Is the clinical trial system an anomaly in an era when we can collect almost unlimited data about the experiences of many different groups of patients? The New York Times isn’t going quite that far but an opinion piece in last Sunday’s Review section points out that randomised clinical trials often seem like a lottery. The group of people participating is normally atypically young with far fewer complications than real patients. It’s also true that if you ask the question often enough, random chance means that you will occasionally get a “yes”.

We often don’t know why a medicine works so it’s not really always clear which sub-groups of patients will benefit. As the piece says, “Researchers are coming to understand just how individualized human physiology and human pathology really are. On a genetic level, the tumors in one person with pancreatic cancer almost surely won’t be identical to those of any other. Even in a more widespread condition like high cholesterol, the variability between individuals can be great, meaning that any two patients may have starkly different reactions to a drug.”