Experimental cancer vaccine, combined with immunotherapy, continues to show benefits against melanoma, trial shows

An investigational mRNA vaccine used along with immunotherapy continues to show benefit for people with high-risk forms of the skin cancer melanoma, the drugmakers said Thursday.

At a three-year follow-up with trial participants who had had a stage III or IV melanoma fully removed but were at high risk of the cancer coming back, those who got the vaccine from Moderna and Merck along with Merck’s Keytruda immunotherapy had a 49% lower risk of recurrence or death and a 62% lower risk of distant tumor cell spread or death compared with those who got Keytruda alone, the companies said in a news release.

A two-year follow-up had found a 44% lower risk of recurrence or death and a 65% lower risk of distant metastasis or death in people who got Keytruda and the vaccine, called mRNA-4157/V940, compared with those who got Keytruda alone.

Moderna Chief Executive Officer Stephane Bancel told CNN Thursday that the company is preparing for potential accelerated approval of the individualized therapy as soon as 2025, and is building a new commercial manufacturing plant in Massachusetts to be ready.

The US Food and Drug Administration first approved Keytruda, which boosts the immune system’s ability to detect and fight cancer cells, for treatment of certain cancers in 2014. The agency has granted a breakthrough therapy designation to mRNA-4157/V940 combined with Keytruda, a status that expedites the development and review of drugs that are intended to treat a serious condition and that preliminary clinical evidence indicates may be a substantial improvement over available therapies.

About a quarter of the trial participants who got Keytruda plus the vaccine reported serious adverse events related to the treatment, compared with about 20% for those who got only Keytruda. The most common side effects that were attributed to the vaccine were fatigue, pain at the injection site and chills.

The data from the Phase 2b trial of the therapies has not been peer-reviewed or published in a professional journal. Moderna and Merck say they have begun Phase 3 trials on stage IIB-IV melanoma and non-small-cell lung cancer, and they plan to expand the research to include further types of tumors.

According to the American Cancer Society, melanoma accounts for about 1% of all skin cancers, but it causes a majority of skin cancer deaths. The group estimated that in 2023, about 100,000 new melanomas would be diagnosed in the US, and almost 8,000 people would die from melanoma.