XTX501: bispecific PD-1 / masked IL-2

XTX501 is a novel bispecific PD-1 / masked IL-2 that has the potential to be a foundational “backbone” therapy for solid tumors. XTX501 is designed to selectively stimulate PD-1 positive, antigen-experienced T cells and enhance their function while overcoming IL-2 receptor-mediated clearance, peripheral activity and tolerability issues associated with non-masked IL-2 agents.

We recently received clearance from the U.S. Food and Drug Administration for our investigational new drug application (IND) to proceed to a Phase 1/2 clinical trial for XTX501.  We plan to initially evaluate the safety and tolerability of XTX501 as a monotherapy in patients with metastatic NSCLC and select advanced solid tumors in the Phase 1 portion of a first-in-human, multi-center, open-label Phase 1/2 clinical trial at multiple sites in the United States. Please refer to NCT07688577 on www.clinicaltrials.gov for additional details.

We expect to initiate dosing in the Phase 1 portion of the trial in the second half of 2026, and we plan to report initial Phase 1 data in patients with metastatic NSCLC in the second half of 2027.