Merck and Moderna melanoma vaccine trial cuts recurrence by 40%

Merck and Moderna announced this week that their jointly developed melanoma cancer vaccine, designated Melanoma‑mRNA‑Vax, produced positive results in a phase III clinical trial. The study enrolled roughly 1,200 patients who had undergone surgical resection, including individuals with high‑risk BRAF mutations or lymph‑node metastases. Over a two‑year follow‑up period, the recurrence rate in the vaccine arm was nearly 40 percent lower than in the placebo arm, and safety data indicated that adverse events were primarily mild to moderate local reactions.

Melanoma is one of the deadliest forms of skin cancer worldwide, with post‑surgical recurrence rates remaining between 30 percent and 50 percent. High‑risk patients in particular lack effective adjuvant therapies. Although immune‑checkpoint inhibitors such as PD‑1 blockers have markedly extended overall survival, they have not been able to eradicate microscopic residual disease. The vaccine leverages messenger‑RNA technology to encode tumor‑associated antigens, with the aim of stimulating patients’ own cellular immunity after surgery, establishing long‑term immune surveillance and reducing the risk of relapse.

Merck, known outside the United States as MSD, is the world’s fifth‑largest biopharmaceutical company. For 2024, the company reported revenue of approximately $6.45 billion, of which 46 percent (about $2.95 billion) derives from the PD‑1 inhibitor Keytruda—a first‑line therapy for multiple cancers—and 13 percent (about $860 million) from the human papillomavirus vaccine Gardasil. As a firm whose core portfolio centers on oncology drugs and vaccines, Merck continues to broaden its immunotherapy footprint, and the partnership with Moderna underscores its strategic investment in emerging mRNA platforms.

Since the global launch of its COVID‑19 vaccine in 2020, Moderna has accumulated extensive experience in mRNA manufacturing and supply‑chain management and is gradually shifting its research focus toward cancer immunotherapy. In 2022 the company established a dedicated cancer‑vaccine division, advancing several tumor‑antigen candidates through clinical testing. The collaboration with Merck combines Merck’s expertise in oncology clinical development and market deployment with Moderna’s mRNA technology platform, allowing the latter to be validated in a large‑scale solid‑tumor indication. Both companies expect to submit a New Drug Application to the U.S. Food and Drug Administration within the next two years.

If approved, the vaccine would provide melanoma patients worldwide with a third therapeutic option beyond surgery and checkpoint inhibitors, and could pave the way for mRNA‑based treatments in other solid tumours. Market analysts estimate the global annual sales potential of the vaccine at several billion dollars, a development that would substantially affect the future revenue composition and research‑and‑development direction of both firms.

For Taiwan, the results highlight the feasibility of mRNA platforms for cancer therapy and offer a reference point for domestic biotech R&D strategies. Although melanoma incidence in Taiwan is relatively low, recent trends of increased ultraviolet exposure and an aging population have driven a gradual rise in cases, and demand for preventive immunotherapies is growing among physicians and patients. Should the United States grant approval, Taiwanese regulatory authorities could draw on the trial’s clinical data and safety profile to accelerate local clinical studies and market review, while also creating opportunities for collaboration in mRNA manufacturing and supply chains, thereby strengthening Taiwan’s role in the global biotechnology value chain.