Merck Stock Surges Near 52-Week High on Positive Melanoma Vaccine Data

Merck & Co., Inc.'s stock is trading near its 52-week high of $154.49, following positive late-stage melanoma vaccine data and a significant recent rerating of the shares.

The personalized cancer vaccine, when combined with Keytruda, improved recurrence-free survival and distant metastasis-free survival in a Phase 3 trial involving 1,137 patients.

Market commentary highlighted that Merck's stock opened at $152.43 on August 24, 2026, and was quoted at $152.85 later that morning, underscoring the strength of the recent move.

The positive data led to a sharp increase in market value, with Merck shares closing up 12.5 percent on the day, adding $43 billion to its market capitalization.