Moderna and Merck announced that their experimental personalised skin cancer vaccine Intismeran successfully stopped melanoma from returning in a landmark final stage trial.
The Phase III trial involved more than 1,000 patients with high-risk melanoma who had already undergone surgery. Results showed that combining the jab with the existing immunotherapy drug Keytruda significantly extended the time patients remained cancer-free compared to receiving Keytruda alone.
The treatment also reduced the risk of melanoma spreading to other areas of the body. Following the announcement, shares in Moderna soared by more than 150 per cent in New York yesterday.
Personalised mRNA Technology
The experimental vaccine uses messenger RNA, or mRNA, which is the same genetic platform behind the Pfizer and Moderna Covid-19 vaccines. Messenger RNA acts as a cellular template, directing body cells to build specific proteins that prompt an immune response.
Unlike conventional vaccines designed to prevent infections, Intismeran is custom made for each individual patient. Doctors remove tumour samples from a patient to identify specific genetic mutations inside the cancer cells, which are then encoded into mRNA strands.
Once injected into the patient, the engineered mRNA teaches the immune system to recognize and attack any remaining cancer cells. Keytruda, manufactured by Merck and already prescribed by the NHS for a dozen types of cancer, works alongside the vaccine to enhance the body's immune reaction.
Stéphane Bancel, the chief executive of Moderna, called the latest trial findings "a pivotal moment for the field of cancer research."
"For many years, the idea of creating an mRNA treatment designed specifically for an individual patient’s cancer was aspirational," Bancel said. "We are now helping turn that vision into a reality."
Melanoma Statistics and Phase Two Results
Melanoma is the deadliest form of skin cancer, killing more than 2,000 people in the UK each year. More than 20,000 people in the country receive a melanoma diagnosis annually, with case numbers expected to rise by more than 25 per cent by 2040.
Patients diagnosed at stage 4, when the cancer has already metastasised throughout the body, face severe outcomes, with half dying within a year. The disease becomes significantly harder to treat once it spreads beyond the primary site.
Earlier results from a smaller Phase II trial published earlier this year showed that combining Intismeran with standard immunotherapy slashed the risk of cancer recurrence or death by 49 per cent. Trial data also identified several side effects from the vaccine, including fatigue, injection site pain and chills.
Clinical Reactions and Future Outlook
Dr Lennard Lee, an associate professor at the University of Oxford and senior national clinical adviser on cancer vaccines, yesterday described the findings as "significant."
"This is the first positive Phase III trial of an individualised neoantigen therapy and an mRNA-based cancer treatment," Dr Lee said. "That makes this an important moment for a field that scientists have been working towards for many years. Within 6 years of the pandemic, we have mRNA vaccines to treat cancer."
Dr Lee noted that full data from the trial has not yet been released. "We should now look forward to seeing the complete data. We do not yet have the magnitude of the Phase III benefit, the detailed subgroup analyses, quality-of-life data or mature overall-survival results," he said. "Those details will allow the scientific and clinical community to understand precisely how large the benefit is, which patients benefit most, and ultimately where this treatment might sit within routine melanoma care."
A detailed breakdown of the Phase III results is scheduled for release later this year. Beside melanoma, Moderna and Merck are testing similar individualised vaccines for bladder cancer, kidney cancer, and non-small cell lung cancer.
Moderna stated that if regulatory authorities approve the treatment, it hopes Intismeran could reach patients as early as next year. However, questions remain regarding the extent of the clinical benefit, potential side effects, and the overall cost and manufacturing complexity of producing custom doses at scale.
