Vigabatrin for infantile spasms

Infantile spasms describe a pediatric epilepsy syndrome characterized by frequent clusters of brief symmetric muscle contractions; the condition is often associated with developmental delay. When infantile spasms are accompanied by hypsarrhythmia on electroencephalogram, the condition is labeled West syndrome. The mainstay of treatment for infantile spasms is adrenocorticotropic hormone; however, vigabatrin, a vinyl derivative of γ-aminobutyric acid, has been used for the treatment of infantile spasms in Europe since 1989. In 2009, vigabatrin was approved by the United States Food and Drug Adminstration (FDA) for use as monotherapy in the treatment of infantile spasms in patients aged 1 month-2 years when the benefits of treatment outweigh the risks. Results from numerous trials examining the role of vigabatrin in infantile spasms have been published; many of these trials were small, open-label, or noncontrolled. Although clinical trials have provided some insight into the utility of vigabatrin for the treatment of infantile spasms, these studies have notable limitations. In addition, vigabatrin is associated with a black-box warning that describes the potential for permanent bilateral concentric visual field defects. Currently, vigabatrin is available through a manufacturer-sponsored program in accordance with its FDA-approved Risk Evaluation and Mitigation Strategy. Although several guidelines recommend vigabatrin as a first-line therapy for infantile spasms, specifically infantile spasms related to tuberous sclerosis, it is still unclear whether vigabatrin should supersede hormone therapy as first-line therapy. Further research comparing the two therapies is needed.