Moderna’s and Merck’s personalized mRNA vaccine shows real promise against deadly skin cancer melanoma in late stage trial and sends stocks soaring

Moderna and Merck announced Wednesday that their personalized mRNA cancer vaccine met its primary objectives in a Phase 3 trial for melanoma, the first time such a therapy has succeeded at this stage of testing. The news caused Moderna's stock to soar over 100% and boosted Merck shares. The vaccine, called intismeran autogene, is created from a patient's own tumor sample and trains the immune system to recognize the unique mutations in that individual's cancer.

In the trial, patients with high-risk melanoma who had previously undergone surgery received either the vaccine plus Merck's immunotherapy Keytruda, or Keytruda alone. Those receiving the vaccine along with Keytruda had longer cancer-free periods compared to those who received Keytruda alone, meeting the trial's main goals. The companies have not yet disclosed the exact figures, but stated the results were "statistically significant and clinically meaningful."

Merck plans to present the full data at an upcoming medical conference and submit it to regulators. This development follows earlier data showing a 49% reduction in recurrence or death risk and a 59% reduction in distant metastasis or death risk compared to Keytruda alone. Experts believe this breakthrough could double the five-year recurrence-free survival rate for advanced melanoma patients, currently around 20 to 35%.