HOLLYWOOD, FLA. – Patients with social phobia responded favorably to treatment with the selegiline transdermal system, showing significant improvement in the anxiety component of the Liebowitz Social Anxiety Scale and other efficacy endpoints in a small phase II study.
Twenty patients participated in this 12-week, open-label, pilot study. They were treated with the selegiline transdermal system (Emsam) at a dose of 6 mg/24 hours. They demonstrated a significant mean 7.1-point drop from a baseline score of 17.6 on the avoidance component of the Liebowitz Social Anxiety Scale, as well as a 6.6-point drop on the scale’s anxiety component, a result that just missed statistical significance (P = .053), Kimberly Portland, Ph.D., reported at a meeting of the New Clinical Drug Evaluation Unit sponsored by the National Institute of Mental Health.
The selegiline transdermal system is approved for the treatment of major depression. Selegiline is an MAO-A and -B inhibitor. Its transdermal administration bypasses the GI tract and liver, thereby essentially eliminating the risks of hypertensive crisis and dietary interactions with tyramine-rich foods, which have demoted the traditional oral monoamine oxidase (MAO) inhibitors in antidepressant treatment hierarchies.
Oral MAO inhibitors previously have been shown in clinical trials to be at least as effective as cognitive-behavioral therapy or benzodiazepines in treating social phobia. So it seemed appropriate to examine the safety and efficacy of the selegiline transdermal system for this condition, which has an estimated prevalence in the United States of 5%-12%. The study was particularly timely because the selegiline transdermal system has dopaminergic effects, and recent evidence points to dopamine systems as playing a role in social phobia, explained Dr. Portland of Mylan Specialty, Basking Ridge, N.J., which markets Emsam.
In addition to the favorable results on the Liebowitz Social Anxiety Scale over the course of 12 weeks, participants also showed statistically significant improvements on the Social Life/Leisure Activities domain of the Sheehan Disability Scale, the Clinical Global Impression Severity of Illness Scale, and the Clinical Global Impression Change Scale.
Three patients dropped out of the study because of adverse events. The most common adverse events in the study were headache, reported by 25% of participants, and application site reactions, reported by 20%.
The major limitation of this pilot study is its small size, Dr. Portland noted. Further studies incorporating larger patient numbers, a double-blind format, and higher doses of the MAO inhibitor are planned.