Surgical resection is the only known effective treatment for the secondary prevention of infantile spasms, after treatment with both zonisamide and topiramate failed to prevent relapse.
Little evidence currently exists to guide the management of infantile spasms after response to initial therapies. Zonisamide and topiramate are commonly used to manage relapse, however risk of adverse events prevent the drugs from being used long-term.
In this study, researchers led by Rajsekar R. Rajaraman, MD, of Mattel Children’s Hospital UCLA and the David Geffen School of Medicine, sought to evaluate the efficacy of zonisamide and topiramate for the secondary prevention of infantile spasms.
One-hundred and six patients with EEG-confirmed infantile spasms were identified retrospectively, of whom 58 responded to hormonal therapy, 25 to vigabatrin, and 23 to surgery. To prevent infantile spasm relapse, 37 patients received zonisamide, 34 received topiramate, 3 patients received both medications, and 38 received neither. In total, 44 relapses were recorded during a median 6.9 months (3.2–10.8) after initial treatment response. Treatment with zonisamide and/or topiramate did not affect time to relapse. Patients who were older (hazard ratio .97 [per month], P= .036) and those who responded to surgical resection (hazard ratio = .28, P= .017) were less likely to have a relapse. Notably, the authors identified a refractory cohort who had multiple treatment failures as well as a delayed time to treatment response.
The authors concluded that neither zonisamide or topiramate were effective in preventing relapse despite dispensing high doses of the drugs. Surgical resection in eligible patients remains the only known treatment that is efficacious in the prevention of secondary infantile spasms.
Rejaraman RR, Lay J, Alayari A, Anderson K, Sankar R, Hussain SA. Prevention of infantile spasms: Zonisamide and topiramate provide no benefit. Epilepsia. 2016; doi:10.1111/epi.13442.