Personalized Melanoma Vaccine Reduces Risk of Recurrence, but Benefit in Other Cancers Is Not Yet Proven

A new personalized skin cancer vaccine, called Intismeran, has shown promising results in a large clinical trial. The trial included 1,137 adults with melanoma, a type of skin cancer, whose tumors had previously been removed through surgery. The vaccine was given together with Keytruda, a drug that already helps the immune system recognize and attack cancer cells.

According to the published results, the combination reduced the risk of melanoma recurrence or death by 42% compared with Keytruda alone. After two years, 82.2% of patients receiving the combination were alive and free of disease recurrence, compared with 70% of those receiving Keytruda alone. The risk of melanoma spreading to other parts of the body was also lower, by 38%.

It is important to interpret these figures correctly. A 42% reduction in risk does not mean that 42% of patients were cured, nor that the vaccine prevented every recurrence. The results apply to a specific group of patients and to a comparison with existing treatment.

The vaccine is made specifically for each patient, based on the genetic characteristics of their tumor. A similar approach is being investigated for kidney, bladder and lung cancers, but success in melanoma does not prove that it will work for other types of cancer.

There are also important limitations. The results have not yet been published in a peer-reviewed medical journal, and patients are still being monitored to determine how long the effect lasts and whether the treatment helps patients live longer. The manufacturers are discussing a possible approval with regulators, but the therapy has not yet been described as widely available.

The conclusion is that this is an important and promising advance in melanoma treatment, not a universal cancer vaccine. The results are worth following, but it is premature to conclude that the problem of cancer treatment has been solved.