Results from 2 randomized, double-blind, placebo-controlled studies of the novel NK1 receptor antagonist casopitant in patients with major depressive disorder.

Clinical study results for neurokinin (NK) receptor antagonists in the treatment of depression have been mixed, with Phase III studies failing to fulfill the early promise demonstrated in Phase II studies. Casopitant, a selective NK1 antagonist that achieves nearly complete receptor occupancy was studied in 2 randomized, placebo-controlled, double-blind, Phase II trials in depressed outpatients to test the hypothesis that nearly complete NK1 receptor occupancy is required to achieve antidepressant efficacy. Study 092 used an interactive voice response system to recruit depressed patients with baseline Hamilton Depression (17-item, HAMD17) total scores higher than 24 who were randomized to fixed-dose casopitant 30 mg/d, 80 mg/d, or placebo for 8 weeks (n = 356). Study 096 required Carroll Depression Scale-Revised self-assessment scores of higher than 24 for randomization to casopitant 120 mg/d, paroxetine 30 mg/d (both reached via forced titration), or placebo for 8 weeks (n = 362). In study 092, casopitant 80 mg but not 30 mg achieved statistically significant improvement versus placebo on the primary outcome measure, week 8 last observation carried forward change from baseline HAMD17 (difference = -2.7; 95% confidence interval, -5.1 to -0.4, P = 0.023). In study 096, neither casopitant nor paroxetine achieved statistical separation from placebo at end point on HAMD17 (casopitant difference = -1.7; 95% CI, -3.8 to 0.4, P = 0.282). Casopitant and paroxetine were generally well tolerated in most patients. These studies suggest that NK1 antagonists that have nearly complete receptor occupancy may be effective in the treatment of depression.

A novel approach to rater training and certification in multinational trials.

Clinical trials are becoming increasingly international in scope. Global studies pose unique challenges in training and calibrating raters owing to language and cultural differences. Recent findings that poorly conducted interviews reduce study power, makes attention to raters' clinical skills critical. In this study, 109 raters from 14 countries went through a two-step certification process on the Hamilton Depression and Anxiety Rating Scales: (i) an online didactic tutorial on scoring conventions, and (ii) applied clinical training, consisting of small language-specific groups in which raters took turns interviewing patients while observed by an expert trainer, and observation and evaluation of individual interviews. Translators were used when native-language trainers were unavailable. Those who were unable to attend the startup meeting received the training individually via telephone. Results found a significant improvement in raters' knowledge of scoring conventions, with the mean number of correct answers on the 20-item test improving from 14.59 to 17.83, P<0.0001. In addition, raters' clinical skills improved significantly, with the mean score on the Rater Applied Performance Scale improving from their first to their second testing from 10.25 to 11.31, P=0.003. These results support the efficacy of this applied training model in improving raters' applied clinical skills in multinational trials.

Efficacy and tolerability of paroxetine for the long-term treatment of generalized anxiety disorder.

BACKGROUND: Paroxetine has demonstrated efficacy in depression and anxiety disorders, including generalized anxiety disorder (GAD). This 32-week study evaluated the maintained efficacy and safety of paroxetine in GAD by assessing the potential for relapse after discontinuation of medication. METHOD: Adults (N = 652) with DSM-IV GAD and a Clinical Global Impressions-Severity of Illness (CGI-S) score > or = 4 received paroxetine (20-50 mg/day) for 8 weeks. Patients whose CGI-S score had decreased by at least 2 points to < or = 3 at week 8 were randomly assigned to double-blind treatment with paroxetine (N = 278) or placebo (N = 288) for a further 24 weeks. The primary efficacy parameter was the proportion of patients relapsing (an increase in CGI-S score of at least 2 points to a score < or = 4 or withdrawal resulting from lack of efficacy) during double-blind treatment. RESULTS: Significantly fewer paroxetine than placebo patients relapsed during the 24-week double-blind phase (10.9% vs. 39.9%; p <.001). Placebo patients were almost 5 times more likely to relapse than paroxetine patients (estimated hazard ratio = 0.213 [95% CI = 0.1 to 0.3]; p <.001). Statistical significance in favor of paroxetine was demonstrated for all secondary efficacy parameters, including functional status. Twice as many paroxetine patients as placebo patients (73%) achieved remission. Paroxetine was well tolerated, with no unexpected adverse events reported. CONCLUSION: Paroxetine was found to be effective and well tolerated for both the short- and long-term treatment of DSM-IV GAD. Continued treatment with paroxetine significantly reduced the potential for relapse of GAD symptoms.