This study evaluated the efficacy of adjunctive pregabalin versus placebo for treatment of patients with generalized anxiety disorder (GAD) who had not optimally responded to previous or prospective monotherapies. This was a phase 3, randomized, double-blind, placebo-controlled study. Patients diagnosed with GAD who had a historical and current lack of response to pharmacotherapy [Hamilton Anxiety Rating Scale (HAM-A) of ≥22 at screening] were randomized to adjunctive treatment with either pregabalin (150–600 mg/day) or placebo. The primary outcome measure was the change in HAM-A total scores after 8 weeks of combination treatment. Adverse events were regularly monitored. Randomized patients (N=356) were treated with pregabalin (n=180) or placebo (n=176). Mean baseline HAM-A scores were 20.7 and 21.4, respectively. After treatment, the mean change in HAM-A was significantly greater for pregabalin compared with placebo (−7.6 vs. −6.4, respectively; P<0.05). HAM-A responder rates (≥50% reduction) were significantly higher for pregabalin (47.5%) versus placebo (35.2%; P=0.0145). The time-to-sustained response favored pregabalin over placebo (P=0.014). Adverse events were consistent with previous studies and discontinuations were infrequent for pregabalin (4.4%) and placebo (2.3%). The study was discontinued early after an interim analysis. The results indicate that adjunctive pregabalin is an efficacious therapy for patients with GAD who experience an inadequate response to established treatments.
aDepartment of Psychiatry, Mood and Anxiety Disorders Section, University of Pennsylvania, Philadelphia, Pennsylvania
bCalifornia Neuroscience Research Medical Group, Inc., Sherman Oaks, California
cPfizer Inc, Groton, Connecticut, USA
Trial registration: NCT00413010.
Correspondence to Karl Rickels, MD, Department of Psychiatry, Mood and Anxiety Disorders Section, University of Pennsylvania, 3535 Market Street, Suite 670, Philadelphia, PA 19104 USA Tel: +1 215 746 6417; fax: +1 215 746 6551; e-mail: firstname.lastname@example.org
Received September 2, 2011
Accepted December 22, 2011