Effectiveness of vigabatrin for infantile epileptic spasm syndrome categorized by etiologies

Purpose: We aimed to assess the effectiveness of vigabatrin (VGB) in patients diagnosed with infantile epileptic spasm syndrome (IESS) and categorize these patients based on their etiologies. Methods: This retrospective study included patients diagnosed with IESS who exhibited epileptic spasms before the age of 2 years between January 1, 2015, and October 31, 2023 at Saitama Children's Medical Center. Patients with tuberous sclerosis as the identified etiology were excluded. The effectiveness of VGB was assessed based on the resolution of ES for three months with the absence of hypsarrhythmia on interictal electroencephalogram. Results: This study analyzed 41 patients (26 boys). The etiologies included genetic, congenital structural, acquired structural, and unknown in 12, 11, 10, and 8 patients, respectively. Patient characteristics did not significantly differ among the four groups. The overall effectiveness of VGB for IESS was 39.0 % (16/41). Categorized based on etiology, VGB was effective in 41.7 % (5/12), 9.1 % (1/11), 50 % (5/10), and 75 % (6/8) in the genetic, congenital structural, acquired structural, and unknown groups, respectively. Statistical analysis revealed a significant difference in effectiveness among the four groups (p = 0.03). Categorized based on diseases, VGB was effective in 28.6 % (2/7) and 50 % (4/8) in trisomy 21 and perinatal brain injury, respectively. Conclusion: The effectiveness of VGB in patients with IESS varied with etiology. Further investigations into the effectiveness of VGB in etiological subtypes of IESS could facilitate the development of tailored treatment algorithms for each etiology, representing valuable guidelines for future medical practice.