Duloxetine Efficacy for Major Depressive Disorder in Male vs. Female Patients: Data From 7 Randomized, Double-Blind, Placebo-Controlled Trials

Susan G. Kornstein, M.D.; Madelaine M. Wohlreich, M.D.; Craig H. Mallinckrodt, Ph.D.; John G. Watkin, D.Phil.; and Donna E. Stewart, M.D.

Objective: A number of studies have suggested potential gender differences in the efficacy of antidepressant medications. Pooled data from double-blind, placebo-controlled studies were utilized to compare the efficacy of duloxetine in the treatment of major depressive disorder (MDD) in male and female patients.

Method: Efficacy data were pooled from 7 randomized, double-blind, placebo-controlled clinical trials of duloxetine. These studies represent all available data from U.S. acute-phase, placebo-controlled studies of duloxetine for the treatment of MDD. Patients (aged > = 18 years) meeting DSM-IV criteria for MDD received duloxetine (40-120 mg/day; men, N = 318; women, N = 578) or placebo (men, N = 242; women, N = 484) for up to 9 weeks. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAM-D₁₇) total score, HAM-D₁₇ subscales (core, Maier, anxiety, retardation, sleep), the Clinical Global Impressions-Severity of Illness scale (CGI-S) and Patient Global Impression of Improvement scale (PGI-I), the Quality of Life in Depression Scale (QLDS), and Visual Analog Scales (VAS) for pain. The first patient visit was February 1, 1999, and the last patient visit was November 27, 2002.

Results: In both male and female patients, duloxetine produced significantly greater improvement in HAM-D₁₇, CGI-S, and PGI-I when compared with placebo (p < .05). Treatment-by-gender interactions did not reach statistical significance, indicating that the magnitude of duloxetine's treatment effects did not differ significantly between male and female patients. However, there was a trend for female patients to show a more robust response than male patients to both duloxetine and placebo. On the basis of VAS assessments of pain severity, duloxetine-treated female patients appeared to exhibit greater improvement than male patients, while women receiving placebo had smaller responses than placebo-treated men. Improvements in quality of life were significantly greater for both men (p = .006) and women (p = .001) receiving duloxetine than placebo and showed no significant difference by gender.

Conclusion: In this analysis of pooled data, the efficacy of duloxetine did not differ significantly in male and female patients.

(J Clin Psychiatry 2006;67:761-770)

Received May 13, 2005; accepted Nov. 7, 2005. From the Department of Psychiatry, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond (Dr. Kornstein); Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Ind. (Drs. Wohlreich, Mallinckrodt, and Watkin); and University Health Network, University of Toronto, Ontario, Canada (Dr. Stewart).

This work was sponsored by Eli Lilly and Co. All of the authors accept full responsibility for this article. All authors discussed the formulation of, contributed to, and reviewed the article. The authors had full access to all data from the trials and participated in the decision to publish the data.

Dr. Kornstein has received grant/research support from Pfizer, Bristol-Myers Squibb, Eli Lilly, Forest, GlaxoSmithKline, Mitsubishi-Tokyo, Pharmacia-Upjohn, Merck, Biovail, Wyeth, Berlex, Novartis, Sepracor, Boehringer Ingelheim, Sanofi-Synthelabo, and AstraZeneca and has served on the advisory boards of Pfizer, Wyeth, Eli Lilly, Bristol-Myers Squibb, Warner Chilcott, Biovail, Berlex, and Forest. Dr. Mallinckrodt is a stock shareholder of Eli Lilly. Dr. Stewart has been a consultant to and has received honoraria from Eli Lilly and Wyeth; has received grant/research support from Eli Lilly; and has served on the speakers or advisory boards of Wyeth, Eli Lilly, and Hoffman. Drs. Wohlreich and Watkin report no other significant commercial relationships relevant to the study.

Corresponding author and reprints: Madelaine M. Wohlreich, M.D., Eli Lilly and Co., Lilly Corporate Center, Indianapolis, IN 46285 (e-mail: mwmd@lilly.com).