The world's first personalised mRNA cancer jab for melanoma has cut the risk of patients dying or cancer returning by 42% when combined with immunotherapy, a large trial shows.
The drug, which was given to patients in the UK and worldwide, is also being tested in other cancers, including kidney, bladder and lung cancer.
Combination therapy results
The personalised Moderna vaccine, known as intismeran, was paired with MSD's immunotherapy Keytruda. It cut the risk of recurrence or death in melanoma patients by 42% two years later, compared with Keytruda alone.
The data also showed that the dual therapy cut the risk of cancer spreading or death by 38%. About 82% of patients on the combination were still alive without melanoma returning two years later, compared with 70% of those who received Keytruda alone, the firms said.
The study included more than 1,100 people with high-risk melanoma that had been surgically removed.
How the vaccine works
Experts have described the vaccine as a "gamechanger" because it is custom-built for each person in just a few weeks. It works by triggering the immune system so it can fight back against the patient's specific type of cancer and tumour.
The vaccine targets tumour neoantigens, which are expressed by tumours in a particular patient. These are markers on the tumour which can potentially be recognised by the immune system. The jab carries coding for up to 34 neoantigens and activates an anti-tumour immune response based on the unique mutations in a patient's cancer.
In order to create the jab, a sample of tumour is removed during the patient's surgery, followed by DNA sequencing and the use of artificial intelligence. The result is a personalised anti-cancer jab.
Expert reaction
Susanna Daniels, chief executive of Melanoma Focus in the UK, said: "These positive trial results represent a really exciting milestone in melanoma skin cancer treatment.
"With melanoma accounting for over 20,000 new diagnoses and 2,600 deaths in the UK each year, innovations that help prevent recurrence and stop the cancer spreading offer vital new hope for melanoma patients."
Alan Melcher, professor of translational immunotherapy at the Institute of Cancer Research (ICR), London, said: "These are very impressive results.
"Cancer vaccines have been researched for many years, but advances in genetic sequencing, immunotherapies and mRNA technology, including experience gained from Covid vaccines, have transformed what is possible.
"What is particularly exciting here is that this vaccine is personalised, using information from each patient's own tumour to identify targets that are specific to their cancer.
"It essentially trains the immune system to recognise those cancer cells as a threat and attack them, while pembrolizumab helps release the brakes on the immune response.
"This is a large phase III trial, so it provides much stronger evidence than we have previously had that a personalised cancer vaccine can make a meaningful difference to patients."
He said vaccines are being investigated in many other cancers, including cancers that are very difficult to treat and do not respond to immunotherapy.
"The challenge now is working out which cancers and which patients are most likely to benefit, and which are the best vaccine targets to go for," he said.
"We're closer to cancer vaccines becoming part of routine treatment than we've ever been, but they are not going to replace existing treatments across the board.
"The more realistic prospect is that they become another powerful tool that we can combine with treatments such as immunotherapy."
Dr Lennard Lee, associate professor of AI and cancer vaccine research at the University of Oxford, said: "This is the Rolls-Royce of clinical trials.
"It is a large, randomised, double-blind, well-controlled study, representing the highest standard of clinical evidence. The results are compelling … This is a major breakthrough for cancer vaccine research."
