Moderna (NASDAQ: MRNA) Surges After Successful Phase 3 Melanoma Vaccine Trial

• Moderna and Merck’s personalized mRNA cancer vaccine, combined with Keytruda, met the primary and secondary endpoints in a Phase 3 melanoma trial.
• Moderna shares more than doubled and traded as high as approximately $163 following the announcement.
• Brookline Capital Markets analyst Leah Rush Cann reiterated a Buy rating and a $135 price target, although the target fell below Moderna’s intraday trading price following the surge.

Moderna (NASDAQ: MRNA) is a biotechnology company known for its messenger RNA technology. While it is widely recognized for its COVID-19 vaccine, the company is developing vaccines and treatments for respiratory diseases, rare diseases, and cancer. One of its most closely watched programs is intismeran autogene, an individualized cancer therapy being developed with Merck.

On August 19, 2026, Moderna and Merck announced positive interim results from the Phase 3 INTerpath-001 trial. The study evaluated intismeran autogene in combination with Merck’s Keytruda in 1,137 patients whose high-risk stage IIB-IV melanoma had been surgically removed.

The combination met the trial’s primary endpoint by producing a statistically significant improvement in recurrence-free survival compared with Keytruda alone. It also met a key secondary endpoint involving distant metastasis-free survival, which measures whether cancer spreads to other parts of the body. No new safety concerns were identified, although the companies have not yet released detailed efficacy data from the Phase 3 trial.

The findings represent the first positive late-stage trial results for an individualized mRNA cancer vaccine. However, the article should not apply the 49% reduction in recurrence or death and the 59% reduction in distant metastasis or death to the Phase 3 study. Those figures came from the smaller Phase 2b trial, while full numerical results from the Phase 3 study remain pending.

The announcement caused Moderna shares to surge as much as approximately 160% during intraday trading, reaching around $163 before giving back part of the gain. Trading volume exceeded 100 million shares as investors reassessed the commercial potential of Moderna’s cancer-treatment pipeline.

Despite the sharp increase, analyst price targets did not immediately move above Moderna’s new market price. Brookline Capital Markets analyst Leah Rush Cann reiterated a Buy rating and maintained a $135 price target following the trial announcement. 

Although the $135 target was below Moderna’s intraday trading price, Cann’s Buy rating was still positive rather than cautious. The difference may indicate that the target had not yet been revised to reflect the unusually large one-day stock move. Investors will now focus on the complete Phase 3 data, regulatory discussions, manufacturing requirements, and the vaccine’s potential commercial launch.