10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2021

Commission File Number 001-40881

Pyxis Oncology, Inc.

(Exact name of Registrant as specified in its Charter)

35 Cambridgepark DriveCambridge, Massachusetts 02140

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (617) 221-9059

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

Title of each class TradingSymbol(s) Name of each exchange on which registered

Common Stock, par value $0.001 per share PYXS Nasdaq Global Select Market

Securities registered pursuant to Section 12(g) of the Act: None

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, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ☐ Accelerated filer ☐

Non-accelerated filer ☒ Smaller reporting company ☒

Emerging growth company ☒

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

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

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

The Registrant did not have a public float on the last business day of its most recently completed second fiscal quarter because there was no public market for the Registrant’s common equity as of such date. The number of shares of Registrant’s Common Stock outstanding as of March 29, 2022 was 32,841,747.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant’s Proxy Statement for its 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein. Such Proxy Statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2021.

Table of Contents

Page

PART I

Item 1. Business 5

Item 1A. Risk Factors 56

Item 1B. Unresolved Staff Comments 107

Item 2. Properties 108

Item 3. Legal Proceedings 108

Item 4. Mine Safety Disclosures 108

PART II

Item 6. [Reserved] 111

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 124

Item 8. Financial Statements and Supplementary Data 124

Item 9A. Controls and Procedures 125

Item 9B. Other Information 125

Item 9C. Disclosure regarding foreign jurisdictions that prevent inspections 125

PART III

Item 10. Directors, Executive Officers and Corporate Governance 126

Item 11. Executive Compensation 126

Item 14. Principal Accounting Fees and Services 126

PART IV

Item 15. Exhibits, Financial Statement Schedules 127

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements concerning our business, operations and financial performance and condition, as well as our plans, objectives and expectations for our business, operations and financial performance and condition. Any statements contained herein that are not statements of historical facts may be deemed to be forward-looking statements. These statements involve known and unknown risks, uncertainties related to the global COVID 19 pandemic and other important factors that are in some cases beyond our control and may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

Unless the context requires otherwise, references in this Annual Report on Form 10-K to “Pyxis Oncology,” the “Company,” “we,” “us,” and “our” refer to Pyxis Oncology, Inc. and its subsidiary. In some cases, you can identify forward-looking statements by terms such as “may,” “would,” “should,” “expects,” “plans,” “anticipates,” “could,” “intends,” “target,” “projects,” “contemplates,” “believes,” “estimates,” “predicts,” “outlook,” “potential” or “continue” or the negative of these terms or other similar expressions. The forward-looking statements in this Annual Report are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this Annual Report on Form 10-K and are subject to a number of risks, uncertainties and assumptions described in the section titled “Risk Factors” and elsewhere in this Annual Report on Form 10-K. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Some of the key factors that could cause actual results to differ from our expectations include:

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our ability to develop and advance our current or future product candidates and programs, and to successfully initiate and complete clinical trials;

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the ability of our clinical trials to demonstrate the safety, purity and potency of our product candidates and other positive results;

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the size of the market opportunity for our product candidates, including our estimates of the number of patients who suffer from the cancers we are targeting;

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our manufacturing, commercialization and marketing capabilities and strategy;

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our plans to further develop the FACT platform and expand our pipeline of product candidates;

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the impact of the COVID-19 pandemic on our business, financial condition, results of operations, and prospects;

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the timing or likelihood of regulatory filings and approvals for our product candidates;

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regulatory developments in the United States and Europe and other foreign countries:

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our expectations and plans to obtain funding for our operations, including from our existing and potential future collaboration and licensing agreements;

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our expectations regarding our ability to obtain and maintain intellectual property protection for our product candidates:

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our continued reliance on third parties to manufacture our product candidates for preclinical studies, and, in the future, to conduct clinical trials and manufacture product candidates for such clinical trials;

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our estimates regarding expenses, future revenue, capital requirements and needs for additional financing.

In addition, statements such as “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report on Form 10-K and, although we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted a thorough inquiry into, or review of, all potentially available relevant information. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events or otherwise.

SUMMARY RISK FACTORS

You should consider carefully the risks described under “Risk Factors” in Part II, Item 1A of this Annual Report on Form 10-K. References to “Pyxis Oncology,” the “Company,” “we,” “us,” and “our” in this section titled “Summary Risk Factors” refer to Pyxis Oncology, Inc. and its wholly owned subsidiary. A summary of the risks that could materially and adversely affect our business, financial condition, operating results and prospects include the following:

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We are a preclinical stage biopharmaceutical company with a limited operating history and have incurred significant losses since our inception. We expect to incur losses over at least the next several years and may never achieve or maintain profitability.

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We will require substantial additional capital to finance our operations, obtain regulatory approval for our product candidates, and commercialize our product candidates. If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce or eliminate one or more of our research and product development programs or future commercialization efforts.

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We are heavily dependent on the success of PYX-201, PYX-202, PYX-203, PYX-106 and PYX-102 all of which are in the early stages of development, and if PYX-201, PYX-202, PYX-203, PYX-106 and/or PYX-102 are not successful in clinical trials or do not receive regulatory approval or licensure or are not successfully commercialized, our business will be materially and adversely affected.

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All of our product candidates are currently in preclinical development. Our product candidates may fail in development or suffer delays that materially and adversely affect their commercial viability. If we or our existing or future collaborators are unable to initiate and complete clinical development of, obtain regulatory licensure for or commercialize our product candidates or experience significant delays in doing so, our business will be materially harmed.

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Our preclinical studies and clinical trials may fail to demonstrate adequately the safety, purity and potency of any of our product candidates, which would prevent or delay development, regulatory licensure and commercialization.

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Our preclinical programs may experience delays or may never advance to clinical trials, which would adversely affect our ability to obtain regulatory licensure or commercialize these programs on a timely basis or at all.

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We face competition from entities that have developed or may develop product candidates for cancer, including companies developing novel treatments and technology platforms. If these companies develop technologies or product candidates more rapidly than we do or their technologies are more effective, our ability to develop and successfully commercialize product candidates may be adversely affected.

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Clinical testing and product development is a lengthy and expensive process with an uncertain outcome. We may incur unexpected costs or experience delays in completing, or ultimately be unable to complete, the clinical testing and the development and commercialization of our product candidates.

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The regulatory licensure and approval processes of the FDA and other comparable regulatory authorities are lengthy, time-consuming and inherently unpredictable and, if we are ultimately unable to obtain marketing licensure or approval for our product candidates, our business will be substantially harmed.

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If we fail to attract and retain qualified senior management and key scientific personnel, our business may be materially and adversely affected.

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We face risks related to health epidemics and outbreaks, including the COVID-19 pandemic, which could significantly disrupt our preclinical studies and clinical trials, and therefore our receipt of necessary regulatory licensure or approvals could be delayed or prevented.

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We rely on third parties to manufacture our product candidates. Any failure by a third-party manufacturer to produce acceptable raw materials or product candidates for us or to obtain authorization from the FDA or comparable foreign regulatory authorities may delay or impair our ability to initiate or complete our clinical trials, obtain regulatory licensure or approvals or commercialize approved products.

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If we are unable to obtain and maintain patent protection for our product candidates, or if the scope of the patent protection obtained is not sufficiently broad, or if our patents are insufficient to protect our product candidates for an adequate amount of time, or if we are unable to obtain adequate protection for our proprietary know-how, we may not be able to compete effectively in our markets.

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If we fail to comply with our obligations under any license, collaboration or other agreements, we may be required to pay damages and could lose intellectual property rights that are necessary for developing and protecting our product candidates or we could lose certain rights to grant sublicenses.

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Licensing of intellectual property is of critical importance to our business and involves complex legal, business and scientific issues. If we breach our University of Chicago, Pfizer, LegoChem, or Biosion license agreements or any of the other agreements under which we acquired, or will acquire, intellectual property rights covering our product candidates, we could lose the ability to continue the development and commercialization of the related product.

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If the market opportunities for any product that we develop are smaller than we believe they are, our revenue may be adversely affected, and our business may suffer.

PART I

Item 1. Business.

Overview

We are a preclinical oncology company focused on developing an arsenal of next-generation therapeutics to target difficult-to-treat cancers and improve quality of life for patients. We develop our product candidates with the objective to directly kill tumor cells, and to address the underlying pathologies created by cancer that enable its uncontrollable proliferation and immune evasion. We are developing multi-asset, multi-modality portfolio aimed at defeating difficult-to-treat cancers. We consider multi-modality as variety of technologies, either stand-alone or in combination with others, to build the effective cancer therapeutics for patients. Since our launch in 2019, we have developed a broad portfolio of novel antibody drug conjugate, or ("ADC"), immuno-oncology, or (“IO”), product candidates, and monoclonal antibody, or mAb, preclinical discovery programs that we are developing as monotherapies and in combination with other therapies.

We take a holistic view of attacking the key drivers of tumor growth and progression within the tumor microenvironment, or TME, including targeting of tumor antigens and modulating the innate and adaptive immune response. The TME is an immunosuppressive environment consisting of cancer cells and stroma, which includes the blood vessels, immune cells, fibroblasts, signaling molecules, and the extracellular matrix that surrounds the tumor. The TME plays multiple roles in tumor formation, progression and metastasis as well as anti-tumor immune activity. We are developing our ADC and IO product candidates to precisely target key modulators of the adaptive and innate immune system within the TME for difficult-to-treat solid and hematologic tumors.

We believe that the diversification of a multi-modality approach optimizes our ability to effectively progress multiple assets for the benefit of patients. By leveraging our expert knowledge of the TME and established business development record, we are developing cancer therapies and technologies through multiple avenues (see Figure 1) including:

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Platform Development: We are capitalizing on years of industry innovation and advancement in ADC platforms to develop and design our product candidates. For example, our product candidates PYX-201 and PYX-203 are built utilizing the Flexible Antibody Conjugation Technology, or FACT, platform technology in-licensed from Pfizer Inc. FACT technology leverages over a decade of investment refining the technical components of ADCs to improve the clinical properties of ADCs. Using our expertise in site-specific antibody conjugation, we are developing next-generation ADCs with customized linker-payload combinations aimed at increasing stability and, consequently, a reduced off target side-effect profile potentially enhancing the therapeutic index, or TI. We are leveraging our FACT ADC Platform to further build our pipeline while we consider expansion opportunities into adjacent modalities.

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Target Catalog: We have a large proprietary target catalog that is based on our own discovery activities and the in-licensed intellectual property, or IP, which formed the founding of the company from the University of Chicago out of the work of Dr. Thomas Gajewski’s laboratory. We believe that our target catalog will enable us to identify new ways to exploit multiple components of the TME for tumor targeting, either as new IO, or ADC targets.

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Forging Creative Business Models and Alliances: We are continuously evaluating business development and alliance opportunities with a variety of third parties. We aim to be unconstrained by conventional ideas and practices to overcome the many and complex challenges of cancer treatment. We are creating development optionality by engaging in creative business models to further expand the pipeline such as our joint venture with Alloy Therapeutics, known as Voxall Therapeutics, LLC, or Voxall. See “Licensing and Collaboration Agreements” in Item 1. Business in this Annual Report on Form 10-K.

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Product In-Licensing and Acquisitions: We selectively seek to in-license product candidates to expand our product pipeline. For example, our PYX-202 (DLK1 ADC) product candidate was in-licensed from LegoChem Biosciences Inc. and our PYX-106 (Siglec-15) product candidate was in-licensed from Biosion Inc. (“Biosion”). Additionally, we also in-licensed PYX-201 (EDB ADC) and PYX-203 (CD123 ADC) from Pfizer Inc. We are actively evaluating opportunities to acquire product candidates which we believe could enable us to quickly reach and deliver value inflection points as we build a durable, multi-asset, multi-modality diversified oncology company.

Figure 1

Recent Developments

PYX-106

On March 28, 2022, we entered into a license agreement, or the “Biosion License Agreement,” with Biosion USA, Inc., or Biosion, pursuant to which we obtained exclusive, worldwide (other than Greater China (mainland China, Hong Kong, Macau and Taiwan)), licenses for development, manufacture and commercialization rights for BSI-060T, a potentially best-in-class Siglec-15 targeting antibody, an IO product candidate (now referred to as PYX-106), and products containing the licensed compound. PYX-106 is a fully human monoclonal antibody and is engineered with high affinity to block Siglec-15 induced immune suppression and therefore restore T cell proliferation, function and anti-tumor immunity in the TME. PYX-106 is a novel immune checkpoint inhibitor targeting Siglec-15, whose expression profile is generally non-overlapping with PD-L1. Siglec-15 is expressed on M2 macrophages but can also be expressed by tumor cells. Binding of Siglec-15 to an as of yet unknown receptor on T cells leads to suppression of T cell proliferation and function. This inhibition also reduces IFNγ secretion which may further promote Siglec-15 expression. PYX-106 may synergize with and rescue PD(L)-1 targeted therapy activity, with the potential for sequential drug administration to synergize for enhanced anti-tumor activity.

We are initially evaluating our Siglec-15 targeting antibody for the treatment of advanced or metastatic solid tumors, which could include thyroid cancer, Head & Neck Squamous Cell Carcinoma, or HNSCC, non-small cell lung cancer, or NSCLC and other solid tumors where high unmet need exists. We plan to submit an IND for PYX-106 in the second half of 2022.

PYX-102

The anti-KLRG1 mAb, which we referred to as PYX-102, is our first organically built IO development candidate from our internal discovery engine. PYX-102 was identified as a promising IO target through our proprietary target catalog licensed from Tom Gajewski’s lab at the University of Chicago. PYX-102 is an inhibitory immunoreceptor trysine-based inhibitory motif-containing receptor expressed on T cells and NK cells in the tumor microenvironment and acts as an inhibitory immune checkpoint receptor via its interactions with E- and N-Cadherin ligands. We believe that targeting KLRG1 to reprogram these suppressed T and NK cells represents an exciting strategy to promote the full anti-tumor activity of cytotoxic T cells and NK cells in the tumor microenvironment. We are working through our development plans and we anticipate IND submission in the second half of 2023.

PYX-202

In December 2020, we entered into a license agreement, or the “LegoChem License Agreement,” with LegoChem Biosciences, Inc., or LegoChem, pursuant to which we licensed worldwide (other than Korea) development and commercialization rights for LCB67, an ADC product candidate targeting DLK1 (now referred to as PYX-202), and products containing the licensed compound. In studies conducted by LegoChem of preclinical small cell lung cancer, or SCLC, PDX models, as well as in a human cell line-based, or CDX, mouse model of cancer, we have observed significant anti-tumor activity as measured by durable tumor regression. In preparation for our IND filing and based on observation of our GLP studies to date, we have determined that we will need to conduct additional GLP and non-GLP toxicity studies to determine whether PYX-202 is a viable clinical candidate. We will continue to monitor the progress of our PYX-202 program and expect to provide an update about PYX-202 in mid-2022.

Our Portfolio

Our portfolio consists of both ADC and IO product candidates. Our pipeline is balanced across programs with an emphasis on solid tumors. We have multiple assets trending towards the clinic in the next 12-24 months. Our ADCs utilize next-generation technologies that, based on observations from preclinical studies, may allow for increased stability and a reduced off target side-effect profile. We in-licensed two ADC programs in March 2021 from Pfizer, one ADC program from LegoChem in December 2020 and one IO program from Biosion in March 2022. See “Licensing and Collaboration Agreements” in Item 1. Business in this Annual Report on Form 10-K. Two of our product candidates, PYX-201, and PYX-106 are scheduled for IND submission in the second half of 2022 whereas PYX-203 and PYX-102 are scheduled for IND submission in the second half of 2023. We have additional preclinical mAb discovery programs derived from work at the laboratory of Dr. Thomas Gajewski. We retain full worldwide development and commercialization rights to all our product candidates, with the exception of PYX-202 in South Korea and PYX-106 in Greater China (mainland China, Hong Kong, Macau and Taiwan). We intend to develop each of our programs as a monotherapy and potentially also in combination with other therapies.

We are focusing our efforts on eliminating tumor cells through the selective antibody mediated delivery of cytotoxic payloads and by modulating key immune-associated pathways in the TME. We believe our pipeline has the potential to profoundly benefit cancer patients and provide effective treatment options for those who do not respond to currently available therapies.

ADCs are an established therapeutic modality, with twelve currently approved by the FDA, including seven since 2019. Additionally, ADCs have received significant strategic interest from several pharmaceutical companies developing oncology therapeutics. ADCs are a combination of three key components—antibody, linker and cytotoxic payload. Many ADCs utilizing conjugation to existing lysine or cystine residues in the antibody, or conventional ADCs, struggled with one or more of these three key components, leading to heightened toxicity and limited efficacy. Despite the improvements that have been seen with currently marketed ADCs, these ADCs still have limitations that impact dosing, and are associated with significant adverse events. We have designed our product candidates to overcome the limitations of ADCs that use conventional conjugation with the aim of providing patients with safer and more efficacious treatment options.

The advent of immuno-oncology therapeutics, particularly immune checkpoint inhibitors, has shifted the treatment paradigm for oncology. We have initiated two monoclonal antibody programs that address critical immunomodulatory pathways within the TME and are exploring additional potential targets. Our programs aim to address critically important tumor infiltrating immune cell populations, such as macrophages, T cells, and natural killer (NK) cells, which may play crucial roles in limiting tumor growth and metastasis. In addition to singling out specific cell types, we believe our IO programs also address mechanisms responsible for T cell exhaustion and the immunosuppressive effects of the TME on T and NK cells. We believe that our two new IO programs, our internally developed anti-KLRG1 mAb PYX-102 and our in-licensed anti-Siglec-15 mAb PYX-106, have the potential to provide additional benefit to cancer patients either alone or in combination with other therapies, including other immuno-therapies.

Our current pipeline is summarized below.

Figure 2

PYX-106 is an investigational fully human IgG1 isotype Siglec-15 targeting antibody that is designed to block Siglec-15 mediated suppression of T-cell proliferation and function. We plan to initially develop this asset for the treatment of thyroid cancer, Head & Neck Squamous Cell Carcinoma, or HNSCC, non-small cell lung cancer, or NSCLC, and other solid tumors. We licensed worldwide rights, other than in Greater China (mainland China, Hong Kong, Macau and Taiwan), to our Siglec-15 targeting antibody from Biosion Inc. We expect to submit an IND in the second half of 2022.

PYX-102 is an investigational immune-therapeutic consisting of a ligand-blocking antibody which rescues KLRG1-mediated suppression of human CD8+ T cells. KLRG1 ligands E-and N-cadherin are expressed in numerous solid cancers. KLRG1 is an inhibitory ITIM-containing receptor expressed on T cells and NK cells. Blocking ligand/receptor interaction will relieve immune inhibition in these tumors. We anticipate submitting an IND in 2023.

PYX-201 is an investigational, novel ADC consisting of an Immunoglobulin G1, or IgG1, anti-fibronectin Extradomain-B, or EDB, mAb site-specifically conjugated to auristatin via a cathepsin B-cleavable linker. Fibronectin is a glycoprotein found in the extracellular matrix. Fibronectin EDB regulates blood vessel morphogenesis, which provides the tumor access to nutrition and oxygen, a means to remove waste, and a pathway for metastasizing cells. EDB is overexpressed in many malignancies and is minimally expressed in most normal adult tissues, making it a potentially attractive means to target tumors while sparing healthy cells. In preclinical models of patient derived xenograft, or PDX models, we observed tumor regression with single agent PYX-201. In addition, we observed that the treatment of preclinical syngeneic tumor models with PYX-201 resulted in enhanced T cell infiltration into the TME, which is a hallmark of immunogenic cell death, or ICD, enabling synergistic activity in combination with a checkpoint inhibitor. We anticipate submitting an IND in the second half of 2022.

PYX-202 is an investigational, novel ADC consisting of an IgG1 anti-Delta-like 1 homolog, or DLK1, mAb conjugated to MMAE via a site-specific plasma-stable ß-glucuronide linker. DLK1 is a transmembrane protein normally expressed in embryonic tissues but highly restricted in healthy adult tissues. DLK1 becomes re-expressed in certain solid tumor malignancies. PYX-202 is designed to use the microtubule-disrupting MMAE payload, which is utilized in three currently marketed ADCs providing clinical support that the payload has anti-tumor effect potential. As discussed in Recent Development section above, we are currently in process of doing further testing and analysis and expect to provide an update about PYX-202 in mid-2022.

PYX-203 is an investigational ADC consisting of an IgG1 anti-CD123 mAb antibody conjugated to a novel cyclopropylpyrroloindoline, or CPI dimer payload via a site-specific plasma-stable, cleavable linker. CD123, or IL-3Ra, is a cell surface antigen highly expressed on leukemic stem cells and leukemic blasts in acute myeloid leukemia, or AML. PYX-203, utilizes a novel DNA-damaging toxin, CPI, and we have observed significant anti-tumor activity as measured by the reduction in the frequency of the leukemic cells in the blood and bone marrow in nine disseminated preclinical AML models. We anticipate submitting an IND in the second half of 2023.

In addition to the programs identified above, we are conducting research and development activities on various targets, leveraging our expertise in monoclonal antibodies and understanding of immuno-oncology. Our preclinical discovery programs are novel antibody programs intended to enhance the anti-tumor activity of natural killer, or NK cells, and T cells and to overcome immunosuppressive activity of tumor resident myeloid cells such as tumor associated macrophages, or TAMs, and myeloid derived suppressor cells, or MDSCs.

Our Strategy

Our goal is to improve the lives of patients with difficult-to-treat cancers by building a superior portfolio of biological products, including ADCs and monoclonal antibody immunotherapies.

Elements of our strategy to achieve our short and long-term goals include:

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Develop multi-asset, multi-modality, durable portfolio aimed at defeating difficult-to-treat cancers. We believe that the diversification of a multi-modality approach optimizes our ability to effectively progress multiple assets for the benefit of patients.

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Progress our most advanced product candidates, PYX-106 and PYX-201, into and through clinical development. We believe that our preclinical data to date support the clinical potential of PYX-106 and PYX-201 as monotherapies and in combination with other cancer therapies, including immunotherapies and product candidates within our own portfolio. We expect to submit INDs for PYX-106 and PYX-201 in the second half of 2022 and INDs for PYX-203 and PYX-102 in the second half of 2023.

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Pursue a multi-modality approach to cancer therapy addressing various key components of the TME. Our approach is to leverage our capabilities to develop investigational products that directly target tumor cells and stromal components of the TME with ADCs as well as enhance effector cell function and overcome key mechanisms of immune-suppression with immunotherapeutic mAbs to improve response rates and/or deliver durable responses for more patients.

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Efficiently progress our preclinical IO programs. We plan to continue the preclinical development of our pipeline of immunotherapies. If approved, we believe these monoclonal antibody programs have the potential to overcome several of the mechanisms responsible for suppressing immune function and effector cell activity, thus enhancing the anti-tumor immune response in the TME. We also plan to leverage the potential ability of certain ADCs to induce immunogenic cell death to support synergistic combinations with IO agents, including those derived through our own programs.

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Continue to leverage the FACT platform and our Target Catalog to expand our pipeline of product candidates. We plan to continue to mine our target catalog to identify new ways to exploit multiple components of the TME for tumor targeting. Our target catalog may help identify critical immunomodulatory pathways within the TME that can be addressed with monoclonal antibodies. We plan to use our target catalog and the FACT platform to develop differentiated ADCs with potentially superior clinical activity relative to the current standards of care including monoclonal antibodies. Additionally, we intend to use the FACT platform to develop ADCs for attractive targets beyond our target catalog.

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Selectively forge alliances to enhance and expand our product pipeline to further leverage our intellectual property. We believe that the potential for single agent anti-tumor activity of our current and future products could be enhanced by incorporating potential collaborator technologies. We intend to selectively form alliances with partners to gain access to complementary technologies and expertise to develop and commercialize product candidates with increased potential for anti-tumor activity and the potential for a strong safety profile. We seek to further leverage our intellectual property portfolio through the formation of these alliances.

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Leverage our team’s deep experience and proficiency in oncology research and development to discover and advance novel ADC and immuno-oncology treatments for patients suffering from difficult-to-treat cancers. We believe our team, which brings deep scientific TME knowledge, functional biology expertise, ADC and IO modality experience, and biologics development capabilities position us to build a leading oncology company focused on developing product candidates for cancers with high unmet need. We intend to continue to augment the team’s experience and proficiency through the addition of new members.

Unmet Need in Oncology

Despite the significant advances in oncology with the approval of several new classes of drugs, there remains significant unmet medical need for novel treatments. According to the World Health Organization, cancer is the second leading cause of death globally, accounting for nearly 10 million deaths in 2020. The key limitations of existing oncology treatments include high toxicity, low or limited response rates, and relapse or recurrence.

Chemotherapy remains one of the most common treatments for cancer, often combined with surgery and radiotherapy depending on the stage and type of tumor. A major challenge in the development of cancer treatments has been the overall complexity and heterogeneity not only of tumors, but of their dynamic surrounding microenvironments. While recent advances in treatment approaches, such as targeting specific tumor mutations that contribute to carcinogenesis or redirecting a patient’s immune system to eliminate tumors, have begun to address these challenges, their focus has largely been on tumor cells. We believe that targeting the TME, which has been shown to play a key role in driving tumor progression, growth and multidrug resistance, represents a novel approach for addressing unmet needs in oncology. For example, while the development of immune checkpoint inhibitors has transformed the treatment paradigm for numerous cancers, many patients who respond to these therapies ultimately develop resistance and experience disease progression. Many features of the TME have been shown to influence response and resistance to immune checkpoint inhibitors and targeting the TME has potential to overcome these limitations. Our development efforts aim to leverage our deep understanding of the TME biology with the goal of designing and developing next-generation ADCs, with site-specific conjugation and customized linker-payload combinations, and immunotherapies that target key modulators of the adaptive and innate immune system found within the TME.

Overview of Antibody Drug Conjugates

ADCs are a therapeutic class in which cytotoxic chemotherapy molecules are linked to a targeting mAb to effectively deliver the tumor killing effect into tumor lesions while limiting systemic toxicity. Systemic toxicity limits the efficacy of chemotherapy, a highly cytotoxic class of anti-tumor medicines. ADCs can significantly improve the therapeutic window of toxic payloads even more cytotoxic than traditional chemotherapies by targeting their delivery to tumorous cells and their local environment and sparing healthy tissue. ADCs achieve this level of precision by pairing payloads with monoclonal antibodies, proteins that can recognize their target antigens with great specificity. ADCs are an established and fast-growing class of biological products. To date, twelve ADCs have been FDA approved, of which seven have entered the market since 2019.

Figure 3

Schematic representation of an ADC, highlighting the three key components; targeted antibody, linker, and payload or cytotoxic agent (dark blue: mAb heavy chain; pink: mAb light chain).

The clinical properties of ADCs are a function of three components (Figure 3):

(1)

A monoclonal antibody that selectively targets a distinct antigen preferentially expressed on tumor cells or other cells in the tumor microenvironment;

(2)

A linker that joins together the antibody and the payload; and

(3)

A payload that can effectively kill the targeted cell.

Ideal ADC targets typically have highly tumor restricted expression to spare healthy tissues, are accessible to circulating antibodies, and have well-defined internalization kinetics or can be effectively bound within the TME. Once administered, an ADC will travel in the bloodstream until it encounters its target antigen followed by release of the toxic payload.

A measure of drug tolerability for ADCs is the preclinical therapeutic index, which is calculated from data to estimate the safety profile (Figure 4). This measure is the preclinical ratio of the highest non-severely toxic dose, or HNSTD in monkeys versus the minimally effective dose, or MED in mouse tumor models. The therapeutic index is defined formulaically as HNSTD (mg/m2) in monkeys / mouse minimal tumor regression dose (mg/m2). As further illustrated in the figure below, a wider therapeutic index is a key attribute of an ADC’s potential clinical success.

Figure 4

The therapeutic index is a measure to estimate the clinical tolerability profile of ADCs based upon the ratio of maximum tolerated dose, or MTD, in monkeys versus the minimally effective dose in rodents from preclinical studies.

Key Areas of Innovation for Engineering the Next-Generation ADCs

Optimizing the Linker

The linker that joins the payload to the antibody should prevent the payload’s premature release while in circulation and ensure efficient release of the payload into the target cell(s) and/or the TME. There are two general classes of linkers:

(1)

Cleavable linkers are designed to conditionally unload cytotoxic agents within the tumor cell or TME in response to the presence of tumor-associated factors such as proteases or highly acidic conditions. Typically, cleavable linkers carry uncharged payloads, allowing the drug to diffuse out of the target cell to kill surrounding “bystander cells.” Bystander killing can also occur when the uncharged payload is unleashed within the TME.

(2)

In contrast, non-cleavable linkers remain intact upon internalization and rely on lysosomal degradation of the entire construct to achieve sufficient payload release. Non-cleavable ADCs typically release their payloads as charged catabolites, which traps the toxin within the cell where it was internalized. As a result, non-cleavable ADCs are naturally well suited to address cancers with a high and uniform expression of the target antigen since cells lacking the target antigen will not be directly affected.

We believe our toolbox of cleavable and non-cleavable linkers allows us to select the optimal linker tailored to each program. We select our linkers based on several factors, including but not limited to the level and distribution of the target antigen and rates of antigen turnover, internalization, lysosomal processing, and degradation.

Site-Specific Conjugation

Site-specific conjugation chemistry enables the engineering of next-generation ADCs with predictable drug-to-antibody ratio, or DAR, with improved ADC pharmacokinetics observed preclinically. This improved PK results in minimizing premature payload release and less off-target toxicity and as a result improves the overall TI of the ADC.

DAR is defined as the number of payload moieties attached to each antibody, which typically range from zero to eight. Ideally, there is limited variability in DAR to allow for ADCs with predictable PK and more predictable efficacy. Variability in DAR and stability are primarily a consequence of the technology used to conjugate the linker to the antibody. The two conventional conjugation approaches employed in conventional ADC conjugation technology utilize either lysine residues or the interchain disulfides located on an antibody. These approaches result in a stochastic mixture of conjugates consisting of a heterogeneous pool of synthesized ADCs, as shown in Figure 5 below. Each bar in the graph consists of an ADC with the number of payloads indicated on the X-axis. Each one of these parts of the mixture of conjugates contributes to the efficacy and toxicity making it difficult to optimize for either property.

In addition to DAR, research has shown conjugate stability and the resulting rate of payload release can vary significantly between specific conjugation sites. Hence, conventional conjugation suffers from unpredictable and premature payload release outside of the tumor resulting in off target toxicities.

Together with our extensive toolbox of linkers, we believe our site-specific conjugation chemistry offers us the advantage of fine-tuning and optimizing the cleavage of the drug in the TME while limiting off-tumor release and allowing for predictable DAR distribution. Site-specific conjugation technologies have led to improved ADC predictability with narrow distribution of DAR to facilitate CMC manufacture and consistent potency (Figure 5).

Figure 5

Depicted above is an illustrative example of DAR distribution for a DAR 4 ADC using different conjugation chemistries which highlights how our site-specific conjugation technology allows for linker/payload to be precisely conjugated, leading to more predictable DAR ADCs. This also improves CMC characteristics and enhances stability of ADCs to maximize tumor delivery of the payload.

The Selection of Cytotoxic Payload

The chemotherapeutic payload is a highly potent toxin that would otherwise carry devastating side effects as a systemically delivered monotherapy. There are several potential payloads, including antineoplastic auristatins, which act on microtubules to inhibit cell division, and alkylating or intercalating agents, which damage DNA.

While an ADC’s primary mode of action is to induce direct cell death through the payload, ADCs can exploit multiple avenues of anti-tumor action beyond direct cytotoxicity. For example, a growing area of interest is applying ADCs to induce ICD allowing for synergy with immunotherapy modalities including checkpoint inhibitors. Rapid cancer cell death caused by ADCs results in the release of damage-associated molecular patterns and tumor antigens, stimulating a tumor-specific immune response and recruitment of T cells into the TME (Figure 6). An emerging area of interest is utilizing ADCs to disrupt various aspects of the TME, such as angiogenesis or tumor-associated fibroblasts. Furthermore, certain payloads, such as auristatins, have been shown to engender the maturation and activation of dendritic cells, a critical compartment of the immune system responsible for initiating and regulating the innate and adaptive immune response.

Figure 6

Overview of the process by which ADCs, particularly those with certain payloads, can potentially trigger hallmarks of immunogenic cell death to enhance tumor cell killing

ADCs have and may continue to revolutionize the treatment paradigm for several cancers. Despite the improvements that have been seen with currently marketed ADCs, these ADCs still have limitations that impact dosing, and are associated with significant adverse events. We have designed our product candidates to overcome the limitations of ADCs that use conventional conjugation with the aim of providing patients with safer and more efficacious treatment options. We believe that our combined expertise in ADC design and insights into TME biology have the potential to yield a holistic treatment spanning multiple mechanisms for patients with difficult-to-treat cancers that will overcome the current limitation of ADCs and result in better outcomes for patients.

FACT Platform

We are developing next-generation ADCs using customized linker-payload combinations that are novel and supported by the preclinical data and site-specific conjugation techniques derived from the FACT platform. We believe that these payloads and linkers could be readily applied to any IgG1 antibodies using our site-specific conjugation techniques to efficiently develop novel product candidates. We licensed the FACT platform from Pfizer in December 2020 and benefit from over a decade of research and investment by Pfizer. See “Licensing and Collaboration Agreements” in Item 1. Business in this Annual Report on Form 10-K. We believe that the site-specific conjugation techniques and ADC technology which underpin the FACT platform enable us to develop next-generation ADCs with more favorable drug properties than traditional technologies based on preclinical studies.

Despite the clinical successes of ADCs as a therapeutic class, many ADCs still utilize conventional non-site-specific conjugation techniques that result in a heterogeneous mixture of ADCs with varying DAR. Recently, preclinical research carried out by Pfizer to empirically assess the impact of conjugation sites on ADC stability and activity in rodent models has indicated that site-specific conjugation techniques may enable enhanced pharmacologic properties and predictable DAR to potentially improve the therapeutic index.

Though multiple reports have shown that site-specific conjugation techniques often result in ADCs with a wider therapeutic index, greater stability, and better efficacy in preclinical in vivo models than traditional non-specific, conventional ADC conjugates, less is understood about how to optimize these sites, as optimization relies upon empirical data generation for each specific linker-payload combination. We believe that the FACT platform has demonstrated that there are multiple biochemical parameters of ADCs impacting performance in vivo and established a framework for optimized conjugation sites for a variety of linker-payload combinations.

Figure 7

The FACT platform technology is designed to empirically define optimal conjugation sites for linker-payloads to generate highly stable and predictable ADCs with potential for improved therapeutic indices.

Pfizer optimized sites for linker-payload conjugation through empirical research

We believe that the FACT platform provides a toolkit of novel and validated payloads, cleavable and non-cleavable linkers, and a strong understanding of optimized conjugation sites. The FACT platform provides the basis for our PYX-201 and PYX-203 preclinical programs and will underpin our development of future ADCs that we believe are optimized for, and guided by the following design elements:

•

ADC cytotoxicity. Target tumor cells require delivery of a certain threshold of payload molecules based on the payload’s biochemical properties to induce cell killing at specific dose levels. Our ADC programs are designed to provide anti-tumor cytotoxicity and, as applicable, immunogenic cell death based on data from preclinical models.

•

Plasma stability and maintenance of the linker-payload. ADCs must be optimized for systemic circulation to prevent premature linker cleavage or release of the linker-payload construct in the blood plasma that can result in off-target toxicity. We are designing our ADC candidates to optimize for stability when in circulation in vivo to avoid premature cleavage and support maximal payload delivery to the target site.

•

Efficient proteolytic cleavage of the linker for payload release. The timing and rate of linker cleavage is important for achieving optimal delivery and release of a specific payload at the target site. We believe that we have the capability to utilize both cleavable and non-cleavable linkers to achieve potential therapeutic effects that are optimized for individual payloads and targets.

•

High target specificity. Our ADC programs are founded on the identification of promising tumor targets and developing highly specific antibodies against these tumor targets. We draw upon our empirical understanding of site-specific conjugation sites and linker-payload toolkit to select combinations that we believe are well-suited for individual targets.

•

Defined and target specific DAR. Intrinsic to the FACT platform and conjugation techniques is the development of products with a consistent DAR, which we believe may enable us to develop a product with optimized stability, tolerability, and cytotoxicity.

We believe that the FACT platform conveys several distinct advantages and flexibility in the development of our ADC candidates, including the following:

•

Improved anti-tumor activity in preclinical models with optimized conjugation sites for linker-payload combinations. The FACT platform is designed to select for optimal conjugation sites that are specific to each linker-payload combination. We employ site-specific conjugation techniques to conserved regions found within the antibody backbones that do not affect antigen binding or other normal antibody functional properties, such as Fc binding when appropriate, which we believe makes our conjugation technology broadly applicable to a wide variety of IgG monoclonal antibodies. Leveraging our diverse toolkit of improved and novel payloads, cleavable and non-cleavable linkers, and deep understanding of optimized site-specific conjugation sites, we have developed payload and linker combinations that can readily be applied to other antibodies in the same class. For example, our auristatin analogues, a potent microtubule inhibitor, and CPI, a highly potent DNA-cross-linking agent, have site-specific conjugation engineering with several linkers alongside IgG1 antibodies. These payloads and linkers could be readily applied to other IgG1 antibodies to efficiently develop novel product candidates.

•

Potential for improved therapeutic index and ADC stability. We believe that our site-specific conjugation technology has potential to mitigate off-target liabilities of ADCs contributing to an enhanced plasma stability and enhanced therapeutic index. As shown in Figure 8 and 9, applying the FACT platform to a well-established antibody, NG-HER2-ADC, to generate a model ADC was observed to mitigate toxicity and increase the TI and PK exposure and half-life of the ADC in vivo. The rate of linker cleavage and release of the linker/payload construct has been observed to be heavily dependent on the conjugation location and we optimize our linkers for both specific targets and payloads. As a result, we believe the FACT platform and our empirical understanding of optimal site-specific conjugation may allow us to generate candidates against a broad set of targets that result in superior cell killing.

Figure 8

Schematic illustration of how the therapeutic index of a model ADC generated using the FACT platform can potentially mitigate toxicity while maximizing PK exposure in vivo (NHP: non-human primates)

Figure 9

Comparison of stability and exposure in cynomolgus monkeys of Pfizer’s NG-HER2-ADC using the same linker-payload and conjugation site chemistry as our PYX-201 ADC was observed to improve the stability and tolerability over conventional ADCs conjugated with the same linker-payload in preclinical studies (NG: next generation).

•

Enhanced anti-tumor activity through bystander activity. As depicted in Figure 10 below, bystander activity occurs when payloads that are delivered to target cells diffuse into and kill neighboring cells in the tumor microenvironment and is of particular importance if the target is not uniformly expressed on all tumor cells. Bystander activity also has the potential to overcome resistance that may occur over time to treatment with ADCs, carrying non-bystander active payloads, as anti-tumor activity is not directly tied to antigen expression at the target site and destruction of a single target cell. We believe our toolkit of novel and validated payloads, linkers and site-specific conjugation techniques will allow us to further develop ADC candidates with bystander activity that may result in greater clinical activity, especially in cases with heterogeneous target expression.

Figure 10

The following table summarizes the potential advantages of our next-generation ADC platform that utilizes preclinically optimized payloads and site-specific conjugation compared to the currently approved ADCs using conventional conjugation:

Pyxis Oncology's Next-Generation ADCs Conventional ADCs

Potential Therapeutic Index •8 – 16 •1 – 5

Our ADC Product Candidates

PYX-201: Site-Specific Investigational ADC Targeting Onco-Fetal Fibronectin EDB

Overview

Our ADC PYX-201 is an investigational human IgG1 isotype site-specifically conjugated with an auristatin toxin targeting EDB that we plan to initially develop for the treatment of non-small cell lung cancer, or NSCLC, breast cancer and other solid tumors. We licensed worldwide rights to PYX-201, built on the FACT platform, from Pfizer. We expect to submit an IND in the second half of 2022.

Non-Small Cell Lung Cancer Overview

NSCLC is a highly prevalent cancer with over 200,000 newly diagnosed patients per year in the United States representing 80-85% of lung cancers and remains the most common cause of cancer related deaths worldwide. The rate of new cases of lung cancer was 53.1 per 100,000 men and women per year. The death rate was 36.7 per 100,000 men and women per year. Per National Cancer Institute, SEER Cancer Statistics Review, in 2018, there were an estimated 582,631 people living with lung cancer in the United States. NSCLC encompasses subtypes of large cell, squamous cell, and adenocarcinoma, with adenocarcinoma accounting for over half of all cases. NSCLC is classified into four stages (I through IV) of disease, depending on how much the cancer has spread. For localized NSCLC (stages I and II), surgery, radiation, and chemotherapy are the first line of therapy. Although surgery is potentially curative in stage one NSCLC, 35-55% of those patients will have a recurrence of their cancer. In addition, roughly 50% of lung cancers are metastatic at diagnosis, and 20-24% are locally advanced.

For later stages III and IV, chemotherapy, radiation, and immunotherapies are used. For patients with non–small-cell adenocarcinomas, biomarker testing can identify genomic biomarkers, which may be druggable and eligible for treatment with targeted therapies. The treatment paradigm for metastatic NSCLC has shifted dramatically with the introduction of targeted therapies addressing druggable driver mutations, such as tyrosine kinase inhibitors, and immunotherapies such as PD-(L)1 checkpoint therapies. However, despite the initial success, resistance to targeted and immunotherapies almost invariably develops and ultimately, chemotherapy becomes the best available option. The five-year survival rate of metastatic NSCLC patients remains only at 7% and effective treatment options beyond frontline therapy are needed for this patient population.

Breast Cancer Overview

Breast Cancer is the second most frequently diagnosed malignancy globally. Breast cancer has an incidence of over 250,000 annually in the United States. The rate of new cases of female breast cancer was 129.1 per 100,000 women per year. The death rate was 19.9 per 100,000 women per year. Per National Cancer Institute, SEER Cancer Statistics Review, in 2018, there were an estimated 3,676,262 women living with female breast cancer in the United States. Most breast cancer patients have disease confined to the breast (stage I to II), however, approximately 20-30% of all breast cancer patients will develop metastatic disease, and the five-year survival is less than 30%. The spectrum of breast cancers includes various clinical subtypes based on expression of certain hormone receptors, or HR, such as estrogen receptors, or ER, and progesterone receptors, or PR, or human epidermal growth factor receptor 2, or HER2. Triple negative breast cancer is a clinical subtype where there is no expression of the identified proteins. The current treatment paradigm still exhibits high unmet need for more effective treatment options.

Rationale for Targeting EDB and Mechanism of Action for PYX-201

Fibronectin is a component of the extracellular matrix and its downstream signaling pathways regulate cell adhesion, migration, differentiation, and wound healing. EDB is an alternatively spliced form of fibronectin, which occurs when RNA is re-arranged to produce multiple variants of the same protein. EDB is typically only spliced during embryogenesis and is rarely found in healthy adult tissues. However, cancer cells take advantage of EBD’s ability to promote neo-vasculature structures, which are critical to feeding and supporting the uncontrolled growth of a tumor.

EDB is overexpressed in a variety of cancers, including, but not limited to, cancers of the lung, breast, ovary, pancreas, head and neck, thyroid, and brain (Figure 11). In vitro studies have shown that down regulation of EDB resulted in a significant reduction in cancer motility. Furthermore, EDB expression is maintained in distal metastasis in human cancer. EDB meets our criteria of a highly desirable ADC target due to its strict preferential expression in tumor tissue and its role as a driver of the poor prognosis in many cancers. Our primary lead indications, NSCLC and breast cancer, were chosen on the basis of unmet need, preclinical data generated, and the well-characterized role EDB plays in these tumors’ pathology.

Figure 11

EDB is highly expressed in a variety of solid tumors with restricted normal tissue expression (IHC: Immunohistochemistry; mRNA: Messenger RNA; TCGA: The Cancer Genome Atlas portal; GTEX: Genotype-Tissue Expression portal).

PYX-201 was developed using the FACT platform to produce an ADC designed to be highly stable and target a DAR of four. The complementarity-determining regions, or CDRs, of the EBD antibody used in PYX-201, which is the part of the antibody responsible for binding to EDB, is well characterized and has been tested clinically in the form of a radio-conjugated antibody for tumor imaging—demonstrating a high degree of tumor-directed specificity. Furthermore, PYX-201 is designed to optimize linker stability to enable delivery of the auristatin payload without required internalization of the ADC into the cancer cell. Unlike currently approved ADCs which bind to the tumor cell surface, PYX-201 is designed to deliver the auristatin payload to the TME consisting of tumor cells, stromal cells and the surrounding blood vessels. PYX-201 is designed to exhibit anti-tumor activity through three distinct modes of action, as illustrated in Figure 12 below. PYX-201 may be internalized prior to extracellular cleavage of the linker due to fibronectin turnover, resulting in the release of the payload in the tumor cell.

Direct killing activity: After binding to EDB locally expressed in the TME, cathepsin B, a protease which is aberrantly overexpressed in and secreted by invasive and metastatic cancers, cleaves the linker enabling the cell-permeable auristatin toxin to kill both the tumor and stromal cells, which play a key role in maintaining the TME. PYX-201 is designed to attack the tumor and the stromal cells, and thus may remodel the TME and may enhance T cell activity.

Bystander effect: Releasing the payload extracellularly within the TME may also confer added cytotoxicity via bystander activity, which may enable killing of cancer cells that do not express EDB.

Immunogenic cell death: Lastly, auristatin has been shown in preclinical models to drive immunogenic cell death by causing the release of tumor antigens and damage-associated molecular patterns, or DAMPs, and promoting dendritic cell maturation and activation, which together initiates an adaptive immune response.

Taken together, we believe that PYX-201 may potentially generate a multi- pronged attack on difficult-to-treat cancers by directly killing cancer cells, modulating the TME, and mobilizing an anti-tumor immune response.

Figure 12

PYX-201 is designed to bind Fibronectin EDB in the surrounding stroma to kill tumor cells and the supporting infrastructure through direct payload-induced cell death, bystander effect and triggering immunogenic cell death based on data from preclinical models

Preclinical Data

PYX-201 has shown promising preclinical results. In preclinical studies, we have observed strong in-vivo activity in NSCLC PDX and in the EMT-6 syngeneic mouse breast cancer models. While PDX mouse models are generated by grafting patient derived cells to immune deficient mice, syngeneic mouse models are grafted with tumors derived from mice which allow the immune system to remain intact. As a result, while PDX models provide the most clinically translatable signals of efficacy in a preclinical setting, syngeneic models allow us to assess the ability of PYX- 201 to generate an immune response. In these syngeneic models, we have been able to show that PYX-201 effectively localizes to cancers and can generate not only significant reductions in tumor burden but can also mobilize an anti-tumor immune response.

In a PDX model of NSCLC, PYX-201 was intravenously administered four days apart for twelve days and a dose-dependent regression in tumor burden and a durable response at 3 mg/kg was observed (Figure 13).

Figure 13

PYX-201 has been shown to be highly active in a PDX model of NSCLC.

The anti-EDB human mAb used in PYX-201 is cross-reactive with mouse EDB-fibronectin. As a result, in syngeneic tumor models conducted in immune competent mice, PYX-201 achieved a durable response with a single dose of 9 mg/kg (Figure 14). In preclinical studies, we observed increased infiltration in CD3 T cells and upregulation of PD-L1 which suggests that PYX-201 may be capable of inducing immunogenic cell death. Combining sub-optimal doses of PYX-201 with checkpoint therapy resulted in synergistic inhibition of tumor growth in the EMT-6 model. Consequently, we believe PYX-201 may synergize with checkpoint inhibitors, as shown in Figure 15. PYX-201 was also well-tolerated in our mouse models and toxicology studies conducted in rat and cynomolgus monkeys. In an exploratory toxicology study in cynomolgus monkeys the HNSTD was found to be greater than 12 mg/kg with three doses of PYX-201 administered every three weeks. There was no differential in body weight or food consumption detected and based on the types of toxicities observed (i.e., no fibrosis, neuropathology etc.), all toxicities are reversible, or are expected to be reversible. PYX-201 was observed to have a preclinical relevant therapeutic index of 16 (the HNSTD in monkeys was 144 mg/m2 and was 16 times greater than the dose required for a complete response in mice of 9 mg/m2), which we believe is promising based on our experience investigating the relative therapeutic index among different ADC constructs.

Figure 14

PYX-201 treatment in vivo of syngeneic cell-derived tumor models has been associated with enhanced T cell infiltration based on increased CD3 positivity. (CR: complete response; rcEDB: Reverse Chimeric EDB)

Figure 15

EDB vc0101 ADC combines with anti-PD-L1 and anti-41-BB to synergistically reduce tumor growth in EMT6 mouse syngeneic model

Clinical Development Plan

We plan to submit an IND by in the second half of 2022. Subject to the FDA’s acceptance, we plan to conduct a Phase 1/2 dose escalation/expansion trial consistent with other Phase 1/2 clinical trial models for solid tumors. Initially, we plan to enroll NSCLC and breast cancer patients and patients with other tumor types with a high frequency of EDB expression to identify a recommended dose for separate expansion cohorts in tumor types that demonstrated activity in dose escalation. We may pursue the development of PYX-201 as a combination therapy with the standard of care as appropriate in future studies. For example, in NSCLC and breast cancer, where immunotherapy is widely used in both first and second-line settings, PYX-201 may provide a synergistic treatment benefit since the auristatin payload has been observed in preclinical studies to trigger hallmarks of immunogenic cell death.

PYX-202: Rationally Designed, Site-Specific, Investigational ADC Targeting Delta Like Non-Canonical Notch Ligand 1

Overview

Our ADC PYX-202 is an investigational novel ADC consisting of an IgG1 anti-Delta-like 1 homolog, or DLK1, mAb site-specifically conjugated to MMAE via a plasma- stable ß-glucuronide linker. Our development plan is initially targeted at the treatment of SCLC, soft tissue sarcoma, or STS, and other solid tumors. We licensed worldwide rights to PYX-202, excluding South Korea, from LegoChem. See “Licensing and Collaboration Agreements” in Item 1. Business in this Annual Report on Form 10-K.

Small Cell Lung Cancer Overview

Approximately 30,000 SCLC patients are diagnosed per year in the United States, representing approximately 15% of all lung cancers. The majority of patients present with symptoms including worsening fatigue, cough, shortness of breath, chest pain, or weight loss, and are diagnosed using imaging (e.g., CT scan, MRI scan) and a biopsy. At the time of diagnosis, more than 90% of patients having locally advanced or metastatic disease at diagnosis. Complete remissions are rare as 75-80% of patients relapse within two years, and response rates in the second-line setting have typically been between 14-30%. Over half of diagnosed patients are expected to require two or more lines of therapy. The five-year survival rates are dismal at only 6%. The disease is typically classified into two main stages: limited disease (LD-SCLC) and extensive disease (ED-SCLC), depending on how localized the tumors are to the ipsilateral hemithorax. For patients with LDSCLC, a combination of radiotherapy along with chemotherapy is the first line of treatment, while the first-line treatment of ED-SCLC is combination chemotherapy alone or in combination with immune checkpoint inhibitors. The median overall survival for patients with extensive-stage SCLC is reported to be 8-13 months from the time of diagnosis. Beyond progression, lurbinectedin and topotecan are standard treatment options used in the second/third line setting and only offer a median survival of four to five months. Effective therapy in this patient population represents high unmet need.

Soft Tissue Sarcoma Overview

In 2020, approximately 13,000 patients were diagnosed with soft tissue sarcoma in the United States, of which about 10% and 40% of patients will either initially present or develop metastatic disease, respectively. Patients with metastatic disease have a poor overall survival ranging from 12-18 months—less than 20% of patients are alive after two years. The current standard of care treatment for metastatic patients is typically a combination of doxorubicin as a monotherapy or in combination with ifosfamide and the median overall survival is approximately 12-14 months. There are limited treatment options beyond chemotherapy medicines, therefore there is significant unmet need for alternative therapeutic options.

Rationale for Targeting DLK1 and Mechanism of Action for PYX-202

DLK1 is a transmembrane protein and non-canonical ligand for Notch, which is implicated in the proliferation, differentiation, and survival of tumor cells. DLK1 plays a key role during fetal development and is involved in the terminal differentiation of the fat, muscle, liver, and pituitary gland, and furthers epithelial branching in the lung and pancreas. DLK1 is absent in most tissues at birth, and in adults, its expression is limited in low amounts to the adrenal and pituitary glands, pancreas, ovary, endometrium, and testis. In certain tumor types, DLK1 is significantly upregulated and has been shown to promote invasion and support the maintenance of cancer stem cells, a subset of cells that has been linked to drug resistance and relapse (Figure 16). In addition to SCLC and STS, DLK1 is also known to be overexpressed in AML and tumors of neuroendocrine origin such as neuroblastoma and rhabdomyosarcoma.

Figure 16

DLK1 Expression in Various Tumors by IHC

Tumor DLK1 (-)ve DLK1 (+)ve Total

Pancreatic Carcinoma Duct Andenocarcinoma 33 (71.7%) 13 (28.3%) 46

Islet Cell Carcinoma 3 (50%) 3 (50%) 6

DLK1 expression was determined by IHC, with DLK1 positive tumors containing more than 10% immunopositive stained cells (either cell membrane or cytoplasmic staining). Source: Yanai H, et al., J Biochem. 2010; 148(1):85.

Due to preferential expression and as a driver of a poor prognosis in many cancers, DLK1 meets the requirements of an ADC target. Our primary lead indications, SCLC and STS, were chosen on the basis of multiple factors including unmet need, preclinical data generated, and the well-characterized role DLK1 plays in its disease pathology.

Figure 17

PYX-202 is designed to be rapidly internalized and the MMAE payload cleaved by glucuronidase within the lysosome to target tubulin and induce tumor cell death. Additionally, bystander effect may augment tumor cell killing by targeting neighboring tumor cells.

PYX-202 is designed to rely upon a tumor-selected beta-glucuronide linker with great plasma stability to deliver a MMAE payload and to limit off-target toxicities. MMAE auristatin is a well-characterized tubulin inhibitor which is currently used in FDA-licensed ADCs such as brentuximab vedotin, polatuzumab vedotin-piiq, and enfortumab vedotin-ejfv. PYX-202 exhibits anti-tumor activity through five distinct modes of action, as illustrated in Figure 17 above:

Targeting: PYX-202 consists of an IgG1 anti-DLK1 mAb designed to enable efficient binding to DLK1 molecules expressed on the tumor cell surface.

Internalization: Once bound to its target, the anti-DLK1 mAb is rapidly internalized into the DLK1-expressing cancer cell.

Drug release: The payload, attached to the anti-DLK1 mAb via a stable b-glucuronide linker, is released when PYX-202 interacts with ß-glucuronidase, an enzyme readily present in lysosomes, after internalization into the cancer cell.

Bystander effect: Payload released from DLK1-positive target cells may confer added cytotoxicity via bystander activity, which may enable killing of cancer cells that do not express DLK1.

Apoptosis and Immunogenic cell death: MMAE, like other derivatives of auristatins, potentially induces immunogenic cell death and the maturation and activation of dendritic cells based on preclinical studies.

In addition, our novel approach employs a site-specific conjugation of a well-studied tubulin inhibitor for enhanced ADC stability targeting a DAR of four and improved construct stability. Taken together, we believe that PYX-202 has the potential to generate a multi-pronged attack on difficult-to-treat cancers by directly killing cancer cells or via the bystander effect and mobilizing an anti-tumor immune response.

Preclinical Data

PYX-202 has shown promising in vivo activity in immune-deficient mice engrafted with patient-derived SCLC tumors. In these PDX models, PYX-202 was intravenously administered every four days for 12 days and caused significant decrease in tumor volume at doses as low as 2 mg/kg and durable regression at 6 and when dosed once a week for four weeks at 9 mg/kg in some mice. In addition, treatment with PYX-202 resulted in durable regressions in the NCI-H69 CDX model(Figure 18).

Figure 18

Activity of PYX-202 was highly active in PDX and cell-derived xenograft models of SCLC.

The anti-DLK1 human mAb used in PYX-202 is cross-reactive with mouse and cynomolgus DLK1. In an exploratory toxicology study in cynomolgus monkeys the HNSTD was found to be equal to or greater than 12 mg/kg with a single dose of PYX-202 administered. No findings for body weight, body temperature, food consumption, serum chemistry, or histology were found after a single 12 mg/kg dose. PYX-202 has a preclinical relative therapeutic index of eight (the HNSTD in monkeys is 144 mg/m2 is eight times greater than the dose required in mice of 18 mg/m2 (the equivalent of 6mpk)), which, based on our experience investigating the relative therapeutic index among different ADC constructs, we believe is promising.

Clinical Development Plan

In preclinical small cell lung cancer, or SCLC, PDX models, as well as in a human cell line-based, or CDX, mouse model of cancer, which were conducted by LegoChem, we have observed significant anti-tumor activity as measured by durable tumor regression. In preparation for our IND filing and based on observation of our GLP studies to date, we have determined that we will need to conduct additional GLP and non-GLP toxicity studies to determine whether PYX-202 is a viable clinical candidate. We will continue to monitor the progress of our PYX-202 program and expect to provide an update about PYX-202 in mid-2022.

PYX-203: Rationally Designed, Investigational, Site-Specific ADC Targeting CD123

Overview

Our ADC, PYX-203, is an investigational human IgG1 isotype mAb targeting CD123 that is site-specifically conjugated to the DNA cross linking toxin CPI dimer that we plan to develop for the treatment of AML and other blood cancers. CD123 is a cell surface antigen widely expressed in AML, including on leukemic stem cells. We licensed worldwide rights to PYX-203 built on the FACT platform. We expect to submit an IND in the second half of 2023.

Acute Myeloid Leukemia Overview

Acute Myeloid Leukemia (AML) is a hematopoietic stem/progenitor cell malignancy, characterized by an aberrant proliferation of abnormal myeloid progenitor cells unable to differentiate into mature blood cells. In 2021, the American Cancer Society estimates there will be approximately 20,000 new cases of AML diagnosed, with incidence increasing with age (median age at diagnosis is 68 years). This accounts for approximately 1% of all new cancer cases in the United States. The rate of new cases of AML was 4.3 per 100,000 men and women per year. AML is a highly heterogeneous disease, although it can be broken down into favorable, intermediate, and adverse-risk groups based on their cytogenetic profile. The majority of patients present with a combination of leukocytosis and signs of bone marrow failure (i.e., thrombocytopenia) and are diagnosed by the presence of 20% or more blasts in the bone marrow or peripheral blood. Standard of care consists of an initial round of induction therapy, if eligible, consisting of what is known as a “7+3” regimen—7 days of continuous infusion with cytarabine with 3 days of anthracycline. Overall, roughly 60%-80% of patients will achieve a complete remission with induction therapy and may be eligible for an allogeneic hematopoietic stem cell transplant (allo-HSCT). Despite a high remission rate after initial treatment, approximately 50-70% patients experience a relapse. The five-year overall survival remains low at approximately 29%, and there is a significant unmet need for patients who relapse after successful first-line treatment or become refractory and resistant to current treatments.

Myeloid Dysplastic Syndrome, or MDS

MDS is a group of disorders characterized by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular bone marrow and a high risk of conversion to AML. Distinct mutations of stem cells are found most frequently in genes involving RNA splicing. It most commonly affects the elderly and up to 20,000 new cases are diagnosed each year in the United States. Symptoms tend to reflect the most affected cell line and may include pallor, weakness and fatigue, fever and infection, bruising and bleeding. Prognosis depends greatly on the exact classification and on any associated disorders. The Revised International Prognostic Scoring System predicts the outcome using cytogenetics, percentage of marrow blasts and degree of cytopenia as risk factors. Patients in the lowest risk category have a median survival of about 8 years whereas those in the highest risk category have a median survival of less than 1 year. Treatment includes symptomatic management, chemotherapy with azacitidine, decitabine or lenalidomide. The one curative therapy is allogeneic stem cell transplant which can only be used in younger medically fit patients. Given the poor outcomes with current treatment there is a large unmet need for novel well tolerated therapies.

Rationale for Targeting CD123 and Mechanism of Action for PYX-203

CD123, also known as interleukin-3 receptor alpha, or IL-3R, is a cell surface antigen that is widely overexpressed on leukemic stem cells, or LSCs, and leukemic blasts in various hematological malignancies, including AML, hairy cell leukemia, Hodgkin lymphoma, and blastic plasmacytoid dendritic neoplasm, or BPDCN. Multiple studies have demonstrated that CD123 expression is significantly lower in normal myeloid progenitors and that high levels of CD123 expression may be associated with worse clinical outcomes and overall survival. Taken together, CD123 is an attractive oncology target that has been exploited by multiple therapeutic modalities, including bispecific antibodies, CAR-T therapies, and other ADCs. In 2018, the FDA approved tagraxofusp-erzs for BPDCN, making it the first ever CD123 targeted agent approved for any indication. Our primary lead indication in AML was chosen based on unmet need, preclinical data generated, and the well-characterized role CD123 overexpression plays in the disease pathology.

Figure 19

CD123 is highly expressed on AML cells, including leukemic stem cells, or LSC, with limited expression on hematopoietic stem cells, or HSC.

PYX-203 leverages site-specific conjugation through the FACT platform with the goal of targeting a DAR of 2 and high construct stability. PYX-203 uses a plasma-stable, cleavable linker with a novel CPI dimer payload designed to alkylate and crosslink DNA to activate multiple DNA damage pathways. In our in vitro cell line models, we have observed that our CPI dimer payload overcame multi-drug resistance, or MDR, and effectively killed cell lines resistant to either cytarabine or calicheamicin which is the payload used in gemtuzumab ozogamicin (Pfizer, Inc.), an FDA approved ADC for AML. The mutations introduced for site-specific conjugation also eliminate the N297 glycation site. Absence of antibody glycation eliminates binding to FC gamma receptors, or FcgRs, and consequently may reduce non-specific uptake of the ADC into FcgR expressing immune cells.

Figure 20

PYX-203 is designed to delivers a highly potent DNA-crosslinking payload (CPI) to kill CD123 expressing cells. The ADC 1) is designed to targets CD123 expressing cells and upon binding to the target 2) is designed to be internalized by AML cells, where 3) the CPI payload is to be cleaved by cathepsin B proteases within the lysosome and cross-link DNA interstrands to 4) induce tumor cell death.

Preclinical Data

We have extensively tested PYX-203 in a variety of in vitro and in vivo preclinical studies. Dose-dependent cytotoxicity of PYX-203 was observed in CD123+ MOLM13 and MV4-11 AML cell lines and PYX-203 did not exhibit cytotoxicity against CD123-negative cell lines (Figure 21). In addition, data from those studies did not show that the cytotoxicity of PYX-203 was not affected by the presence of recombinant human IL-3, which binds CD123 endogenously to transmit IL-3 signals, thereby suggesting that IL-3 may not compete with PYX-203 at the CD123 target site.

Figure 21

In vitro cytotoxicity assay of PYX-203 in MV4-11 and MOLM-13 cells in the absence or presence of recombinant human IL-3 (rIL-3), which showed IL-3 did not affect PYX-203 specificity or cytotoxicity. Viability was measured by Cell titre Glo (CTG) luminescent cell viability assay kit.

In addition to in vitro cytotoxicity, significant anti-tumor activity of PYX-203 has been observed preclinically as measured by the reduction in the frequency of the leukemic cells in the blood and bone marrow in nine disseminated AML PDX mouse models which were selected to represent the broad heterogeneity of AML cytogenetic profiles, molecular abnormalities, and disease stages observed clinically. PYX-203 doses of 0.1 and 0.03 mg/kg were associated with significant anti-tumor activity across this range of samples from subsets of AML patients, suggesting PYX-203 may have the potential to treat a broad spectrum of the AML population (Figure 22).

Figure 22

PYX-203 has demonstrated anti-tumor activity in a range of AML models in vivo

The anti-CD123 human mAb used in PYX-203 is cross-reactive with cynomolgous CD123. PYX-203 has exhibited favorable tolerability data in toxicology studies conducted in non-human primates. Moderate decreases of white blood cell counts were observed in PYX-203 at doses up to 1 mg/kg in non-human primates. Single dose studies in rat demonstrated improved tolerability for PYX-203 compared to a similarly prepared ADC using anti-CD33 as a model antibody conjugated to the pyrolobenzodiazepine, or PBD, or calicheamicin payloads (internal data). PYX-203 had a preclinical relative therapeutic index of 8 (the HNSTD in monkeys was 12 mg/m2 which is eight times greater than the dose required for a complete response in mice of 1.5 mg/m2). In addition, these data, which are supported by the literature, shows that CD123 expression was restricted to specific cell types of peripheral blood and bone marrow cells in human and cynomolgus monkeys which we believe may translate to lower off-target toxicity in the clinic as compared to CD33, the target of gemtuzumab ozogamicin. PYX-203 was tested preclinically with three doses of 1 mg/kg and 3 mg/kg, with doses £1 mg/kg associated with minimal and non-adverse toxicity events. This corresponded to a TI of 8, with the bone marrow and esophagus identified as the organs of primary dose-limiting toxicity in cynomolgus monkeys.

Clinical Development Plan

We plan to submit an IND in the second half of 2023. Subject to the FDA’s acceptance, we plan to conduct a Phase 1/2 dose escalation/expansion trial consistent with other Phase 1/2 clinical trial models for hematologic malignancies. Initially, we plan to enroll AML and with other hematologic malignancies with a high frequency of CD123 expression to identify a recommended dose for separate expansion cohorts in tumor types that demonstrated activity in dose escalation. To examine the potential benefit of PYX-203 in a broader range of patients in earlier stages of the disease, we may pursue combination therapy with the standard of care as appropriate in future studies.

Immuno-Oncology Programs and Target Catalog Overview

Background on Current Immuno-Oncology Therapeutics

The advent of immuno-oncology therapeutics, particularly immune checkpoint inhibitors, has shifted the treatment paradigm for oncology. The immune system has the capability to recognize and eliminate cancer, but tumor cells take advantage of immune checkpoint pathways, which normally prevent autoimmunity, to suppress and evade immune effector cell activity. The first generation of drugs that interrupt these pathways, including PD-L(1) and cytotoxic T-lymphocyte associated protein 4, or CTLA-4, inhibitors, has generated significant enthusiasm due to their ability to achieve durable responses in some patients. While these drugs provide significant therapeutic benefit for durable responders, response rates remain low for most patients, particularly for tumors with low levels of T cells infiltrating the tumor. These non-inflamed (i.e., “cold”) tumors can suppress the adaptive immune response through a variety of mechanisms within the TME.

Target Catalog Overview

We have a large proprietary target catalog that we have assembled through both our own discovery activities and through an exclusive license from the University of Chicago for the work on immunotherapy targets out of Dr. Thomas Gajewski’s laboratory. We are also building a large “cold” tumor target discovery database leveraging several human tumor databases.

The target catalog is based upon findings from an in vivo mouse model system which examined tumor tissue for functional and dysfunctional T cells based on the ability of the T cells to produce the cytokine IL-2. Furthermore, since 4-1BB and LAG3 positive T cells do not secrete IL-2, the CD8+ T cells were sorted based on cell surface marker expression i.e., 4-1BB and LAG3, which further defined functional or dysfunctional T cells. Gene expression analysis identified upregulated cell surface molecules in dysfunctional cells which included well established markers such as PD1, CTLA4, and TIM3, while many other novel targets were identified of which we have prioritized a select subset for discovery research based on bioinformatics and deep biological rationale.

Our cold tumor target discovery database used RNA-seq transcriptome analysis of human tumor databases to identify potential novel targets involved in regulation of T cell function and/or infiltration leading to cold tumors. We have supplemented this database with additional resources which we continue to mine to identify additional novel targets for immunomodulation. These cold tumor targets are potentially dominant immune suppressors that are expressed across a variety of tumor associated cells, including immune cells, tumors cells, and stroma, offering the potential to uncover not only novel IO mechanisms, but additional novel targets for our ADC platform.

Immuno-Oncology Programs Overview

We have initiated multiple monoclonal antibody programs that address critical immunomodulatory pathways within the TME and are exploring additional potential targets. Our programs address critically important tumor infiltrating immune cell populations, such as macrophages, T cells, and natural killer (NK) cells, which may play crucial roles in limiting tumor growth and metastasis. In addition to singling out specific cell types, we believe our IO programs also address mechanisms responsible for T cell exhaustion and the immunosuppressive effects of the TME on T and NK cells. These effects can occur due to chronic exposure to tumor antigens within the TME and direct exposure to immunosuppressive cytokines and other signaling molecules. Though PD-(L)1 therapies can help reinvigorate T cells, they are often not sufficient to overcome T cell exhaustion and many patients do not respond to standard checkpoint therapy. Several immunosuppressive pathways can also directly limit T cell activity and other critical components of the anti-tumor immune response, such as direct tumor killing by NK cells. Therapies that target both T cell and NK cells to counteract these pathways have the promise to restore immune effector function, either alone or in combination with checkpoint inhibitors. Furthermore, MDSCs/TAMs are another major component of the TME with significant immunosuppressive activity. These cells represent a mixed population of immature myeloid cells and are actively recruited to the TME where they broadly suppress immune activity. MDSCs and tumor-associated macrophages, or TAMs, support tumor growth by depriving other immune cells of key amino acids essential for immune function, producing signaling molecules that block immune effector function, and enhancing activation of regulatory T cells. Furthermore, MDSCs and TAMS promote tumor angiogenesis and growth and are a marker associated with poor outcomes and linked to poor response to PD-(L)1 therapy. We believe our IO programs represent potential novel therapies that have the potential to overcome multiple protumor mechanisms by enhancing T and NK cell activity, or by inhibiting immune suppressive functions of MDSCs and TAMs within the TME.

PYX-106: Investigational IgG1 isotype anti-Siglec-15 Targeting Antibody

Overview

PYX-106 is an investigational fully human IgG1 isotype antibody that is designed to block Siglec-15 mediated suppression of T-cell proliferation and function. We plan to initially develop this asset for the treatment of thyroid cancer, Head & Neck Squamous Cell Carcinoma, or HNSCC, non-small cell lung cancer, or NSCLC, and other solid tumors. We licensed worldwide rights to our Siglec-15 targeting antibody from Biosion USA, Inc. We expect to submit an IND in the second half of 2022.

Rationale for Targeting Siglec-15 and Mechanism of Action for our Siglec-15 targeting antibody

Siglec-15 is a member of the Siglec family (Sialic acid-binding ImmunoGlobulin Lectins), a distinct subgroup of immunoglobulin (Ig) superfamily proteins involved in immune regulation. Siglecs recognize and bind to sialic acid on the surface of cells and this binding can affect cell signaling on immune cells. Siglec-15 is a single-pass type I membrane protein that has been shown to associate with the activating adaptor proteins DNAX activation protein (DAP)12 and DAP10 via its lysine residue in the transmembrane domain, implying that it functions as an activating signaling molecule. While Siglec-15 is minimally expressed on normal tissues, it is highly expressed on both tumor cells and M2 macrophages in the tumor microenvironment (TME) across multiple tumor types, including thyroid cancer, HNSCC, lung cancer, breast cancer, cholangiocarcinoma. The increased presence of highly immunosuppressive M2 macrophages within tumors leads to impaired T cell proliferation and function, causing a decreased anti-tumor immune response. Additionally, Siglec-15 may exacerbate this immunosuppressive effect by interacting with tumor associated myeloid cells to promote their survival and differentiation to drive a tumor-promoting environment. Interestingly, Siglec-15 appears to function independently from the PD-L1 pathway with largely non-overlapping expression in select tumor samples. Therefore, targeting Siglec-15 in the TME may be a promising therapeutic option for patients less likely to respond to a PD-1/PD-L1 targeted therapy.

An overview of the role of Siglec-15 in regulating the immune system and driving anti-tumor immune dysfunction.

Figure 23

(Source: American Association for Cancer Research Journal - Cancer Clinical Research Review - Siglec-15 as an Emerging Target for Next-generation Cancer Immunotherapy by Jingwei Sun, Qiao Lu, Miguel F. Sanmamed and Jun Wang)

Our Siglec-15 targeting antibody is a fully human monoclonal antibody and is engineered with high affinity to block Siglec-15 induced immune suppression and therefore restore T cell proliferation, function and anti-tumor immunity in the TME. Overall, by binding and blocking Siglec-15 activity on myeloid cells and tumors, our Siglec-15 targeting antibody is designed to enhance immune cell mediated tumor cell kill. Given the broad tumor expression profile of Siglec-15, our Siglec-15 targeting antibody has the potential to treat multiple oncology indications including those where PD-1/PD-L1 directed cancer therapies are ineffective. We are initially evaluating our Siglec-15 targeting antibody for the treatment of advanced or metastatic solid tumors, which could include thyroid cancer, HNSCC, NSCLC, breast cancer, and cholangiocarcinoma where high unmet need exists. We plan to submit an IND in the second half of 2022.

Forging Creative Business Models and Alliances

We continuously evaluate a robust set of business development opportunities to build alliances with partners. The set of opportunities include, but are not limited to, joint ventures, spin-offs, discovery partnerships and licenses. Furthermore, we intend to retain the optionality to explore the potential for creative business models.

The Voxall Joint Venture

One such endeavor is Voxall Therapeutics, LLC, or Voxall, which is a 50:50 co-owned joint venture formed by us and Alloy Therapeutics, Inc., or Alloy, to accelerate the discovery and development of drugs to address cancer and autoimmune diseases.

We bring to Voxall targets from our target catalog and expertise in stromal and immune biology while Alloy contributes its ATX-Gx transgenic mouse and other discovery services which accelerate antibody drug discovery. Both provide FTEs and project execution and project oversight. Under the collaboration agreement, the parties will conduct research under a mutually agreed research plan for up to six research programs focused on mutually selected targets. With this initial wave of targets, we retain an exclusive option to obtain an exclusive license to further develop and commercialize development candidates at our discretion.

Additional Discovery Efforts

We believe our broad expertise enables us to pioneer scientific scholarship in immune biology of the TME and beyond. We have a flexible pathway to do so via platform development, forging creative business models and alliance building, in-licensing and leveraging target catalogs to expand our portfolio of differentiated therapeutics for difficult-to-treat cancers. The realization of this vision will necessitate rapid innovation and operational excellence from a scientific and business perspective. As such, our mission is to take the next step towards creating an oncology company of the future — an oncology company unconstrained by conventional ideas and conventional practices, an oncology company that will rise to meet the many and complex challenges of difficult-to-treat cancers, and an oncology company that will have a significant impact on the lives of patients with limited effective treatment options.

Competition

The biotechnology and pharmaceutical industries, including the oncology subsector, are characterized by rapidly evolving technologies, intense competition, and a strong defense of intellectual property and proprietary technologies. Any product candidates that we successfully commercialize may be competitive with currently marketed therapies and any new therapies commercialized in the future. While we believe our technology, drug development expertise, leadership team and strong scientific understanding of cancer targets and biology provides us with certain competitive advantages, we face potential competition from many sources, including major pharmaceutical, biotechnology, academic institutions, and other public and private research institutions.

Many companies are active across various stages of development in the oncology subsector and are marketing and developing products that employ similar ADC and immunotherapy approaches. As of April 2021, there were approximately 275 ADCs in clinical or preclinical development worldwide, of which the vast majority are being developed for the treatment of various cancer indications. Additionally, there are several large and small companies working on various immunotherapy approaches for treatement of cancer. Multiple companies are also involved in the marketing of ADC therapeutics and Immunotherapy which include, but are not limited to, ADC Therapeutics SA, Astellas Pharma, Inc., AstraZeneca plc, Daiichi Sankyo Company, Ltd., Genentech, Inc., Gilead Sciences, Inc, GlaxoSmithKline, plc, Pfizer, Inc., Rakuten Medical, Inc., Seagen, Inc., Nextcure, Inc. and Abcure, Inc.

Our preclinical ADC and immunotherapy candidates may face substantial competition from alternative therapeutic modalities, such as CAR-T therapies, bispecific antibodies, and small molecules that are being developed for the same cancer types that we are targeting with our pipeline candidates. These approaches could prove to be more effective, safer, or convey other advantages over any products resulting from our technology. In addition, we also face competition on specific targets, including the target of our PYX-201 candidate, EDB, from Philogen S.p.A., the target of our PYX-202 candidate, DLK-1, from Chiome Bioscience, Inc., the target of our PYX-203, product candidate, CD123, from ImmunoGen, Inc., Vincerx Pharma, Inc., Macrogenics and Byondis B.V., the target of our PYX-106 product candidate, BSI-060T, from Nextcure, Inc. lead program - NC318 and the target of our PYX-102 product candidate, Anti-KLRG1, from Abcuro, Inc. Additionally, there is a wide array of activity in the development of immunotherapies for oncology which may be competitive with our preclinical discovery programs. Furthermore, if any of our product candidates are approved in oncology indications such as lung, hematological and other cancers, they may compete with existing approaches to treating cancer including surgery, radiation, and drug therapy, including conventional chemotherapy, biological products, and targeted drug small molecule therapies.

Our competitors may possess greater scientific, research and development capabilities, as well as greater financial, technical, manufacturing, marketing, sales and supply resources or experience than we do. These competitors compete with us on the basis of establishing clinical trial sites and patient registration, recruiting and retaining qualified scientific and management personnel, and acquiring new technologies that may complementary, or necessary for, our programs. Our commercial opportunity for our product candidates may be dependent on the ability of our competitors to develop new products that may be more effective, safer, or less expensive than any products that we may develop. Our competitors may succeed in developing competing products before we do, obtaining marketing approval for products and gaining acceptance for such products in the same markets that we are targeting. Smaller or earlier-stage companies that seek collaborative arrangements with large and established companies, may prove to be significant competitors. In addition, our ability to compete may be affected by the availability of reimbursement from government and other third-party payors.

Competitive factors affecting the success of our programs, if approved, will likely be based on their safety and effectiveness, the timing and scope of marketing approvals, the availability and cost of supply, the depth of marketing and sales capabilities, and reimbursement coverage.

Chemistry, Manufacturing and Controls

We believe the manufacturing of our ADCs and monoclonal antibodies requires considerable expertise, know-how, and resources. We do not own or operate and currently have no plans to establish any cGMP compliant manufacturing facilities. We currently rely, and expect to continue to rely, on external Contract Manufacturing Organizations, or CMOs, for the manufacture of product to support non-clinical and clinical testing, as well as for commercial manufacture if our product candidates receive marketing approval. Furthermore, the raw materials and intermediates for our product candidates may be sourced, in some cases, from a single-source supplier. As part of the manufacture and design process for our product candidates, we rely on internal scientific and manufacturing know-how and trade secrets and the know-how and trade secrets of third-party manufacturers. We believe that this strategy allows us to maintain a more efficient infrastructure by eliminating the need for us to invest in our own manufacturing facilities, equipment and personnel while also enabling us to focus our expertise and resources on the development of our current product candidates. We maintain agreements with our manufacturers that include confidentiality and intellectual property provisions to protect our proprietary rights related to our product candidates. We have personnel with significant technical, manufacturing, analytical, quality, including cGMP, and project management experience to oversee our third-party manufacturers and to manage manufacturing and quality data and information for regulatory compliance purposes.

Commercialization Plans

We retain full commercialization rights for all our product candidates, including those obtained through exclusive collaboration agreements, with the exception of PYX-202 in South Korea and PYX-106 in Greater China (mainland China, Hong Kong, Macau and Taiwan). We have not yet established our own commercial organization or distribution capabilities because our product candidates are still in preclinical development. Should any of our candidates receive marketing approval or licensure in the United States or elsewhere, we will need to develop a plan to realize the commercial value of the approved product candidate. At the appropriate time, we plan to build our own specialized sales and marketing organization to support the sales commercialization of approved candidates in the United States. We may also pursue collaboration, co-promotion, distribution and/or other marketing arrangements with one or more third parties to commercialize our product candidates in markets outside the United States. We may also pursue these arrangements for situations in which a larger sales and marketing organization is necessary to realize the full commercial value of any approved wholly owned or collaboration product candidates.

Licensing and Collaboration Agreements

License Agreement with Pfizer, Inc.

In December 2020, we entered into a license agreement, as amended, the “Pfizer License Agreement,” with Pfizer, Inc., or Pfizer, for worldwide development and commercialization rights to two of Pfizer’s proprietary ADC product candidates (now referred to as PYX-201 and PYX-203), as well as other ADC product candidates directed to the licensed targets. The Pfizer License Agreement became effective for the Company in March 2021. The initial exclusively licensed targets are extra domain B (EBD of fibronectin) and CD123 and we have the option to expand the scope of our license to add other licensed targets. Pfizer has also granted us a non-exclusive license to use Pfizer’s FACT platform technology to develop and commercialize the licensed ADCs. In March 2021, we entered into an amendment to the Pfizer License Agreement to include additional know-how within the scope of our license.

Pursuant to the Pfizer License Agreement, we incurred a combined $25.0 million for license fee, consisting of an upfront fee of $5.0 million and issued 12,152,145 shares of Series B convertible preferred stock in 2021 to Pfizer, and are obligated to pay future contingent payments and royalties, including up to an aggregate of $660 million in milestones for the first four licensed ADCs. Additional ADC targets may be licensed for an additional upfront fee, and such targets would be subject to additional regulatory and commercial sales milestones. Additionally, if products are launched, we will pay Pfizer tiered royalties on net sales of licensed products in varying royalty rates ranging from low single digits to mid-teens. Our royalty obligations apply on a licensed product-by-licensed product and country-by-country basis from first commercial sale until the latest to occur of: (1) 12 years from first commercial sale; (2) the expiration of all regulatory or data exclusivity; and (3) the expiration of the last valid claim of a licensed patent covering the licensed product in a country. We are also obligated to pay Pfizer a percentage of certain sublicensing revenue ranging from low-double digits to thirty percent based on the stage of development of the licensed product at the time of entering into the applicable sublicense.

Under the Pfizer License Agreement, we are obligated to use commercially reasonable efforts to nominate a clinical candidate within four years of a target becoming a licensed target. We are also required to use commercially reasonable efforts to develop and seek regulatory approval for at least one licensed product directed to each licensed target in the United States and at least one other major market country (France, Germany, Italy, Japan, Spain and the United Kingdom), and to commercialize any licensed product in each such country after receiving regulatory approval. We control prosecution and enforcement with respect to any exclusively licensed patents, and Pfizer has prosecution and enforcement rights if we elect not to exercise such rights.

The Pfizer License Agreement will remain in effect until the expiration of the last to expire royalty term, unless terminated in accordance with the following: (1) by either party for the other party’s material breach if such party fails to cure such breach within the specified cure period; (2) by either party upon certain insolvency events of the other party; or (3) prior to receipt of the first regulatory approval for a licensed product, by us for any reason upon 90 days’ prior written notice, or after receipt of the first regulatory approval for a licensed product, by us for any reason upon one years’ prior written notice.

License Agreement with the University of Chicago

In April 2020, we entered into a license agreement, or the “University License Agreement,” with the University of Chicago, or the University, to obtain an exclusive license under certain patents resulting from research performed, in-part, by our scientific founder, Dr. Thomas Gajewski, as well as a non-exclusive license to certain know-how and materials. Under the terms of the license, we have the exclusive global right to develop and commercialize products that are covered by a valid claim of a licensed patent, incorporate or use the licensed know-how and materials or are known to assess, modulate or utilize the activity of certain specified biological targets.

In partial consideration for the license from the University, we issued to the University 48,919 shares of our Common Stock in 2020. Pursuant to the University License Agreement, we are obligated to pay to the University an annual maintenance fee of $10,000 commencing on the third anniversary of the effective date, potential development and commercial milestones of up to an aggregate of $7.7 million as well as running royalties on net sales of licensed products at varying rates ranging from less than one percent to the low single digits, subject to a minimum annual royalty ranging from $1.0 million to $3.0 million during certain years following the first commercial sale of a licensed product. Our royalty obligations apply on a licensed product-by-licensed product and country-by-country basis until: (1) for licensed products covered by a valid claim of a licensed patent in a given country, the expiration of such valid claims; and (2) for all other licensed products, 10 years from the first commercial sale of a licensed product in a given country. We are also obligated to pay the University a percentage of certain sublicensing revenue ranging from low- to mid-teens based on the date of entering into the applicable sublicense.

Under the University License Agreement, we are obligated to use commercially reasonable efforts to develop and bring licensed products to market, meet certain preclinical and clinical development milestones by specific dates, and promote and sell licensed products after receipt of regulatory approval, subject to certain free and payment-based extensions. The University controls prosecution of the licensed patents at our cost and we have the first right to enforce the licensed patents subject to the University’s backup enforcement rights.

The University License Agreement will remain in effect on a licensed product-by-licensed product basis until the expiration of all royalty obligations with respect to a licensed product, unless terminated in accordance with the following: (1) by the University upon 30 days’ prior written notice for any uncured payment breaches or 90 days prior written notice for all other uncured breaches; (2) by the University upon certain insolvency events or dissolution by us or any affiliate; or (3) by us in full or with respect to a particular licensed product at the end of the calendar quarter following the calendar quarter when we provide written notice of termination.

The Voxall Joint Venture with Alloy Therapeutics, Inc.

In March 2021, we entered into definitive transaction agreements with Alloy to finance and operate Voxall, a joint venture company formed in collaboration with Alloy to leverage Pyxis Oncology’s site-specific target catalog and Alloy’s ATX-GxTM platform and antibody discovery services.

Voxall granted to both Pyxis Oncology and Alloy 50% of the voting membership units of Voxall in exchange for certain initial contributions. Our initial contribution included $50,000 and a non-exclusive fully paid-up license to certain intellectual property owned or controlled by us to enable the collaboration with Voxall as further described below. Alloy’s initial contribution included $50,000 and the execution of a license agreement and a services agreement to enable the collaboration with Voxall as further described below. Voxall is governed by a board of directors consisting of an equal number of our representatives and Alloy’s representatives. We have designated our CEO, Lara Sullivan M.D., as our board representative. The protective provisions under Voxall’s operating agreement require the approval of both Pyxis Oncology and Alloy before Voxall may take certain actions.

In connection with the formation of Voxall, we entered into a three-year research collaboration with Alloy and Voxall to identify and select certain biological targets and create development candidate antibodies directed to those targets for further preclinical development, clinical development and commercialization. Under the collaboration agreement, the parties will conduct research under a mutually agreed research plan and budget for up to six research programs focused on mutually selected targets. Each of us and Alloy will provide research support for the collaboration through separate services agreements with Voxall, which services will be paid in the form of promissory notes issued by Voxall. Voxall will own all intellectual property arising from the collaboration, subject to certain exceptions for intellectual property relating to Alloy’s ATX-GxTM platform.

If a development candidate antibody under a research program meets certain mutually agreed selection criteria, we will have the exclusive option to obtain an exclusive license from Voxall to further develop and commercialize all the development candidate antibodies discovered under that research program. We may in-license one research program on certain pre-agreed financial terms. For all other in-licensed research programs, we will be obligated to pay fair market value as determined by a third-party valuation. Any research program that we do not in-license may be licensed by Voxall to a third party.

Agreements with LegoChem Biosciences, Inc.

In December 2020, we entered into a license agreement, or the “LegoChem License Agreement,” with LegoChem Biosciences, Inc., or LegoChem, pursuant to which we licensed worldwide (other than Korea) development and commercialization rights for LCB67, an ADC product candidate targeting DLK1 (now referred to as PYX-202), and products containing the licensed compound. We have the right to ask LegoChem to use commercially reasonable efforts at our cost to modify the licensed compound if there are certain technical failures of the licensed compound that we believe are attributable to the linker or the payload used in the licensed compound, and the modified compound will replace the unmodified version as the licensed compound. In February 2021, we entered into an amendment to the LegoChem License Agreement to include additional patents within the scope of our license.

Pursuant to the LegoChem License Agreement, we paid an upfront fee of $0.5 million in 2020 and $9.0 million in 2021 and are required to purchase certain initial quantities of licensed product from LegoChem for an estimated cost of $7.0 million. We are also obligated to pay up to an aggregate of $284.5 million to LegoChem if certain development, regulatory and sales milestones are achieved, as well as tiered royalties on net sales of licensed products ranging from mid-single digit to high single digit royalty rates. Our royalty obligations apply on a licensed product-by-licensed product and country-by-country basis until the latest to occur of: (1) the date of expiration of the last valid claim of a licensed patent covering the licensed product; (2) 10 years from first commercial sale; and (3) the expiration of regulatory or data exclusivity.

Under the LegoChem License Agreement, we are obligated to use commercially reasonable efforts to develop at least one licensed product for at least one indication and, upon receipt of regulatory approval in the United States, China, Japan or any three or more of the major European countries (United Kingdom, Spain, France or Germany), to commercialize at least one licensed product for at least one indication in such countries. We have agreed to purchase certain initial quantities of licensed product from LegoChem and have the right to manufacture the licensed products, provided that LegoChem has the right to control the manufacture and use of the conjugation methods and materials, linker and payload elements included in the licensed intellectual property. We control prosecution, enforcement and defense of the licensed patents that are specific to the licensed products, and LegoChem has backup rights if we elect not to exercise our rights.

During the term of the LegoChem License Agreement, neither party may, either directly or through an affiliate or sublicensee, research, in-license, develop or commercialize in the licensed territory any other ADC directed to DLK-1, including any ADC directed to more than one epitope of DLK1 (a multi-epitope DLK1) or a modification or derivative of the licensed compound. This restriction does not apply to any ADC being developed by LegoChem that is subject to our right of first negotiation. We have the right of first negotiation to obtain a license to any ADC directed to DLK1 other than a multi-epitope DLK1 controlled by LegoChem that LegoChem proposes to include in a GLP toxicology study or to license to a third party.

The LegoChem License Agreement will remain in effect on a country-by-country basis until the expiration of the obligation to pay royalties, unless terminated as follows: (1) by either party for the other party’s material breach if such party fails to cure such breach within the specified cure period; (2) by either party upon cessation of business activities or certain insolvency events of the other party; (3) by us if there are certain technical failures of the licensed compound; or (4) by us for any reason upon 90 days’ prior written notice. If we challenge the scope, ownership, validity or enforceability of a licensed patent, LegoChem may convert our exclusive license to a non-exclusive license or terminate the LegoChem License Agreement.

In December 2020, we also entered into an opt-in, investment and additional consideration agreement with LegoChem, or the “Opt-In Agreement.” Under the Opt-In Agreement, we issued to LegoChem shares of Series B convertible preferred stock as part of our Series B financing in March 2021. We are also obligated to pay LegoChem a percentage of sublicensing revenue ranging from low-double digits to thirty percent based on the stage of development of the licensed product at the time of entering into the applicable sublicense, which percentage may be increased to up to fifty percent for any upfront payment from a sublicensee under certain circumstances. LegoChem has exercised its option under the Opt-In Agreement to make a $8.0 million payment to us, which payment was made in April 2021, in exchange for the right to receive an extra milestone payment of $9.6 million upon the earliest to occur of certain events, including the date of pricing or offer of the first public offering of our common stock or if we are the subject of a change of control transaction. LegoChem may elect to receive payment for up to 50% of this extra milestone payment as well as certain development milestone payments under the LegoChem License Agreement in shares of our preferred stock.

License Agreement with Biosion USA Inc.

On March 28, 2022, we entered into a license agreement, or the “Biosion License Agreement”, with Biosion USA, Inc., or Biosion, pursuant to which we obtained exclusive, worldwide (other than Greater China (mainland China, Hong Kong, Macau and Taiwan)), licenses for development, manufacture and commercialization rights for BSI-060T, a Siglec-15 targeting antibody, an IO product candidate (now referred to as PYX-106), and products containing the licensed compound.

Pursuant to the Biosion License Agreement, we agreed to pay an upfront fee of $10 million and are obligated to pay future contingent payments including development, regulatory and commercial milestone up to an aggregate of $217.5 million in case of normal approval and $222.5 million in case of accelerated approval. Additionally, if products are launched, we will pay Biosion tiered royalties on net sales of licensed products in varying royalty rates ranging from low single digits to low teens. Our royalty obligations apply on a licensed product-by-licensed product and country-by-country basis from first commercial sale until the latest to occur of: (1) 12 years from first commercial sale; (2) the expiration of all regulatory or data exclusivity; and (3) the expiration of the last valid claim of a licensed patent covering the licensed product in a country.

Intellectual Property

Our intellectual property is critical to our business, and we strive to protect it, including by obtaining and maintaining patent protection in the United States and internationally for our product candidates, new therapeutic approaches and potential indications, and other inventions that are important to our business. We also rely on trade secrets and proprietary know-how to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection.

Our patent portfolio includes patents and patent applications that are exclusively licensed from the University of Chicago, Pfizer, and LegoChem and patent applications that are owned by us. Our patent portfolio includes patents and patent applications that cover our product candidates PYX-201, PYX-202, PYX-203, PYX-106 and PYX-102 and the use of these candidates for therapeutic purposes in certain territories. Our proprietary technology has been developed primarily through relationships with academic institutions, Pfizer, LegoChem, Biosion and contract research organizations.

For our product candidates, we will, in general, initially pursue patent protection covering compositions of matter and methods of use. Throughout the development of our product candidates, we seek to identify additional means of obtaining patent protection that would potentially enhance commercial success, including through additional methods of use, process of making, formulation and dosing regimen-related claims.

For all patent applications, we determine claiming strategy on a case-by-case basis. Advice of counsel and our business model and needs are always considered. We file patent applications containing claims for protection of useful applications of our proprietary technologies and any products, as well as new applications and/or uses we discover for existing technologies and products, assuming these are strategically valuable. We continuously reassess the number and type of patent applications, as well as the existing patent claims to ensure that maximum coverage and value are obtained for our processes and compositions, given existing patent office rules and regulations. Further, claims may be modified during patent prosecution to meet our intellectual property and business needs.

We recognize that the ability to obtain patent protection and the degree of such protection depends on a number of factors, including the extent of the prior art, the novelty and non-obviousness of the invention and the ability to satisfy the enablement requirement of the patent laws. The patent positions of immuno-oncology companies like ours are generally uncertain and involve complex legal, scientific and factual questions. In addition, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted or further altered even after patent issuance. Consequently, we may not obtain or maintain adequate patent protection for any of our future product candidates or for our platform technology. 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.

Regardless of the coverage we seek under our existing patent applications, there is always a risk that an alteration to the product or process may provide sufficient basis for a competitor to avoid infringement claims. In addition, the coverage claimed in a patent application can be significantly reduced before a patent is issued, and courts can reinterpret patent scope after issuance. Moreover, many jurisdictions, including the United States, permit third parties to challenge allowed or issued patents in administrative proceedings, which may result in further narrowing or even cancellation of patent claims. Moreover, we cannot provide any assurance that any patents will be issued from our pending or any future applications or that any current or future issued patents will adequately protect our products.

In total, our patent portfolio, including patents licensed from the University of Chicago, Pfizer, LegoChem and Biosion and patents owned by us, comprises eight different patent families, filed in various jurisdictions worldwide, including families directed to composition of matter for antibody drug conjugates, and families directed to methods of treating cancer and identifying potential targets. Our patent portfolio includes issued patents in the United States, Taiwan, and Australia. Our patent portfolio as of December 31, 2021, is outlined below:

Composition of Matter Patents

PYX-201. We have exclusively licensed from Pfizer a patent family that includes two issued patents, one each in Australia and Korea, and pending applications in Australia, Brazil, Canada, China, Europe, Hong Kong, India, Israel, Japan, Mexico, Russia, Singapore, South Africa, and the United States that claim the composition of matter and certain methods of use with respect to PYX-201. The 20-year term of the patents in this family runs through October 2037, absent any available patent term adjustments or extensions.

PYX-202. We have exclusively licensed from LegoChem a patent family that includes pending patent applications in Australia, Brazil, Canada, China, Europe, India, Israel, Japan, South Korea, Mexico, New Zealand, Russia, Singapore, Ukraine, Taiwan, Hong Kong, and the United States, that claims the composition of matter of and certain methods of use with respect to PYX-202. The 20-year term of the patents in this family runs through March 2040, absent any available patent term adjustments or extensions.

PYX-203. We have exclusively licensed from Pfizer a patent family that includes one issued patent in Taiwan, 23 pending applications in Australia, Brazil, Canada, China, Colombia, Europe, Hong Kong, India, Indonesia, Israel, Japan, South Korea, Malaysia, Mexico, New Zealand, Peru, Philippines, Russia, Saudi Arabia, Singapore, South Africa, Taiwan, and the United States that claim the composition of matter and certain methods of use with respect to PYX-203. The 20-year term of the patents in this family runs through October 2038, absent any available patent term adjustments or extensions.

PYX-106. We have exclusively licensed from Biosion USA, Inc. a patent family that includes one pending international patent application filed under the Patent Cooperation Treaty, or PCT, that claims the composition of matter of and certain methods of use with respect to PYX-106. We intend to file national phase applications based on this PCT application before applicable deadlines. Written Opinion of Search Authority found that all claims were deemed novel, inventive, and useful. The Search Authority cited no anticipatory or obvious-rendering prior art.

Projected Expiration of granted patents from this PCT Application is March 2041, absent any available patent term adjustments or extensions.

Methods related to T Cell Activity

We have exclusively licensed from the University of Chicago a patent family that includes two issued patents in the United States and pending applications in Europe and the United States that claim methods for treating patients with immunotherapy based on the identification of the patient as having non-anergic T cells after measuring expression levels of various genes. The 20-year term for patents in this family runs through March 2034, absent any available patent term adjustments or extensions.

Methods of treating solid tumor cancers

We have exclusively licensed from the University of Chicago a patent family that includes one issued patent and one pending application in the United States that claim methods for treating solid tumor cancers. The 20-year term for patents in this family runs through March 2036, absent any available patent term adjustments or extensions.

Methods of treating cancer by targeting dysfunctional tumor antigen-specific CD8+ T cells

We have exclusively licensed from the University of Chicago a patent family that includes six pending applications in Canada, China, Europe, Japan, Hong Kong, and the United States that claim methods of treating cancer comprising administering an agent that specifically targets dysfunctional tumor antigen-specific CD8+ T cells. The 20-year term for patents in this family runs through January 2038, absent any available patent term adjustments or extensions.

Methods of generating target lists

We own a pending PCT application directed to methods of identifying potential targets. The 20-year term for patents in this family runs through to 2041, excluding any extension of patent term that may be available.

We expect to file future patent applications on innovations that are developed in the course of advancing our pipeline through preclinical and clinical development.

Patent Term and Term Extensions

Individual patents have terms for varying periods depending on the date of filing of the patent application or the date of patent issuance and the legal term of patents in the countries in which they are obtained. Generally, utility patents issued for applications filed in the United States are granted a term of 20 years from the earliest effective filing date of a non-provisional patent application. In addition, in certain instances, the term of a U.S. patent can be extended to recapture a portion of the United States Patent and Trademark Office, or the USPTO, delay in issuing the patent as well as a portion of the term effectively lost as a result of the FDA regulatory review period. However, as to the FDA component, the restoration period cannot be longer than five years and the restoration period cannot extend the patent term beyond 14 years from FDA approval. In addition, only one patent applicable to an approved drug is eligible for the extension, and only those claims covering the approved drug, a method for using it, or a method of manufacturing may be extended. Similar provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an approved drug. We will, in general, pursue available patent term extensions in the U.S. and in foreign jurisdictions that provide for patent term extensions, however, there is no guarantee that the applicable authorities, including the FDA in the United States, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions. All taxes, annuities or maintenance fees for a patent, as required by the USPTO and various foreign jurisdictions, must be timely paid in order for the patent to remain in force during this period of time.

The actual protection afforded by a patent may vary on a product-by-product basis, from country to country, and can depend upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions and the availability of legal remedies in a particular country and the validity and enforceability of the patent.

Our patents and patent applications may be subject to procedural or legal challenges by others. We may be unable to obtain, maintain and protect the intellectual property rights necessary to conduct our business, and we may be subject to claims that we infringe or otherwise violate the intellectual property rights of others, which could materially harm our business. For more information, see the section titled “Risk Factors—Risks Related to Our Intellectual Property.”

Trademarks and Know-How

In connection with the ongoing development and advancement of our product candidates in the United States and various international jurisdictions, we seek to create protection for our marks and enhance their value by pursuing trademarks where available and when appropriate. In addition to patent and trademark protection, we rely upon trade secrets and know-how and continuing technological innovation to develop and maintain our competitive position. We seek to protect our proprietary information, in part, using confidentiality agreements with our commercial partners, collaborators, employees and consultants and invention assignment agreements with our employees and selected consultants. We also seek to preserve the integrity and confidentiality of our data and trade secrets by maintaining physical security of our premises and physical and electronic security of our information technology systems. While we have confidence in these individuals, organizations and systems, agreements or security measures may be breached, and our trade secrets and other proprietary information may be disclosed. We may not have adequate remedies for any breach and could lose our trade secrets and other proprietary information through such a breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our consultants, contractors or collaborators use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting trade secrets, know-how and inventions.

Our commercial success will also depend in part on not infringing the proprietary rights of third parties. In addition, we have licensed rights under proprietary technologies of third parties to develop, manufacture and commercialize specific aspects of our future products and services. It is uncertain whether the issuance of any third-party patent would require us to alter our development or commercial strategies, alter our processes, obtain licenses or cease certain activities. The expiration of patents or patent applications licensed from third parties or our breach of any license agreements or failure to obtain a license to proprietary rights that we may require to develop or commercialize our future technology may have a material adverse impact on us. If third parties prepare and file patent applications in the United States that also claim technology to which we have rights, we may have to participate in interference proceedings in the USPTO to determine priority of invention.

For more information regarding the risks related to our intellectual property, please see “Risk Factors—Risks Related to Our Intellectual Property.”

Government Regulation

The research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, recordkeeping, serialization and tracking, promotion, advertising, distribution and marketing, post-approval or licensure monitoring and reporting, and export and import, among other things, of our product candidates are extensively regulated by governmental authorities in the United States and other countries. In the United States, the FDA regulates biological products under the Federal Food, Drug, and Cosmetic Act, or the FDCA, and its implementing regulations, and the Public Health Service Act, or the PHSA, and its implementing regulations. Failure to comply with the applicable U.S. requirements may subject us to administrative or judicial sanctions, such as the FDA’s refusal to approve a Biologics License Application (BLA), warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions and/or criminal prosecution.

Approval and Licensure Process for Biological Products

Biological products such as ours may not be commercially marketed without prior licensure from the FDA and approval or licensure from comparable regulatory agencies in other countries. In the United States, the process for receiving such licensure is long, expensive and risky, and includes the following steps:

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preclinical laboratory tests, animal studies, and formulation studies;

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submission to the FDA of an Investigational New Drug (IND) application for human clinical testing, which must become effective before human clinical trials may begin;

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approval by an IRB at each clinical site before each trial may be initiated;

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adequate and well-controlled human clinical trials to establish the safety, purity, and potency of the drug for each indication;

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submission to the FDA of a BLA;

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satisfactory completion of an FDA advisory committee review, if applicable;

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satisfactory completion of an FDA inspection of the manufacturing facility or facilities at which the biological product is produced to assess compliance with cGMP;

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a potential FDA audit of the preclinical and clinical trial sites that generated the data in support of the BLA;

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the ability to obtain clearance or approval of companion diagnostic tests, if required, on a timely basis, or at all;

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FDA review and approval of the BLA prior to any commercial marketing or sale of the drug in the United States; and

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compliance with any post-approval requirements and/or commitments, including the potential requirement to implement a REMS, and the potential requirement to conduct post-approval studies.

In guidance, FDA has stated that it considers antibody-drug conjugates to be combination biological product-drug products for which a BLA should be submitted. FDA has also stated in guidance that it regulates monoclonal antibodies as biological products which require a BLA. FDA has issued guidance on product development considerations for antibody-drug conjugates, including dosing and clinical pharmacology testing recommendations.

Regulation by U.S. and foreign governmental authorities is a significant factor affecting our ability to commercialize any of our products, as well as the timing of such commercialization and our ongoing research and development activities. The commercialization of drug products requires regulatory approval by governmental agencies prior to commercialization. Various laws and regulations govern or influence the research and development, non-clinical and clinical testing, manufacturing, processing, packaging, validation, safety, labeling, storage, record keeping, registration, listing, distribution, advertising, sale, marketing and postmarketing requirements and/or commitments of our products. The lengthy process of seeking these approvals, and the subsequent compliance with applicable laws and regulations, require expending substantial resources.

The results of preclinical testing, which include laboratory evaluation of product chemistry, formulation, toxicity and carcinogenicity, animal studies to assess the potential safety, purity and potency of the product and its formulations, details concerning the drug manufacturing process and its controls, and a proposed clinical trial protocol and other information must be submitted to the FDA as part of an IND that must be reviewed and become effective before clinical testing can begin. The study protocol and informed consent information for patients in clinical trials must also be submitted to an independent Institutional Review Board, or IRB, for approval covering each institution at which the clinical trial will be conducted. Once a sponsor submits an IND, the sponsor must wait 30 calendar days before initiating any clinical trials. If the FDA has comments or questions within this 30-day period, the issue(s) must be resolved to the satisfaction of the FDA before a clinical trial can begin. In addition, the FDA or an IRB may impose a clinical hold on ongoing clinical trials if, among other things, it believes that a clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable and significant risk to clinical trial patients. If the FDA imposes a clinical hold, clinical trials can only proceed under terms authorized by the FDA. If applicable, our preclinical and clinical studies must conform to the FDA’s Good Laboratory Practice, or GLP, and Good Clinical Practice, or GCP, requirements, respectively, which are designed to ensure the quality and integrity of submitted data and protect the rights and well-being of study patients. Information for certain clinical trials also must be publicly disclosed within certain time limits on the clinical trial registry and results databank maintained by the NIH.

Typically, clinical testing involves a three-phase process; however, the phases may overlap or be combined:

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Phase 1 clinical trials typically are conducted in a small number of volunteers or patients to assess the early tolerability and safety profile, the pattern of drug absorption, distribution and metabolism, the mechanism of action in humans, and may include studies where investigational drugs are used as research to explore biological phenomena or disease processes;

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Phase 2 clinical trials typically are conducted in a limited patient population with a specific disease in order to assess appropriate dosages and dose regimens, expand evidence of the safety profile and evaluate preliminary efficacy; and

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Phase 3 clinical trials typically are larger scale, multicenter, well-controlled trials conducted on patients with a specific disease to generate enough data to statistically evaluate the efficacy and safety of the product, to establish the overall benefit-risk relationship of the drug and to provide adequate information for the labeling of the drug.

A therapeutic product candidate being studied in clinical trials may be made available for treatment of individual patients, intermediate-size patient populations, or for widespread treatment use under an expanded access protocol, under certain circumstances. Pursuant to the 21st Century Cures Act, or Cures Act, which was signed into law in December 2016, the manufacturer of one or more investigational products for the diagnosis, monitoring, or treatment of one or more serious diseases or conditions is required to make available, such as by posting on its website, its policy on evaluating and responding to requests for individual patient access to such investigational product.

Additionally, on May 30, 2018, the Trickett Wendler, Frank Mongiello, Jordan McLinn, and Matthew Bellina Right to Try Act of 2017 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 obtaining FDA authorization under an FDA expanded access program; however, manufacturers are not obligated to provide investigational new drug products under the current federal right to try law.

Disclosure of Clinical Trial Information

Sponsors of certain clinical trials of FDA-regulated products are required to register and disclose certain clinical trial information. Information related to the product, patient population, phase of investigation, trial sites and investigators, and other aspects of the clinical trial are then made public as part of the registration. Sponsors are also obligated to disclose the results of their clinical trials after completion. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs.

Orphan Drugs

Under the Orphan Drug Act, the FDA may grant orphan drug designation to therapeutic candidates (drugs or biological products) intended to treat a rare disease or condition, which is a disease or condition that affects fewer than 200,000 individuals in the U.S. or more than 200,000 individuals in the U.S. and for which there is no reasonable expectation that the cost of developing and making available in the U.S. a therapeutic candidate for this type of disease or condition will be recovered from sales in the U.S. for that therapeutic candidate. Orphan drug designation must be requested before submitting a marketing application for the therapeutic candidate for that particular disease or condition. After the FDA grants orphan drug designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan drug designation does not convey any advantage in or shorten the duration of the regulatory review and approval process. Among the other benefits of orphan drug designation are tax credits for certain research and an exemption from the BLA application fee. The FDA may revoke orphan drug designation, and if it does, it will publicly disclose that the product is no longer designated as an orphan drug.

If a product that has orphan drug designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan drug exclusivity, which means that the FDA may not approve any other applications, including a full BLA, to market the same biological product for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the biological product was designated. Orphan drug exclusivity does not prevent the FDA from approving a different biological product for the same disease or condition, or the same biological product for a different disease or condition.

A designated orphan drug may not receive orphan drug exclusivity if it is licensed for a use that is broader than the indication for which it received orphan designation. In addition, exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

Expedited Development and Review Programs

The FDA has a number of programs intended to expedite the development and review of product candidates. These programs include fast track designation, breakthrough therapy designation, priority review designation, accelerated approval, and regenerative medicine advanced therapy (“RMAT”) designation. Fast Track designation is intended to expedite or facilitate the process for reviewing new biological products that meet certain criteria. Specifically, new biological products are eligible for Fast Track designation if they are intended to treat a serious or life-threatening condition and demonstrate the potential to address unmet medical needs for the condition. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a new biological product may request the FDA to designate the biological product as a Fast Track product at any time during the clinical development of the product. Unique to a Fast Track product, the FDA may consider for review sections of the marketing application on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the application, the FDA agrees to accept sections of the application and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the application. FDA may revoke the Fast Track designation if it believes that the designation is no longer supported by data emerging in the clinical trial process.

Under the Breakthrough Therapy program, products intended to treat a serious or life-threatening disease or condition may be eligible for Breakthrough Therapy designation, which includes eligibility for the benefits of the Fast Track program, when preliminary clinical evidence demonstrates that such product may have substantial improvement on one or more clinically significant endpoints over existing therapies. Additionally, FDA will seek to ensure the sponsor of a breakthrough therapy product receives timely advice and interactive communications to help the sponsor design and conduct a development program as efficiently as possible.

A product is eligible for priority review if it is intended to treat a serious condition and, if approved or licensed, it would provide a significant improvement in safety or effectiveness. FDA intends to take action on a priority review marketing application within six months of receipt, compared to 10 months of receipt for regular review submissions.

Additionally, a product may be eligible for accelerated approval if it is intended to treat a serious or life-threatening disease or condition and would provide meaningful therapeutic benefit over existing treatments. Accelerated approval may be granted on the basis of adequate and well-controlled clinical studies establishing that the product has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality and is reasonably likely to predict an effect on irreversible morbidity, mortality, or other clinical benefit. As a condition of approval, the FDA may require that a sponsor of a biological product receiving accelerated approval diligently perform adequate and well-controlled postmarketing clinical studies demonstrating clinical benefit. In addition, the FDA requires as a condition for accelerated approval the submission of promotional materials, which could adversely impact the timing of the commercial launch of the product. Fast Track designation, Breakthrough Therapy designation, priority review and accelerated approval do not change the standards for licensure but may expedite the review process.

PYXS US Equity

PYXS · 10-K · period ended 2021-12-31

Item 1. Business.

PYXS US Equity☆

PYXS · 10-K · period ended 2021-12-31

Item 1. Business.

PYXS US Equity