Vaccine could prevent some people from developing ovarian cancer

A vaccine trial will test whether an mRNA jab can help stop precancerous cells developing into bowel and ovarian cancer in people with Lynch syndrome.

The first stage is due to launch this summer and will assess whether the jab can train the immune system to recognise and eliminate precancerous cells before cancer develops.

Around 175,000 people in England have Lynch syndrome, but only five per cent, or around 10,000 people, know they have it.

The inherited condition increases the risk of developing bowel cancer by 80 per cent and is linked to around 1,100 bowel cancer cases each year.

Lynch syndrome is also linked to a far higher risk of bowel, womb and ovarian cancer, alongside other types including stomach, pancreatic, kidney and skin cancer.

While the syndrome does not directly cause cancer, the genetic changes can lead to more abnormal cells developing, which then multiply and increase the risk of cancers such as bowel, prostate and endometrial cancer.

It is caused by an alteration in a mismatch repair gene. Carriers do not have any symptoms.

The new Intercept-Lynch trial is part of a scientific collaboration between the University of Oxford and Moderna, while Cancer Research UK has backed the vaccine’s development.

Once patients receive the new mRNA-4194 jab, experts will analyse their immune responses, assess the best dose and check whether the jab is safe.

The second phase of the study will include multiple centres across the UK, including Oxford, and is expected to begin in 2027.

The aim of the trial is to train the immune system with a vaccine to recognise abnormalities and stop them developing into cancer.

Professor David Church, Cancer Research UK senior cancer research fellow in the University of Oxford’s centre for human genetics and lead investigator of the trial, said: “People with Lynch syndrome are at risk of cancers over their entire lives.

“So, it’s very common, for instance, a woman to have a first cancer of her womb, and then some years later have a bowel cancer, or vice versa.

“The targets we’ve chosen for the vaccine were chosen based on their sharedness across multiple cancer types in Lynch syndrome, so we think they should provide broad protection, if the vaccine works.”

In people with Lynch syndrome, mutations can build up, making the cells containing them more likely to turn into cancerous cells.

However, those mutations can be made visible to the immune system and, with enough stimulation, the immune system can attack the abnormal cells and stop cancer from forming.

Professor Church said the mRNA jab acts as “an instruction manual” for the body to attack precancerous cells.

He added that, as with many vaccines, patients may need a booster jab at some stage.

On whether similar approaches could help prevent cancers not caused by Lynch syndrome, Professor Church said: “In terms of proof of principle that we can train the immune system to recognise these cancer-associated alterations and enhance the immune response against them to prevent these pre-cancers or prevent the progression of pre-cancer to cancer, that proof of principle should give us insights that are generalisable.”

David Berman, chief development officer at Moderna, said: “By applying mRNA technology earlier in the patient journey, we aim to harness the immune system when it can have the greatest impact.

“We are proud to bring this innovation to the UK, building on our long-standing collaboration with leading UK institutions to advance mRNA research and development.”