Experts urge caution as results remain interim and not yet peer-reviewed
Merck and Moderna reported this week that their personalized mRNA vaccine, given alongside the immunotherapy drug Keytruda, extended the time high-risk melanoma patients remained cancer-free after surgery in a phase 3 clinical trial — a result Moderna chief executive Stephane Bancel called a “pivotal moment” in cancer research.
The two drugmakers said the combination significantly increased the time patients remained cancer-free and reduced the risk that the disease would spread to other organs, compared with taking Keytruda alone. They cautioned that the results were interim and had not yet been peer-reviewed, meaning independent experts have not yet examined the underlying trial data. More detailed findings are scheduled to be presented at a medical conference in October.
The phase 3 trial enrolled more than 1,000 patients with high-risk stage 2, 3, or 4 melanoma — a range that spans large tumors confined to a single area to cancers that had already metastasized to other parts of the body. All participants had surgery before receiving the experimental treatment.
To produce the vaccine, called Intismeran, scientists surgically removed a small portion of each patient’s tumor and sequenced its DNA, identifying the specific mutations in that patient’s cancer cells. Using mRNA technology — the same platform that produced some Covid-19 vaccines — they then built a personalized injection designed to instruct the patient’s immune system to recognize and attack any remaining tumor cells carrying those same mutations.
Prof Peter Johnson, National Clinical Director for Cancer at NHS England, told the BBC’s Today Programme that the treatment “feels like it’s a very important advance for us.” He added: “Most of the cancer immune treatments we have been using up til now have been about cutting the immune system loose and hoping that it recognises the cancer. This [new treatment] is a way to direct it very specifically.” Johnson said the NHS was preparing to bring this type of treatment to patients.
Dr Talisia Quallo, head of prevention and early detection at Cancer Research UK, said the research “shows promise” but noted that the interim data still needs to be fully reviewed. “It’s vital that research like this continues to be funded so that more people with cancer can have personalised treatment options to help them live longer, better lives,” she added.
Dr Lennard Lee, a consultant medical oncologist and associate professor at the University of Oxford, said: “This is certainly good news for patients with melanoma, but the study has much wider implications. It provides proof of principle that personalised cancer vaccines work.”
The two companies are also testing similar personalized vaccines against lung, bladder and kidney cancers.
Even if the trial concludes successfully, the treatment would still need approval from regulators, followed by a separate process before it could be made available on the NHS. Shares in both Moderna and Merck surged following the announcement.