About XTX501

XTX501 is a novel bispecific PD-1 / masked IL-2 designed to selectively stimulate PD-1 positive, antigen-experienced T cells and enhance their function. XTX501 incorporates masking and is designed to overcome IL-2 receptor-mediated clearance, peripheral activity and tolerability issues associated with non-masked IL-2 agents. In preclinical studies, XTX501 demonstrated robust monotherapy activity (including in settings insensitive to PD-1 therapy) and tumor-selective pharmacodynamics consistent with its intended mechanism of action.

We plan to submit an IND application for XTX501 in the middle of 2026 and initiate a Phase 1 trial for XTX501 in the second half of 2026.

We plan to initially evaluate XTX501 in patients with metastatic non-small cell lung cancer (NSCLC) before expanding development to other solid tumor types, including tumors that are insensitive to PD-1 therapy.

XTX501 also has the potential to be a foundational “backbone” therapy for combination treatment with other agents.