Moderna stock jumped more than 90% in premarket trading on Wednesday after the company and Merck reported a successful Phase 3 trial of their personalized mRNA cancer treatment in melanoma. Shares of Merck rose about 7% before market opening.
Merck and Moderna’s INTerpath-001 trial found that intismeran autogene, a personalized mRNA cancer vaccine designed to teach the immune system to recognize and target a patient’s tumor, delivered noteworthy improvements in both the time patients remained free of cancer and the time they remained free of cancer spread when combined with Merck’s KEYTRUDA.
The Phase 3 trial met its main goal of improving recurrence-free survival as well as a key secondary goal of improving distant metastasis-free survival at a planned interim analysis.
The results were considered statistically significant and clinically meaningful among patients with completely removed stage IIB, IIC, III or IV melanoma who had not previously received systemic therapy. The trial will continue to track patients for additional outcomes, including overall survival.
The readout represents a major milestone for the technology, marking the first successful Phase 3 result for individualized neoantigen therapy and an mRNA-based cancer treatment. It is also the first Phase 3 trial to demonstrate a meaningful benefit over KEYTRUDA alone for patients receiving treatment after melanoma surgery, according to the companies.
Intismeran autogene, or V940/mRNA-4157, is a cancer vaccine customized to each patient. Researchers identify mutations unique to the patient’s tumor and use that information to develop an mRNA treatment intended to train the immune system to recognize those cancer cells and attack them. The treatment is being jointly developed by Moderna and Merck.
Moderna and Merck said they will present the full findings at an upcoming international medical meeting and engage with regulators on potential submissions for the combination. If the detailed data support the topline findings, the treatment could help establish personalized cancer vaccines as a new option for patients after surgery.
The latest results follow positive Phase 2b findings from KEYNOTE-942/mRNA-4157-P201. Five-year data presented at ASCO 2026 showed that the combination reduced the risk of cancer recurrence or death by 49% versus KEYTRUDA alone. It also lowered the risk of distant cancer spread or death by 59%, providing earlier evidence for the Phase 3 program.
The companies are now testing intismeran in nine Phase 2 and Phase 3 trials across multiple cancers. The INTerpath program includes studies in melanoma, non-small cell lung cancer, bladder cancer and kidney cancer, with additional clinical work exploring pancreatic cancer, gastric cancer and different uses of the treatment in lung cancer.