A new personalised cancer vaccine given alongside a widely used immunotherapy drug has cut the risk of patients dying or their skin cancer returning by 42% in a major clinical trial. The results, published by researchers and drugmakers MSD and Moderna, represent a significant shift toward tailored treatments for melanoma.
The trial involved 1,137 adults who had already undergone surgery to remove their tumours. Participants received Keytruda, an established immunotherapy drug that helps the body’s immune system identify and attack cancer cells. About two-thirds of these patients also received an experimental vaccine called Intismeran, while the remainder were given a placebo.
Intismeran uses the same messenger RNA technology found in some Covid-19 vaccines. Unlike standard treatments, this vaccine is personalised to each patient. Scientists use genetic information from the patient’s own tumour to train their immune system to recognise specific cancer cells, preparing the body to target any remaining cells if the disease returns.
Distinct outcomes for recurrence and spread
It is important to distinguish between the different metrics reported in the study. The 42% reduction in risk applies specifically to the combined outcome of death or the cancer returning. A separate figure of 38% reflects the reduced risk of melanoma spreading across the body over a two-year period.
Independent experts described the findings as impressive but cautioned that longer-term studies are necessary. While the initial data is promising, researchers need more time to determine if the treatment ultimately helps most patients live longer on average. Professor Alan Melcher from the Institute of Cancer Research in London, who was not involved in the research, called the results a strong proof of principle but warned against assuming the approach will work for all cancer types.
Real-world impact on patients
The trial included patients like Tony Chapman, a 75-year-old from Corby in the East Midlands. Chapman was diagnosed with melanoma in 2019. After having a tumour removed from his chest, a lump appeared under his arm, indicating a return of the disease. He underwent a second operation and then volunteered for the study.
Like all participants, Chapman does not know whether he received the experimental vaccine or the placebo. Three years after his initial diagnosis and treatment, he remains cancer-free and undergoes checks every six months. He described his participation as a way to move science forward while potentially benefiting himself.
Prof Pippa Corrie, a consultant medical oncologist at Addenbrooke’s Hospital in Cambridge who helped run part of the study, highlighted the significance of the technology. She noted that personalisation is the next step in cancer care and called the trial the first proof of principle for this approach.
Regulatory steps and market reaction
Shares in MSD and Moderna surged after the companies first hinted at the vaccine’s success earlier this year. However, stock prices dipped on Thursday after financial analysts noted that the results were not as strong as those seen in an earlier, smaller trial. Both companies stated they are now engaging with regulatory authorities and could file for approval as soon as next year.
Widespread adoption on the NHS will depend heavily on cost. Each patient requires their tumour to be genetically analysed and a unique vaccine manufactured, a process that is resource-intensive. The drugmakers also confirmed that the same personalised approach is already being tested against other tumours, including kidney, bladder, and lung cancers.
The trial will continue to monitor patients to see if the cancer returns over time and to assess the drug’s effect on overall survival. For now, the data provides a concrete foundation for the future of personalised oncology.
Source: BBC
