Abstracts

Rationale: Vigabatrin was approved in 2009 by the U.S. FDA for treatment of infantile spasms in children ages 1 month to 2 years and as add-on therapy in adults with refractory complex partial seizures. We evaluated the efficacy and safety of vigabatrin in pediatric epilepsy as adverse effects continue to be a major concern.Methods: Patients with epilepsy from a pediatric tertiary center who used vigabatrin were retrospectively reviewed (1/2013 to 2/2014).Results: Of 103 patients, median epilepsy onset age was 0.3 yrs (IQR:0.1-0.6; 55 (53.4%) female), epilepsy duration was 0.3 yrs (IQR:0.1-0.7), vigabatrin initiation age was 0.7 yrs (IQR:0.4-1.3), treatment duration was 1.1 yrs (IQR:0.4-1.9) with median start dose of 48 mg/kg/day (IQR:29.7-52) and last follow-up dose of 90.1 mg/kg/day (IQR:48.8-129) . Etiology was structural/metabolic in 48.5% (50), unknown in 27.2% (28) and genetic in 24.3% (25) patients. At time of vigabatrin initiation, 91.3% (94) had epileptic spasms, 14.6% (15) had focal, 9.7% (10) had generalized, 4.9% (5) had generalized myoclonic, 4.9% (5) had generalized tonic-clonic, 3.9% (4) had generalized atonic and 0.97% (1) had generalized absence seizures. Patients were treated with a median of 1 concomitant AED, with 35% (36) on levetiracetam, 31.1% (32) on topiramate and 25.2% (26) on phenobarbital. 11.7% (12) of patients were also treated with pyridoxine, 10.7% (11) with a steroid and 1.9% were on the ketogenic diet. Hypotonia was observed in 61.2% (63) patients, 33% (34) were normal, 7.8% (8) had quadriplegia, 5.8% (6) had hemiplegia, 4.9% (5) had cranial abnormalities, 0.9% (1) had monoplegia and 0.9 % (1) had extrapyramidal syndrome. Intellectual and developmental disabilities were detected in 74.8% (77), while 24.3% (25) had no comorbidities, 3.9% (4) had autism, 1.9% (2) had behavioral problems and 1.9% (2) had ADHD. Of 100 patients with an EEG, 57% had generalized, 18% had focal, 62% had multifocal patterns, while 1 had a normal EEG and 91% also had spikes and sharp waves and 40% had slowing. 68.9% (71/103) of patients discontinued vigabatrin due to controlled seizures in 31/71; unsatisfactory therapeutic effect in 23/71, adverse effects in 5/71, vision abnormalities in 4/71, unknown reasons in 5/71, controlled hypsarrhythmia in 1/71 and 2/71 expired from unknown reasons. Median seizure reduction from baseline to 1st follow-up was 83.3% (IQR:27.4-99.8) with a 1.6 month follow-up median duration (IQR:0.9-2.5). Seizure freedom during both treatment and following discontinuation was observed in 24/62, while 4/62 relapsed. Treatment response (>50% seizure reduction) was observed in 76.8% (76/99) of patients with no difference regarding etiology and seizure type (Kruskal-Wallis test, p=0.7 and p=0.6, respectively) with a median seizure reduction of 97.1% (IQR:44.4-100%). The dosage of vigabatrin had no influence in the treatment response.Conclusions: Vigabatrin is efficacious in all seizure types, independent of etiology and dosage did not influence the treatment response between responders and non-responders. Adverse effects were rarely observed in our sample (Supported by Lundbeck LLC).