Key Takeaway:
- Lower recurrence risk: A personalized mRNA vaccine combined with immunotherapy reduced melanoma recurrence or death risk by 42% over two years.
- Personalized treatment: The vaccine trains the immune system to recognize mutations specific to a patient’s tumor.
- Further research needed: The vaccine remains experimental, and researchers must confirm its long-term benefits and safety.
Moderna and Merck reported that an experimental mRNA personalized cancer vaccine reduced the risk of melanoma recurrence or death by 42% over two years when added to immunotherapy after surgery, according to trial results presented in Madrid.
Clinical Trial Shows Promising Results for Melanoma Patients
The Phase 3 INTerpath-001 trial involved 1,137 patients with high-risk melanoma whose tumors had been surgically removed. Researchers compared pembrolizumab, an immunotherapy drug sold as Keytruda, alone with the same treatment combined with an experimental vaccine tailored to each patient’s tumor.
After two years, 82% of patients who received the vaccine combination remained free of cancer recurrence, compared with 70% of those who received pembrolizumab alone, according to results announced by the drugmakers and presented at the European Society for Medical Oncology Congress.
The vaccine, called intismeran autogene, uses messenger RNA, or mRNA, technology to help the immune system recognize proteins associated with a patient’s specific tumor. Scientists analyze tumor tissue to identify mutations that produce abnormal proteins, then use that information to design a personalized vaccine.
The treatment aims to help immune cells recognize and attack cancer cells that may remain after surgery. Pembrolizumab works differently by blocking a protein pathway that can prevent immune cells from attacking tumors.
Dr. Hussein Tawbi, a melanoma specialist at MD Anderson Cancer Center who participated in the international trial, described the findings as a significant advance.
“The field has been looking for a win and I think this one is a big one,” Tawbi told The Associated Press.
Researchers Explore a New Approach to Cancer Treatment
The results strengthen interest in personalized cancer vaccines, which differ from preventive vaccines against infections such as human papillomavirus and hepatitis B. Those vaccines reduce the risk of certain cancers by preventing infections that can cause them, while intismeran is designed to reduce the chance of an existing cancer returning.
Professor Georgina Long, the trial’s global principal investigator and medical director of Melanoma Institute Australia, called the findings a major shift in cancer treatment.
“These findings are a foundational shift in our approach to cancer: harnessing the immune system in a more personalised way to reduce the risk of melanoma recurrence or death,” Long said in a statement from the University of Sydney.
Researchers are investigating personalized cancer vaccines for other cancers, including lung, pancreatic and kidney cancers. However, the approach may not work equally well across cancer types, and further trials will be needed to establish its effectiveness beyond melanoma.
Further Research Must Confirm Long-Term Benefits
Although the results are encouraging, the trial has not yet established whether the vaccine combination improves overall survival. Researchers are continuing to monitor participants to determine whether the benefits persist over a longer period.
The treatment also requires tumor analysis and individualized manufacturing, which could make production more complex and expensive than standard medicines. Moderna and Merck are discussing regulatory next steps, but the vaccine is not yet approved for routine clinical use.
Dr. Michael Postow, chief of the Melanoma Service at Memorial Sloan Kettering Cancer Center, said the approach works by strengthening the immune system’s ability to identify a patient’s own cancer cells. The research center said patients are continuing to undergo follow-up monitoring to assess longer-term outcomes.
Melanoma is a potentially aggressive form of skin cancer that can spread to other parts of the body. Surgery remains a key treatment for localized disease, while immunotherapy can help reduce the risk of recurrence in eligible patients.
The findings offer evidence that personalized vaccines could become an additional tool in cancer care, but researchers caution that patients should continue to follow established treatment recommendations while the experimental approach undergoes further evaluation.
