What changed in this filing

/stocks — the workspaceLOADING

Item 1. Business

2024-02-29 compared with 2023-02-27 · 255 added, 271 removed, 399 unchanged (57% of the section changed)

We are a clinical-stage biopharmaceutical company focused on discovering and developing engineered monoclonal antibody and cytokine therapeutics to treat patients with cancer and autoimmune diseases who have unmet medical needs.

We are a clinical-stage biopharmaceutical company focused on discovering and developing engineered antibody therapeutics to treat patients with cancer and other serious diseases, who have unmet medical needs.

We use our protein engineering capabilities to increase our understanding of protein structures and interactions and to design new technologies and XmAb® drug candidates with improved properties.

We advance these candidates into clinical-stage development, where we are conducting Phase 1 and Phase 2 studies for a broad portfolio of programs, to determine which programs we advance into later stages of development and potentially commercialization, which programs we partner to access complementary resources to optimize development, or which programs we terminate.

Our approach to protein design includes engineering Fc domains, the parts of antibodies that interact with multiple segments of the immune system and controls antibody structural architecture.

Our approach to protein design includes engineering Fc domains, the parts of antibodies that interact with multiple segments of the immune system and control antibody structure.

The Fc domain is constant and interchangeable among antibodies, and our engineered XmAb Fc domains can be readily substituted for natural Fc domains.

Our protein engineering capabilities and Fc technologies enable us and our partners to develop XmAb antibodies and biotherapeutic drug candidates with improved properties and functionality, which can provide innovative approaches to treating disease and potential clinical advantage over other treatment options.

Our protein engineering capabilities and Fc technologies enable us and our partners to develop XmAb antibodies and other types of biotherapeutic drug candidates with improved properties and functionality, which can provide innovative approaches to treating disease and potential clinical advantage over other treatment options.

For example, we have developed an antibody scaffold to rapidly create novel multi-specific antibodies that bind two or more different targets simultaneously, creating entirely new biological mechanisms.

Other applications of our protein engineering technologies enhance antibody performance by increasing immune inhibitory activity, improving cytotoxicity, extending circulating half-life and stabilizing novel protein structures, such as engineered cytokines.

Three marketed XmAb medicines have been developed with our protein engineering technologies and are generating royalties for us.

Three marketed XmAb medicines have been developed with our protein engineering technologies.

Our protein engineering capabilities allow us to continually explore new functionality in the Fc region, which provides us with opportunities to:

2 unchanged sentences

• Provide collaboration and licensing opportunities with partners for application of our technologies, access to our technologies, access to our drug candidates, or combinations of each.

Our goal is to become a leading biopharmaceutical company focused on developing and commercializing engineered biologic medicines to treat patients with severe and life-threatening diseases with unmet medical needs.

Our goal is to become a leading biopharmaceutical company that develops and commercializes engineered biologic medicines to treat patients with severe and life-threatening diseases with unmet medical needs.

Key elements of our strategy are to:

Advance the clinical development of our XmAb bispecific antibody and cytokine drug candidates.

Advance the development of our XmAb antibody programs for oncology and other serious diseases.

Our modular bispecific technology and protein engineering capabilities enable us to rapidly advance multiple drug candidates into clinical development for ourselves and our partners.

We and our partners are enrolling patients in multiple clinical studies to evaluate our candidates.

Build and manage a large and diversified portfolio of XmAb drug candidates.

We advance multiple candidates that we create from each of our XmAb technologies into early stages of development and evaluate data from such studies in managing our portfolio of candidates.

We make additional investments in those candidates that demonstrate encouraging early clinical and scientific data, partner certain drug candidates to third-party biotechnology and pharmaceutical companies, and stop development of candidates based on the evaluation of emerging clinical and scientific data and the competitive environment for such programs.

Build and manage a diversified portfolio of XmAb drug candidates.

We advance multiple XmAb drug candidates into early stages of clinical development and evaluate data from studies in managing our portfolio of candidates.

Based on the evaluation of emerging data and the competitive environment for such portfolio programs, we make additional investments in those candidates that demonstrate encouraging proof of concept, partner certain drug candidates to third-party biotechnology and pharmaceutical companies, and stop development of some candidates due to emerging data and resource allocation across our pipeline.

Leverage our protein engineering capabilities, XmAb Fc domains, and XmAb drug candidates with partnerships, collaborations, and licenses to generate revenue streams, create new drug candidates and combination treatments, and identify new indications for our pipeline of drug candidates.

Table of Contents `

Generate revenue streams.

The plug-and-play nature of our Fc technologies and our ability to generate multiple drug candidates efficiently provides us opportunities to generate revenue from licensing and collaboration arrangements.

The plug-and-play nature of our Fc technologies and our ability to generate multiple drug candidates efficiently provides us opportunities to generate revenue from licensing and

collaboration arrangements.

In 2023, we received total proceeds of $111.7 million in upfront payments, milestone payments and royalties from such arrangements.

We also received $215.0 million for the sale of a portion of our royalties due to us under our Alexion and MorphoSys agreements, as defined and discussed below.

Create new XmAb drug candidates and investigate novel combination therapies .

1 unchanged sentence

Identify new indications for our pipeline of drug candidates.

We continue to support Investigator Sponsored Trials (ISTs) in which investigators may explore additional therapeutic indications with XmAb drug candidates.

Broaden the functionality of our XmAb Fc technology platforms.

We are conducting further research into the function and application of antibody Fc domains in order to expand the scope of our XmAb Fc technology platforms.

We use the modularity of our XmAb bispecific Fc domains to engineer bispecific antibodies and cytokines in a variety of structural formats.

We use the modularity of our XmAb bispecific Fc domains to engineer XmAb drug candidates in a variety of structural formats.

Continue to expand our patent portfolio protecting our Fc technologies and XmAb drug candidates.

We seek to expand our intellectual property estate and protect our proprietary Fc technologies, our development programs, and XmAb drug candidates by filing and prosecuting patents in the United States and other countries.

Where appropriate, we will seek expansion and extension of patents issued for our product candidates and for partnered product candidates that incorporate one of our Fc technologies.

Where appropriate, we will seek expansion and extension of patents issued for our product candidates and for partnered product candidates that incorporate our Fc technologies.

XmAb Bispecific Fc Domain and New Multi-Specific Antibody Formats

Our modular approach to protein engineering is a distinguishing feature of our Fc technologies.

This inherent flexibility enables us to design multiple XmAb bispecific antibody and cytokine drug candidates with distinct and novel mechanisms-of-action and to seek out new applications of the XmAb Bispecific Fc Domain.

Our business, research, and clinical efforts are to develop and advance our Fc technologies and our portfolio of XmAb bispecific antibody and engineered cytokine drug candidates in oncology and autoimmune diseases.

This inherent flexibility enables us to design multiple XmAb drug candidates with distinct and novel mechanisms-of-action and to seek out new applications of the XmAb Bispecific Fc Domain.

Our business, research, and clinical efforts are to develop and advance our Fc technologies and our portfolio of XmAb drug candidates in oncology and other serious diseases.

CD3 candidates:

CD3 bispecific antibody candidates are designed to redirect T cells to tumor cells through the engagement of an antigen on tumor cells and CD3, an activating receptor on T cells.

We have significantly expanded the potential of our CD3 bispecific antibodies with the multi-specific XmAb 2+1 bispecific antibody format, utilizing two identical tumor targeting domains and one CD3 targeting domain.

CD3 T cell engaging bispecific antibodies are designed to redirect T cells to tumor cells through the engagement of an antigen on tumor cells and CD3, an activating receptor on T cells.

We have significantly expanded the potential of our CD3 T cell engagers with the multi-specific XmAb 2+1 bispecific antibody format, utilizing two identical tumor targeting domains and one CD3 targeting domain.

The affinities for antigen binding are engineered to enable selective engagement and killing of high antigen-expressing tumor cells over low antigen-expressing normal cells.

1 unchanged sentence

We believe that these properties will be particularly important when developing bispecific antibodies against many solid tumor targets, where standard monovalent targeting of tumor antigens could lead to poor tolerability because such targets are often expressed on a range of normal tissues, including critical organs.

Our XmAb819 and XmAb541 CD3 candidates have been designed using our CD3 2+1 format.

CD28 candidates:

2 unchanged sentences

however, the ligands that activate T cells through CD28 are often not expressed on tumor cells.

Targeted CD28 bispecific antibodies may provide conditional co-stimulation of T cells, for example, to T cells recognizing neoantigens or in concert with CD3 T-cell engaging bispecific antibodies.

We have engineered XmAb bispecific antibodies to provide selective CD28 co-stimulation of T cells, activating them when bound to tumor cells.

TME activator candidates:

Our tumor microenvironment (TME) activators have been designed to promote tumor-selective T-cell activation by targeting multiple checkpoints or co-stimulating receptors.

These candidates also incorporate our Xtend™ technology for longer half-life.

Table of Contents `

Targeted CD28 T cell engaging bispecific antibodies may provide conditional co-stimulation of T cells, for example, to T cells recognizing neoantigens or in concert with CD3 T-cell engaging bispecific antibodies.

Our XmAb808 CD28 candidate has been engineered to provide selective CD28 co-stimulation of T cells, activating them when bound to tumor cells.

TME activator candidate:

Our tumor microenvironment (TME) activator candidate, vudalimab, has been designed to promote tumor-selective T-cell activation by targeting multiple checkpoints.

Vudalimab also incorporates our Xtend™ technology for longer half-life.

Cytokine candidates:

Our engineered novel cytokine candidates are fusions of XmAb Bispecific Fc Domains and immune signaling proteins.

We engineer our cytokine candidates with reduced potency to improve therapeutic index and with our Xtend technology for longer half-life.

Our cytokine candidates efbalropendekin alfa (XmAb306), XmAb564 and XmAb662 have been designed with reduced potency to improve therapeutic index and with our Xtend technology for longer half-life.

We continue to invest in our protein engineering efforts to identify novel technologies and drug candidates.

11 unchanged sentences

Vir Biotechnology, Inc.

and its partner GlaxoSmithKline Plc have made available sotrovimab, an antibody that targets the SARS-CoV-2 virus, and in 2021 they received an emergency use authorization (EUA) from the United States Food and Drug Administration (FDA) for the treatment of mild-to-moderate COVID-19 in high-risk adults and pediatric patients.

In the first quarter of 2022, the FDA deauthorized sotrovimab in treating patients with COVID-19.

Sotrovimab has been granted a marketing authorization in the European Union (EU), approved via Japan’s Special Approval for Emergency Pathway in Japan, and granted conditional, provisional, or temporary authorizations in more than 40 other countries.

GSK supplies sotrovimab under the name Xevudy .

and its partner GSK have made available sotrovimab, an antibody that targets the SARS-CoV-2 virus, which in May 2021 received an emergency use authorization (EUA) from the United States Food and Drug Administration (FDA) for the early treatment of mild-to-moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing at least 40 kg) with positive results of direct SARS-CoV-2 viral testing, and at high risk for progression to severe COVID-19, including hospitalization or death.

In March 2022, the FDA deauthorized sotrovimab’s use in all U.S.

regions due to increases in the proportion of COVID-19 cases caused by the Omicron BA.2 subvariant.

Sotrovimab has obtained emergency authorization, temporary authorization or marketing approval (under the brand name Xevudy®) for early treatment of COVID-19 in more than 30 countries.

Sotrovimab incorporates our Xtend Fc domain for longer duration of action.

Xevudy is a registered trademark of GSK.

• Ultomiris ® (ravulizumab-cwvz) :

Alexion’s Ultomiris is approved in the U.S., Europe, and Japan for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) and for the treatment of patients with atypical hemolytic uremic syndrome (aHUS).

In April 2022, Ultomiris was approved by the FDA for the treatment of adult patients with generalized myasthenia gravis (bMG) who are anti-acetylcholine receptor (AChR) antibody positive.

Alexion is also evaluating Ultomiris in a broad late-stage development program across many indications in neurology and nephrology.

Alexion’s Ultomiris is approved in the U.S., Europe, and Japan for the treatment of certain patients with paroxysmal nocturnal hemoglobinuria (PNH), certain patients with atypical hemolytic uremic syndrome (aHUS) and certain patients with generalized myasthenia gravis (gMG).

In May 2023, Ultomiris was approved in the EU and Japan for the treatment of certain adult patients with neuromyelitis optica spectrum disorder (NMOSD).

Alexion is also evaluating Ultomiris in a broad late-stage development program across additional hematology and neurology indications.

Alexion used our Xtend™ Fc Domain to enhance the half-life of Ultomiris to allow for a longer duration of action, less frequent dosing and reduced patient burden of therapy compared to the previous generation therapy, Soliris®.

4 unchanged sentences

Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).

In August 2021, the European Commission granted conditional marketing authorization for Minjuvi ® (tafasitamab) in combination with lenalidomide, followed by tafasitamab monotherapy, for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) who are not eligible for autologous stem cell transplantation (ASCT).

MorphoSys and Incyte are also conducting studies of tafasitamab in additional B-cell indications.

In August 2021, the European Commission granted conditional marketing authorization for Minjuvi ® (tafasitamab) in combination with lenalidomide, followed by tafasitamab monotherapy, for the treatment of adult patients with relapsed or refractory DLBCL who are not eligible for autologous stem cell transplantation (ASCT).

In addition to its approved indication, tafasitamab is being evaluated as a therapeutic option in ongoing pivotal trials for first-line DLBCL, relapsed or refractory follicular lymphoma (FL) and relapsed or refractory marginal zone lymphoma (MZL).

Tafasitamab was created and initially developed by us.

Tafasitamab is co-marketed by Incyte and MorphoSys under the brand name Monjuvi in the U.S.

and is marketed by Incyte under the brand name Minjuvi in Europe and Canada.

Incyte has exclusive commercialization rights to tafasitamab outside the U.S.

Monjuvi ® and Minjuvi ® are registered trademarks of MorphoSys AG.

Table of Contents `

Tafasitamab is marketed by Incyte under the brand name Monjuvi in the U.S.

and under the brand name Minjuvi in Europe and Canada.

Monjuvi ® and Minjuvi ® are registered trademarks of Incyte.

Drug Candidates in Clinical Development

There are currently 21 clinical-stage drug candidates or marketed medicines that have been developed with one or more of our Fc technologies.

There are currently 22 clinical-stage drug candidates or marketed medicines that have been developed with one or more of our XmAb technologies.

A partner is also advancing a drug candidate that incorporates our DN-TNF technology.

1 unchanged sentence

Vudalimab Plamotamab Obexelimab Ultomiris*

XmAb104 XmAb306/RG6323 VIR-3434 Monjuvi*

XmAb564 VIR-2482 Sotrovimab

XmAb819 AMG 509

XmAb808 ASP2138

Novartis bispecific antibody

Teropavimab and zinlirvimab

Tobevibart (VIR-3434)

Xaluritamig (AMG 509)

Efbalropendekin alfa**

XmAb541 (IND open)

Novartis antibody

Xpro1595/INB03

* Alexion and MorphoSys are conducting additional Phase 3 studies in new indications with these candidates.

We are also supporting investigator sponsored trials evaluating vibecotamab (CD123 x CD3) and XmAb968 (CD38 x CD3).

We regularly evaluate our portfolio of candidates and make additional investments in candidates with promising early-stage clinical data, partner out other candidates, and stop development of candidates where early clinical data does not support further investment.

• We initiated a second Phase 2 study for our vudalimab program,

• We initiated Phase 1 studies for our XmAb819 and XmAb808 programs,

• We initiated a Phase1b study for our XmAb564 program, and

• We stopped development of the tidutamab and XmAb841 programs and also stopped development of our plamotamab, tafasitamab and lenalidomide combination study.

XmAb Bispecific Fc Drug Candidates in Clinical Development

Currently, 10 XmAb drug candidates that have been engineered with our XmAb bispecific Fc domain are in active clinical development internally or with our partners.

• Five candidates are wholly owned and are being evaluated by us in Phase 2 or Phase 1 studies;

• Two candidates are being co-developed with partners;

• Three additional candidates are being advanced by partners.

* Alexion and Incyte are conducting additional Phase 3 studies in new indications with these candidates.

** Beginning in June 2024, our collaboration regarding efbalropendekin alfa will convert from a cost and profit-sharing arrangement into a royalty and milestone payment-based arrangement in which Genentech will assume full responsibility for development of the program.

We are also supporting an investigator sponsored trial evaluating vibecotamab (CD123 x CD3).

• We initiated a Phase 1b/2 study of vudalimab in combination with chemotherapy, as a first-line treatment in patients with advanced non-small cell lung cancer;

• We initiated a Phase 1 study for our XmAb662 program;

• We submitted an investigational new drug (IND) application for our XmAb541 program;

• We stopped development of the XmAb104 program, and we also closed gynecologic tumor cohorts in the Phase 2 vudalimab monotherapy study due to the rapidly changing competitive environment in these indications;

• We appointed Nancy Valente, M.D., as our Chief Development Officer, a role in which she is responsible for leading our clinical and medical strategy and execution.

XmAb Bispecific Antibody Drug Candidates in Clinical Development

Currently, 10 XmAb bispecific antibody drug candidates are in active clinical development internally or with our partners:

• Three candidates are wholly owned and are being evaluated by us in Phase 2 or Phase 1 studies;

one wholly owned candidate has an open IND and is pending Phase 1 study initiation;

• One candidate is being co-developed with partners;

• Five additional candidates are being advanced by partners.

Additional candidates are advancing through the preclinical stages of development.

Drug candidates with our bispecific Fc domain, both bispecific antibodies and cytokines, in clinical development include:

XmAb bispecific antibody drug candidates in clinical development include:

Wholly Owned Development Candidates

Vudalimab is a bispecific antibody that targets PD-1 and CTLA-4, two immune checkpoint receptors, and is designed to promote tumor-selective T-cell activation.

We are conducting a Phase 2 clinical study of vudalimab in patients with mCRPC, as a monotherapy or in combination depending on molecular subtype, and a Phase 2 clinical study in patients with advanced gynecologic malignancies and clinically defined high-risk mCRPC.

We continue to enroll patients into these clinical studies.

Table of Contents `

XmAb104 is a bispecific antibody that targets PD-1 and ICOS, an immune co-stimulatory receptor, and is being developed in multiple oncology indications.

We are conducting a Phase 1 study to assess the safety, tolerability, and preliminary anti-tumor activity of XmAb104 in patients with selected solid tumors.

Initial data reported in 2022 indicated XmAb104 was well tolerated and exhibited a distinct safety profile compared to other clinical-stage ICOS programs.

We continue to enroll patients with select solid tumors in the dose expansion portion of the study, evaluating XmAb104 as a monotherapy and in combination with ipilimumab, an anti-CTLA4 antibody.

XmAb564 is a monovalent, potency-reduced interleukin-2 Fc (IL-2-Fc) fusion protein, engineered to selectively activate and expand regulatory T cells (Tregs) for the potential treatment of patients with autoimmune diseases.

XmAb564 is engineered with reduced binding affinity for IL-2's beta receptor and increased binding affinity for its alpha receptor.

In a Phase 1a clinical study of XmAb564, a single dose of XmAb564, administered subcutaneously in healthy volunteers, was well tolerated and generated durable, dose-dependent and selective expansion of Tregs.

We are conducting a randomized, double-blind, placebo-controlled Phase 1b clinical study to evaluate the safety and tolerability of multiple ascending doses of XmAb564, administered subcutaneously in patients with atopic dermatitis or psoriasis.

Data from a Phase 1 study that enrolled heavily pretreated patients with multiple solid tumor types indicated that vudalimab was generally well-tolerated with encouraging clinical activity.

We continue to develop vudalimab for patients with metastatic castration-resistant prostate cancer (mCRPC) and patients with locally advanced or metastatic non-small cell lung cancer.

We are conducting two Phase 2 clinical studies of vudalimab in patients with mCRPC, a study of vudalimab as a monotherapy in the clinically defined high-risk patient population and a study of vudalimab in combination with chemotherapy, in the aggressive variant patient population.

In the Phase 2 monotherapy study, vudalimab has been generally well tolerated and associated with response to treatment in multiple patients who have visceral or lymph node metastases.We are also conducting a Phase 1b/2 study evaluating vudalimab as a first-line treatment in patients with locally advanced or metastatic non-small cell lung cancer.

XmAb819 is a first-in-class ENPP3 x CD3 XmAb 2+1 bispecific antibody that we are developing for patients with renal cell carcinoma (RCC).

The XmAb 2+1 multivalent format enables greater selectivity for ENPP3 expressing tumor cells compared to normal cells, which also express ENPP3 at lower levels.

We are conducting a Phase 1 study evaluating XmAb819 in patients with RCC.

We are conducting a Phase 1 study evaluating XmAb819 in patients with advanced clear cell RCC.

XmAb808 is a tumor-selective, co-stimulatory XmAb 2+1 bispecific antibody designed to bind to the broadly expressed tumor antigen B7-H3, and selectively to the CD28 T-cell co-receptor only when bound to tumor cells, which was demonstrated in in vitro studies.

In vivo studies further demonstrated strong potentiation of checkpoint and CD3 cytotoxic activity.

Xencor is conducting a Phase 1 study of XmAb808 in combination with pembrolizumab in patients with advanced solid tumors.

We are conducting a Phase 1 study of XmAb808 in combination with pembrolizumab in patients with advanced solid tumors.

XmAb541 is a Claudin-6 (CLDN6) x CD3 XmAb 2+1 bispecific antibody that we are developing for patients with ovarian cancer and other solid tumor types.

The XmAb 2+1 multivalent format enables greater selectivity for CLDN6 over similar Claudin family members, such as CLDN9, CLDN3 and CLDN4.

The investigational new drug (IND) application for XmAb541 has been allowed to proceed by the FDA, and we plan to initiate a Phase 1 study in the first half of 2024.

Candidates Co-Developed with Partners

Plamotamab is a bispecific antibody that targets CD20, an antigen on B-cell tumors, and CD3, an activating receptor on T cells.

In October 2021, we entered into a global collaboration and license agreement with Janssen to advance plamotamab and XmAb CD28 bispecific antibody combinations for the treatment of patients with B-cell malignancies.

Janssen received worldwide exclusive development and commercial rights to plamotamab, and we are collaborating with Janssen on further clinical development of plamotamab, with us paying 20% of costs.

We are conducting a Phase 1 study of plamotamab in patients with non-Hodgkin's lymphomas, and we continue enrolling patients into subcutaneous dose escalation cohorts of this study.

XmAb306 (RO7310729) is a potency-reduced IL15/IL15-receptor alpha complex fused to our bispecific Fc domain (IL15/IL15Rα-Fc).

The Fc domain also incorporates our Xtend technology for extended half-life.

Xencor is co-developing the program in collaboration with Genentech, a member of the Roche Group.

Genentech is conducting a Phase 1 study of XmAb306 as a single agent and in combination with atezolizumab in patients with advanced solid tumors.

Genentech is also conducting two additional Phase 1 studies, evaluating XmAb306 in patients with relapsed/refractory multiple myeloma, either in combination with daratumumab (anti-CD38 antibody) or in combination with cevostamab (FcRH5 x CD3 bispecific antibody).

We continue to support enrollment into these clinical studies.

In October 2021, we entered into a global collaboration and license agreement with Janssen Biotech, Inc.

(Janssen), a Johnson & Johnson company, to advance plamotamab and XmAb CD28 bispecific antibody combinations for the treatment of patients with B-cell malignancies (2021 J&J collaboration).

J&J received worldwide exclusive development and commercial rights to plamotamab, and we are collaborating with J&J on further clinical development of plamotamab, with us paying 20% of costs.

We conducted a Phase 1 study of plamotamab in patients with non-Hodgkin's lymphomas.

Results from the expansion portion of the study indicate that intravenous plamotamab monotherapy was well tolerated and demonstrated encouraging clinical activity in heavily pretreated patients at the recommended Phase 2 intravenous dose.

In 2023, we completed enrolling patients in subcutaneous dose escalation cohorts of this study.

Candidates Advanced by Partners

AMG 509 is a STEAP1 x CD3 2+1 bispecific antibody that our partner Amgen is advancing for the treatment of patients with prostate cancer.

Xaluritamig (AMG 509) is a STEAP1 x CD3 2+1 bispecific antibody that our partner Amgen is advancing for the treatment of patients with prostate cancer.

The XmAb 2+1 multivalent format enables higher binding capability for STEAP1 expressing cells.

Amgen is currently enrolling patients in a Phase 1 study of AMG 509 in patients with mCRPC.

In February 2022, Amgen presented encouraging, preliminary pharmacodynamic activity by induction of percent maximum PSA decline among 30 patients in the study, which provides an early signal of activity and validation of the potential of the XmAb 2+1 format.

Amgen is completing patient enrollment in the dose expansion portion of a Phase 1 study of xaluritamig in patients with mCRPC.

In October 2023, at the European Society for Medical Oncology (ESMO) Congress, encouraging interim clinical results from the study were presented during an oral proffered paper session, validating the potential of the XmAb 2+1 format.

Amgen is planning two additional Phase 1 studies of xaluritamig to evaluate preliminary efficacy and safety in patients with early prostate cancer.

ASP2138 is a Claudin-18.2 x CD3 2+1 bispecific antibody that our partner Astellas is advancing for the treatment of patients with gastric, gastroesophageal and pancreatic cancers and is currently being evaluated in a Phase 1 study.

The XmAb 2+1 multivalent format enables higher binding capability for Claudin-18.2 expressing cells.

Table of Contents `

Novartis XmAb undisclosed bispecific antibody candidate.

Novartis is conducting a Phase 1 clinical study with an undisclosed bispecific antibody candidate that was developed with our bispecific Fc technology under our collaboration with them.

XmAb, Xtend, and Cytotoxic Fc Drug Candidates in Clinical Development

JNJ-9401 is a PSMA x CD28 bispecific antibody that J&J is advancing for the treatment of patients with prostate cancer and is currently being evaluated in a Phase 1 study.

JNJ-9401 was developed with J&J under our 2020 collaboration.

JNJ-1493 is a B-cell x CD28 bispecific antibody that J&J is advancing for the treatment of patients with B-cell malignancies and is currently being evaluated in a Phase 1 study.

JNJ-1493 was developed with J&J under our 2021 collaboration.

Novartis XmAb undisclosed antibody candidate.

Novartis is evaluating an undisclosed antibody drug candidate that was developed with our bispecific Fc technology under our collaboration with them.

Cytokine Drug Candidates in Clinical Development

Currently, 3 XmAb cytokine drug candidates are in active clinical development internally or with our partners, which include:

Efbalropendekin alfa (XmAb306/RG6323) is a potency-reduced IL15/IL15-receptor alpha complex fused to our bispecific Fc domain (IL15/IL15Rα-Fc).

We are co-developing the program in collaboration with Genentech, a member of the Roche Group.

Genentech is conducting a Phase 1 study of XmAb306 as a single agent and in combination with atezolizumab in patients with advanced solid tumors and is also conducting Phase 1 studies, evaluating XmAb306 in patients with relapsed/refractory multiple myeloma, either in combination with daratumumab (anti-CD38 antibody) or in combination with cevostamab (FcRH5 x CD3 bispecific antibody).

In the fourth quarter of 2023, we agreed with Genentech to convert our current development cost and profit-sharing arrangement into a royalty and milestone payment-based arrangement.

Pursuant to the terms of the amended agreement with Genentech, effective June 1, 2024, Genentech will assume sole responsibility over all clinical, regulatory and commercial activities.

Under the amended agreement, we will be eligible for up to $600 million in milestones and tiered royalties on approved products ranging from low double-digit to mid-teens percentages.

XmAb564 is engineered with reduced binding affinity for IL-2's beta receptor and increased binding affinity for its alpha receptor.

We have been conducting a randomized, double-blind, placebo-controlled Phase 1b clinical study to evaluate the safety and tolerability of multiple ascending doses of XmAb564, administered subcutaneously in patients with atopic dermatitis or psoriasis.

We plan to conclude the Phase 1b study in the first half of 2024 and pause further development of XmAb564 until after assessment of future data from competitor programs in this class and review of safety and biomarker data in the Phase 1b study.

XmAb662 is a potency-reduced interleukin-12 Fc (IL12-Fc) fusion protein engineered to increase anti-tumor activity and immunogenicity in the tumor microenvironment by promoting high levels of interferon gamma secretion from T cells and NK cells.

In preclinical testing, our engineered IL12-Fc fusions demonstrated an improved pharmacokinetic profile and therapeutic window compared to a native IL12-Fc fusion, with superior exposure, a more gradual dose response and more sustained interferon gamma response.

XmAb662 demonstrated significant anti-tumor activity, along with increases in NK cells, T cells, serum IP-10 and interferon gamma, which were further enhanced when combined with an anti-PD-1 antibody.

We have been conducting a Phase 1 study to evaluate XmAb662 in patients with advanced solid tumors.

We plan to conclude the Phase 1 study in the first half of 2024 and pause further development of XmAb662 until after assessment of future data from competitor programs in this class and review of safety and biomarker data in the Phase 1 study.

Xtend and Cytotoxic Fc Drug Candidates in Clinical Development

Currently, two drugs engineered with our Xtend Fc Domain and one drug we engineered with our XmAb Cytotoxic Fc Domain are marketed commercially by partners.

In addition to these approved drugs, our partners are advancing multiple clinical-stage programs with antibodies engineered with XmAb, Xtend, and/or Cytotoxic Fc Domains, including:

In addition to these approved drugs, our partners are

advancing multiple clinical-stage programs with antibodies engineered with Xtend and/or Cytotoxic Fc Domains, including:

• Vir Biotechnology, Inc.:

Vir is advancing two candidates in clinical development.

VIR-3434 is being evaluated in a Phase 2 combination study as a potential treatment for patients with hepatitis B virus infection.

VIR-2482 is being evaluated in a Phase 2 study as a universal prophylactic for influenza A.

Vir is advancing tobevibart (VIR-3434) in a Phase 2 combination study as a potential treatment for patients with hepatitis B virus infection and in a Phase 2 combination study as a potential treatment for patients with hepatitis Delta virus infection;

• Gilead Sciences, Inc.:

Gilead is supporting HIV candidates in clinical development that are broadly neutralizing antibodies that incorporate our Fc technologies;

Gilead is advancing teropavimab and zinlirvimab, two broadly neutralizing antibodies, in combination with lenacapavir, as a long-acting treatment for virologically suppressed people living with HIV;

• Omeros Corporation:

Omeros is advancing multiple Phase 2 studies evaluating OMS906 for the treatment of patients with PNH and other alternative pathway disorders;

• Our partners are conducting preclinical studies of additional drug candidates engineered with these XmAb Fc domains.

Other Clinical Stage Drug Candidates

• AIMab7195 (XmAb7195) uses our XmAb Immune Inhibitor Fc Domain and is designed to reduce blood levels of IgE, which mediates allergic responses and allergic disease.

In February 2020, we licensed this drug candidate to Aimmune Therapeutics, Inc., now a wholly owned subsidiary of Nestlé S.A., which is advancing the candidate in clinical studies for allergic indications.

• Obexelimab targets CD19 with its variable domain and uses our XmAb Immune Inhibitor Fc Domain, which is designed to inhibit the function of B cells, an important component of the immune system.

In November 2021, we licensed this drug candidate to Zenas BioPharma, which initiated a Phase 3 study with obexelimab in January 2023 in immunoglobulin G4-related disease (IgG4-RD).

In November 2021, we licensed this drug candidate to Zenas BioPharma, which is conducting a Phase 3 study in patients with immunoglobulin G4-related disease (IgG4-RD) and a Phase 2 study in patients with warm autoimmune hemolytic anemia (wAIHA).

• AIMab7195 (XmAb7195) uses our XmAb Immune Inhibitor Fc Domain and is designed to reduce blood levels of IgE, which mediates allergic responses and allergic disease.

In February 2020, we licensed this drug candidate to Aimmune Therapeutics, Inc., now a wholly owned subsidiary of Nestlé S.A., which is evaluating the candidate in clinical studies for allergic indications.

• Xpro1595 is a proprietary TNF inhibitor candidate which we licensed to INmune Bio, Inc., in October 2017.

INmune is currently advancing Xpro1595 through clinical development for patients with Alzheimer’s disease, mild cognitive impairment and treatment-resistant depression.

INmune is currently advancing Xpro1595 through clinical development for patients with Alzheimer’s disease and treatment-resistant depression.

Collaborations, Partnerships and Licensing Arrangements

4 unchanged sentences

• Product Licenses:

Janssen Biotech, Inc., Genentech, MorphoSys AG, Nestlé S.A., Zenas BioPharma, INmune Bio, Inc.

Johnson & Johnson, Genentech, Incyte Corporation, Nestlé S.A., Zenas BioPharma, Inc., INmune Bio, Inc.

• Novel Bispecific Antibody Collaborations:

Janssen Biotech, Inc., Astellas Pharma, Inc., Amgen Inc., Novartis AG

Johnson & Johnson, Astellas Pharma Inc., Amgen Inc., Novartis AG

• Technology Licensing Agreements:

Alexion Pharmaceuticals, Inc., Vir Biotechnology, Inc., Gilead Sciences, Inc., Novartis AG, Omeros Corporation, Viridian Therapeutics, Inc., Astria Therapeutics, Inc.

Alexion Pharmaceuticals, Inc., Vir Biotechnology, Inc., Gilead Sciences, Inc., Omeros Corporation, Astria Therapeutics, Inc.

• Strategic Collaborations:

Atreca, Inc., The University of Texas MD Anderson Cancer Center, Caris Life Sciences

Caris Life Sciences

Product Licenses

Product licenses are arrangements in which we license to third parties partial or full rights to develop and commercialize our internally developed drug candidates.

We seek partners that can provide infrastructure and resources to

Table of Contents `

successfully develop our drug candidates, have a track record of successfully developing and commercializing medicines, or have a portfolio of development-stage candidates and commercialized medicines which could potentially be developed in rational combinations with our drug candidates.

Janssen Biotech, Inc.

In October 2021, we entered into an agreement with Janssen Biotech, Inc.

(Janssen) to develop, manufacture, and commercialize plamotamab and pursuant to which we, together, will conduct research and development activities to discover novel CD28 bispecific antibodies against undisclosed B cell tumor targets.

Janssen will receive exclusive worldwide rights, subject to certain Xencor opt-in rights, to develop, manufacture and commercialize pharmaceutical products that contain one or more of such CD28 bispecific antibodies.

We received a $100.0 million upfront payment, and Johnson & Johnson Innovation, JJDC, Inc., purchased $25.0 million of newly issued unregistered shares of our common stock.

In addition, we are eligible to receive milestone payments and royalties on net sales as follows:

• Plamotamab.

We are eligible to receive up to a total of $517.5 million in milestone payments, which includes $120.0 million in development milestones, $137.5 million in regulatory milestones, and $260.0 million in sales milestones, as well as tiered royalties in the mid-teen to low-twenties percent range on net sales of products containing plamotamab, including CD28/plamotamab combination products.

• CD28 Licensed Antibodies.

We are eligible to receive up to a total of $670.0 million in milestone payments, which includes an aggregate of $169.4 million in development milestones and $240.6 million in regulatory milestones.

For any products containing CD28 bispecific antibodies, but excluding CD28/plamotamab combination products, we are eligible to receive $260.0 million in sales milestones, as well as tiered royalties in the high-single digit to low-double digit range on net sales.

We are collaborating with Janssen on further clinical development of plamotamab with Janssen paying 80% and the Company paying 20% of costs.

We are generally responsible for conducting research activities, and Janssen is generally responsible for all development, manufacturing, and commercialization activities for CD28 bispecific antibodies that are advanced.

Independent of plamotamab development activities, upon clinical proof-of-concept for a CD28 bispecific antibody that is being developed outside of a plamotamab combination, we have the right to opt-in to fund 15% of development costs and, if we opt in to fund such development costs, to perform up to 30% of the detailing efforts in the United States.

We would then be eligible for low-double digit to mid-teen percent royalties on net sales of those products.

In January 2023, Janssen selected a CD28 candidate that we developed under the collaboration for further development.

In February 2019, we entered into an agreement with Genentech to develop and commercialize novel IL-15 cytokine therapeutics that use our bispecific Fc technology, including XmAb306, declared as a Collaboration Product under the agreement.

We are jointly collaborating on the worldwide development of XmAb306 with Genentech maintaining worldwide commercialization rights, subject to us having a co-promotion option in the U.S.

We retain the right to perform clinical studies with XmAb306 at our sole expense in combination with other therapeutic agents, subject to certain restrictions.

Genentech received a worldwide exclusive license to XmAb306.

We received an upfront payment of $120.0 million.

We are eligible to receive up to $160.0 million in clinical milestone payments for XmAb306, up to $180.0 million in clinical milestone payments for each new Collaboration Product, and a 45% share of net profits from sales from all Collaboration Products, while also sharing in the net losses at the same percentage rate.

We are sharing in 45% of development and commercialization costs of Collaboration Products, while Genentech will pay for commercial launch costs.

We seek partners that can provide infrastructure and resources to successfully develop our drug candidates, have a track record of successfully developing and commercializing medicines, or have a portfolio of development-stage candidates and commercialized medicines which could potentially be developed in rational combinations with our drug candidates.

Janssen Biotech, Inc., a Johnson & Johnson company

In October 2021, we entered into an agreement with Janssen Biotech, Inc., a Johnson & Johnson company, to develop, manufacture, and commercialize plamotamab and to conduct research and development activities to discover novel CD28 bispecific antibodies against undisclosed B cell tumor targets.

J&J will receive exclusive worldwide rights, subject to certain of our opt-in rights, to develop, manufacture and commercialize pharmaceutical products that contain one or more of such CD28 bispecific antibodies.

Pursuant to the agreement, we are collaborating with J&J on further clinical development of plamotamab with J&J paying 80% and the Company paying 20% of costs.

With respect to the CD28 bispecific antibody collaboration, we are generally responsible for conducting research activities, and J&J is generally responsible for all development, manufacturing, and commercialization activities for CD28 bispecific antibodies that are advanced.

In the first quarter of 2023, J&J selected a CD28 candidate that we developed under the collaboration for further development.

In the third quarter of 2023, J&J exercised its option on two additional CD28 candidates that were developed under the agreement.

In the fourth quarter of 2023, J&J initiated a Phase 1 study with a CD28 candidate that was developed under the agreement.

In 2023, we received $30.0 million of milestones related to the CD28 collaboration, and we are eligible to receive additional milestone payments up to a total of $640.0 million, which include an aggregate of $139.4 million in development milestones and $240.6 million in regulatory milestones.

For any CD28 bispecific antibodies approved, we are eligible to receive $260.0 million in sales milestones and tiered royalties in the high-single to low-double digit range on net sales.

In February 2019, we entered into an agreement with Genentech to develop and commercialize novel IL-15 cytokine therapeutics that use our bispecific Fc technology, including efbalropendekin alfa (XmAb306), declared as a Collaboration Product under the agreement.

Under the current agreement, we are sharing in 45% of development and commercialization costs of Collaboration Products, and we are eligible to share in 45% of net profits and losses from the sale of approved products.

However, in the fourth quarter of 2023, we agreed with Genentech to convert our current development cost and profit-sharing arrangement into a royalty and milestone payment-based arrangement.

Pursuant to the terms of the amended agreement with Genentech, effective June 1, 2024, Genentech will assume sole responsibility over all clinical, regulatory and commercial activities.

Under the amended agreement, we are eligible to receive up to $600.0 million in milestones, including $115.0 million in development milestones, $185.0 million in regulatory milestones and $300.0 million in sales-based milestones and tiered royalties ranging from low double-digit to mid-teens percentages.

Incyte Corporation

In July 2020, the FDA approved Monjuvi® (tafasitamab-cxix) in combination with lenalidomide for treating certain patients with DLBCL, and the European Commission granted conditional marketing authorization to tafasitamab for treating certain patients with DLBCL, which is marketed as Minjuvi® in Europe, in August 2021.

In 2010, we licensed exclusive worldwide rights to develop and commercialize tafasitamab (formerly MOR208 and XmAb5574) to MorphoSys.

Table of Contents `

In 2010, we licensed exclusive worldwide rights to develop and commercialize tafasitamab (formerly MOR208 and XmAb5574) to MorphoSys AG.

In February 2024, Incyte acquired exclusive global development and commercialization rights to tafasitamab.

Tafasitamab, which we engineered with an XmAb Cytotoxic Fc Domain, is the second XmAb medicine to be approved by the FDA.

2 unchanged sentences

We are entitled to receive tiered royalties in the high-single digit to low-double digit percent range on net sales.

Tafasitamab is co-marketed by Incyte and MorphoSys under the brand name Monjuvi® in the U.S., and is marketed by Incyte under the brand name Minjuvi® in Europe and Canada.

Incyte has exclusive commercialization rights to tafasitamab outside the U.S.

Tafasitamab is marketed by Incyte under the brand name Monjuvi® in the U.S.

and is marketed under the brand name Minjuvi® in Europe and Canada.

In 2023, we sold a portion of the royalties due to us under the MorphoSys agreement for $22.5 million.

Nestlé S.A./Aimmune Therapeutics, Inc.

1 unchanged sentence

Aimmune was subsequently acquired by Nestlé S.A.

We received an upfront payment and we are eligible to receive development, regulatory and sales milestones and tiered royalties in the high-single to mid-teen percent range on net sales of approved products.

Nestlé is responsible for all further development of AIMab7195 and is planning additional studies of the candidate.

received an upfront payment, and we are eligible to receive development, regulatory and sales milestones and tiered royalties in the high-single to mid-teen percent range on net sales of approved products.

Nestlé is responsible for all further development of AIMab7195.

INmune Bio, Inc.

In October 2017, we entered into an agreement with INmune Bio, Inc., for an exclusive license to our Xpro1595 drug candidate.

In connection with the license, we received shares of INmune common stock, an option to acquire additional outstanding shares of INmune , and a second option to acquire additional shares of Inmune common stock.

In 2021, we sold the initial option to INmune, and we received $15.0 million in cash proceeds and additional shares of INmune common stock.

In 2021, we exercised the second option to acquire additional shares of common stock.

In connection with the license, we received shares of INmune common stock.

We are also eligible to receive a percentage of sublicensing revenue received for Xpro1595 and royalties in the mid-single digit percentage range on the sale of approved products.

INmune is currently planning Phase 2 studies in Alzheimer’s disease, mild cognitive impairment, and treatment-resistant depression, as Xpro1595;

Phase 2 studies in patients with non-alcoholic steatohepatitis, as LIVNate;

and additional studies in MUC4-positive cancers, as INB03.

Zenas BioPharma (Cayman) Limited

In November 2020, we entered into an agreement with Zenas BioPharma (Cayman) Limited (Zenas) to which we licensed the exclusive worldwide rights to develop and commercialize three preclinical-stage Fc-engineered drug candidates for autoimmune disease:

XmAb6755, Xpro9523, and XmAb10171.

INmune is currently conducting Phase 2 studies in early Alzheimer’s disease and treatment resistant depression.

Zenas BioPharma, Inc.

In November 2020, we entered into an agreement with Zenas BioPharma (Cayman) Limited, now Zenas BioPharma, Inc., (Zenas) to which we licensed the exclusive worldwide rights to develop and commercialize three preclinical-stage Fc-engineered drug candidates for autoimmune disease:

XmAb6755 (ZB002), XPro9523 (ZB004), and XmAb10171 (ZB003).

These programs incorporate an Xtend Fc Domain, a Cytotoxic Fc Domain, or both.

We received a 15% equity interest in Zenas, and we will also receive royalties on net sales of approved products in the mid-single digit to mid-teen percentage range.

We received an equity interest in Zenas, and we will also receive royalties on net sales of approved products in the mid-single digit to mid-teen percentage range.

In November 2021, we entered into a second agreement with Zenas to which we licensed the exclusive worldwide rights to develop and commercialize obexelimab, a bifunctional antibody that targets CD19 with its variable domain and uses our XmAb Immune Inhibitor Fc Domain.

3 unchanged sentences

Zenas will have sole responsibility for advancing the research, development, regulatory and commercial activities of obexelimab worldwide.

In January 2023, Zenas initiated a Phase 3 study of obexelimab.

In 2023, Zenas initiated a Phase 3 study in patients with immunoglobulin G4-related disease (IgG4-RD) and a Phase 2 study in patients with warm autoimmune hemolytic anemia (wAIHA), and we received a milestone payment in additional equity in Zenas with a fair value of $10.0 million.

Novel Bispecific Antibody Collaborations

1 unchanged sentence

Our partners provide an antibody or an antigen against tumors, and we conduct limited research and development activities to create potential bispecific antibody candidates for further development and commercialization by our partners.

Table of Contents `

Janssen Biotech, Inc.

In November 2020, we entered into an agreement, with Janssen Biotech, Inc.

(Janssen), to develop XmAb bispecific antibodies against CD28 and an undisclosed prostate tumor target, for the potential treatment of patients with prostate cancer.

Under the agreement, we conducted research activities to develop CD28 bispecific drug candidates for further development by Janssen.

Preclinical activities and all clinical development, regulatory and commercial activities will be conducted by Janssen, which has exclusive worldwide rights to develop and commercialize the novel drug candidates developed in the collaboration.

We received a $50.0 million upfront payment and are eligible to receive development, regulatory and sales milestones, and we are also eligible to receive tiered royalties in the high-single to low-double digit percentage range on net sales.

Upon development of a bispecific candidate by Janssen through proof of concept, the agreement provides us the right to opt-in to fund 20% of development costs and to perform up to 30% of detailing efforts in the U.S.

Janssen Biotech, Inc., a Johnson & Johnson company

In November 2020, we entered into an agreement, with J&J to develop XmAb bispecific antibodies against CD28 and a prostate tumor target, for the potential treatment of patients with prostate cancer.

Under the agreement, we conducted research activities to develop CD28 bispecific drug candidates for further development by J&J.

Upon development of a bispecific candidate by J&J through proof of concept, the agreement provides us the right to opt-in to fund 20% of development costs and to perform up to 30% of detailing efforts in the U.S.

If we exercise this right, we will be eligible to receive tiered royalties in the low-double digit to mid-teen digit percentage range.

Both we and Janssen also have the right to access predefined agents from each other’s portfolios to evaluate potential combination therapies in prostate cancer, subject to certain limitations.

In 2021, Janssen selected a candidate developed under the agreement for further development and we received a milestone payment, and we are eligible to receive an additional $156.9 million in development milestones as the program advances.

We, along with J&J, have the right to access predefined agents from each other’s portfolios to evaluate potential combination therapies in prostate cancer, subject to certain limitations.

In 2021, J&J selected JNJ-9401, a PSMA x CD28 bispecific antibody developed under the agreement, for further development, and we received a milestone payment.

In 2023, J&J submitted an IND and initiated a clinical trial, and we

received another milestone payment.

J&J is conducting a Phase 1 study evaluating JNJ-9401 in patients with mCRPC.

In 2023, we received $17.5 million in milestones under the agreement, and we are eligible to receive an additional $139.4 million in development milestones in addition to tiered royalties on approved products ranging from high-single to low-double digit range as the program advances.

Astellas Pharma Inc.

1 unchanged sentence

Astellas was granted a worldwide exclusive license, with the right to sublicense products in the field created by the research activities.

Astellas has selected a bispecific antibody developed under the collaboration, ASP2138, a CLDN18.2 x CD3 XmAb 2+1 bispecific antibody, for further development to treat patients with gastric, gastroesophageal, and pancreatic cancers.

We received an upfront payment and we are eligible to receive development, regulatory and sales milestones and royalties on net sales in the high-single to low-double digit percentage range.

In 2022, we received a $5.0 million milestone payment related to Astellas advancing the ASP2138 candidate into Phase 1 studies, and we are eligible to receive an additional $25.0 million in development milestones as the program advances.

Astellas selected ASP2138, a CLDN18.2 x CD3 XmAb 2+1 bispecific antibody developed under the collaboration, for further development and is conducting a Phase 1 study of ASP2138 in patients with gastric, gastroesophageal, and pancreatic cancers.

We are eligible to receive an additional $232.5 million in milestones which include, $25.0 million in development milestones, $57.5 million in regulatory milestones and $150.0 million in sales milestones and tiered royalties from the high-single to low-double digit range as the program advances.

In September 2015, we entered into an agreement with Amgen Inc.

to develop and commercialize bispecific antibody product candidates using our proprietary XmAb bispecific Fc technology.

Amgen applied our XmAb bispecific Fc technology to create AMG 509, a STEAP1 x CD3 XmAb 2+1 bispecific antibody.

We have received a total of $60.5 million in upfront and milestone payments and are eligible to receive up to $255.0 million in future development, regulatory and sales milestone payments in total for AMG 509 and royalties on net sales.

Amgen applied our XmAb bispecific Fc technology to create xaluritamig (AMG 509), a STEAP1 x CD3 XmAb 2+1 bispecific antibody.

Amgen is currently completing enrollment in a Phase 1 study of xaluritamig in patients with mCRPC.

In October 2023 at the European Society for Medical Oncology (ESMO) Congress, encouraging interim clinical results from the study were presented during an oral proffered paper session, which we believe validates the potential of the XmAb 2+1 format.

Amgen is planning two additional Phase 1 studies of xaluritamig to evaluate preliminary efficacy and safety in patients with early prostate cancer.

In connection with our June 2016 agreement with Novartis, we applied our XmAb bispecific Fc technology to a target pair antibody selected by Novartis.

1 unchanged sentence

We are eligible to receive development, regulatory and sales milestone payments and royalties in the mid-single digit percent range on net sales of approved products.

Novartis is conducting a Phase 1 study of an undisclosed bispecific antibody candidate.

Novartis is evaluating an undisclosed XmAb bispecific antibody candidate.

Technology Licensing Agreements

1 unchanged sentence

Our partners are responsible for all research, development and commercialization activities of the drug candidates.

The plug-and-play

Table of Contents `

nature of XmAb Fc domains allows us to license access to our platforms with no internal research and development activities required of us.

The plug-and-play nature of XmAb Fc domains allows us to license access to our platforms with no internal research and development activities required of us.

Alexion Pharmaceuticals, Inc.

1 unchanged sentence

It is approved in the U.S.

and multiple global markets for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) and for the treatment of patients with atypical hemolytic uremic syndrome (aHUS).

and multiple global markets for the treatment of certain patients with paroxysmal nocturnal hemoglobinuria (PNH), certain patients with atypical hemolytic uremic syndrome (aHUS) and certain patients with generalized myasthenia gravis (gMG).

It is approved in the EU and Japan for the treatment of certain

adult patients with neuromyelitis optica spectrum disorder (NMOSD).

Ultomiris is commercialized by Alexion Pharmaceuticals, Inc.

1 unchanged sentence

The Xtend technology increased the circulating half-life of Ultomiris by over three-fold compared to Soliris and extended the dosing schedule to bimonthly for Ultomiris compared to biweekly for Soliris.

During 2022, we recorded royalty revenue of $29.4 million.

We are eligible to receive an additional $20.0 million in sales milestones and a low-single digit percent royalty on the sale of approved products.

We are eligible to receive a low-single digit percent royalty on the sale of approved products.

During 2023, we recorded royalty revenue of $38.6 million and a $20.0 million sales milestone.

In the fourth quarter of 2023, we sold a portion of the royalties due us under the Alexion agreement for $192.5 million.

Vir Biotechnology, Inc.

Sotrovimab, an antibody that targets the SARS-CoV-2 virus, has received an emergency use authorization from the FDA and temporary authorizations in multiple global markets for the treatment of mild-to-moderate COVID-19 in high-risk adults and pediatric patients.

In March 2020, we entered into an agreement in which we provided Vir a non-exclusive license to our Xtend technology to extend the half-life of novel antibodies, including sotrovimab, that Vir is investigating as potential treatments for patients with COVID-19.

Vir, along with alliance partner GlaxoSmithKline Plc, is responsible for all research, development, regulatory and commercial activities for COVID-19 antibodies, and we are eligible to receive royalties on the net sales of approved products in the mid-single digit percentage range.

In March 2020, we entered into an agreement in which we provided Vir a non-exclusive license to our Xtend technology to extend the half-life of novel antibodies, including sotrovimab, that Vir has investigated as potential treatments for patients with COVID-19.

Vir, along with alliance partner GSK, is responsible for all research, development, regulatory and commercial activities for COVID-19 antibodies, and we are eligible to receive royalties on the net sales of approved products in the mid-single digit percentage range.

During 2023, we recorded royalty revenue of $2.2 million.

In August 2019, we entered into an agreement with Vir Biotechnology, Inc., in which we provided Vir a non-exclusive license to our Xtend technology for two targets in infectious disease.

We have received a total of $2.0 million in upfront and milestone payments, and we are eligible to receive additional milestones of $154.0 million, including $4.0 million of development milestones, $30.0 million of regulatory milestones and $120.0 million of sales milestones.

We are also eligible to receive royalties on the net sales in the low single digit percentage range.

Vir has advanced two programs under this agreement.

VIR-2482 is being evaluated in a Phase 2 study as a universal prophylactic for influenza A, and VIR-3434 is being evaluated in a Phase 2 combination study as a potential treatment for patients with hepatitis B virus infection.

Tobevibart (VIR-3434) is being evaluated in a Phase 2 combination study as a potential treatment for patients with hepatitis B virus infection and in a Phase 2 combination study as a potential treatment for patients with hepatitis Delta virus infection.

Gilead Sciences, Inc.

3 unchanged sentences

We are also eligible to receive royalties in the low-single digit percentage range on net sales of approved products.

In 2023, Gilead initiated a Phase 2 study including two antibody candidates developed with our Fc technologies, teropavimab and zinlirvimab, and we received $6.0 million in milestone payments.

Omeros Corporation

1 unchanged sentence

Omeros is responsible for all development and commercialization activities.

OMS906, a MASP-3 targeted antibody, is being evaluated in a Phase 1 study in patients with PNH and other alternative pathway disorders.

We received an upfront payment and we are eligible to receive development, regulatory and sales milestones and we are also eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

Table of Contents `

Viridian Therapeutics, Inc.

In December 2020, we entered into an agreement with Viridian Therapeutics, Inc., in which we provided Viridian a non-exclusive license to our Xtend Fc technology and an exclusive license to apply our Xtend Fc technology to antibodies targeting IGF-1R.

Viridian is responsible for all development and commercialization activities.

We received shares of Viridian common stock valued at $6.0 million as an upfront payment and are eligible to receive development, regulatory and sales milestones and we are also eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

In December 2021, we entered into a second agreement with Viridian for a non-exclusive license to certain antibody libraries developed by us.

Under the agreement, Viridian received a research license to review the antibodies and the right to select a limited number of antibodies for further development.

Viridian is responsible for all further development of the selected antibodies.

We received Viridian common stock valued at $7.5 million as an upfront payment and are eligible to receive development, regulatory and sales milestones in addition to royalties on net sales of approved products under the agreement.

Astria Therapeutics, Inc/Catabasis Pharmaceuticals, Inc./Quellis Biosciences, Inc.

In May 2018, we entered into an agreement with Quellis Biosciences, Inc., in which we provided Quellis a non-exclusive license to our Xtend Fc technology to apply to an identified antibody.

Quellis is responsible for all development and commercialization activities.

We received an equity interest in Quellis, and in January 2021, upon Quellis merging into Catabasis Pharmaceuticals, Inc., we received common and preferred shares of Catabasis stock in exchange for our equity in Quellis.

Catabasis subsequently changed its name to Astria Therapeutics, Inc.

In 2023, Omeros initiated a Phase 2 study of OMS906, a MASP-3 targeted antibody, in patients with PNH, and we received a $5.0 million milestone.

We are eligible to receive up to an additional $60.0 million in development, regulatory and sales milestones and royalties in the mid-single digit percentage range on net sales of approved products.

Astria Therapeutics, Inc.

In May 2018, we entered into an agreement with Astria Therapeutics, Inc (formerly Quellis Biosciences, Inc.), in which we provided Astria a non-exclusive license to our Xtend Fc technology to apply to an identified antibody.

Astria is responsible for all development and commercialization activities.

Our upfront payment included common stock in Astria.

In addition to equity shares in Astria, we are eligible to receive development, regulatory and sales milestones and we are also eligible to receive royalties in the mid-single digit percentage range on net sales of approved products.

2 unchanged sentences

Through these arrangements we seek to create new drug candidates, investigate novel combination therapies and potentially identify additional indications for our portfolio of XmAb drug candidates.

In July 2020, we entered into an agreement with Atreca, Inc., to research, develop and commercialize novel CD3 bispecific antibodies as potential therapeutics in oncology.

During a three-year research term, Atreca will provide antibodies against novel tumor targets through its discovery platform from which we will engineer XmAb bispecific antibodies that bind to the CD3 receptor on T cells.

The two companies will share research costs equally during the research term.

Up to two joint programs are eligible to be mutually selected for further development and commercialization, with each partner sharing 50% of costs and profits.

Each company has the option to lead development, regulatory and commercialization activities for one of the joint programs.

In addition, each partner has the option to pursue up to two programs independently, with a royalty in the mid- to high-single digit percentage range payable on net sales to the other partner.

In January 2023, we and Atreca selected a candidate to be developed under the collaboration.

The University of Texas MD Anderson Cancer Center

In September 2020, we entered into an agreement with MD Anderson, in which we will provide funding over a five-year period, and MD Anderson will collaborate to design and execute additional clinical studies with our portfolio of XmAb drug candidates, including novel bispecific antibody and cytokine candidates.

We own all rights to the programs and results generated from these studies.

In December 2021, we extended the agreement for an additional year at the same level of committed funding.

MD Andersen is conducting clinical studies with our vudalimab candidate.

In December 2020, we entered into a second agreement with MD Anderson to develop novel CD3 bispecific antibody therapeutics for the potential treatment of patients with cancer.

MD Anderson will work to identify and develop potential antibodies, and we will apply our Fc bispecific technology to create therapeutic candidates.

MD Anderson will then conduct and fund all preclinical activities to advance candidates toward clinical studies.

We have certain exclusive options to license worldwide rights to develop and commercialize potential new medicines arising from the collaboration.

Table of Contents `

Caris Life Sciences

In July 2022, we entered into an agreement with Caris Life Sciences (Caris), under which Caris will apply its proprietary end-to-end discover platform to identify novel targets for XmAb bispecific antibody drug candidates for the treatment of patients with cancer.

In July 2022, we entered into a research discovery agreement with Caris Life Sciences (Caris).

We received exclusive options to research, develop and commercialize products directed up to three targets.

1 unchanged sentence

In December 2022, we expanded our Caris collaboration with a second agreement.

The second agreement increased the number of targets that Caris will provide and also the tumor types that are being investigated.

We paid Caris an upfront payment and Caris is eligible for additional licensing fees, milestones and royalty payments on net sales of each product commercialized by us.

Technology License Agreement and Service Agreement with Gale Therapeutics Inc.

In the fourth quarter of 2023, we formed a subsidiary, Gale Therapeutics Inc.

(Gale), to develop novel drug candidates that incorporate our XmAb technologies.

In December 2023, we entered into a Technology License Agreement (Gale License Agreement) with Gale, in which Gale received an exclusive worldwide, royalty-bearing, non-transferable license to preclinical assets in exchange for royalties on future sales and an option on future drug candidates that Gale will develop.

Concurrently, we entered into a Services Agreement (Gale Services Agreement) to provide research and development services and administrative support to Gale.

In exchange for $7.5 million of funding, we acquired a majority stake in Gale.

Our Research and Development Pipeline

We have used our XmAb Fc platforms and protein engineering capabilities to produce a growing pipeline of drug candidates in clinical and preclinical development.

These include multiple oncology candidates using our bispecific Fc domain, including bispecific antibody and cytokine candidates.

These include multiple oncology candidates using our bispecific Fc domain.

We continue to advance these candidates as additional options for clinical development by us or as out-licensing opportunities.

5 unchanged sentences

We seek and support a diverse population of employees without regard to race, gender or sexual orientation.

As of December 31, 2022, we had 281 full-time employees, representing an 11% increase in our employee workforce as compared to December 31, 2021.

Of these, 233 were engaged in research and development activities, and 48 were engaged in business development, information systems, facilities, human resources, or administrative support.

As of December 31, 2023, we had 280 full-time employees, of which 231 were engaged in research and development activities, and 49 were engaged in business development, information systems, facilities, human resources, or administrative support.

Of these employees, 68 hold Ph.D.

6 unchanged sentences

We strive to build and nurture a culture where all employees feel empowered to be their authentic selves.

In January 2024, in connection with re-prioritization of our development programs, we completed a reduction in force (RIF) affecting approximately 10% of the total employee headcount.

The RIF was applied across all functional areas.

As of February 1, 2024, we had 256 full-time employees.

We seek to provide human capital and employee health and safety policies that provide for the health, safety, and welfare of our employees.

We continue practices that address the COVID-19 pandemic consistent with government guidelines to mitigate and prevent the spread of disease, such as masking, social distancing, contact tracing, and encouraging vaccinations.

In 2022, in connection with the ongoing pandemic we adopted the following practices:

• Provided a remote or hybrid work option for all non-laboratory staff with technical support, training, and equipment to enable employees to continue to perform their responsibilities while working remotely;

• Conducted safety procedures for all onsite staff which included offering weekly onsite SARS-CoV-2 virus testing for all employees and their household members and providing paid time off for any employee that missed time due to the COVID-19 virus including for the care of family members.

Table of Contents `

We continue practices that address the COVID-19 pandemic consistent with government

guidelines to mitigate and prevent the spread of disease, such as masking, social distancing, providing hybrid work opportunities where possible, contact tracing, and encouraging vaccinations.

Compensation, Benefits, and Development

2 unchanged sentences

We regularly evaluate our compensation programs with an independent compensation consultant and utilize industry benchmarking in an effort to ensure they are competitive compared to similar biotechnology and biopharmaceutical companies with which we compete for talent and that they are fair and equitable across our workforce with respect to gender, race, and other personal characteristics.

All employees are eligible to participate in the Employee Stock Purchase Plan where they can purchase shares of Xencor common stock at a discounted price.

All employees are eligible to participate in the Employee Stock Purchase Plan where they can purchase shares of our common stock at a discounted price.

This plan, and our other equity compensation plans, assists us in building long-term relationships with our employees and aligns the interest of employees with stockholders.

4 unchanged sentences

Market Opportunity

Our drug candidates that use the XmAb bispecific Fc domain, including plamotamab, vudalimab, XmAb104, XmAb306, XmAb819, XmAb808, and XmAb564 :

We are developing our bispecific antibody and cytokine candidates to treat cancer and autoimmune diseases.

Our wholly owned drug candidates that use the XmAb bispecific Fc domain, which we are actively advancing in clinical development, including vudalimab, XmAb819, XmAb808 and XmAb541 :

We are developing these bispecific antibody drug candidates to treat cancer.

Cancer is a broad group of diseases in which cells divide and grow in an uncontrolled fashion, forming malignancies that can invade other parts of the body, and it is the second leading cause of death in the United States (U.S.).

2 unchanged sentences

population, medical expenditures for cancer in the year 2030 are projected to reach at least $245.6 billion.

We are evaluating XmAb564 as a potential treatment for patients with autoimmune diseases.

The autoimmune disease therapeutic market generally presents an opportunity in various small and large market indications, some of which may be appropriate for XmAb564.

Autoimmune diseases represent the third most common cause of chronic illnesses in the United States.

The National Institutes for Health (NIH) estimates that they collectively affect between 5% and 8% of the US population and currently more than 50 million Americans have one or more autoimmune diseases.

Globally, the autoimmune disease therapeutics market was estimated to be $92 billion in 2022 (GlobalData).

Intellectual Property

8 unchanged sentences

We also have a large number of issued patents and pending patent applications with claims directed specifically to our XmAb technology and candidates.

Table of Contents `

The patent expiration in the U.S.

37 unchanged sentences

There have been recent proposals to repeal or modify the ACA, and it is uncertain how any of those proposals, if approved, would affect these provisions.

Table of Contents `

In addition to patent protection, we rely on trade secret protection and know-how to expand our proprietary position around our technology and other discoveries and inventions that we consider important to our business.

10 unchanged sentences

We have used third party manufacturers for all our bispecific antibody and cytokine candidates which include:

plamotamab, vudalimab, XmAb104, XmAb306, XmAb564, XmAb819 and, XmAb808.

plamotamab, vudalimab, XmAb104, XmAb306, XmAb564, XmAb819 XmAb808, XmAb662 and, XmAb541.

Additional contract manufacturers are used to fill, label, package and distribute investigational drug products.

4 unchanged sentences

We have engaged KBI under the KBI Agreement for process development, clinical scale-up, analytical method development, formulation development, and other services related to drug substance and drug product for our bispecific antibody and cytokine development candidates:

plamotamab, vudalimab, XmAb104, XmAb306, and XmAb564 in accordance with cGMP regulations.

plamotamab, vudalimab, XmAb104, XmAb306, XmAb564 and XmAb541 in accordance with cGMP regulations.

For each bispecific program, we have entered into a separate agreement with the terms and conditions of services and payment.

9 unchanged sentences

plamotamab, vudalimab, XmAb104, XmAb306, XmAb564, and XmAb819.

Table of Contents `

License Agreement with BIO-TECHNE

In February 2018, we entered into an agreement with BIO-TECHNE for a non-exclusive license to a certain recombinant monoclonal antibody reactive with human programmed death protein, PD-1.

We expect to use this protein in certain of our oncology drug candidates.

Under the terms of this agreement, we made an upfront payment and are obligated to make payments upon the achievement of certain development, regulatory and sales milestones, and royalties based on a percentage of net sales from products that are derived from the PD-1 antibody.

The royalty is 1%.

In April 2021, we entered into an agreement with BIO-TECHNE for a non-exclusive license to a certain recombinant monoclonal antibody reactive with human Claudin-6 (CLDN6).

We are using this protein in our XmAb541 drug candidate.

The royalty is less than 1%.

Umbrella Development Services Agreement with Patheon Biologics LLC

4 unchanged sentences

Patheon has the unilateral right to terminate the Patheon Agreement if we request to reschedule work beyond 120 days, the project work is not progressing according to our expectations and we cannot agree on appropriate changes, after six months of inactivity on a project at our request or if Patheon determines it is unable to perform its obligations in a safe and effective way in compliance with applicable regulatory requirements.

Patheon is currently manufacturing drug substance material for our XmAb819 program.

Patheon is currently manufacturing drug substance material for our XmAb819 program and drug product for our plamotamab program.

Master Services Agreement with WuXi Biologics (Hong Kong) Limited

5 unchanged sentences

WuXi has the unilateral right to terminate the WuXi Agreement only if the services cannot be performed due to technical difficulties or the performance of the services is not permitted under applicable law.

WuXi is currently manufacturing drug substance and drug product for XmAb808 and XmAb662.

WuXi is currently manufacturing drug substance and drug product for our XmAb808 and XmAb662 programs.

Master Clinical Services Agreement with ICON Clinical Research Limited

In April 2016, we entered into a Master Clinical Services Agreement (ICON Agreement) with ICON Clinical Research Limited (ICON).

In April 2016, we entered into a Master Clinical Services Agreement (ICON Agreement) with ICON Clinical Research Limited (ICON) which was amended in April 2021.

Under the terms of the ICON Agreement, ICON and its affiliates will perform clinical trial services (including site selection, study design, site monitoring, management and training, and patient selection) for Xencor in accordance with applicable regulations.

1 unchanged sentence

Each party may terminate the ICON Agreement upon 30 days’ prior written notice to the other party for any reason, however such termination would not affect any ongoing project under the ICON Agreement.

We may unilaterally terminate any project under the ICON Agreement upon 30 days’ prior written notice to ICON for any reason, subject to applicable termination fees.

We may unilaterally terminate any project under the ICON Agreement upon 30 days’ prior written notice to ICON for any reason, subject to applicable close-out costs.

ICON is currently providing services to us in connection with ongoing Xencor-sponsored clinical trial that target oncology indications.

2 unchanged sentences

(Innovaderm).

Under the terms of the Innovaderm Agreement, Innovaderm will perform clinical trial management and clinical development services (including site selection, study design, site monitoring, management and training, and patient

Table of Contents `

selection) for Xencor in accordance with applicable regulations.

The Innovaderm Agreement may be terminated by either party for a breach upon fifteen (15) day written notice, if such breach is not cured within thirty (30) days.

We may terminate the Innovaderm Agreement upon thirty (30) days written notice to Innovaderm for any reason, however, we will be obligated for any costs incurred through the cancellation date and any non-refundable and non-cancellable commitments incurred by Innovaderm.

Under the terms of the Innovaderm Agreement, Innovaderm will perform clinical trial management and

clinical development services (including site selection, study design, site monitoring, management and training, and patient selection) for Xencor in accordance with applicable regulations.

The Innovaderm Agreement may be terminated by either party for a breach upon 15 days' written notice, if such breach is not cured within 30 days.

We may terminate the Innovaderm Agreement upon 30 days' written notice to Innovaderm for any reason;

however, we will be obligated for any costs incurred through the cancellation date and any non-refundable and non-cancellable commitments incurred by Innovaderm.

Innovaderm is currently conducting clinical studies for our XmAb564 program.

Master Services Agreement with PPD Development, L.P.

In June 2015, we entered into a Master Services Agreement (PPD Agreement) with PPD Development, L.P.(PPD).

Under the terms of the PPD Agreement, PPD will perform clinical trial management and clinical development services (including site selection, study design, site monitoring, management and training, and patient selection) for Xencor in accordance with applicable regulations.

The PPD Agreement may be terminated by either party for a breach upon 30 days' written notice, if such breach is not cured within 30 days.

We may terminate the PPD Agreement upon 30 days' written notice to PPD for any reason;

however, we will be obligated for any costs incurred through the cancellation date and any non-refundable and non-cancellable commitments incurred by PPD.

PPD is currently conducting clinical studies for our vudalimab program.

Master Services Agreement with Vetter Pharma International GmbH

In October 2020, we entered into a master services agreement (Vetter Agreement) with Vetter Pharma International GmbH (Vetter).

We have engaged Vetter under the Vetter Agreement for clinical scale-up, analytical method development, formulation development, and other services related to manufacturing drug product for our bispecific antibody candidates vudalimab and XmAb541 in accordance with cGMP regulations.

For each bispecific program, we have entered into a separate agreement with the terms and conditions of services and payment.

The Vetter Agreement is for a eight-year term but is automatically extended on an annual basis until the services are completed.

The Vetter Agreement may be terminated by either party for a breach that is not remedied within 60 days after notice or 60 days after notice of the existence of an incurable scientific or technical issue that renders Vetter unable to render services under the Vetter Agreement.

For termination other than a material breach by Vetter, we must pay for all services conducted prior to the termination and to wind down the activities.

Vetter is currently manufacturing drug product for our vudalimab and XmAb541 programs.

Master Services Agreement with OncoBay Clinical, Inc.

In August 2023, we entered into a Master Services Agreement (OncoBay Agreement) with OncoBay Clinical, Inc.

Under the terms of the OncoBay Agreement, OncoBay will perform Contract Research Organization (CRO) services including clinical trial management and clinical development services (including site selection, study design, site monitoring, management and training, and patient selection) for Xencor in accordance with applicable regulations.

The OncoBay Agreement may be terminated by either party for a breach upon 30 days' written notice, if such breach is not cured within thirty (30) days.

We may terminate the OncoBay Agreement upon 60 days' written notice to OncoBay for any reason;

however, we will be obligated for any costs incurred through the cancellation date and any non-refundable and non-cancellable commitments incurred by OncoBay.

OncoBay is currently conducting clinical studies for our XmAb541 program.

We compete in an industry that is characterized by rapidly advancing technologies, intense competition, and a strong emphasis on proprietary products.

2 unchanged sentences

Many competitors and potential competitors have substantially greater scientific, research, and product development capabilities as well as greater financial, marketing and sales, and human resources than we do.

In addition, many specialized biotechnology firms have formed collaborations with large, established companies to support the research, development, and commercialization of products that may be competitive with ours.

In addition, many specialized biotechnology firms have formed collaborations with large, established companies to support the research,

development, and commercialization of products that may be competitive with ours.

Accordingly, our competitors may be more successful than we may be in developing, commercializing, and achieving widespread market acceptance.

5 unchanged sentences

and Roche Holding AG.

We are developing bispecific antibody drug candidates engineered to direct cytotoxic T cell killing of tumor cells, by engaging the CD3 receptor on T cells and an antigen on tumor cells.

Other companies conducting clinical trials to evaluate CD3 bispecific antibodies directed to antigens expressed on tumors include AbbVie Inc.;

IGM Biosciences, Inc.;

We are developing bispecific antibody drug candidates engineered to direct cytotoxic T cell killing of solid tumor cells, by engaging the CD3 or CD28 receptor on T cells and an antigen on tumor cells.

Other companies conducting clinical trials to evaluate CD3 or CD28 bispecific antibodies directed to antigens expressed on solid tumors include Amgen Inc.;

Astellas Pharma Inc.;

BioAtla, Inc.;

CytomX Therapeutics, Inc.;

Immunocore Holdings plc;

Janux Therapeutics, Inc.;

Johnson & Johnson;

Pfizer, Inc.;

Regeneron Pharmaceuticals, Inc.;

and Roche Holding AG.

Other antibodies, antibody drug candidates and cell therapies are in development or approved to treat patients with cancer.

Roche Holding AG;

and Takeda Pharmaceutical Co.

Other antibodies, antibody drug conjugates and cell therapies are in development or approved to treat patients with cancer.

We are also developing several bispecific antibody drug candidates engineered to selectively engage the immune system in order to treat patients with cancer.

8 unchanged sentences

and Macrogenics, Inc.

Several companies are developing engineered cytokines intended to activate specific immune cell populations in order to treat patients with cancer and/or autoimmune diseases, including Alkermes plc;

Asher Biotherapeutics, Inc.;

Cue Biopharma, Inc.;

Eli Lilly and Company;

IGM Biosciences, Inc.;

ImmunityBio, Inc.;

Kadmon Holdings, Inc.;

Medicenna Therapeutics Corp.;

Merck & Co., Inc.;

Nektar Therapeutics, Inc.;

Neoleukin Therapeutics, Inc.;

Roche Holding AG;

Sotio Biotech;

Sutro Biopharma, Inc.;

Synthekine, Inc.;

and Xilio Therapeutics, Inc.

In addition, we are aware of a number of other companies with development-stage programs that may compete with the drug candidates we and our licensees are developing in the future.

We anticipate that we will face intense and increasing competition as new treatments enter the market and advanced technologies become available.

Table of Contents `

Regulatory Overview

27 unchanged sentences

FDA review and approval of the BLA prior to any commercial marketing or sale.

Table of Contents `

Before testing any compounds with potential therapeutic value in humans, the product candidate enters the preclinical testing stage.

25 unchanged sentences

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or partial waivers from the pediatric data requirements.

Table of Contents `

The FDA will issue a complete response letter describing deficiencies in the BLA and recommend actions if the agency decides not to approve the BLA.

4 unchanged sentences

Any biologic products for which we or our collaborators receive FDA approvals are subject to continuing regulation by the FDA, including, among other things, cGMP compliance for product manufacture, record-keeping requirements, reporting of adverse experiences with the product, providing the FDA with updated safety and efficacy information, product sampling and distribution requirements, complying with certain electronic records and signature requirements, and complying with FDA promotion and advertising requirements, which include, among others, restrictions on direct-to-consumer advertising, promoting biologics for uses or in patient populations that are not described in the product’s approved labeling (known as “off-label use”), industry-sponsored scientific and educational activities, and promotional activities involving the internet.

Failure to comply with these or other FDA requirements can subject a manufacturer to possible legal or regulatory action, such as product reclass, warning letters, suspension of manufacturing, seizure of product, injunctive action, mandated corrective advertising or communications with healthcare professionals, possible civil or criminal penalties, or other negative consequences, including adverse publicity.

Failure to comply with these or other FDA requirements can subject a manufacturer to possible legal or regulatory action, such as product reclass, warning letters, suspension of manufacturing,

seizure of product, injunctive action, mandated corrective advertising or communications with healthcare professionals, possible civil or criminal penalties, or other negative consequences, including adverse publicity.

Patent Term Restoration and Marketing Exclusivity

12 unchanged sentences

In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives.

Table of Contents `

Other Healthcare Laws and Compliance Requirements

10 unchanged sentences

In September 2004, we reincorporated in the state of Delaware under the name Xencor, Inc.

Our principal offices are located at 111 West Lemon Avenue, Monrovia, CA 91016, and our telephone number is (626) 305-5900.

Our principal offices are located at 465 North Halstead Street, Suite 200 , Pasadena, CA, 91107, and our telephone number is (626) 305-5900.

Our website address is www.xencor.com.

3 unchanged sentences

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1. Business