A vaccine that appears to slow the progression of one of the most deadly cancers could be manufactured in bulk, researchers say.
The jab has given hope to patients after a trial found it increased the survival of more than half of participants with pancreatic cancer.
Researchers described the findings as “remarkable” and have already started testing the efficiency of the jab among a larger group of pancreatic and bowel cancer patients.
The jab uses a new type of immunotherapy. It’s designed to improve vaccine delivery to the lymph nodes, which act as filters for foreign substances in the body including cancer cells and infections.
Pancreatic and bowel cancers frequently carry a mutation in a gene called KRAS, which plays a key role in tumour growth, and scientists developed the jab to recognise and attack KRAS-mutant cancer cells.
The study, which has been published in the journal Nature Medicine, tested the jab on 20 patients with pancreatic cancer and five patients with bowel cancer.
When participants were followed up after 20 months, 68 per cent had developed strong immune responses specific to mutant KRAS tumour proteins.
Participants who had the strongest immune responses lived longer and stayed cancer-free for longer than those with weaker responses.
Researchers found patients survived about two years and five months after receiving that vaccine.
In comparison, just three in 10 people diagnosed with pancreatic cancer survive for a year.
Pancreatic cancer has some of the poorest survival rates due to late detection. It doesn’t usually cause symptoms in the early stages, and as it grows, it can cause tummy pain, yellowing of the skin, unexplained weight loss and changes in stools.
Once they do receive a diagnosis, many patients see their cancer returning even after treatments such as radiotherapy and chemotherapy.
But the trial showed the jab could help prevent the cancer from returning for more than 15 months.
Unlike other cancer jabs which are personalised to individual patients, this vaccine, ELI-002 2P, has a single version which can be given to all patients.
This “off-the-shelf” version means that it can be manufactured in bulk and given more rapidly.
Dr Dani Edmunds, research information manager at Cancer Research UK, said: “Although we’ve helped to double cancer survival in the UK in the past 50 years, progress has not been the same for pancreatic cancer which remains hard to treat.
“Therefore, it’s promising to see that vaccines could help people with pancreatic and bowel cancer live cancer-free for longer.
“The results suggest that the vaccine can boost the immune system against cancer in some people following standard treatment.
“These people survived and stayed free from disease for longer than people who didn’t get as strong an immune boost following vaccination.
“Larger controlled trials are needed to confirm these initial findings about the benefits of the vaccine.
“More research is needed to understand why some people benefit from the vaccine while others don’t, so that we can make sure we’re beating cancer for everyone.”
However, Professor Richard Sullivan, director of the Centre for Conflict and Health Research at King’s College London, has suggested the study doesn’t prove the vaccine is ready for use.
“There is some interesting science in this study, but this is a long way from proving any sort of clinical utility,” he said.
“They mix colorectal cancers with pancreatic cancers – two widely different cancers with very different prognosis, even if the latter is surgically resected. The former has very good prognosis even with late stage disease whereas the latter is poor even if early-stage, and resected.”
