Trial Shows 42% Drop in Melanoma Death, Recurrence Risk

Researchers have been hunting for cancer treatments tailored to individual patients for years, and on Thursday, pharmaceutical partners Merck and Moderna released data on an experimental vaccine designed to do exactly that. The companies announced results from a late-stage trial of a personalized mRNA vaccine against melanoma, the deadliest form of skin cancer. The trial found that patients receiving the vaccine alongside standard treatment experienced a 42 percent reduction in the risk of death or recurrence of the disease compared with those receiving standard treatment alone.

The companies are already engaging with regulatory authorities to seek approval for the vaccine. The data is scheduled to be presented on Saturday at the European Society for Medical Oncology conference in Madrid, Spain. However, the top-line results were released early after an oncology news site reported them, breaking the embargo set for the presentation. The full data set has been accepted for publication in the New England Journal of Medicine.

The trial involved 1,137 patients with stage IIB through IV melanoma whose tumors had already been surgically removed. Participants were randomized in a two-to-one ratio. One group received the personalized mRNA vaccine combined with a standard treatment, while the other group received only the standard treatment. The standard treatment used in the study was Merck's monoclonal antibody cancer therapy, Keytruda.

The companies first reported in August that the vaccine had succeeded in the trial but withheld specific details until the data could be presented at the upcoming medical conference. The results now released show a 42 percent reduction in the risk of death or recurrence for patients receiving the vaccine compared to those receiving standard treatment alone.

Moderna CEO Stéphane Bancel said the trial results mark a defining moment for the company's vision of using mRNA technology to develop cancer treatments uniquely matched to each patient's tumor. He said the data shows what is possible when how medicines are made is rethought and added that the findings reinforce the company's conviction that mRNA has the potential to fundamentally change how cancer is treated.

The success of the vaccine in this trial bolsters broader hopes that mRNA vaccines and individualized cancer-targeting medicines could represent a new paradigm in cancer therapies. Melanoma is the deadliest form of skin cancer, and reducing the risk of death or recurrence by 42 percent represents a significant advance in its treatment.

The trial results are specific to melanoma patients whose tumors were surgically removed before enrollment. The study compared a combination of the personalized mRNA vaccine and standard treatment against standard treatment alone, with the standard treatment being Merck's established antibody therapy Keytruda. The full data set has been accepted for publication in the New England Journal of Medicine, though that publication has not yet occurred as of Thursday.

Regulatory authorities have not yet approved the vaccine, and no timeline for a decision has been announced. The companies are engaging with regulators to pursue approval, but questions about the vaccine's availability and pricing remain open. The full trial data is scheduled to be presented at the European Society for Medical Oncology conference in Madrid on Saturday.