A randomized, double-blind, placebo-controlled study of escitalopram in patients with social anxiety disorder in Japan

Satoshi Asakura, Taiji Hayano, Atsushi Hagino, Tsukasa Koyama

Objective This randomized, double-blind placebo-controlled study compared the efficacy and tolerability of escitalopram (10 and 20 mg/day) in Japanese patients with social anxiety disorder (SAD). Research design and methods Patients aged 18-64 years with a primary diagnosis of DSM-IV-TR defined SAD, a Liebowitz Social Anxiety Scale Japanese version (LSAS-J) total score ≥60 and a Clinical Global Impression-Severity (CGI-S) score ≥4 at baseline were randomly assigned (1:1:1) to placebo, escitalopram 10 mg or escitalopram 20 mg. The primary endpoint was change from baseline to Week 12 in the LSAS-J total score for both escitalopram 10 mg and 20 mg versus placebo (ANCOVA, FAS, LOCF), using a hierarchical testing procedure. Pre-specified secondary endpoints included LSAS-J sensitivity analyses. Clinical trial registration This study has the www.japic.or.jp identifier: JapicCTI-121842. Results For the primary efficacy endpoint, the difference from placebo in the LSAS-J was -3.9 (p = 0.089) for escitalopram 10 mg. Since the superiority of escitalopram 10 mg over placebo was not confirmed, an analysis without multiplicity adjustment was made, which showed a difference for escitalopram 20 mg versus placebo of -9.8 (p < 0.001). In pre-specified sensitivity analyses, the difference versus placebo was -4.9 (p = 0.035) (ANCOVA, FAS, OC) and -5.0 (p = 0.028) (MMRM, FAS) (escitalopram 10 mg) and -10.1 (p < 0.001) (ANCOVA, FAS, OC) and -10.6 (p < 0.001) (MMRM, FAS) (escitalopram 20 mg). Common adverse events (incidence ≥5% and significantly different from placebo) were somnolence, nausea and ejaculation disorder. Conclusion Escitalopram was efficacious, safe and well tolerated by patients with SAD in Japan. Study limitations are discussed including patient characteristics.