Xencor to Present Multiple Posters 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 three poster presentations at the 38th Annual Meeting of the Society for Immunotherapy of Cancer (SITC), being held in San Diego, November 1-5, 2023.

Poster Presentation Details

Clinical Trials in Progress

• Abstract 764, "A Phase 1, first-in-human (FIH), open-label, dose-finding and expansion study of XmAb808, a B7H3 x CD28 bispecific antibody, in combination with pembrolizumab in patients with advanced solid tumors"

Preclinical Programs

• Abstract 1060, "Optimally engineered IL18-Fc fusion proteins balance potency and pharmacokinetics to promote strong anti-tumor activity"
• Abstract 1193, "Synergistic targeting of multiple activating pathways with Natural Killer cell Engagers"

Posters will be available in the poster hall and virtually to registrants of the SITC Annual Meeting, beginning at 9:00 a.m. PT on Friday, November 3. In the poster hall, odd-numbered posters will be displayed on Friday, November 3, and even-numbered posters will be displayed on Saturday, November 4. Posters will be archived under "Events & Presentations" in the Investors section of the Company's website located at www.xencor.com.

About XmAb^®808 (B7-H3 x CD28)

Xencor is conducting a Phase 1 study of XmAb808 in patients with advanced solid tumors. 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. Strong potentiation of checkpoint and CD3 cytotoxic activity was also observed in vivo. XmAb808 is a wholly owned Xencor program.

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. 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 clinical trial design 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, 2022 as well as Xencor's subsequent filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on 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.