Which children receive vigabatrin? Characteristics of pediatric patients enrolled in the mandatory FDA registry.

Abstract

Vigabatrin (Sabril®) is an antiepileptic drug (AED) currently indicated in the US as a monotherapy for patients 1month to 2years of age with infantile spasms (IS) and as adjunctive therapy for patients ≥10years of age with refractory complex partial seizures (rCPS) whose seizures have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. The approval required an FDA mandated registry. This article describes 5years of demographic and treatment exposure data from US pediatric patients (<17years). Participation is mandatory for all US Sabril® prescribers and patients. A benefit-risk assessment must be documented for patient progression to maintenance therapy. This includes demographic diagnosis and reports of ophthalmologic assessments (where available). Patient data were grouped by age as proxies for indication (IS: <3years, rCPS: ≥3 to <17years). As of August 26, 2014, 5546/6823 enrolled patients were pediatric/total; 4472 (81%) were vigabatrin-naïve. Seventy-one percent of patients were <3years of age; 29% were ≥3 to <17years of age. Etiologies of IS were identified as cryptogenic (21%), symptomatic tuberous sclerosis (17%), and symptomatic other (42%). The majority of patients with IS (56%) attempted no prior treatments; 16% received adrenocorticotropic hormone prior to vigabatrin. A third of patients with IS were receiving 1 concomitant treatment with vigabatrin. For patients with rCPS, 39% attempted 1-3 prior treatments; 27% were receiving 2 concomitant treatments at enrollment. A total of 1852 (41%) patients did not undergo baseline ophthalmological assessment; 25% of patients with IS and 42% of patients with rCPS were exempted for neurologic disabilities. Kaplan-Meier estimates predict that 71% and 65% of vigabatrin-naïve patients with IS and rCPS, respectively, would remain in the registry at 6months. Most pediatric vigabatrin patients have IS as an underlying diagnosis, especially those <3years of age. A proportion of those with rCPS remain on long-term vigabatrin despite the risk of adverse events.