of the target market, the size of a commercial infrastructure and manufacturing needs may all influence our strategies in the United States, Europe and the rest of the world.

Manufacturing and Supply

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We rely on and expect to continue to rely on third-party contract manufacturing organizations, or CMOs, for both drug substance and finished drug product as well as for the synthesis of compounds in our pre-clinical research and development activities. We have engaged third-party manufacturers to supply the drug substances and building blocks for those substances for ARV-110 and ARV-471. We have also engaged third-party manufacturers to develop and manufacture finished drug product for ARV-110 and ARV-471 that we are using and plan to use in our Phase 1/2 clinical trials. We currently obtain our supplies from these manufacturers on a purchase order basis and do not have long-term supply arrangements in place. Should any of these manufacturers become unavailable to us for any reason, we believe that there are a number of potential replacements, although we may incur some delay in identifying and qualifying such replacements.

All of our drug candidates are organic compounds of low molecular weight, generally called small molecules, but which are larger than traditional small molecule therapeutics. We have selected these compounds not only on the basis of their potential efficacy and safety, but also for their ease of synthesis and reasonable cost of goods. In particular, our lead product candidates are manufactured using reliable and reproducible synthetic processes from readily available starting materials. The chemistry is amenable to scale up and does not require unusual equipment in the manufacturing process. We expect to continue to develop drug candidates that can be produced cost-effectively at contract manufacturing facilities.

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 European Union, extensively regulate, among other things, the research, development, testing, manufacture, pricing, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, sales, reimbursement, post-approval monitoring and reporting, and import and export of biopharmaceutical products. The processes for obtaining marketing approvals in the United States and in foreign countries and jurisdictions, along with compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

Approval and Regulation of Drugs in the United States

In the United States, drug products are regulated under the Federal Food, Drug, and Cosmetic Act, or FDCA, and applicable implementing regulations and guidance. The failure of an applicant to comply with the applicable regulatory requirements at any time during the product development process, including nonclinical testing, clinical testing, the approval process or post-approval process, may result in delays to the conduct of a study, regulatory review and approval and/or administrative or judicial sanctions.

An applicant seeking approval to market and distribute a new drug in the United States generally must satisfactorily complete each of the following steps before the product candidate will be approved by the FDA:

Preclinical Studies

Before an applicant begins testing a product candidate with potential therapeutic value in humans, the product candidate enters the preclinical testing stage, including in vitro and animal studies to assess the safety and activity of the drug for initial testing in humans and to establish rationale for therapeutic use. Preclinical tests include laboratory evaluations of product chemistry, formulation and stability, as well as other studies to evaluate, among other things, the toxicity of the product candidate. The conduct of the preclinical tests and formulation of the compounds for testing must comply with federal regulations and requirements, including GLP regulations and standards. Some long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity, and long-term toxicity studies, may continue after the IND is submitted.

The IND and IRB Processes

An IND is an exemption from the FDCA that allows an unapproved product candidate to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer such investigational product to humans. Such authorization must be secured prior to interstate shipment and administration of any product candidate that is not the subject of an approved NDA. In support of a request for an IND, applicants must submit a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. 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, must be 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, or thereafter, the FDA may raise concerns or questions about the conduct of the trials as outlined in the IND and impose a clinical hold or partial clinical hold. In this case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin or recommence.

Following commencement of a clinical trial under an IND, the FDA may also place a clinical hold or partial clinical hold on that trial. Clinical holds are imposed by the FDA whenever there is concern for patient safety and may be a result of new data, findings, or developments in clinical, nonclinical, and/or chemistry, manufacturing, and controls, or CMC. 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 FDA IND requirements must be met unless waived. When a foreign clinical study is not conducted under an IND, the sponsor must ensure that the study complies with certain regulatory requirements of the FDA in order to use the study as support for an IND or application for marketing approval. Specifically, such studies must be conducted in accordance with GCP including review and approval by an independent ethics committee, or IEC, and informed consent from subjects. 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 studies, 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.

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, or DSMB. This group provides authorization as to whether or not a trial may move forward at designated check points based on certain available data from the study to which only the DSMB may access. 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 clinical trials must be submitted within specific timeframes to the National Institutes of Health, or NIH, for public dissemination on its ClinicalTrials.gov website.

Expanded Access to an Investigational Drug for Treatment Use

Expanded access, sometimes called “compassionate use,” is the use of investigational new drug products outside of clinical trials to treat patients with serious or immediately life-threatening diseases or conditions when there are no comparable or satisfactory alternative treatment options. The rules and regulations related to expanded access are intended to improve access to investigational drugs for patients who may benefit from investigational therapies. FDA regulations allow access to investigational drugs under an IND by the company or the treating physician for treatment purposes on a case-by-case basis for: individual patients (single-patient IND applications for treatment in emergency settings and non-emergency settings); intermediate-size patient populations; and larger populations for use of the drug under a treatment protocol or Treatment IND Application.

When considering an IND application for expanded access to an investigational product with the purpose of treating a patient or a group of patients, the sponsor and treating physicians or investigators will determine suitability when all of the following criteria apply: patient(s) have a serious or immediately life-threatening disease or condition, and there is no comparable or satisfactory alternative therapy to diagnose, monitor, or treat the disease or condition; the potential patient benefit justifies the potential risks of the treatment and the potential risks are not unreasonable in the context or condition to be treated; and the expanded use of the investigational drug for the requested treatment will not interfere initiation, conduct, or completion of clinical investigations that could support marketing approval of the product or otherwise compromise the potential development of the product.

There is no obligation for a sponsor to make its drug products available for expanded access; however, as required by the 21st Century Cures Act, or Cures Act, passed in 2016, if a sponsor has a policy regarding how it responds to expanded access requests, it must make that policy available. This provision requires drug and biologic companies to make publicly available their policies for expanded access for individual patient access to products intended for serious diseases. Sponsors are required to make such policies publicly available upon the earlier of initiation of a Phase 2 or Phase 3 study; or 15 days after the drug or biologic receives designation as a breakthrough therapy, fast track product, or regenerative medicine advanced therapy. We received fast track designation for ARV-110 for mCRPC in May 2019.

In addition, on May 30, 2018, the Right to Try Act, was signed into law. The law, among other things, provides a federal framework for certain patients to access certain investigational new drug products that have completed a Phase 1 clinical trial and that are undergoing investigation for FDA approval. Under certain circumstances, eligible patients can seek treatment without enrolling in clinical trials and without needing FDA approval under the FDA expanded access program. There is no obligation for a drug manufacturer to make its drug products available to eligible patients under the Right to Try Act.

Human Clinical Trials in Support of an NDA

Clinical trials involve the administration of the investigational product candidate to human subjects under the supervision of a qualified investigator 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 clinical trial protocols detailing, among other things, the objectives of the study, inclusion and exclusion criteria, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated.

Human clinical trials are typically conducted in three sequential phases, but the phases may overlap or be combined. Additional studies may also be required after approval.

Phase 1 clinical trials are initially conducted in a limited population to test the product candidate for safety, including adverse effects, dose tolerance, absorption, metabolism, distribution, excretion and pharmacodynamics in healthy humans or in patients. During Phase 1 clinical trials, information about the investigational drug product’s pharmacokinetics and pharmacological effects may be obtained to permit the design of well-controlled and scientifically valid Phase 2 clinical trials.

Phase 2 clinical trials are generally conducted in a limited patient population to identify possible adverse effects and safety risks, evaluate the efficacy of the product candidate for specific targeted indications and determine dose tolerance and optimal dosage. Multiple Phase 2 clinical trials may be conducted by the sponsor to obtain information prior to beginning larger and more costly Phase 3 clinical trials. Phase 2 clinical trials are well controlled, closely monitored and conducted in a limited patient population.

ARVN US Equity

ARVN · 10-K · period ended 2020-12-31

Item 1. Business.

ARVN US Equity☆

ARVN · 10-K · period ended 2020-12-31

Item 1. Business.

ARVN US Equity