Merck & Co’s stock slipped 1.1% in pre-market trading on Thursday after the company and partner Moderna announced positive late-stage results for their personalized mRNA cancer vaccine, intismeran autogene, combined with Merck’s immunotherapy Keytruda.
The Phase 3 INTerpath-001 trial, involving over 1,100 high-risk melanoma patients, met both primary and key secondary endpoints, including recurrence-free survival and distant metastasis-free survival. The milestone marks the first positive outcome in a late-stage trial for any mRNA-based cancer therapy, reinforcing the potential of the experimental treatment.
Shares had surged to a new 52-week high of $153.50 in the prior session, prompting profit-taking that contributed to Thursday’s decline. A prominent valuation model estimated Merck’s stock was approximately 27% overvalued relative to its intrinsic value at Wednesday’s close, adding to selling pressure.
Insider activity over the past year has been net negative, with no recorded purchases, further tempering investor enthusiasm despite the clinical breakthrough. Analysts remain divided: Morgan Stanley upgraded Merck to Overweight from Equal Weight, while Citi flagged lingering questions about the efficacy data.
The broader market showed little direction, with the S&P 500, Dow Jones, and Nasdaq all trading fractionally lower in pre-market trading.
