Merck says intismeran with Keytruda cuts melanoma recurrence or death risk 42%

A second measure showed a 58% reduction, and Merck said no new safety signals were seen.

Merck said that in the Phase 3 INTERPATH-001 trial, intismeran plus Keytruda significantly reduced the risk of recurrence or death by 42% compared with Keytruda alone. A second measure showed a 58% reduction. Merck said the safety profile was generally consistent with earlier studies of the combination.

Intismeran is a personalized cancer vaccine. The trial tests it with Keytruda in melanoma.

Merck shares are down 3.1% on Thursday, in step with a sector-wide slide tied to Moderna's fall. Moderna shares are down 25% on the day. The drop in Merck shares is not tied to company-specific fundamentals.

The vaccine works by a mechanism distinct from the diabetic eye trial and the KRAS licensing deal, both of which had been widening Merck's pipeline beyond its core franchise. A 42% cut in recurrence risk strengthens Keytruda itself rather than moving Merck away from it. That matters because Keytruda's patent cliff looms, and Merck has been under pressure to show next-generation value in oncology, not only outside it. For Merck shares, the data offer a specific offset to the sympathy sell-off, rather than a fix for the wider pharma sentiment problem.