In a traditional clinical trial, a random group of participants receives one potential treatment from a small list of options. Other participants in the same trial receive a different treatment from that list. For example, in a clinical trial of an antiviral drug, some participants may receive one of the drugs being tested, while others receive a placebo (a so-called “sugar pill” that resembles the actual drug but has no treatment benefit). Comparing the outcomes from patients who take the actual drugs with those who take the placebos allows researchers to determine whether the actual drugs are effective. But these types of trials also have limitations:
They usually only test one narrow question — whether one treatment is superior to another on average. They don’t consider that there are often multiple treatment options available, that many options can be given in combination, or that effects may vary across different types of patients.
They typically assign half of all patients to either the “placebo” or the control group, and do so for the entire period of the trial. This means there is little or no ability to learn or adapt during the trial from either the information discovered in the trial or from any other evidence that emerges.
With only a 50/50 chance of receiving the active drug, patients may feel there is little value in participating in a clinical trial other than as an altruistic act to help others.