Moderna, Merck say mRNA cancer vaccine cut melanoma recurrence in trial

The latest:

An experimental personalized mRNA vaccine helped people with high-risk melanoma live longer without their cancer returning, Moderna and Merck said Wednesday. The companies released only the broad outline of results from a 1,137-patient late-stage trial, saying patients who got the vaccine alongside the immunotherapy drug Keytruda were less likely to see their cancer recur or spread than those given Keytruda alone.

Details:

• The trial: According to the companies, the study enrolled 1,137 people with high-risk melanoma who had already undergone surgery to remove their tumors. One group received the vaccine, called intismeran, combined with Keytruda; the comparison group received Keytruda alone. Moderna and Merck reported a lower likelihood of recurrence or spread in the vaccine arm.
• What was withheld: The two companies disclosed only the headline outcome and did not release the underlying figures. They said the detailed data will be presented at an international medical meeting and submitted to regulators. No date was announced for either the presentation or a regulatory filing.
• How it works: Scientists sequence each patient’s tumor and select neoantigens, molecular markers that teach the immune system how to attack that specific cancer. Those targets are then built into an individual mRNA vaccine, a manufacturing process the companies said takes roughly six weeks per patient.
• Outside reaction: Dr. Elias Sayour, a pediatric oncologist at the University of Florida who was not involved in the trial, called the result a big deal and said it could help usher in a new wave of cancer treatments. He added that he saw substantial room to improve on the approach.
• The field’s origin: Dr. Catherine Wu, a professor at Harvard Medical School and the Dana-Farber Cancer Institute, said in an email it was gratifying to see the results come full circle from early proof-of-concept work. Her lab demonstrated the promise of customized neoantigen vaccines in 2017.
• The next hurdle: Wu said the studies that launched the field were small, under 20 patients each. The next challenge, she said, is extending the method to cancers that may prove harder to treat than melanoma.
• The disease: Melanoma is a deadly form of skin cancer with an estimated 112,000 new cases each year in the United States, according to the report. The trial population was restricted to patients classified as high-risk after surgical removal of their tumors.
• Wider pipeline: The Moderna and Merck study is the most advanced of several trials testing individualized cancer vaccines, with others targeting lung, bladder, kidney and pancreatic cancer. Researchers treated this trial as a bellwether for whether the technology can work at scale.
• The mRNA link: The same mRNA platform behind the rapid Covid-19 vaccine development supplied the speed and flexibility that made bespoke cancer vaccines feasible, allowing each shot to be matched to the genetics of an individual patient’s tumor.

Background:

Therapeutic cancer vaccines have been pursued for decades on the premise that a patient’s own immune system can be trained to attack tumors. Until now the approach had been tested mainly in small studies, without a large late-stage trial to show whether it holds up.

Between the lines:

The significance rests on scale as much as biology. Earlier neoantigen studies involved fewer than 20 patients; this one involved 1,137, which is why researchers describe it as a bellwether. But with only the broad outline released and no figures published, the size of the benefit remains unknown until the companies present the data and file with regulators.

What’s next

Watch for the full data presentation at an international medical meeting and the companies’ submissions to regulators. Also watch the parallel trials applying the same platform to lung, bladder, kidney and pancreatic cancer.