A newly developed liquid biopsy can identify stomach or oesophageal cancer patients who could benefit from targeted treatment, according to a study published today.
Researchers from The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, say a simple and inexpensive liquid biopsy detects cancer DNA in the bloodstream to reveal if stomach and oesophageal cancers are being driven by the presence of too many copies of EGFR.
It could be used to identify patients who might benefit from drugs such as panitumumab, they say.
However, they say their study, which is published in today’s edition of Gut, established that EGFR inhibitors should never be combined with epirubicin because their effects seem to cancel each other out.
The findings explain why previous trials that have combined those drugs failed and will have major implications for the design of future trials in gastro-oesophageal and other cancers, where these two drug types are being tested.
The ICR and The Royal Marsden teams examined a number of EGFR gene copies in tissue and liquid biopsies from patients with advanced stomach and oesophageal cancer who were enrolled in the REAL3 phase III clinical trial.
They found that abnormally high numbers of copies of the EGFR gene could be detected in tissue and liquid biopsies, which were in agreement 95% of the time and so could preclude the need for tissue biopsies in future trials and in the clinic.
Advanced stomach and oesophageal cancers are usually treated with a combination of chemotherapy drugs, including epirubicin.
The REAL3 trial was launched in 2009 and looked to see if adding the EGFR inhibitor drug panitumumab was better than having chemotherapy on its own but results in 2013 revealed that it was not helpful and the trial was closed early.
When the research team looked back at samples on patients with abnormally high levels of EGFR, they discovered that 78% responded to chemotherapy on its own, but that only 50% responded to the panitumumab and chemotherapy combination.
They went on to grow ‘mini-tumours’ in the lab and found that when the anti-EGFR drugs were given to treat a tumour that was also being treated with epirubicin chemotherapy, the cancer cells divided faster and increased tumour growth.
Study co-leader Professor Nicola Valeri, professor of gastrointestinal oncology at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, said: “We have shown that a blood test can pick out just as well as a tissue biopsy cancer patients whose tumours are likely to respond to an important family of targeted drugs. That’s important because it is much faster, cheaper and more comfortable for patients to assess them with a blood test than taking a biopsy.”
Study co-leader Professor David Cunningham, director of clinical research at The Royal Marsden NHS Trust and director of the NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research, added: “The potential to replace tissue biopsies with a liquid biopsy in some cancers and for some patients could transform our approach to cancer treatment. These results underline the importance of using translational biology to interrogate the results of clinical trials which can be used to determine why treatments fail or succeed.”
Gut 17 November 2020
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