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An Analysis of Relapse Rates and Predictors of Relapse in 2 Randomized, Placebo-Controlled Trials of Desvenlafaxine
Roger S McIntyre1, Rana S Fayyad1, Christine J Guico-Pabia1
1Department of Psychiatry and Pharmacology, University of Toronto, Toronto, Ontario, Canada (Dr McIntyre); Pfizer Inc, New York, New York (Dr Fayyad); CGP Strategic Solutions LLC Lansdale, Pennsylvania (Dr Guico-Pabia); and Pfizer Canada, Inc, Kirkland, Quebec, Canada (Dr Boucher).
Objective:
To evaluate relapse rates and predictors of relapse in 2 randomized, placebo-controlled trials of desvenlafaxine for major depressive disorder (MDD).
Method:
Study 1: week 8 responders to open-label desvenlafaxine 50 mg/d entered a 12-week open-label stability phase. Patients with a continuing, stable response at week 20 were randomly assigned to 6-month, double-blind treatment (desvenlafaxine 50 mg/d or placebo). Study 1 was conducted between June 2009 and March 2011 at 87 sites worldwide. Study 2: week 12 responders to open-label desvenlafaxine 200 or 400 mg/d were randomly assigned to 6-month, double-blind treatment (desvenlafaxine 200 mg/d, 400 mg/d, or placebo). Study 2 was conducted between June 2003 and August 2005 at 49 sites in Europe, the United States, and Taiwan. Relapse was assessed separately by study with log-rank test using protocol definitions of relapse and with 17-item Hamilton Depression Rating Scale (HDRS-17) score ≥ 16 at any time during the double-blind phase. Kaplan-Meier estimates evaluated time to relapse, censoring data at months 1, 2, and 3 and overall; treatments were compared using hazard ratios. Cox proportional hazards models assessed relapse predictors.
Results:
Overall relapse rates for all definitions were significantly lower for desvenlafaxine versus placebo for both studies (all P ≤ .002). In study 1, rates were significantly lower for desvenlafaxine versus placebo at month 2 (P = .016) and month 3 (P = .007) using the protocol definition. In study 2, relapse rates were significantly lower for desvenlafaxine versus placebo at months 1, 2, and 3 for both definitions (P < .0001-.002). Hazard ratios were similar at months 1, 2, and 3 and overall for both studies (0.382-0.639).
Conclusions:
Desvenlafaxine 50 to 400 mg/d effectively prevented relapse at 6 months. Desvenlafaxine significantly prevented relapse early (month 1) versus placebo only in study 2.
Trial Registration:
ClinicalTrials.gov identifiers:NCT00887224 and NCT00075257.
