Merck and Moderna's Cancer Vaccine Shows Promising Results in Late-Stage Trial

A groundbreaking cancer vaccine developed by Merck and Moderna has shown positive results in its first late-stage trial, bringing it closer to regulatory review. The mRNA-based vaccine, combined with Merck's Keytruda immunotherapy, significantly extended the period patients remained free of recurring melanoma compared to Keytruda alone.

The Phase 3 study involved over 1,100 melanoma patients whose tumors had been surgically removed. It also lowered the risk of the cancer spreading to distant organs. The companies have not announced when they will seek US approval for the vaccine.

Merck's shares gained more than 1% in premarket trading, while Moderna rose over 10%. The personalized vaccine is designed to identify mutations unique to each patient's tumor and train the immune system to attack those cancer markers. The companies are also testing this approach against other cancers.