Study shows certain genetic faults help predict immunotherapy success in cancer
New research conducted by John Hopkins University in Baltimore, US, has found that a certain group of genetic faults can be used to predict the success of immunotherapy in cancer patients.
The study revealed that a significant number of patients whose tumours had defects in genes involved in DNA repair responded to the immunotherapy treatment, pembrolizumab (Keytruda).
The researchers discovered that all the patients who responded to pembrolizumab had cancers with defects in a set of genes, known as mismatch repair genes.
Pembrolizumab is used to target and block a protein called PD-L1 on the surface of certain immune cells known as T-cells.
Blocking the PD-L1 enables the T-cells to identify and kill the cancer cells.
The current trial involved 86 patients and studied 12 different types of cancer.
The test results showed that pembrolizumab controlled the disease for 66 patients, with tumours completely disappearing in 18 patients.
The trial suggested that pembrolizumab or similar drugs can be used for the treatment of multiple types of cancer.
Cancer Research UK cancer immunology expert Dr Edd James said: “These results are interesting because patients who had tumours with these genetic faults responded well to immunotherapy treatment.”
Clinical tests for these genetic defects are widely available and have the possibility to help doctors determine if immunotherapy is the best option for a cancer patient before treatment is started.
Though the trial is currently ongoing, 11 of the 86 patients have now stopped receiving the pembrolizumab therapy and remained disease-free, with no evidence of cancer recurrence.
James added: “These patients now need to be monitored to see if the effects are long lasting.”
The treatment is currently approved for only a few types of cancer cases.
Image: DNA sequencing. Photo: courtesy of Flikr / CC by 2.0 Andy Leppard.