UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 7, 2018

XENCOR, INC.

(Exact name of registrant as specified in its charter)

111 West Lemon Avenue

Monrovia, California 91016

(Address of principal executive offices and zip code)

Registrant’s telephone number, including area code: (626) 305-5900

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company o

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

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(d) On November 7, 2018, Ellen Feigal, M.D. was appointed to the Board of Directors (the “Board”) of Xencor, Inc. (the “Company”).

In accordance with the Company’s amended and restated non-employee director compensation policy, Dr. Feigal is entitled to receive an initial grant consisting of a nonstatutory stock option to purchase shares of the Company’s common stock (the “Common Stock”) with an aggregate Black Scholes option value of $400,000, one-third of which shares will vest on the one year anniversary of the grant date and the balance of the shares will vest in a series of 24 equal monthly installments thereafter, such that the option is fully vested on the third anniversary of the date of grant, subject to Dr. Feigal’s continuous service through each such vesting date. Dr. Feigal will also be entitled to receive a $40,000 annual cash retainer for service as director, and will be eligible to receive additional equity compensation in the future. Dr. Feigal will enter into the Company’s standard form of indemnification agreement. The Company is not aware of any transaction involving Dr. Feigal requiring disclosure under Item 404(a) of Regulation S-K.

On November 8, 2018, the Company issued a press release announcing the appointment of Dr. Feigal to the Board, a copy of which is attached hereto as Exhibit 99.1.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

3

Exhibit 99.1

Xencor Appoints Ellen G. Feigal, M.D., to Board of Directors

MONROVIA, Calif., November 8, 2018 — Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical company developing engineered monoclonal antibodies for the treatment of autoimmune diseases, asthma and allergic diseases and cancer, today announced the appointment of Ellen G. Feigal, M.D., to its board of directors. Dr. Feigal is currently a partner at NDA Partners, a strategy consulting firm, where she leads efforts in designing and executing product development and regulatory strategies in the areas of cell therapies, medical imaging, hematology and oncology. She is also adjunct faculty at the Sandra Day O’Connor College of Law, Arizona State University, where she teaches FDA drug law and medical research ethics and law.

“Dr. Feigal’s exceptional career as an oncologist in clinical development spans 30 years across leadership roles in industry, academia, public service and nonprofits, and she has accrued a unique perspective from this wealth of experience,” said Bassil Dahiyat, Ph.D., president and chief executive officer at Xencor. “We are excited to benefit from her contributions to the board as we advance our pipeline of XmAb antibodies in autoimmune disease and oncology, grow our pipeline with novel bispecific antibodies and continue to expand the potential of our bispecific antibody technologies.”

“With twelve clinical programs engineered using Xencor’s innovative technology, the company has a tremendous opportunity to potentially improve the treatment of patients who have limited options, and I look forward to serving on the board of directors as the company continues to advance its programs,” said Dr. Feigal.

Dr. Feigal was formerly senior vice president of research and development at the California Institute for Regenerative Medicine; executive medical director, global development, at Amgen; and chief medical officer at Insys Therapeutics. She was a founding director of the American Course on Drug Development and Regulatory Sciences at the University of California, San Francisco. Prior to UCSF, Dr. Feigal was director of medical devices and imaging at the Critical Path Institute and vice president of clinical sciences at the Translational Genomics Research Institute. From 1992 to 2004, she held leadership roles at the National Cancer Institute, where she directed the Division of Cancer Treatment and Diagnosis after serving as deputy director of the division and as a senior investigator in the Cancer Therapy Evaluation Program. Dr. Feigal received her M.D. from the University of California, Davis and completed an internal medicine residency at Stanford University and a hematology/oncology fellowship at University of California, San Francisco.

About Xencor, Inc.

Xencor is a clinical-stage biopharmaceutical company developing engineered monoclonal antibodies for the treatment of autoimmune diseases, asthma and allergic diseases and cancer. Currently, 12 candidates engineered with Xencor’s XmAb® technology are in clinical development internally and with partners. Xencor’s internal programs include: XmAb®5871 in Phase 2 development for the treatment of IgG4-related disease, and also for the treatment of systemic lupus erythematosus; XmAb®7195 in Phase 1 development for the treatment of asthma and allergic diseases; XmAb®14045 in Phase 1 development for acute myeloid leukemia; XmAb®13676 in Phase 1 development for B-cell malignancies; XmAb®18087 in Phase 1 development for the treatment of neuroendocrine tumors and gastrointestinal stromal tumors; XmAb®20717 in Phase 1 development for the treatment of advanced solid tumors, and XmAb®22841, XmAb®23104 and XmAb®24306 in preclinical development for the treatment of multiple cancers. Xencor’s XmAb antibody engineering technology enables small changes to the structure of monoclonal antibodies resulting in new mechanisms of therapeutic action. Xencor partners include Novartis, Amgen, MorphoSys, CSL, Alexion and Boehringer Ingelheim. For more information, please visit www.xencor.com.

Forward Looking Statements

Statements contained in this press release regarding matters that are not historical facts are forward-looking statements within the meaning of applicable securities laws, including, but not limited to, the quotations from Xencor’s president and chief executive officer and any expectations relating to Xencor’s financial expectations and business, the timing and success of clinical trials, future product candidates, Xencor’s research and development programs, partnering efforts and capital requirements. Such statements involve known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements and the timing of events to be materially different from those implied by such statements, and therefore these statements should not be read as guarantees of future performance or results. Such risks include, without limitation, the risks associated with the process of discovering, developing, manufacturing and commercializing drugs that are safe and effective for use as human therapeutics and other risks described in Xencor’s public securities filings. For a discussion of these and other factors, please refer to Xencor’s annual report on Form 10-K for the year ended December 31, 2017 as well as Xencor’s subsequent filings with the Securities and Exchange Commission. All forward-looking statements are based on Xencor’s current information and belief as well as assumptions made by Xencor. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All forward-looking statements are qualified in their entirety by this cautionary statement and Xencor undertakes no obligation to revise or update this press release to reflect events or circumstances after the date hereof, except as required by law.

Investor Contact: John Kuch, Senior Vice President, Finance and Chief Financial Officer, Xencor, Tel: 626-737-8013, jkuch@xencor.com ; Corporate Communications Contact: Jason I. Spark, Canale Communications for Xencor, Tel: 619-849-6005, jason@canalecomm.com