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.
Keywords: Escitalopram; Japan; Liebowitz Social Anxiety Scale Japanese version (LSAS-J); Randomized placebo-controlled study; Social anxiety disorder (SAD).