FDA Approves Botox for Lower Limb Spasticity in Pediatric Patients

The US Food and Drug Administration has expanded the indication for Allergan’s Botox (onabotulinumtoxinA) as a treatment for lower limb spasticity in pediatric patients, excluding those with cerebral palsy (CP).

The injection was approved for pediatric upper limb spasticity earlier this year, and is also approved for treatment of both upper and lower limb spasticity in adults.

"Lower limb spasticity can impact many aspects of a child's life and have a drastic influence on their overall development and quality of life," David Nicholson, chief research and development officer, Allergan, said in a statement. "This milestone will continue to support and advance care for children and their caregivers who may be struggling with lower limb spasticity.”

The approval was based on findings from a phase 3 study in more than 300 patients aged 2-17 with lower limb spasticity.

The 12-week, double-blind, placebo-controlled study also included a 1-year open-label extension study. Notably, while trial participants had CP, the FDA-approved indication excludes lower limb spasticity caused by CP due to marketing exclusivity by another company.

The FDA approved a recommend dose per treatment session of 4-8 U/kg divided among affected lower limbs, with the total dose per treatment session not exceeding 8 U/kg or 300 U, whichever is lower.

When using onabotulinumtoxinA to treat both lower or upper limbs or upper and lower limbs in combination, patients should not exceed a total dose of 10 U/kg body weight or 340 U, whichever is lower, in a 3-month period.

Common adverse events include dry mouth, injection site pain or discomfort, tiredness, headache, neck pain, eye problems, including double vision, blurred vision, decreased eyesight, drooping eyelids, swelling of your eyelids, dry eyes, and drooping eyebrows, and upper respiratory tract infection.

Findings of a sub-analysis were recently presented at the 2019 Child Neurology Society Annual Meeting in Charlotte, North Carolina, where investigators reported significant achievement in active and passive goals among patients with CP who were randomly assigned to receive treatment with onabotulinumtoxinA 4 U/kg, 8 U/kg, or placebo plus weekly standardized physiotherapy (PT) as part of the 12-week trial.

At baseline, 265 patients set active goals related to walking and moving, while 289 patients set passive goals related to symptoms of pain, spasm, or orthosis/brace wear. Investigators assessed patients using the Goal Attainment Scale (GAS), while a subset of 65 patients were assessed using the Edinburgh Visual Gait (EVG).

Overall, improvements in GAS were significant for onabotulinumtoxinA plus PT versus placebo plus PT for both active and passive goals at weeks 8 and 12 for patients who received the 8 U/kg dose (P <.010).

Patients who received the 4 U/kg dose plus PT saw significant improvements at week 8 (P <.047).

Patients who received either the 4 U/kg or 8 U/kg doses plus PT demonstrated a dose dependent improvement in total EVG score as well as select individual items, including foot stance and swing, compared with placebo. Notably, the 8 U/kg group reached statistical significance versus placebo at week 8 (P =.018).

The approval marks the 11^th time the FDA has approved Botox for a therapeutic indication.

This article was originally published in Neurology Live®.