Skin cancer recurrence risk reduced by personalised mRNA vaccine in major trial

A custom-built cancer vaccine given together with immunotherapy has significantly decreased the chances of melanoma recurring or proving fatal, according to findings from a large clinical study.

Researchers evaluated the treatment regimen in 1,137 adult patients who had previously undergone surgery to take out their tumours. Across a two-year observation period, combining the experimental jab with the established immunotherapy medicine Keytruda cut the likelihood of death or cancer return by 42 percent compared with immunotherapy alone. The therapy also curbed the risk of the disease spreading to other parts of the body by 38 percent.

The trial tested an mRNA-based vaccine named Intismeran, developed jointly by pharmaceutical companies MSD and Moderna. Using genetic details derived from an individual's own resected tumour, the injection instructs the immune system to identify and attack any remaining or resurfacing cancer cells. About two-thirds of the trial participants received the tailored vaccine in addition to Keytruda, while the remaining third were administered a dummy shot alongside the standard drug.

Scientists involved in the study believe the data represents a milestone for individualised oncology. Professor Pippa Corrie, a consultant medical oncologist at Addenbrooke's Hospital in Cambridge who assisted with the trial, highlighted the significance of the findings, noting that the research served as an essential initial proof of principle for personalised treatments.

Trial participant Tony Chapman, 75, from Corby, enrolled in the study after his melanoma returned following initial surgery and spread to his lymph nodes. Chapman, who remains unaware of whether he received the active vaccine or a placebo, reported that he continues to be cancer-free three years later and undergoes health checks twice a year.

Independent specialists have welcomed the developments with measured optimism. Professor Alan Melcher of the Institute of Cancer Research in London termed the findings very impressive, but cautioned that success in skin cancer does not guarantee equal effectiveness against other malignancies. He also stressed that extended monitoring will be necessary to determine whether the combination truly enhances overall survival times.

MSD and Moderna have indicated that the platform is currently undergoing evaluations for other conditions, such as lung, bladder, and kidney tumours. Both firms confirmed they are in discussions with regulatory bodies, pointing toward potential licensing submissions as early as next year.

Full findings are scheduled for presentation at the European Society of Medical Oncology meeting in Madrid, though the study has not yet undergone formal peer review in a medical journal. Future availability within public healthcare systems, including the NHS, will also rely on cost assessments, as the production process requires individualised genetic profiling and bespoke manufacturing for every patient.