Moderna shares fell as much as 25 percent Thursday after a partial data leak about its cancer vaccine partnership with Merck, though full results released later in the day showed meaningful clinical efficacy. The sell-off appears to be an overreaction to incomplete information.
mRNA-4157/V940, an individualized neoantigen therapy, met its primary endpoint when combined with Merck's Keytruda in high-risk melanoma patients, reducing recurrence or death risk. The data exceeded the cautious guidance several analysts had published before the full release. Merck's stock barely budged on the same news—a sign that investors properly valued the upside once they saw the complete picture.
The intraday crash has repriced Moderna at a notable discount to the vaccine's commercial opportunity. The individualized cancer vaccine market is projected to reach several billion dollars annually, and Moderna is years ahead of competitors in bringing a treatment to market. For investors confident in the mRNA platform's oncology thesis, the 25 percent dip is a rare entry point at a rational valuation.
Moderna and Merck will present full Phase 3 data at an upcoming medical conference and file for regulatory approval in the United States and key international markets. A label approval in high-risk melanoma could launch commercial revenue within 12-18 months. Institutional investors should watch the health authority filing timeline closely—a near-term catalyst that will reset the stock's valuation multiple once the regulatory path becomes certain.
