Long-term Safety of Asenapine in Pediatric Patients Diagnosed With Bipolar I Disorder: A 50-Week Open-Label, Flexible-Dose Trial

Background Sublingually administered asenapine was approved in March 2015 by the United States Food and Drug Administration for patients aged 10-17 years with an acute manic or mixed episode associated with bipolar I disorder (BP-1). This is the first long-term safety and tolerability study of asenapine in this population. Methods Following the 3-week randomized, double-blind, placebo-controlled trial of patients aged 10-17 years with an acute manic or mixed episode associated with BP-1, patients could enroll in this flexible-dose (2.5-10 mg twice daily) open-label extension (OLE) study for an additional 50 weeks, conducted from August 2011 to September 2014 in the United States and Russia. Treatment-emergent adverse events (TEAEs) were assessed and predefined TEAEs of interest reported in addition to metabolic and anthropometric parameters. The Young Mania Rating Scale (YMRS) and Clinical Global Impressions scale in bipolar illness (CGI-BP) were used to assess effectiveness. Results A total of 321 patients (lead-in study treatment: placebo, n = 80; asenapine, n = 241) were included; 267 (83.2 %) reported one or more TEAE and 181 (56.4 %) discontinued early, 48 (15.0 %) due to TEAEs. Of the predefined TEAEs of interest, combined somnolence/sedation/hypersomnia occurred most frequently (42.4 %) followed by oral hypoesthesia/dysgeusia (7.5 %). In total, 109 (34.8 %) patients experienced clinically significant weight gain (>= 7 % increase). No clinically meaningful changes were noted for laboratory parameters measured. Eighteen patients met the criteria for new-onset metabolic syndrome (MBS) post-baseline during the extension study, whereas 10 patients who met MBS criteria at baseline did not meet MBS criteria at endpoint. A total of 12 patients met MBS at baseline and endpoint. Mean change in YMRS total score from OLE baseline was -9.2 points at week 50, and change in CGI-BP severity overall score was similar among all treatment groups (those who initially received asenapine and those who initially received placebo). After 26 weeks of treatment in the OLE, 79.2 % of patients were classified as YMRS 50 % responders relative to acute trial baseline. Conclusions Asenapine was generally well tolerated in pediatric patients with BP-1 during <= 50 weeks of open-label treatment; among predefined TEAEs of interest, the combination of somnolence/sedation/hypersomnia was the most common.