Personalised mRNA vaccine cuts melanoma recurrence risk

The European Society for Medical Oncology (ESMO) conference in Madrid on 23 October revealed the results of a phase‑3 trial called INTerpath 001, in which the personalised mRNA vaccine Intismeran was given together with the immunotherapy drug pembrolizumab (Keytruda). The study showed that patients whose cancer had been surgically removed and who received the vaccine had a 42 % lower risk of dying or having melanoma return over two years compared with those who received immunotherapy alone. The vaccine uses the same mRNA platform that underpinned COVID‑19 shots but is tailored to each patient’s tumour. The data were announced ahead of the conference and are being presented at ESMO for the first time.

The trial enrolled more than 1,100 high‑risk melanoma patients who had had surgery to remove their tumors. Each participant received nine doses of the custom‑made vaccine, given three weeks apart, alongside the standard post‑surgery treatment Keytruda. At the two‑year follow‑up, 82 % of patients who received the vaccine were alive without recurrence, compared with 70 % of those who received only Keytruda. The vaccine teaches the immune system to recognise unique proteins—neoantigens—created by mutations in each patient’s tumour.

Although the results are encouraging, the researchers say personalised cancer vaccines are still far from routine use. The process of analysing a tumour’s genetics, designing a patient‑specific mRNA sequence and producing the vaccine can take up to six weeks and is expensive and time‑consuming. Regulatory authorities will need to review the final trial data, which may take several years, before the vaccine could be approved for wider clinical use. The team also cautions that success in melanoma does not guarantee similar outcomes for other cancer types.

Experts in the field welcomed the findings as a milestone for oncology. Dr. Hussein Tawbi of MD Anderson praised the study as “a big one” and Parker Institute CEO Karen Knudsen called it a “new frontier.” Moderna has said that its manufacturing facility is producing doses for thousands of patients in multiple studies, and both Moderna and Merck are in talks with regulators about approval. The companies have not disclosed the cost of a personalised vaccine, though the manufacturing time and complexity are noted as major hurdles.