Moderna shares surge on melanoma vaccine breakthrough

Moderna shares surged as much as 150% Wednesday after the company and Merck announced positive late-stage results for a personalized mRNA melanoma treatment, marking a major milestone for efforts to use mRNA technology against cancer.

The Phase 3 trial met its primary goal of reducing melanoma recurrences when Moderna’s individualized cancer treatment, intismeran autogene, was used alongside Merck’s Keytruda. The combination also significantly reduced the risk of cancer spreading to distant parts of the body compared with Keytruda alone, the companies said.

The findings represent the first positive Phase 3 trial for an individualized neoantigen therapy and the first successful late-stage trial of an mRNA-based cancer treatment, providing some of the strongest evidence yet that the technology behind Moderna’s COVID-19 vaccines could have applications well beyond infectious disease.

Moderna shares more than doubled following the announcement, climbing roughly 129% to about $144 by midmorning after trading as much as 150% higher earlier in the session. Merck shares rose nearly 12%.

Unlike a traditional vaccine designed to prevent an infection, intismeran is a therapeutic cancer treatment manufactured specifically for each patient. Researchers analyze mutations in a patient’s tumor and use that information to create an individualized mRNA treatment targeting as many as 34 tumor-specific markers, known as neoantigens.

The treatment is intended to train the patient’s immune system to identify and attack cancer cells carrying those mutations. Keytruda, an established immunotherapy drug, helps the immune system recognize and fight tumor cells.

The global Phase 3 INTerpath-001 trial enrolled 1,137 patients with stage IIB through stage IV melanoma whose tumors had been completely removed through surgery. Patients were randomly assigned to receive either intismeran with Keytruda or Keytruda alone.

The study met its primary endpoint of recurrence-free survival and a key secondary endpoint measuring distant metastasis-free survival. Merck and Moderna described both improvements as statistically significant and clinically meaningful.

The companies have not yet disclosed the precise reduction in recurrence or metastasis risk from the Phase 3 trial. Full results are expected to be presented at an international medical meeting and submitted to regulators. The study is also continuing to determine whether the combination improves overall survival.

Earlier research has already provided an indication of the treatment’s potential. Five-year results from a smaller Phase 2b study released in January showed that intismeran combined with Keytruda reduced the risk of melanoma recurrence or death by 49% compared with Keytruda alone. The combination also reduced the risk of distant metastasis or death by 59%.

The much larger Phase 3 trial now provides stronger evidence that those benefits can be reproduced across a broader group of patients.

Melanoma is the most serious form of skin cancer. Roughly 112,000 Americans are diagnosed with the disease each year and about 8,500 die from it, according to the American Cancer Society. More than 1.5 million people in the United States were living with melanoma as of 2023.

Merck Research Laboratories President Dr. Dean Li said the companies are likely to begin discussions with regulatory agencies about the treatment and its safety in the coming months as they consider potential approval filings.

No new safety concerns were identified in the Phase 3 trial, according to the companies, which said the safety profile remained consistent with earlier studies of the combination. The treatment remains experimental and has not been approved for use.

The results are particularly significant for Moderna, which became one of the world’s best-known biotechnology companies during the COVID-19 pandemic before seeing its shares fall sharply as demand for coronavirus vaccines declined. A successful cancer product would provide some of the clearest evidence yet that Moderna’s mRNA platform can generate commercially significant treatments outside infectious diseases.

Merck could also benefit substantially. Keytruda is already one of the world’s leading cancer drugs, and a personalized therapy capable of further reducing recurrence among high-risk patients could extend its importance across oncology.

The companies are also testing intismeran in other cancers, with nine Phase 2 and Phase 3 studies underway across melanoma, non-small cell lung cancer, bladder cancer, kidney cancer and other settings.

This is a developing story. Check back for updates.