Xilio Therapeutics to Present Initial Phase 1C Dose Escalation Data for XTX101 (Vilastobart) in Combination with Atezolizumab in a Late-Breaker Poster at the Society for Immunotherapy of Cancer (SITC) 39th Annual Meeting

Xilio Therapeutics, Inc. (Nasdaq: XLO), a clinical-stage biotechnology company discovering and developing tumor-activated immuno-oncology therapies for people living with cancer, today announced that initial data from its Phase 1C dose escalation of XTX101 (vilastobart) in combination with atezolizumab in patients with advanced solid tumors will be presented in a late-breaker poster session at the Society for Immunotherapy of Cancer (SITC) 39th Annual Meeting taking place in Houston, Texas, from November 6-10, 2024.

Poster presentation details:

• Title: Phase 1/2 Study of Vilastobart (formerly XTX101), a Tumor-Activated, Fc-enhanced Anti-CTLA-4 Monoclonal Antibody, in Combination with Atezolizumab in Patients with Advanced Solid Tumors
• Abstract Number: 1455
• Presentation Date: Friday, Nov. 8, 2024
• Poster Hall Hours: 9 a.m. – 7 p.m. CST
• Location: George R. Brown Convention Center

About Vilastobart (XTX101) and the Phase 1/2 Combination Clinical Trial

Vilastobart is an investigational tumor-activated, Fc-enhanced, high affinity binding anti-CTLA-4 monoclonal antibody designed to block CTLA-4 and deplete regulatory T cells when activated in the tumor microenvironment (TME). In 2023, Xilio entered into a co-funded clinical trial collaboration with Roche to evaluate vilastobart in combination with atezolizumab (Tecentriq®) in a multi-center, open-label Phase 1/2 clinical trial. Xilio is currently evaluating the safety of the combination in a Phase 1C dose escalation in patients with advanced solid tumors and the safety and efficacy of the combination in a Phase 2 clinical trial in patients with microsatellite stable colorectal cancer (MSS CRC), including both patients with and without liver metastases. Please refer to NCT04896697 on www.clinicaltrials.gov for additional details.

About Xilio Therapeutics

Xilio Therapeutics is a clinical-stage biotechnology company discovering and developing tumor-activated immuno-oncology (I-O) therapies with the goal of significantly improving outcomes for people living with cancer without the systemic side effects of current I-O treatments. The company is using its proprietary platform to advance a pipeline of novel, tumor-activated clinical and preclinical I-O molecules that are designed to optimize the therapeutic index by localizing anti-tumor activity within the tumor microenvironment, including tumor-activated cytokines, antibodies, bispecifics and immune cell engagers. Learn more by visiting www.xiliotx.com and follow us on LinkedIn (Xilio Therapeutics, Inc.).

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding plans to present clinical data from Phase 1C dose escalation for vilastobart (XTX101) in combination with atezolizumab in patients with advanced solid tumors; and Xilio’s strategy, goals, business plans and focus. The words “aim,” “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “seek,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of important risks, uncertainties and other factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, general market conditions; risks and uncertainties related to ongoing and planned research and development activities, including initiating, conducting or completing preclinical studies and clinical trials and the timing and results of such preclinical studies or clinical trials; the delay of any current or planned preclinical studies or clinical trials or the development of Xilio’s current or future product candidates; Xilio’s ability to obtain and maintain sufficient preclinical and clinical supply of current or future product candidates; Xilio’s advancement of multiple early-stage immune cell engager programs; interim or preliminary preclinical or clinical data or results, which may not be replicated in or predictive of future preclinical or clinical data or results; Xilio’s ability to successfully demonstrate the safety and efficacy of its product candidates and gain approval of its product candidates on a timely basis, if at all; results from preclinical studies or clinical trials for Xilio’s product candidates, which may not support further development of such product candidates; actions of regulatory agencies, which may affect the initiation, timing and progress of current or future clinical trials; Xilio’s ability to obtain, maintain and enforce patent and other intellectual property protection for current or future product candidates; Xilio’s ability to obtain and maintain sufficient cash resources to fund its operations; the impact of international trade policies on Xilio’s business, including U.S. and China trade policies; Xilio’s ability to maintain its clinical trial collaboration with Roche to develop vilastobart in combination with atezolizumab; and Xilio’s ability to maintain its license agreement with Gilead to develop and commercialize XTX301. These and other risks and uncertainties are described in greater detail in the sections entitled “Risk Factor Summary” and “Risk Factors” in Xilio’s filings with the U.S. Securities and Exchange Commission (SEC), including Xilio’s most recent Quarterly Report on Form 10-Q and any other filings that Xilio has made or may make with the SEC in the future. Any forward-looking statements contained in this press release represent Xilio’s views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. Except as required by law, Xilio explicitly disclaims any obligation to update any forward-looking statements.

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Investor and Media Contact 

Scott YoungVice President, Investor Relations and Corporate [e-mail]