Xencor to Present Seven Posters on Multiple Clinical Trials and Research-stage Programs at the SITC Annual Meeting

Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical company developing engineered antibodies and cytokines for the treatment of cancer and autoimmune diseases, today announced seven poster presentations at the 37th Annual Meeting of the Society for Immunotherapy of Cancer, being held in Boston, November 10-12, 2022.

Data from the first patients enrolled in a Phase 2 study of vudalimab, Xencor's selective PD-1 x CTLA-4 bispecific antibody, plus chemotherapy in patients with metastatic castration-resistant prostate cancer, will be presented in abstract 668.

Presentation Details

Clinical Trials in Progress

• Abstract 667, "A Phase 1, multiple-dose study to evaluate the safety and tolerability of XmAb^®819 (ENPP3 x CD3) in subjects with relapsed or refractory clear cell renal cell carcinoma (RCC)"
• Abstract 668, "A Phase 2 study of vudalimab, a PD-1 x CTLA-4 bispecific antibody, plus chemotherapy or targeted therapy in patients with molecularly defined subtypes of metastatic castration-resistant prostate cancer"
• Abstract 733, "A Phase 2 study of vudalimab (XmAb^®20717), an anti-PD-1/CTLA-4 bispecific antibody, in patients with selected gynecological malignancies and high-risk metastatic castration-resistant prostate-cancer"

Preclinical Programs

• Abstract 1067, "Synergistic combination of Natural Killer cell engagers (NKEs) with proinflammatory cytokines"
• Abstract 1073, "Costimulatory CD28 trispecific antibodies targeting PDL1 and PDL2 enhance T cell activation in solid tumors"
• Abstract 1079, "LAG3-targeted IL15/IL15R?-Fc (LAG3 x IL15) fusion proteins for preferential TIL expansion via cis delivery of IL15 to LAG3+ cells"
• Abstract 1372, "XmAb143, an engineered IL18 heterodimeric Fc-fusion, features improved stability, reduced potency, and insensitivity to IL18BP"

Posters will be available in the poster hall and virtually to registrants of the SITC Annual Meeting, beginning at 9:00 a.m. ET on Thursday, November 10. In the poster hall, odd numbered posters will be displayed on Thursday, November 10, and even numbered posters will be displayed on Friday, November 11. Posters will be archived under "Events & Presentations" in the Investors section of the Company's website located at www.xencor.com.

About Vudalimab

Vudalimab is an XmAb bispecific antibody that simultaneously targets immune checkpoint receptors PD-1 and CTLA-4 and is designed to promote tumor-selective T-cell activation. Xencor's approach to dual checkpoint inhibition reduces the need for multiple antibodies and allows for more selective targeting of T cells with high checkpoint expression of both targets, which may potentially improve the therapeutic index of combination immunotherapies. In preclinical studies, dual blockade of PD-1 and CTLA-4 with vudalimab significantly enhanced T cell proliferation and activation, and anti-tumor activity in vivo. Xencor is conducting a Phase 2 clinical study of vudalimab in patients with metastatic castration resistant prostate cancer (mCRPC), plus chemotherapy for certain patient populations, and a Phase 2 clinical study in patients with advanced gynecologic and genitourinary malignancies, as well as high-risk mCRPC.

About XmAb^®819

XmAb^®819 is a tumor-targeted, T-cell engaging XmAb 2+1 bispecific antibody in development for patients with renal cell carcinoma (RCC). XmAb819 engages the immune system by activating T cells for highly potent and targeted killing of tumor cells expressing ENPP3, an antigen highly expressed on kidney cancers. ENPP3 is differentially expressed between RCC (high expression) and normal tissues (low expression). To attack RCC cells selectively, XmAb819 was engineered as an XmAb 2+1 bispecific antibody with two binding domains against ENPP3 and one cytotoxic T-cell binding domain against CD3, a component of the T-cell receptor (TCR) complex. Xencor's XmAb Bispecific Fc Domain serves as the scaffold for these binding domains and provides long circulating half-life, stability and ease of manufacture. Xencor is conducting a Phase 1 study of XmAb819 in patients with advanced renal cell carcinoma.

About Xencor

Xencor is a clinical-stage biopharmaceutical company developing engineered antibodies and cytokines for the treatment of patients with cancer and autoimmune diseases. More than 20 candidates engineered with Xencor's XmAb® technology are in clinical development, and three XmAb medicines are marketed by partners. Xencor's XmAb engineering technology enables small changes to a protein's structure that result in new mechanisms of therapeutic action. For more information, please visit www.xencor.com.

Forward-Looking Statements

Certain statements contained in this press release may constitute forward-looking statements within the meaning of applicable securities laws. Forward-looking statements include statements that are not purely statements of historical fact, and can generally be identified by the use of words such as "potential," "can," "will," "plan," "may," "could," "would," "expect," "anticipate," "seek," "look forward," "believe," "committed," "investigational," and similar terms, or by express or implied discussions relating to Xencor's business, including, but not limited to, statements regarding the timing of data from Xencor's early and clinical-stage programs and other statements that are not purely statements of historical fact. Such statements are made on the basis of the current beliefs, expectations, and assumptions of the management of Xencor and are subject to significant 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, including the ability of publicly disclosed preliminary clinical trial data to support continued clinical development and regulatory approval for specific treatments, in each case as 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, 2021 as well as Xencor's subsequent filings with the Securities and Exchange Commission. 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, as amended to date. 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.