Background. This study evaluated the efficacy and safety of low-dose desvenlafaxine (administered as desvenlafaxine succinate) in treating major depressive disorder (MDD). Methods. Adult outpatients (aged 18 years) in the United States and (aged 20 years) in Japan, who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for MDD and had a 17-item Hamilton Depression Rating Scale (HAM-D17) score 20, were ran-domly assigned to placebo, low-dose desvenlafaxine (25 mg/day), or the recommended dose (50 mg/day) after a 6to 14-day placebo lead-in, in an 8-week, fixed-dose trial. The primary efficacy variable was change from baseline in HAMD17 total score at final on-therapy evaluation. Efficacy analyses were based on the intent-totreat (ITT) population, using the last observation carried forward. Results. The ITT population included 699 patients. Reduction in HAM-D17 scores from baseline to final evaluation was not significantly greater for desvenlafaxine 25 mg/day (–8.98) but was significantly greater for desvenlafaxine 50 mg/day (–10.02; P = 0.016) versus placebo (–8.52) after adjusting for multiplicity. P-values were < 0.05 versus placebo for percentage of patients responding to treatment ( 50% decrease in HAM-D17 score) with desven-lafaxine 50 mg/day (46%; P = 0.015), but not with desvenlafaxine 25 mg/day (42% versus 35% with placebo). P-values for remission rates (HAM-D17 score ≤ 7) were not < 0.05 versus placebo for either desvenlafaxine treatment group. Discontinuations due to adverse events were observed in 2.6%, 3.4%, and 3.4% of patients treated with placebo, desvenlafaxine 25 mg/day, and desvenlafaxine 50 mg/day, respectively. Conclusions. Consistent with other clinical studies, desvenlafaxine 50 mg/day demonstrated antidepressant efficacy and appears to be the minimally effective dosage for MDD. ClinicalTrials study identifier NCT00798707
IWATA: Fujita Health University Hospital, Toyoake, Aichi, Japan; TOURIAN, HWANG, and MELE: Pfizer Inc, Collegeville, PA; VIALET: Pfizer, Paris, France
Conflicts of Interest & Source of Funding: Dr. Iwata does not have any conflicts of interest to disclose. Dr. Tourian was a fulltime employee of Pfizer at the time this study was conducted and the manuscript was written. Dr. Hwang and Ms. Mele and Vialet are full time employees of Pfizer. This study was sponsored by Wyeth Research, which was acquired by Pfizer in October 2009.
Acknowledgments: Medical writing support for this manuscript was provided by Traci Anna Stuve, MA, and Ira Mills, PhD, of Embryon LLC, A Division of Advanced Health Media, and was funded by Pfizer. Editorial support in addressing journal comments was provided by Kathleen Dorries, PhD, at Peloton Advantage LLC and was funded by Pfizer.
Please send correspondence to: Eunhee Hwang, PhD, Pfizer Inc., 500 Arcola Rd, Collegeville, PA 19426. Eunhee.Hwang@pfizer.com.