Merck Stock Jumps on Positive Trial Results, Surpasses 52-Week High

Merck's stock has surged by 6.2% in pre-open trading after the company announced that its intismeran autogene combined with Keytruda met its primary and secondary endpoints in a Phase 3 trial for patients with completely resected stage IIB-IV melanoma.

The INTerpath-001 trial, which enrolled 1,137 patients, represents the first large-scale Phase 3 confirmation of the mRNA-based individualized neoantigen therapy platform. This success is seen as a major milestone in Merck's expanding oncology and HIV pipeline.

Analysts had been anticipating strong results given previous Phase 2b data that showed a 49% reduction in the risk of recurrence or death compared to Keytruda alone. The latest upgrade cycle, including Daiwa upgrading Merck to Outperform from Neutral on August 17, has amplified the stock's response.

The trial result arrives on the heels of positive analyst actions, with Wells Fargo issuing a Buy rating on the same day as the upgrade. This move reflects growing conviction that Merck's post-Keytruda patent-cliff narrative is being de-risked by its expanding pipeline.