Merck's Stock Soars on Positive Cancer Vaccine Trial Results

Merck's stock surged by as much as 7.5% before opening on Wednesday, following positive results from its Phase 3 trial for an mRNA cancer vaccine. The company partnered with Moderna to develop the personalized vaccine, which showed statistically significant improvements in both recurrence-free survival and distant-metastasis-free survival endpoints compared to Keytruda alone.

The trial enrolled 1,137 patients with high-risk melanoma that had already been surgically removed, who were tested against either Keytruda or a combination of Keytruda and intismeran. The results indicate that the personalized vaccine, when added to Keytruda, performs better on both key measures.

Keytruda remains Merck's top-selling franchise, generating $8.4 billion in second-quarter sales against a total company revenue of $16.6 billion. A successful cancer vaccine could provide another growth engine for the company as Keytruda approaches patent expiration later this decade.