Merck's KEYTRUDA Surges 10.6% on Positive Melanoma Study Results

Merck & Co's stock surged 10.6% on August 19, 2026, following positive late-stage oncology update results for its KEYTRUDA franchise.

The company and its partner announced that the Phase 3 INTerpath-001 study of intismeran autogene plus KEYTRUDA met both recurrence-free survival and distant metastasis-free survival endpoints in patients with completely resected stage IIB-IV melanoma.

This outcome appears to have strengthened investor confidence in KEYTRUDA's long-term growth runway, which had already shown durable benefit trends for the program in high-risk melanoma earlier this year.