Personalized mRNA vaccine combination improves melanoma outcomes in phase 3 trial

A personalized mRNA cancer vaccine used with Keytruda improved recurrence-free survival for people whose high-risk melanoma had been surgically removed, compared with Keytruda alone, according to top-line results from a phase 3 trial. The study enrolled 1,137 patients, and the companies developing the treatment said the difference was statistically significant. The combination also reduced the risk of cancer spreading to distant parts of the body.

The vaccine, intismeran autogene, is made to match mutations found in each patient’s tumor. Its mRNA instructions prompt cells to produce selected proteins, training the immune system to recognize cancer cells, while Keytruda helps that immune response attack them. The result is the first reported positive phase 3 outcome for an mRNA-based cancer therapy, following years of efforts to adapt the technology to oncology.

Important questions remain. Detailed trial data have not yet been presented, and researchers are still assessing overall survival, so the announcement does not show that patients live longer. The treatment is not approved. The companies plan to present the findings at a medical meeting and seek regulatory review. Independent oncologists called the results encouraging and an important proof of concept, while stressing the need to examine the full evidence.