Abstracts

Rationale: Vigabatrin (VGB), an antiepileptic drug (AED), was approved in August 2009 as monotherapy for patients 1 month to 2 years of age with infantile spasms (IS). VGB works by inhibiting GABA transaminase. Diagnosis of IS requires a substantial degree of clinical suspicion, and, if left untreated, the disease can have dire neuro-developmental consequences. IS is frequently refractory, and often requires therapy trials with several AEDs before one is found that controls seizures. In this retrospective analysis, we investigated our clinical experience with VGB for IS. Methods: The Children s Hospital of Michigan is a major referring center for IS patients who require surgical evaluation, especially for those with intractable spasms. We employed records from our IS database of 263 patients treated 1999-2009. Many patients have been receiving VGB, while others have received alternative AEDs, including hormonal therapy (i.e., ACTH). We performed a retrospective review of data for our patients with IS via our electronic health records (EHRs), as well as follow-up telephone calls to patients parents/caregivers, to assess the efficacy of VGB in controlling patients clinical seizures. We assigned subjective ratings of 1) poor or no control of seizures with VGB, 2) moderate to good control of seizures with VGB, and 3) excellent control of seizures with VGB for each patient as a way of assessing VGB s effect in our large cohort of real-world patients. Results: As of June 2009, of the 263 patients in our IS database, 130 (49.4%) had been receiving VGB. Of these 130, 71 (54.6%) had achieved excellent seizure control, (21.5%) had achieved moderate to good control, and 31 (23.8%) had poor or no seizure control with VGB. The percentage of VGB patients achieving excellent control versus those achieving poor or no control was highly statistically significant (p<0.0001, chi-square test). In addition, a PubMed search indicated no publications of single-arm cohorts with as many patients as included in this cohort. Conclusions: Our results indicate that VGB is effective in clinically controlling seizures in a large cohort of patients with IS. To prevent a devastating neuro-developmental sequalae of untreated IS, VGB should be initiated early in the clinical course of IS. However, judicious use of VGB is essential, and careful visual field testing should be conducted regularly to assess potential retinopathy associated with VGB. To our knowledge, this is the largest single-center cohort of IS patients treated with VGB, and these patients will be tracked to assess long-term outcomes.