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# Merck, Moderna Report Positive Data for Cancer Vaccine
- URL: https://www.fdaweb.com/merck-moderna-report-positive-data-for-cancer-vaccine/
- Published: 2026-10-23T13:35:47.000Z
- Updated: 2026-10-23T13:35:47.000Z
- Author: David McFarland
- Tags: Biologics

Merck and Moderna are reporting positive recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) results from a highly anticipated Phase 3 trial evaluating their personalized cancer vaccine, intismeran autogene, in combination with Keytruda (pembrolizumab).

The Phase 3 INTerpath-001 trial is evaluating intismeran autogene, an investigational mRNA-based individualized neoantigen therapy (INT), in patients with completely resected stage IIB–IV melanoma. The vaccine is manufactured individually using a patient's tumor sample to identify the cancer's unique mutational signature and generate an antitumor immune response.

Results released early following a leak showed that, after a median follow-up of 24.6 months, the combination therapy significantly reduced the risk of recurrence or death by 42% compared with Keytruda alone, the companies reported.

Intismeran plus Keytruda also significantly reduced the risk of distant metastasis or death by 38% (HR=0.62; 95% CI, 0.45–0.85; p=0.002). According to the companies, improvements in RFS and DMFS were generally consistent across prespecified patient subgroups.

At two years, the RFS rate was 82.2% for the combination therapy compared with 70.0% for Keytruda alone. Median RFS had not been reached in either treatment arm. The two-year DMFS rate was 88.5% for intismeran plus Keytruda compared with 80.2% for Keytruda alone.

The companies said overall survival (OS) data remain immature, although a “favorable trend” has been observed. The study is continuing to evaluate OS and other key endpoints.

“The safety profile of intismeran plus Keytruda was generally consistent with previously reported studies of the combination, and no new safety signals were observed,” the companies reported. “Based on these data, we are engaging with regulatory authorities.”

Treatment-related adverse events occurred in 95.8% of patients receiving the combination and 90.0% receiving Keytruda alone. Grade 3–5 treatment-related adverse events occurred in 14.2% and 13.4% of patients, respectively. The most common adverse events in the combination arm were pyrexia (52.2%), injection-site pain (51.0%) and fatigue (38.5%).

Meanwhile, Wall Street analysts generally characterized the Phase 3 findings as clinically meaningful and supportive of potential FDA approval, despite a sharp decline in Moderna's shares following the announcement. Some analysts attributed the market reaction to elevated investor expectations and profit-taking rather than concerns about the trial's primary efficacy results.

However, analysts also raised questions about the vaccine's commercial potential and whether the results would translate into similarly strong benefits in other tumor types.