Xilio Therapeutics has unveiled promising preclinical data for XTX601, a masked T cell engager specifically targeting claudin 18.2 (CLDN18.2), at the AACR Annual Meeting. This innovation leverages Xilio’s clinically-validated masking technology to selectively activate the therapeutic agent within the tumor microenvironment, minimizing systemic toxicity—a significant hurdle in the development of T cell engagers for solid tumors. The data indicates that XTX601 exhibits protease-dependent activation and effective tumor cell killing across various CLDN18.2-expressing tumor models, showcasing its potential as a first-in-class therapy.

The significance of these findings lies in XTX601’s favorable therapeutic index, demonstrated through robust anti-tumor activity in murine models and well-tolerated profiles in non-human primates. Notably, the absence of cytokine release syndrome and stable liver enzyme levels in primate studies underscore the safety of this approach. The adaptable design of XTX601 allows for rapid evaluation of multiple configurations, including modifications to the CLDN18.2 binding domain and the incorporation of co-stimulatory elements, which could enhance its clinical efficacy.

The implications for the field are substantial, as XTX601 represents a potential paradigm shift in the development of immuno-oncology therapies. By addressing the systemic toxicity associated with traditional T cell engagers, this approach could accelerate the timeline for clinical applications in treating gastric, pancreatic, and esophageal cancers. Xilio plans to advance XTX601 into IND-enabling studies, with an IND application anticipated in 2027, marking a critical step toward translating these findings into clinical practice.

Source: globenewswire.com