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The objective of this study was to assess the efficacy, safety, and tolerability of desvenlafaxine (administered as desvenlafaxine succinate) 50 and 100 mg/day for major depressive disorder (MDD). A multicenter, randomized, double-blind, placebo-controlled trial was conducted in Europe and South Africa. Outpatients with MDD received fixed-dose desvenlafaxine (50 or 100 mg/day) or placebo for 8 weeks. The primary efficacy variable was the 17-item Hamilton Rating Scale for Depression total score; secondary measures included Clinical Global Impressions-Improvement scores. The intent-to-treat population included 483 patients: desvenlafaxine 50 mg (n=164), desvenlafaxine 100 mg (n=158), and placebo (n=161). At the last-observation-carried-forward analysis (final evaluation) using analysis of covariance, adjusted mean changes from baseline on the Hamilton Rating Scale for Depression were significantly greater for both desvenlafaxine 50 mg (-13.2; P=0.002) and 100 mg (-13.7; P<0.001) versus placebo (-10.7). Significant differences on the Clinical Global Impressions-Improvement scores were observed for desvenlafaxine 50 mg (P=0.002) and 100 mg (P<0.001) versus placebo. Both doses of desvenlafaxine were generally well tolerated. The most common treatment-emergent adverse events were nausea, dizziness, insomnia, constipation, fatigue, anxiety, and decreased appetite. Fixed doses of desvenlafaxine 50 and 100 mg/day are safe, generally well tolerated, and effective at a clinically relevant level for the treatment of MDD.

The main goals in an adaptive dose-ranging study are to detect dose response, to determine if any doses(s) meets clinical relevance, to estimate the dose-response, and then to decide on the dose(s) (if any) to take into the confirmatory Phase III. Adaptive dose-ranging study designs may result in power gains to detect dose response and higher precision in estimating the target dose and the dose response curve. In this article, we complement the library of available methods with five new adaptive doseranging designs. Due to their inherent complexity, the operating characteristics can be assessed only through intensive simulations. We present here results of a comprehensive simulation study that compares and contrasts these designs for a variety of different scenarios.

No abstract

We propose an adaptive procedure for dose-finding in clinical trials when the primary efficacy endpoint is continuous. We model the mean of the efficacy endpoint, given the dose, as a four-parameter logistic function. The efficacy endpoint at each dose is distributed according to either a normal or a gamma distribution. We consider the cases of fixed variance and fixed coefficient of variation assuming them to be both known and unknown. The analytic formulae for the Fisher information matrix are obtained, which are used to build the locally and adaptive D-optimal designs.