Immunotherapy for bowel cancer could change clinical practice

A large international trial involving UCL and UCLH has found that pembrolizumab, a form of immunotherapy, more than doubled the 'progression free survival' time of patients with a specific subtype of advanced bowel cancer, when compared with chemotherapy. 'Progression free survival' is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a new treatment works. As part of an interim analysis of clinical trial data, presented at the American Society of Clinical Oncology (ASCO) Annual Meeting, researchers found patients who were treated with pembrolizumab (also known as Keytruda) had 'progression-free survival' of 16.5 months (on average), compared with 8.2 months for those who were treated with chemotherapy. In addition, 11% of patients who were treated with pembrolizumab were also found to have a 'complete response' where their disease had disappeared from scans. Furthermore, in almost half the patients who had pembrolizumab (48.3%), their disease had not progressed after two years versus only a fifth of patients who had had chemotherapy (18.6%), which means the beneficial effects are also durable. The trial's UK Chief Investigator, Dr Kai-Keen Shiu, Honorary Associate Professor in Oncology at UCL Cancer Institute and Consultant Medical Oncologist at UCLH, said:  "This is the first randomised controlled study to show that first-line immunotherapy is significantly better than chemotherapy at shrinking metastatic bowel cancers with these specific DNA mutations, and delaying the time it takes for the cancer to progress.