Placebo-controlled clinical trials in gastroenterology. A position paper of the American College of Gastroenterology.

Treatment programs for digestive diseases should be evaluated by randomized clinical trials. Under most circumstances, the best design for such trials requires placebo controls. For example, clinical trials should include groups of placebo-treated patients when there is no commonly accepted standard patients when there is no commonly accepted standard therapy for the disease under study, when standard therapy is of doubtful efficacy, or when standard therapy is unacceptably toxic. Moreover, illnesses--including peptic ulcer and IBD--may have sufficiently high response rates to placebo therapy as to favor placebo-controlled study designs. Placebo treatment is also free of substantial risk, at least compared to active drug treatment, when the disease process is very mild or when the study period is very short. Acceptable alternatives to placebo control include direct comparisons of new agents to standard therapy and addition of either new agents or placebo to a continuing baseline of standard therapy. Similarly, both placebo and active-treatment groups can sometimes be permitted access to standard therapy on a p.r.n. basis, with utilization thereof serving as one of the criteria of therapeutic response. Placebo-controlled trials are therefore generally feasible and desirable methods for testing the safety and efficacy of various proposed treatments for gastrointestinal diseases. High ethical standards in clinical medicine depend on high scientific standards in clinical research.