Moderna to present data from Phase 1/2 study of mRNA-4359 at AACR

Moderna (MRNA) announced that the Company will present data from a Phase 1/2 study of mRNA-4359, an investigational cancer antigen therapy, at the American Association for Cancer Research Annual Meeting in San Diego, CA, on April 17-22, 2026. The presentation reports safety, efficacy and translational data from a Phase 2 dose-expansion cohort of the Phase 1/2 study, which evaluated mRNA-4359 + pembrolizumab as a first-line therapy in patients with locally advanced or metastatic melanoma. Among 12 participants, mRNA-4359 + pembrolizumab resulted in an overall response rate of 83%, with two patients achieving a complete response and eight achieving a partial response, as well as a disease control rate of 92%. The median time to response was six weeks. Responses occurred across baseline tumor PD-L1 expression categories, with an ORR of 88% among patients with PD-L1+ tumors, and 67% among patients with PD-L1- tumors. Consistent with mRNA-4359’s mechanistic rationale, antigen-specific T-cell responses and novel expanded T-cell receptor clonality was observed in all patients with evaluable samples. mRNA-4359 + pembrolizumab demonstrated a manageable safety profile, with no new immune-related adverse events. “This study evaluating mRNA-4359 + pembrolizumab as a first-line treatment option reflects our ambition to demonstrate the potential of mRNA technology throughout a cancer patient’s journey. While conducted among a small patient population, we are encouraged by the high response rates and mechanistic translational results,” said David Berman, M.D., Ph.D., Chief Development Officer of Moderna. “We look forward to further evaluating the potential of mRNA-4359 in patients with melanoma.”