A personalised mRNA vaccine gives hope for treating pancreatic cancer

An mRNA vaccine for pancreatic cancer patients has shown promising results in a small study conducted by New York researchers and Germany’s BioNTech, staving off the return of the tumour in half of those treated.

Pancreatic cancer is one of the deadliest forms of cancer around, estimated to kill 88 per cent of patients. It’s also one of the most virulent cancers: the disease is known to quickly return even after a patient has successfully removed it. About 90 per cent of patients experience a relapse within seven to nine months after surgery.

But a targeted mRNA vaccine could offer some hope. This week, a group of scientists at Memorial Sloan Kettering (MSK) Cancer Center in New York published in the journal Nature the results of a small study they conducted on pancreatic cancer patients over several years.

The study used a pancreatic cancer mRNA vaccine tailored to each patient’s tumour to potentially help provoke an immune response.

What’s revolutionary about the vaccines tested by the scientists in Germany is that they tailored them to the mutated proteins found on the surface of cancer cells – rather than a mix of tumour and normal cells, as it’s been tried for decades.

The cells were extracted from patients’ tumours by researchers at Memorial Sloan Kettering (MSK) Cancer Center in New York and sent to BioNTech – the German company that created the highly effective COVID-19 vaccine with Pfizer.

The scientists then personalised the vaccine to the immune system of each of the 16 patients involved in the study, which began in December 2019. All patients were white. The patients were given the vaccine together with chemotherapy and a drug which is targeted at keeping tumours from evading a patient’s immune system’s response.

Half of the patients who were administered the vaccine responded: their immune systems learned how to recognise and fight off the cancer cells, and for the 18 months they were tracked they showed no signs of relapse.

Exciting results

“These exciting results indicate we may be able to use vaccines as a therapy against pancreatic cancer,” MSK doctor and cancer specialist Vinod P. Balachandran, who led the research, said in a statement. “The evidence supports our strategy to tailor each vaccine to each patient’s tumour”.

For the eight other patients who did not appear to respond to the vaccine, the pancreatic cancer returned after about 13 months after they had removal surgery. Only two did not see their cancer return.

Unfortunately, the scientists could not completely rule out that other factors, besides the vaccine, might have contributed to a patient producing an immune response. But researchers suspect that the vaccine was more successful in patients who had their spleen still intact: out of seven participants in the study who had their spleen removed, five did not respond to the vaccine.

While promising, personalised mRNA cancer vaccines are still in their infancy. This type of vaccine is still too costly to be broadly used, and by definition cannot be manufactured in large batches.

But the results of the recent study suggest that researchers are on the right track to treat pancreatic cancers and potentially other types of aggressive tumours. Going forward, MSK researchers are planning to start a larger, randomised clinical trial at multiple sites in various countries. Patients will be enrolled starting this summer.

“It’s exciting to see that a personalised vaccine could enlist the immune system to fight pancreatic cancer – which urgently needs better treatments,” Balachandran said.

“It’s also motivating as we may be able to use such personalised vaccines to treat other deadly cancers”.