Abstracts

Rationale: Vigabatrin (VGB) is a selective, irreversible inhibitor of GABA transaminase that has been available as treatment for infantile spasms (IS) outside the US for decades. Due to the adverse effect of irreversible peripheral visual field defect, the FDA was reluctant to grant VGB approval in the US. FDA approval was given to VGB in August 2009 as monotherapy for children aged 1 month to 2 years with infantile spasms. VGB (Sabril) is now available through a restricted access program with mandatory guidelines for early detection of vision abnormalities. Methods: A retrospective chart review was performed on patients treated with VGB at Stony Brook University Medical Center. Patients were identified through a keyword search of a computer log of dictations from January 2001 to April 2010, using the keywords, vigabatrin , and Sabril . Data was obtained on demographics, and etiology/classification of IS as symptomatic, cryptogenic or idiopathic. Variables included length of treatment, dosing, treatment response, adverse effects, and treatment after VGB was discontinued. The outcome measure of efficacy was spasm cessation and/or resolution of seizures with minimal adverse effects. Results: Ten patients were identified, 4 males, 6 females, ages 1-14 years. One hundred percent had IS (symptomatic 9/10, idiopathic 1/10). Two of the patients had tuberous sclerosis, and two developed Lennox-Gastaut syndrome. Mean dose was 123 mg/kg/day (range 69 - 182 mg/day) divided BID. Ninety-percent of the patients were treated with a medication prior to VGB (ACTH 6/10, topiramate 3/10, zonisamide 3/10, Phenobarbital 2/10, carbamazepine 1/10, felbamate 1/10, levetiracetam 1/10, and valproic acid 1/10), and one was on a ketogenic diet. Prior to treatment, 4 were cortically blind. Fifty-percent showed cessation of spasms with VGB treatment. Only one patient had an adverse effect consisting of a rash. After treatment with VGB, patients were treated with topiramate (3), zonisamide (3), lamotrigine (1), valproic acid (1), and rufinamide (1). At the time of the study, 5 remained on VGB with a mean treatment duration of 18 months. All patients followed the protocol for ophthalmologic surveillance during treatment and none developed any visual field abnormalities. Conclusions: VGB is a relatively well tolerated and effective medication for IS, in children with or without tuberous sclerosis. There was no evidence of the development of ophthalmic abnormalities in our limited population. Further analysis of clinical experience is warranted regarding the use of VGB in larger clinical study populations.