Analysts warm to Merck–Moderna cancer vaccine after ESMO presentation

After analysts reviewed the full Phase 3 INTerpath-001 presentation at ESMO 2026, several viewed Merck and Moderna’s personalized cancer vaccine results more favorably than they had after the data first surfaced early.

In 1,137 patients with surgically removed, high-risk stage 2B–4 melanoma, intismeran autogene plus Merck’s Keytruda reduced the risk of recurrence or death by 42% versus Keytruda alone (hazard ratio 0.58).

The combination also reduced the risk of distant metastasis or death by 38%. At two years, 82.2% of patients on the combination were alive and cancer-free, compared with 70% on Keytruda alone.

The premature release disrupted the planned ESMO presentation and was followed by a sharp fall in both companies’ shares. Some investors had hoped for stronger results and clearer evidence the approach could work in other cancers.

Analysts who saw the full presentation called the findings clinically meaningful, while questions remain about overall survival and whether the results will extend beyond melanoma. The companies reported no new safety concerns.