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Apr 17, 2023

Xencor Highlights CD28 Bispecific Antibody Platform at AACR Annual Meeting 2023

PASADENA, Calif.--(BUSINESS WIRE)--Apr. 17, 2023-- Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical company developing engineered antibodies and cytokines for the treatment of cancer and autoimmune diseases, today presented new preclinical data generated from engineered CD28 bispecific antibodies targeting the solid tumor antigens CEACAM5, ENPP3, mesothelin, STEAP1 and Trop-2. For each molecule, in vitro T cell activation was enhanced in combination with a CD3 T cell engager. The data were presented in a poster titled “Tumor-specific CD28 costimulatory bispecific antibodies enhance T cell activation in multiple solid tumors” (Abstract 2983) at the American Association for Cancer Research (AACR) Annual Meeting in Orlando, Florida.

T cells in the tumor microenvironment require engagement of both their T cell receptor (TCR) and their co-stimulatory receptors, like CD28, to achieve full activation. The CD28 signal is diminished in cancer because tumor cells do not typically express CD28 ligands (i.e., CD80 and CD86), which leads to potentially compromised activity of CD3 T cell engagers or anti-PD1 checkpoint inhibitors.

Xencor has developed a modular XmAb® bispecific antibody platform that allows for the rapid generation of drug candidates that co-stimulate CD28 only in the presence of tumor cells and TCR engagement. Xencor’s XmAb bispecific Fc domain serves as a scaffold for a non-superagonist anti-CD28 binding domain and any tumor-associated antigen of interest. Xencor’s Xtend™ Fc technology further enhances circulating half-life of the antibody.

“Xencor has rapidly generated multiple CD28 co-stimulatory bispecific antibodies with potential broad applicability across a range of solid tumors, and each of these programs has demonstrated compelling activity,” said John Desjarlais, Ph.D., executive vice president and chief scientific officer at Xencor. “We are leveraging the plug-and-play nature of our XmAb bispecific antibody platforms to generate and explore additional CD28 drug candidates against a broader universe of solid tumor targets.”

The poster will be archived under "Events & Presentations" in the Investors section of the Company's website located at www.xencor.com.

About XmAb808 (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 proteins 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 research programs, the quotations from Xencor's executive vice president and chief scientific officer, 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, 2022, 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.

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Source: Xencor, Inc.