Schizophrenia Bulletin Advance Access published online on August 22, 2008
Schizophrenia Bulletin, doi:10.1093/schbul/sbn110
What Is Causing the Reduced Drug-Placebo Difference in Recent Schizophrenia Clinical Trials and What Can be Done About It?
2 Psychiatry and Human Behavior, University of California, Irvine, CA
3 Psychiatry, Downstate Medical Center, State University of New York, Brooklyn, NY
4 Quintiles Inc, San Diego, CA
5 Psychiatry, University of California, San Diego, CA
6 Ortho-McNeil Janssen Scientific Affairs, Titusville, NJ
7 Anand Pharma Consulting, Oberwil, Switzerland
8 Clarke Institute of Psychiatry, University of Toronto and Mental Health Program, Humber River Regional Hospital, Toronto, Canada
9 Psychiatry, Chaim Sheba Medical Center, Tel Aviv, Israel
10 Lilly Development Laboratories, Eli Lilly and Company, Indianapolis, IN
11 California Clinical Trials, Los Angeles, CA
12 Hoffman-La Roche, Medical Affairs, Nutley, NJ
13 Psychiatry and Public Health, Weill Medical College of Cornell University, New York, NY
14 Service de Psychiatrie, Hôpital Lariboisière Fernand Widal, Paris, France
15 Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
1 To whom correspondence should be addressed; tel: 714-456-8690; fax: 714-456-5967, UCI Neuropsychiatric Center, 101 The City Drive South, Orange, CA 92868; e-mail: akemp{at}uci.edu.
On September 18, 2007, a collaborative session between the International Society for CNS Clinical Trials and Methodology and the International Society for CNS Drug Development was held in Brussels, Belgium. Both groups, with membership from industry, academia, and governmental and nongovernmental agencies, have been formed to address scientific, clinical, regulatory, and methodological challenges in the development of central nervous system therapeutic agents. The focus of this joint session was the apparent diminution of drug-placebo differences in recent multicenter trials of antipsychotic medications for schizophrenia. To characterize the nature of the problem, some presenters reported data from several recent trials that indicated higher rates of placebo response and lower rates of drug response (even to previously established, comparator drugs), when compared with earlier trials. As a means to identify the possible causes of the problem, discussions covered a range of methodological factors such as participant characteristics, trial designs, site characteristics, clinical setting (inpatient vs outpatient), inclusion/exclusion criteria, and diagnostic specificity. Finally, possible solutions were discussed, such as improving precision of participant selection criteria, improving assessment instruments and/or assessment methodology to increase reliability of outcome measures, innovative methods to encourage greater subject adherence and investigator involvement, improved rater training and accountability metrics at clinical sites to increase quality assurance, and advanced methods of pharmacokinetic/pharmacodynamic modeling to optimize dosing prior to initiating large phase 3 trials. The session closed with a roundtable discussion and recommendations for data sharing to further explore potential causes and viable solutions to be applied in future trials.
Keywords: schizophrenia / clinical trials / placebo response / signal detection / meeting summary / ISCTM / ISCDD