Moderna Merck mRNA Therapy Achieves Breakthrough in Melanoma Trial

August 2026 was a busy month for clinical trials, with 93 updates tracked by BioWorld. Late-stage programs dominated the activity, with 41 phase III readouts, compared to 26 each for phase I and phase II. Oncology led the way with 21 updates, followed by cardiovascular and neurology/psychiatric programs.

The standout success of the month came from Moderna Inc. and Merck & Co. Inc., who reported positive phase III results from the Interpath-001 trial. Their personalized mRNA-based neoantigen therapy, intismeran autogene, combined with Keytruda (pembrolizumab), met the primary endpoint of recurrence-free survival and the key secondary endpoint of distant metastasis-free survival in patients with resected stage IIb-IV melanoma. This marks the first positive late-stage results for an individualized neoantigen therapy and an mRNA-based cancer therapy, as well as the first phase III study to show a clinically meaningful improvement over Keytruda alone in this setting. The news sent Moderna shares soaring by 177% and Merck shares up by 12.6%.

Other notable phase III successes included Akeso Inc.'s ivonescimab in biliary tract cancer, Amylyx Pharmaceuticals Inc.'s avexitide for post-bariatric hypoglycemia, and Arrowhead Pharmaceuticals Inc.'s Redemplo for severe hypertriglyceridemia. In the immune space, Argenx SE reported positive results for Vyvgart in immune-mediated necrotizing myopathy, and AstraZeneca and Amgen's Tezspire showed promise in eosinophilic esophagitis.

However, not all trials were successful. Tenax Therapeutics Inc.'s TNX-103 failed its phase III trial in pulmonary hypertension due to heart failure with preserved ejection fraction, leading to a 90% drop in the company's shares.