By RYAN MORRISON FOR MAILONLINE

• Researchers take a biopsy of a cancerous tumour to look for certain proteins
• Each patient has a ‘different cancer’ and the treatment is specifically targeted
• It is given alongside chemotherapy drugs to boost the body’s immune response
• So far only eight per cent of patients saw their tumour reduce but this was a very early clinical trial of purely advanced cancer patients, researchers said

A personalised cancer vaccine designed to boost the body’s own natural defences when used alongside chemotherapy shows ‘promising signs’ after a clinical trial.

The treatment is created by taking a biopsy of a tumour and then using artificial intelligence to identify certain proteins not recognised by the immune system.

They use these proteins to create tailor-made vaccines for each individual cancer patients and then administer them alongside immunotherapy drug atezolizumab.

So far researchers have only tested it on patients with advanced cancers and just 8 per cent saw their tumours shrink – with 49 per cent seeing no change.

An international team of researchers found the treatment, known as RO7198457, was ‘well tolerated’ by patients and the they experienced ‘low-to-moderate’ side effects.

This is early days in the development of the treatment as the clinical trials were only designed to test its safety, further testing is needed to see how effective it is.

Researchers found the treatment showed some clinical benefit in patients with a range of advanced cancer types and they believe it could be even more beneficial for people with earlier-stage disease who have undergone less treatment.

The team are looking to expand their investigation to understand more about the potential benefits of personalised vaccines for patients with earlier-stage cancers.

An international team of scientists, led by clinicians in the UK Institute of Cancer Research, investigated the effects of personalised vaccines in 144 patients.

They all had different types of advanced cancers, including lung, breast and bowel.

Patients on the trial received a vaccine which is unique to their tumour based on the genetic information found in tumour biopsies and blood samples.

Dr Juanita Lopez, a consultant medical oncologist at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, led the trial.

‘Many cancers are able to successfully avoid the immune system, and we are only starting to understand the myriad ways in which cancers can do this,’ she said.

To develop the vaccine, the scientists first took a biopsy of a patients tumour and used artificial intelligence to identify a group of proteins known as neoantigens.

As tumours grow, they produce neoantigens, which should help the immune system recognise the tumour as ‘foreign’ and attack it – except cancers have also developed ways to hide from the immune system.

The vaccine helps unmask cancer to the immune system by activating immune cells called T-cells, and encouraging the immune system to produce more of them.

Using this information, they were able to design a type of cancer vaccine known as messenger RNA vaccine, which can be tailored to target the ‘unique differences’ in tumours of every cancer patient.

‘Because many mutations are not shared between cancers, a personalised treatment approach that targets individual tumour neoantigens may be a viable immunotherapeutic strategy for numerous patients with cancer,’ said Dr Lopez.

During the induction phase of the trial, patients received one of the different doses of the vaccines, ranging from 15 to 50 micrograms once per week, for six weeks.

The seventh and eighth doses were administered fortnightly, while the chemotherapy drug atezolizumab was given on a 21-day cycle.

Patients received a booster dose of the vaccine during the seventh cycle of atezolizumab, along with a maintenance dose of the vaccine every 24 weeks following the induction phase.

The personalised treatment was well tolerated, with patients largely experiencing low-to-moderate side effects, the researchers said.

But only eight per cent of patients saw a reduction in their tumours and 49 per cent had stable disease, where their tumours were neither growing nor shrinking.

This low clinical response rate is ‘likely because many of the patients treated in our study had very advanced disease, and were heavily pre-treated’, Lopez said.

However, analysed blood samples from 63 patients showed that the immune system had been activated in 73 per cent of them.

This is a response to the personalised vaccine treatment, the research team claim.

However, further studies with a larger patient population are needed to understand more about the benefits of this treatment, including in patients with early cancer.

‘We are now exploring this treatment in patients with previously untreated melanoma and in patients who have had surgery for early-stage non-small cell lung cancer,’ said Lopez.

The findings of this early clinical trial were presented in the AACR Virtual Annual Meeting II, a scientific conference running from June 22-25.