Announcement • May 12
Xilio Therapeutics, Inc. has filed a Follow-on Equity Offering in the amount of $17.22 million. Xilio Therapeutics, Inc. has filed a Follow-on Equity Offering in the amount of $17.22 million.
Security Name: Common Stock
Security Type: Common Stock
Transaction Features: At the Market Offering Announcement • Apr 29
Xilio Therapeutics, Inc., Annual General Meeting, Jun 10, 2026 Xilio Therapeutics, Inc., Annual General Meeting, Jun 10, 2026. Announcement • Apr 18
Xilio Therapeutics Announces New Preclinical Data For XTX601, A Masked T Cell Engager Targeting CLDN18.2 Xilio Therapeutics, Inc. announced new preclinical data for XTX601, a masked T cell engager targeting claudin 18.2 (CLDN18.2), at the American Association for Cancer Research Annual Meeting, taking place from April 17–22, 2026 at the San Diego Convention Center in San Diego, California. XTX601 demonstrated protease-dependent, tumor-selective activation and potent anti-tumor activity in multiple preclinical models. XTX601 was well tolerated in non-human primates with a favorable therapeutic index. XTX601 is a potentially first-in-class masked T cell engager designed to selectively target CLDN18.2, a tumor-associated antigen expressed in gastric, pancreatic and esophageal cancers. XTX601 incorporates Xilio’s clinically-validated masking technology and advanced tumor-activated cell engager format, which consists of a T cell engager with a masked CD3 targeting domain, with the goal of minimizing systemic T cell engagement in healthy tissue and overcoming the significant systemic toxicities that have limited non-masked T cell engagers targeting CLDN18.2. In addition, XTX601 is designed with a conditional half-life modulation element for antibody-like pharmacokinetics in its masked state and a short half-life upon activation in the tumor microenvironment to further limit peripheral exposure. In preclinical studies, XTX601 demonstrated the potential to achieve a wide therapeutic index. XTX601 demonstrated protease-dependent activation and tumor cell killing in high- and low-expression settings for CLDN18.2, with effective masking of the anti-CD3 domain. XTX601 exhibited robust, dose-dependent anti-tumor activity in multiple murine cell line-derived xenograft models, including GSU gastric carcinoma and OE19 esophageal adenocarcinoma models engrafted with human T cells. Consistent with its masked design, XTX601 was well tolerated in non-human primates with no evidence of cytokine release syndrome and no changes in liver enzymes. Integration of drug exposure data from murine tumor models and non-human primate studies indicated a favorable, positive therapeutic index for XTX601 and supports the potential for XTX601 to achieve meaningful anti-tumor activity at doses that are well-tolerated systemically. Xilio plans to advance its masked T cell engager program targeting CLDN18.2 into investigational new drug-enabling studies and submit an investigational new drug application for this program in 2027. 
