New clinical trial results show that a personalised mRNA-based melanoma vaccine significantly reduces the risk of cancer recurrence or death within two years. The vaccine, called intismeran, is custom-made to target genetic mutations unique to an individual's melanoma and is the first individualised cancer vaccine to show positive results in a phase III clinical trial.
Trial Details and Findings
The Australian-led trial included 1,137 patients whose melanoma had been surgically removed but who were at high risk of it returning. All participants were treated with an immunotherapy drug called pembrolizumab for twelve months, and some were also given the personalised intismeran vaccine.
The trial found that at two years post treatment, the combination of intismeran and pembrolizumab reduced the risk of melanoma recurrence or death by 42% compared with treatment with pembrolizumab alone. Of those receiving the combination, 82% were alive and recurrence-free after two years, compared with 70% of participants treated with pembrolizumab alone.
Expert Reactions
Prof Georgina Long, medical director at the Melanoma Institute Australia and 2024 Australian of the Year, described the findings as "a foundational shift in our approach to cancer", allowing scientists to "harness … the immune system in a more personalised way to reduce the risk of melanoma recurrence or death. This has not been achieved before in the history of cancer drug development."
Dr Jessamy Tiffen, acting deputy director of the Centre for Cancer Innovations at the Centenary Institute, who was not involved in the research, said what was "truly remarkable" about the vaccine was the "deeply personalised nature of the treatment, something cancer researchers have been striving to achieve for decades". She noted that the vaccine targets up to 34 gene mutations unique to each patient, training the immune system to recognise and eliminate the melanoma and stop it from coming back.
Next Steps and Limitations
The results have been accepted for publication in the New England Journal of Medicine and will need to go through a process of peer review. Long will present the results at the European Society for Medical Oncology's annual congress in Madrid on the weekend.
The personalised vaccine will not be available as a standard melanoma treatment until it has gone through further study and regulatory review, a process that may take several years. The drug manufacturers said it was too early to tell from the data whether the combination treatment improved long-term survival.
