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): December 18, 2017

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))

o                                    Pre-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 December 18, 2017, Richard Ranieri 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, Mr. Ranieri is entitled to receive an initial grant consisting of a nonstatutory stock option to purchase 15,000 shares of the Company’s common stock (the “Common Stock”), 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 Mr. Ranieri’s continuous service through each such vesting date. Mr. Ranieri 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. Mr. Ranieri will enter into the Company’s standard form of indemnification agreement. The Company is not aware of any transaction involving Mr. Ranieri requiring disclosure under Item 404(a) of Regulation S-K.

On December 19, 2017, the Company issued a press release announcing the appointment of Mr. Ranieri to the Board, a copy of which is attached hereto as Exhibit 99.1.

Item 9.01                                           Financial Statements and Exhibits.

(d)                                 Exhibits

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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.

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Exhibit 99.1

Xencor Appoints Richard Ranieri to Board of Directors

Monrovia, Calif. — December 19, 2017 — 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 Richard Ranieri to its board of directors.

“Mr. Ranieri has a wealth of experience building biotechnology companies through major growth phases and the transition from research and development to commercial stage,” said Bassil Dahiyat, Ph.D., president and chief executive officer of Xencor. “Mr. Ranieri’s knowledge of the industry, its people and how biotech organizations should be managed to attract, retain, and engage their human capital will help to fill an important organization development role on Xencor’s board. He will be a tremendous asset by helping us build our team to execute our ambitious plans to advance our clinal-stage programs and bispecific oncology pipeline.”

“I am looking forward to working with the Xencor team to leverage the XmAb technology and the broad and innovative pipeline they have built,” said Mr. Ranieri. “This is an exciting time to be a part of a biotech such as Xencor advancing a robust pipeline and powerful technology platform.”

Mr. Ranieri has more than twenty years of senior level biopharma human resources leadership and currently serves as executive vice president of human resources and corporate affairs at BioMarin, where he manages and directs human resources worldwide. Prior to this role he served as executive vice president, human resources at Dendreon Corporation, and executive vice president, human resources & administration at Sepracor, Inc. Earlier in his career, Mr. Ranieri served in executive positions at Neurocrine Biosciences, Inc., Genencor International, and Smithkline Beecham. He received a B.A. from Villanova University, and an M.A. in organizational development from Rider University.

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, 11 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 pre-clinical development for the treatment of neuroendocrine tumors; and XmAb®20717 in pre-clinical 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, Merck, CSL/Janssen, Alexion and Boehringer Ingelheim. For more information, please visit www.xencor.com.

Forward Looking Statements:

Statements contained in this press release and the related abstracts and presentations regarding matters that are not historical facts are forward-looking statements within the meaning of applicable securities laws, including any expectations relating to our business, research and development programs, partnering efforts or our 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. All forward-looking statements are based on Xencor’s current information and belief as well as assumptions made by Xencor. Readers are cautioned not to place undue reliance on such statements and Xencor disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.