The Food and Drug Administration (FDA) has approved Botox (onabotulinumtoxinA; Allergan) for the treatment of lower limb spasticity in pediatric patients 2 to 17 years of age, excluding spasticity caused by cerebral palsy. The treatment was already approved for pediatric upper limb spasticity earlier this year.

This new approval was based on data from a phase 3 trial evaluating the safety and efficacy of Botox in 381 pediatric patients with lower limb spasticity (modified Ashworth Scale ankle score of at least 2). Patients were randomized to receive Botox 4 Units/kg intramuscularly (IM), Botox 8 Units/kg IM or placebo into specified muscles of the lower limb and were followed for 12 weeks after injection. 

The co-primary end points of the study were the change from baseline in modified Ashworth Scale (MAS) ankle score and the average of the Clinical Global Impression of Overall Change by Physician (CGI; -4=very marked worsening to +4=very marked improvement), both at Weeks 4 and 6.

Results showed a statistically significant difference in MAS (-1.06) and CGI (1.65) with the 8 Units/kg dose of Botox vs placebo (P <.05). Moreover, improvements in mean change from baseline for the MAS and mean CGI score for lower limb spasticity were observed at timepoints up to Week 12 in patients treated with Botox compared with placebo.

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“Pediatric lower limb spasticity inhibits normal muscular movement and function and can result in delayed or impaired motor development, as well as difficulty with posture and positioning,” said Mark Gormley, Jr. MD, Pediatric Rehabilitation Medicine Specialist, Gillette Children’s Specialty Healthcare-St. Paul. “Botox has a well-established safety and efficacy profile, and supports children and adolescents successfully manage both their upper and lower limb spasticity.”

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