A Phase 1/2 clinical trial involving 29 patients with checkpoint inhibitor-resistant or refractory melanoma reported an objective response rate (ORR) of 24% and a disease control rate (DCR) of 60%, with notably higher ORR of 67% in patients with PD-L1+ tumors, suggesting PD-L1 as a potential predictive biomarker.

Moderna announced promising early data for its investigational cancer therapy, mRNA-4359, at the 2025 European Society for Medical Oncology (ESMO) Congress in Berlin, held from October 17-21, 2025.

The company will present initial clinical, safety, and translational data for mRNA-4359, a cancer antigen therapy, during the congress.

Early results from Moderna's Phase 1/2 trial of mRNA-4359 indicate a promising safety profile and evidence of immune activation, including induction of peripheral antigen-specific T cell responses and generation of novel T cell receptor clones.

The safety profile of mRNA-4359 combined with pembrolizumab was manageable, with no new immune-related adverse events reported, supporting its further evaluation both as a monotherapy and in combination.

Data also showed that mRNA-4359 successfully stimulated antigen-specific T cell responses and generated new T cell receptor clones, indicating immune activation.

Moderna aims to leverage its mRNA platform to develop therapies for various diseases, including immuno-oncology, with mRNA-4359 targeting immune escape pathways to overcome resistance.

The ongoing trial (NCT05533697) is evaluating mRNA-4359 as both a monotherapy and in combination with pembrolizumab in patients with advanced melanoma and non-small cell lung cancer.

Results support further development of mRNA-4359, especially in PD-L1+ tumors, highlighting its potential to address high unmet medical needs in cancer treatment.

The detailed clinical outcomes and PD-L1 expression analyses will be presented on October 17, 2025, during a mini oral session at the ESMO Congress, with a webcast for investors scheduled later that day.

The presentation will be given by Dr. David J. Pinato, and the session will include a live investor webcast at 6:00 PM CET.

The trial involves administering mRNA-4359 at doses of 400 μg and 1,000 μg every three weeks for up to nine doses, with the median duration of response not yet reached, indicating potential durability.