‘Bespoke’ mRNA vaccine significantly reduces risk of melanoma recurrence or death, clinical trial shows
A personalised mRNA vaccine significantly reduces the risk of melanoma recurrence or death within two years, new clinical trial results show.
The Australian-led trial included 1,137 patients whose melanoma had been surgically removed but were at high risk of it returning. All 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.
Patients in the trial, conducted across 157 sites worldwide, had not previously received any cancer drug treatment. Of those receiving the combination of intismeran and pembrolizumab, 82% were alive and recurrence-free after two years, compared with 70% of participants treated with pembrolizumab alone.
a foundational shift in our approach to cancer
Targeting unique mutations
The vaccine, intismeran, is custom-made to target genetic mutations unique to an individual’s melanoma. It is the first individualised cancer vaccine to show positive results in a phase III clinical trial.
Prof Georgina Long, medical director at the Melanoma Institute Australia and 2024 Australian of the Year, will present the findings at the European Society for Medical Oncology’s annual congress in Madrid on the weekend.
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.
Where previously oncologists could pick a targeted therapy based on a single gene mutation present in the melanoma, this bespoke mRNA vaccine targets up to 34 gene mutations, unique to each patient.
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.
Prof Christopher Sweeney, director of the South Australian immunoGENomics Cancer Institute at Adelaide University, described the vaccine as a step-change approach for how to improve the body’s immune system to see cancer cells as foreign and then augment the ability to prevent the cancer cells growing and recurring.
He said more research was needed to see if the approach was effective in patients who have cancer we can see, or who were not responsive to the immune enhancer pembrolizumab.
The drug manufacturers said it was too early to tell from the data whether the combination treatment improved long-term survival.
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.
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