Adding a personalised mRNA vaccine to standard immunotherapy after surgery significantly reduced the risk of melanoma returning or causing death, according to results from the first Phase III trial of its kind.
The INTerpath-001 trial, presented at the ESMO Congress 2026, included 1,137 patients with high-risk melanoma (stage IIB to IV) who had undergone surgical removal but had not received prior drug treatment. Researchers compared treatment with intismeran, a personalised therapeutic cancer vaccine, combined with pembrolizumab immunotherapy against pembrolizumab alone.
The combination reduced the risk of recurrence or death by 42% compared with pembrolizumab alone. For patients who remained recurrence-free beyond six months from starting treatment, the reduction was even greater at 58%.
Unlike traditional vaccines that prevent disease, intismeran is a therapeutic vaccine designed for patients at high risk of cancer returning after surgery. The treatment uses mRNA technology to create a personalised “wanted poster” of each patient’s cancer based on their tumour’s unique neoantigen fingerprint.
The vaccine helps the immune system identify the individual patient’s tumour cells, whilst pembrolizumab releases the brakes that tumours place on immune cells. Treatment was well tolerated, with the vaccine causing only transient low-grade side effects such as injection-site pain, headache and chills in some patients.
Professor Georgina Long, global principal investigator and medical director at Melanoma Institute Australia, described the findings as a foundational shift in cancer treatment, demonstrating that therapy built from a patient’s own tumour signature can work alongside checkpoint inhibitor immunotherapy.
The results now enter regulatory review, which may take several years depending on the country. Until approval, the treatment remains unavailable outside clinical trials.
Source: Long G et al. INTerpath-001 Phase III trial results. Presented at ESMO Congress 2026.
