Merck–Moderna Personalized Cancer Vaccine Shows Positive Phase 3 Results

Merck and Moderna said their personalized mRNA cancer vaccine, intismeran autogene (mRNA-4157/V940), met both key efficacy goals in a Phase 3 trial involving more than 1,100 patients with surgically removed, high-risk melanoma.

When combined with Merck’s Keytruda, the vaccine significantly extended recurrence-free survival compared with Keytruda alone and also improved distant-metastasis-free survival. The companies described the benefits as statistically significant and clinically meaningful, but have not yet released detailed Phase 3 figures.

The trial’s interim analysis allowed the companies to begin discussions with regulators about potential filing submissions. Because the vaccine has FDA Breakthrough Therapy designation, an accelerated approval pathway may be possible, though approval is not guaranteed.

The Phase 3 study will continue to evaluate overall survival. Merck and Moderna plan to present the full data at an upcoming international medical meeting.

The development is important because the vaccine is customized to each patient’s tumor mutations, aiming to train the immune system to recognize and attack residual cancer cells after surgery. Shares of Moderna reportedly surged sharply following the announcement.