mRNA cancer drug cuts melanoma recurrence in trial

Merck and Moderna said their experimental personalised mRNA cancer treatment reduced melanoma recurrence in a large late-stage trial when used with pembrolizumab, the current standard-of-care drug.

The drug, called intismeran autogene, is based on the same messenger RNA technology used in Covid-19 vaccines. The companies said it was the first time an mRNA-based cancer treatment had shown positive results in a large Phase 3 trial.

The trial lasted about a year and involved 1,137 patients after surgical removal of their cancers. Two-thirds received intismeran autogene plus pembrolizumab, while the rest received pembrolizumab alone.

The companies said they would present the data at an upcoming international conference and begin regulatory filings for approval.

The announcement sent Moderna shares up 145 percent to $154, while Merck's stock rose more than 12 percent to $152.

Moderna CEO Stephane Bancel called the result an “extraordinary milestone” for Moderna, mRNA science and cancer patients. He said Merck and Moderna are studying intismeran with pembrolizumab and other anti-cancer therapies, and as a monotherapy, across several tumor types and disease stages, including melanoma, lung, bladder and kidney cancers.

Lennard Lee, an oncologist and assistant professor at the University of Oxford who was not involved in the trial, called the results “very encouraging” and said complete data should now be reviewed.

Marco Gerlinger, a professor at London's Barts Cancer Institute, said the results were good news for patients with melanoma and proof of principle that personalised cancer vaccines work. He said it was fair to call the result a breakthrough in developing new cancer immunotherapies, while noting that the companies' press release was short on details.

The treatment is designed for an individual patient. It uses a sample of the patient's tumor to identify a unique mutational “fingerprint”, then uses mRNA technology to help the immune system target it.

Melanoma is among the deadliest forms of skin cancer, with more than 330,000 new cases diagnosed worldwide in 2022.