Research design features and patient characteristics associated with the outcome of antidepressant clinical trials.
OBJECTIVE
The authors examined which, if any, research design features and patient characteristics would significantly differ between successful and unsuccessful antidepressant trials.


METHODS
Clinical trial data were reviewed for nine antidepressants approved by the Food and Drug Administration between 1985 and 2000. From the antidepressant research programs on these medications, 52 clinical trials were included in the study. The authors evaluated trial design features, patient characteristics, and difference in response between placebo and antidepressant.


RESULTS
Nine trial design features and patient characteristics were present in the research programs for all nine of the antidepressants. The severity of depressive symptoms before patient randomization, the dosing schedule (flexible versus fixed), the number of treatment arms, and the percentage of female patients were significantly associated with the difference in response to antidepressant and placebo. The duration of the antidepressant trial, number of patients per treatment arm, number of sites, and mean age of the patients were similar in successful trials (with a greater antidepressant-placebo difference) and less successful trials (with a smaller antidepressant-placebo difference).


CONCLUSIONS
These findings may help in the design of future antidepressant trials.
Khan
Arif
A
Northwest Clinical Research Center, Number 112, 1900 116th Avenue NE, Bellevue, WA 98004, USA. akhan@nwcrc.net
Kolts
Russell L
RL
Thase
Michael E
ME
Krishnan
K Ranga Rama
KR
Brown
Walter
W
D000928:Antidepressive Agents / Q000627:therapeutic use*; D002985:Clinical Protocols / Q000592:standards; D017277:Drug Approval; D006801:Humans; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012107:Research Design; D016896:Treatment Outcome; D014481:United States; D014486:United States Food and Drug Administration
D000928:Antidepressive Agents