Drugmakers Moderna and Merck have reported positive Phase 3 trial results for a personalized mRNA vaccine designed to help prevent the recurrence of melanoma, the deadliest form of skin cancer. The investigational vaccine, known as intisemran, when used in combination with Merck's immunotherapy drug Keytruda (pembrolizumab), showed a meaningful improvement compared to Keytruda alone.
Melanoma is a significant health concern in the United States, with an estimated 112,000 new cases expected to be diagnosed this year and over 8,500 deaths projected by 2026. For patients with later-stage melanoma (stage 2B to stage 4), the risk of recurrence can be substantial, with some facing an 85% chance of the cancer returning after initial treatment.
The new vaccine operates on principles similar to mRNA COVID-19 vaccines, providing the body with instructions to identify and combat disease. However, intisemran is personalized, meaning each vaccine is tailored to an individual patient's specific cancer. This approach aims to train the immune system to recognize and destroy cancer cells more effectively and precisely than treatments like chemotherapy, which can affect both healthy and cancerous cells.
In the Phase 3 trial, the combination of intisemran and Keytruda helped patients with advanced melanoma go longer without their cancer returning or spreading to other parts of the body. While the personalized vaccine teaches the immune system what to target, tumors can sometimes evade detection by the immune system. Keytruda works in tandem with the vaccine by helping to prevent cancer cells from hiding, thereby enabling the immune system's T-cells to effectively attack and kill them.
These findings represent a significant advancement in the development of cancer vaccines, a field experts believe holds substantial promise for long-term protection against cancer recurrence. The companies are also exploring intisemran in Phase 2 and 3 trials for other cancers, including lung, bladder, and kidney cancer. The ultimate goal, according to experts, is to use such vaccines to help eradicate advanced cancers, cure patients in adjuvant settings, and prevent malignancy in high-risk individuals.