20 August 2026
A personalized mRNA vaccine for melanoma reduced the risk of the cancer returning in a phase III clinical trial, the companies behind the trial announced this week. The vaccine – which relies on the same mRNA technology used to develop COVID-19 shots – is the first mRNA-based cancer treatment to show success in a late-stage trial.
How does the vaccine work?
The vaccine, called intismeran, doesn’t prevent a person from developing cancer in the first place, rather it seeks to prevent it from recurring.
The study enrolled around 1,100 people with advanced melanoma that had been completely surgically removed. They received either the vaccine combined with an immunotherapy drug used to treat the cancer called pembrolizumab, or they received pembrolizumab alone.
The companies said that people on the combined treatment survived for longer without recurrence than did those who received only pembrolizumab.
To create intismeran, a sample of a patient’s tumour is sequenced to identify mutations that have developed in their cancer cells. An mRNA vaccine is developed according to each person’s cancer neoantigens, and once injected, it instructs the body to make the neoantigens — priming the body to recognize the threat.
What are the challenges of making these types of vaccine?
Although the latest trial results show that intismeran reduced the risk of recurrence, participants will need to be followed for many years to determine whether the treatment extends their lifespan.
The personalized nature of the vaccines is the biggest challenge for widespread use. After collecting a sample of a person’s cancer, each vaccine can take several months to make.
What other cancer vaccines are being tested?
Several other groups are working on personalized cancer vaccines. Merck and Moderna are trialling the same personalized vaccine approach in a phase I trial for pancreatic, gastric and lung cancers.
BioNTech is also trialling personalized vaccines for colorectal, pancreatic and triple-negative breast cancers. Shenzhen Xinhe Biomedical in Shenzhen, China, is trialling a personalized vaccine for gastric and liver cancers.
