A personalised mRNA vaccine made from each patient's own tumour has succeeded in a large late-stage clinical trial for the first time, cutting the risk of melanoma returning or causing death by 42%, trending per news coverage across the world on October 23, 2026. The result, reported by Reuters, CNN, the BBC and the University of Sydney within hours of each other, is being described by oncologists as a potential turning point in how cancer is treated.
The international phase 3 trial, called INTerpath-001, enrolled 1,137 patients whose melanoma had been surgically removed but who faced a very high risk of it returning. All participants received the immunotherapy drug pembrolizumab, widely known by its brand name Keytruda; about two-thirds also received an experimental personalised vaccine called intismeran (also known as V940 or mRNA-4157), while the rest received a placebo. After two years, 82.2 per cent of those who received the vaccine remained cancer-free, compared with 70 per cent of those on immunotherapy alone — a 42 per cent reduction in the risk of recurrence or death, and a 38 per cent reduction in the risk of the disease spreading.
Intismeran is an individualised neoantigen therapy: it is manufactured from the unique mutations of each patient's own tumour, training the immune system to recognise and destroy cancer cells that surgery alone might miss. It was developed jointly by Moderna and MSD (known as Merck in the United States), and tested alongside Merck's blockbuster immunotherapy Keytruda, one of the world's biggest-selling medicines.
"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," said Professor Georgina Long AO, Global Principal Investigator of the trial and Medical Director of Melanoma Institute Australia, who will present the full results at the ESMO (European Society for Medical Oncology) Congress in Madrid on Saturday. "This has not been achieved before in the history of cancer drug development."
The University of Sydney, where Professor Long chairs melanoma medical oncology and translational research, noted that Australia has one of the highest melanoma rates in the world, with one person diagnosed every 30 minutes — making the trial's success particularly significant for the country.
The data arrive one day after Moderna shares plunged more than 20 per cent when partial trial results leaked on an oncology website, wiping billions from the company's market value even as the trial itself was succeeding. The companies released the full headline data on Thursday after the leak, and said they are now "engaging with regulatory authorities" — language that implies a filing with the US Food and Drug Administration may come imminently. The results are scheduled for formal presentation in Madrid on Saturday and are expected to be published in full in the New England Journal of Medicine.
Crucially, the companies are already testing the same personalised-mRNA approach in other cancers, including lung and pancreatic cancers. Dr Michael Postow, chief of the melanoma service at Memorial Sloan Kettering Cancer Center, told CNN the vaccine showed efficacy "we've never really seen before in terms of the way that it works." If the technology proves itself beyond melanoma, the INTerpath-001 result could be the proof of concept for an entirely new class of cancer treatment: off-the-shelf immunotherapy, customised to each patient.
It is worth keeping expectations grounded: the vaccine is not available to patients yet, and regulatory review can take years. Treatment cost is also an open question — personalised therapies are expensive to manufacture, though pricing moves in markets like India's recent cap on cancer-drug trade margins show governments are watching affordability closely. Patients should speak with their own oncologist rather than waiting for the vaccine.
Still, for a disease that was until recently among the most feared in oncology, the numbers mark a genuine milestone: a world-first mRNA cancer treatment and the first individualised neoantigen therapy proven in a trial of this scale — and the strongest evidence yet that medicine's future may be built around each patient's own biology.
Sources: Reuters (October 22, 2026); CNN (October 22, 2026); BBC News (October 23, 2026); University of Sydney (October 23, 2026); Melanoma Institute Australia (October 23, 2026).