The melanoma removed at surgery supplies the instructions for a treatment designed to attack what surgery may have left behind. Researchers analyse the tumour’s genetic changes, then build an mRNA vaccine encoding abnormal proteins specific to that patient’s cancer. [2]

The removed tumour becomes a guide to recognising its remnants. [3]

In INTerpath-001, a randomised, double-blind phase III trial involving 1,137 adults with completely resected stage IIB to IV cutaneous melanoma, adding intismeran autogene to pembrolizumab improved recurrence-free survival. Results presented at ESMO on 24 October put the two-year rate at 82.2%, compared with 70.0% for pembrolizumab alone. [1] [2] [3]

That is a 12.2 percentage-point improvement in the estimated proportion alive without recurrence at two years. The two-year recurrence-free survival estimate starts at randomisation and counts patients who are alive without a recurrence. [1]

The treatment begins with abnormal proteins called neoantigens, which provide distinctive targets for immune recognition. Researchers compare information from the patient’s tumour and normal DNA, then select targets associated with that cancer’s mutations. [2] [1]

Intismeran carries mRNA instructions for making those targets. The body’s cells translate the instructions into proteins and present them to the immune system, helping generate T cells that recognise cancer carrying the same targets. [1]

Pembrolizumab works on another part of the process. It blocks PD-1, a receptor involved in restraining immune activity, allowing T cells to attack more readily. The vaccine supplies selected targets; the antibody releases an immune brake. [1]

The developers’ headline figure, a 42% reduction, describes the relative hazard of recurrence or death during follow-up. It does not mean a 42 percentage-point improvement. The two-year rates make the absolute benefit easier to grasp. [1]

The trial’s median follow-up was 24.6 months. ESMO describes overall-survival data as immature, with longer follow-up needed. The evidence establishes improved recurrence-free survival; a longer life or a cure has yet to be established. [1] [2]

Treatment also carries a burden. ESMO reported grade 3 or higher adverse events in 23.6% of patients receiving the combination, compared with 20.3% receiving pembrolizumab alone. Fever and injection-site pain were more common with intismeran. These broader adverse-event figures should be distinguished from the developers’ narrower figures for events attributed to treatment. [2] [1]

Merck Sharp & Dohme and Moderna funded the trial. Global principal investigator Georgina Long, of Melanoma Institute Australia and the University of Sydney, led research spanning 157 sites, including Australian centres. The developers say the results were accepted by the New England Journal of Medicine. The evidence supplied here comes from company, conference and university announcements. [3] [1] [2]

The result applies to treatment after surgery for high-risk melanoma. It supplies no evidence that intismeran prevents melanoma in healthy people or works against other cancers. [2]

For patients asking whether they can receive it, intismeran remains investigational. Availability will depend on regulatory approval in each country. [1] [3]