Somnolence and Sedation Were Transient Adverse Events for Most Patients Receiving Clobazam Therapy: Post Hoc Analysis of Trial OV-1012 Data

James Benjamin Renfroe, Jouko Isojarvi, Deborah Lee


Background: Somnolence-related adverse events (AEs) are common with benzodiazepine treatment. Clobazam is a uniquely structured 1,5-benzodiazepine indicated in the US for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients ≥ 2 years old. This post hoc analysis of the phase III OV-1012 trial evaluated the incidence, as well as time to onset and resolution, of somnolence and/or sedation AEs following treatment with clobazam for patients with LGS.

Methods: OV-1012 was a double-blind, placebo-controlled study that compared three oral dosages of clobazam with placebo as adjunctive therapy in patients 2 - 60 years of age with LGS. Following a 4-week baseline phase, patients who had ≥ 2 drop seizures per week were randomized to placebo or clobazam 0.25, 0.5, or 1.0 mg/kg/day (low-dosage, medium-dosage, and high-dosage, respectively). Treatment included a 3-week titration phase, followed by a 12-week maintenance phase. Incidence, time to onset, duration, and time to resolution of somnolence/sedation AEs were analyzed for patients treated with placebo, or low-, medium-, or high-dosage clobazam.

Results: The incidence of somnolence and/or sedation was greater for patients treated with any dosage of clobazam (26%) than placebo (15%), and the incidence increased with greater dosages of clobazam (low-dosage, 17%; medium-dosage, 27%; and high-dosage, 32%). For most patients, onset of these events was within the first 3 weeks of treatment, corresponding to the titration phase. The majority of these events resolved (placebo, 73%; low-dosage, 82%; medium-dosage, 63%; and high-dosage, 83%). The median duration of these somnolence/sedation AEs was 1 month for all clobazam treatment groups.

Conclusions: Somnolence and sedation were relatively common AEs observed during clobazam treatment for LGS in OV-1012 and were dosage-related. Most of these events were transient and resolved within a few weeks.

J Neurol Res. 2015;5(4-5):252-256


Keywords (3-8)*

Clobazam; Lennox-Gastaut syndrome; Post hoc analyses; Somnolence; Sedation; Safety

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