The world's first personalised mRNA cancer jab for melanoma - which also has the potential to stop lung, bladder and kidney cancer - is being tested in British patients.
The jab, which offers hope of a cure, is custom-built for each person in just a few weeks.
It works by telling the body to hunt down cancer cells and prevent the deadly disease from coming back.
A stage 2 trial of the jab, involving pharma firms Moderna and MSD, found it dramatically reduced the risk of the cancer returning in melanoma patients.
Now a final phase 3 trial has been launched, led by University College London Hospitals NHS Foundation Trust (UCLH).
Dr Heather Shaw, national co-ordinating investigator for the trial, said the jab had the potential to cure people with melanoma and was being tested in other cancers.
"This is one of the most exciting things we've seen in a really long time," she said .
"This is a really finely honed tool. These things are hugely technical and finely generated for the patient. The patients are really excited about them."
The new jab is an individualised neoantigen therapy (INT) and is sometimes referred to as a cancer vaccine.
It is designed to trigger the immune system so it can fight back against the patient's specific type of cancer and tumour.
Known as mRNA-4157 (V940), the jab is created to target 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 which is specific to the patient's tumour.
"This is very much an individualised therapy and it's far cleverer in some senses than a vaccine," Shaw said.
"It is absolutely custom built for the patient - you couldn't give this to the next patient in the line because you wouldn't expect it to work.
"They may have some shared new antigens, but they're likely to have their own very individual new antigens that are important to their tumour and so, therefore, it is truly personalised."
The ultimate aim was to cure patients of their cancer.
"Absolutely, that's the drive. With (this) therapy, what you're doing is dealing with the theoretical risk that the cancer could recur," Shaw said.
Phase 2 data, published in December, found people with serious high-risk melanomas who received the jab alongside MSD's immunotherapy Keytruda were almost half (49 per cent) as likely to die or have their cancer come back after three years than those who were given only Keytruda.
Patients received one milligram of the mRNA vaccine every three weeks for a maximum of nine doses, and 200 milligrams of Keytruda every three weeks (maximum 18 doses) for about a year.
The phase 3 global trial will now include a wider range of patients, and hopes to recruit about 1100 people.
The therapy combination is also being trialled in lung, bladder and kidney cancer.
"I think there is a real hope that these will be the gamechangers in immunotherapy," Shaw said.
Shaw said side effects included tiredness and a sore arm where the jab was given.
Australian Associated Press
