Breakthrough for Moderna and Merck: Promising results in advanced melanoma vaccine trial

An experimental personalized cancer vaccine for melanoma from Merck and Moderna has shown positive preliminary results in its first late-stage trial, the companies announced on Wednesday. The results bring them one step closer to submitting an application to the U.S. Food and Drug Administration (FDA) for approval of the treatment.

The vaccine, based on mRNA technology, was administered in combination with Merck's immunotherapy drug Keytruda and met the primary endpoints of the Phase 3 trial. The study involved more than 1,100 patients with high-risk or advanced melanoma whose detectable tumor was completely removed by surgery. The combination therapy significantly extended the length of time patients lived without the melanoma returning compared to treatment with Keytruda alone. The treatment also reduced the risk of the cancer spreading to distant areas of the body.

The results build on positive data from a Phase 2 trial of the same combination treatment published earlier this year. The Phase 3 trial will continue to examine additional metrics, including the effect of the combination therapy on overall survival rates. The companies plan to present the data at an upcoming international medical conference.

While it is not yet clear when they intend to submit applications for approval in the U.S., the preliminary data suggest that the combination therapy could become a new treatment option for melanoma — a type of cancer that accounts for only about 1% of skin cancer cases, but for the vast majority of deaths from them. Most recurrences of melanoma occur in the first two to three years after initial treatment and tumor removal.

"Melanoma patients are forced to deal with the new and difficult reality that a diagnosis brings, and then undergo unpleasant treatments like surgery, and after all that they are still afraid that the cancer will return," said Dr. Jane Healy, head of early development in oncology at Merck.

Healy described the results as "very exciting" and said the treatment led to a "clinically meaningful improvement" compared to Keytruda. According to her, patients responded well to it, and side effects were similar to those characteristic of other vaccines. These results reinforce the personalized treatment approach that Merck and Moderna have been developing for decades.