Botulinum Toxin Type A Neuromuscular Blockade in the Treatment of Equinus Foot Deformity in Cerebral Palsy: A Multicenter, Open-Label Clinical Trial

Abstract

Background. Focal spasticity of the gastrocnemius-soleus muscles causes equinus gait in children with cerebral palsy (CP). Botulinum toxin type A (BTX-A), a neuromuscular blocking agent, reduces muscle tone/overactivity in dystonia, stroke, and CP. Objective. A prospective, open-label, multicenter clinical trial evaluated the long-term safety and efficacy of repeated intramuscular injections of BTX-A on equinus gait in CP children. Methods. Nine centers enrolled 207 children. BTX-A injections (4 U/Kg) were given approximately every 3 months (maximum dose 200 U per treatment). Outcome measures included a Physician Rating Scale of gait, ankle range of motion measurements, and the incidence and profile of adverse events. Results. One hundred fifty-five (75%) of 207 children completed at least 1 year with a total of 302 patient years of BTX-A treatment. The mean duration of BTX-A exposure was 1.46 years per patient. Dynamic gait pattern on the Physician Rating Scale improved in 46% of patients (86/185) at first follow-up. The response was maintained in 41% to 58% of patients for 2 years. Both gait pattern and ankle position improved at every visit. The most common treatment-related adverse events included increased stumbling, leg cramps, leg weakness, and calf atrophy in 1% to 11% of patients. No treatment-related serious adverse events were reported. Only 6% (7/117) of patients with pre- and postantibody samples had both detectable antibodies and a subsequent treatment failure. Conclusion. BTX-A proved both safe and effective in the chronic management of focal muscle spasticity in children with equinus gait.