Merck & Company, Inc. (MRK) shares surged 12.12% to $151.56 on Wednesday after the company and Moderna reported positive Phase 3 melanoma trial results. The stock extended its rally after rising sharply from an intraday low near $135.17. The results added another data point to Merck’s oncology portfolio at a time when KEYTRUDA remains central to the company’s cancer business and future pipeline updates can draw close investor attention.

Merck & Co., Inc., MRK

Merck Stock Rises After Phase 3 Melanoma Success

Merck and Moderna announced positive topline results from the Phase 3 INTerpath-001 clinical trial. The study evaluated intismeran autogene together with Merck’s KEYTRUDA treatment in patients with surgically removed melanoma. The trial met its primary endpoint of recurrence-free survival.

The combination also met a key secondary endpoint measuring distant metastasis-free survival. The companies said the results showed statistically significant improvements compared with KEYTRUDA treatment alone. They also reported clinically meaningful benefits among patients with completely resected stage IIB through IV melanoma.

The trial enrolled patients who had not previously received systemic therapy for their melanoma. Merck and Moderna will continue the study while evaluating additional secondary endpoints, including overall survival, which remains an important long-term measure of treatment effectiveness.

Intismeran and KEYTRUDA Reach a Major Milestone

Intismeran is an individualized mRNA-based neoantigen therapy developed jointly by Merck and Moderna. The treatment is designed to target unique mutations found in an individual patient’s tumor and direct immune responses against cancer cells carrying those mutations.

The Phase 3 results mark an important milestone for individualized neoantigen therapies. The study produced the first positive Phase 3 results for an individualized neoantigen therapy, and it also marked the first positive Phase 3 readout for an mRNA-based cancer treatment.

The combination did not produce any new safety signals during the trial. Its safety profile remained consistent with findings from previously reported studies of intismeran and KEYTRUDA. Merck and Moderna plan to present detailed results at an upcoming international medical meeting.

Merck and Moderna Expand the INTerpath Program

Merck and Moderna have expanded their INTerpath development program across multiple cancer types and disease stages. The program now includes nine Phase 2 and Phase 3 clinical trials. These studies evaluate intismeran with KEYTRUDA, with other cancer treatments, and as a standalone therapy.

The companies are studying the approach in melanoma, bladder cancer, renal cell carcinoma, and non-small cell lung cancer. Their broader research program also includes an earlier Phase 2b study in patients with melanoma. In addition, another study covers pancreatic, gastric, and non-small cell lung cancers in different treatment settings.

Merck has built a major oncology business around KEYTRUDA, making further treatment advances strategically important. The new results may help shape the next phase of review discussions as Merck and Moderna prepare to share the Phase 3 findings with regulatory authorities for further review.