Progress toward a more ethical method for clinical trials.

Methodology for conducting clinical trials of new drugs and treatments on people need not be regarded as fixed. After reviewing the currently most popular method (randomization) and its ethical problems, this paper explores the possibilities of a new method for conducting such trials. It relies on new Bayesian technology for eliciting the opinions of medical experts. These opinions are conditioned on specific predictor variables, and are held in a computer. At any stage in a trial, these opinions can be updated in the computer using the information collected in the trial up to that point. Consider as an admissible treatment for a patient having specific values of predictor variables only those treatments that at least one expert regards as best (in the computer model) for this patient. It is proposed that only admissible treatments, so defined, be allowed to be assigned to the patient. The ethical and statistical consequences of this principle are explored. Experience to date with a trial at Johns Hopkins designed on this principle is reported.