The FDA has approved the supplemental biologics license application for Dysport (abobotulinumtoxinA, Ipsen Biopharmaceuticals) for injection for the treatment of lower- limb spasticity in pediatric patients 2 years of age and older. Dysport is the only FDA-approved botulinum toxin for the treatment of pediatric lower-limb spasticity.
Dysport is an injectable form of botulinum toxin type A (BoNT-A), which is isolated and purified from Clostridium bacteria producing BoNT-A. It is supplied as a lyophilized powder. Dysport was previously approved in the United States for the treatment of adults with cervical dystonia or upper-limb spasticity to reduce the severity of increased muscle tone in elbow, wrist, and finger flexors.
The FDA’s label update was based on results from a pivotal phase 3, randomized, double-blind, placebo-controlled, international study in 235 patients 2 to 17 years of age with lower-limb spasticity due to cerebral palsy causing dynamic equinus foot deformity. The patients were randomly assigned to receive Dysport 10 U/kg/leg, Dysport 15 U/kg/leg, or placebo injected into the gastrocnemius-soleus muscle complex located in the calf. The study included patients who were botulinum toxin naïve or previously treated with a botulinum toxin more than six months before study entry.
The coprimary efficacy endpoints showed a statistically significant improvement in the mean change from baseline in the Modified Ashworth Scale (MAS) in ankle plantar flexor muscle tone with both doses of Dysport compared with placebo at week 4. The mean treatment differences were –0.9 for Dysport 10 U/kg/leg and –1.0 for Dysport 15 U/kg/leg compared with –0.5 for placebo (P < 0.05).
A statistically significant improvement was also observed in the mean Physician’s Global Assessment (PGA) response-to-treatment score at week 4. The mean treatment differences were 1.5 for Dysport 10 U/kg/leg and 1.5 for Dysport 15 U/kg/leg compared with 0.7 for placebo (P < 0.05). At week 12, the mean PGA response-to-treatment scores were 0.8 for Dysport 10 U/kg/leg and 1.0 for Dysport 15 U/kg/leg compared with 0.4 for placebo (P < 0.05).
Dysport and all botulinum toxin products have a boxed warning stating that the effects of the botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism. Those symptoms include swallowing and breathing difficulties that can be life-threatening. Dysport is contraindicated in patients with known hypersensitivity to any botulinum toxin preparation or to any of the components; or in the presence of infection at the proposed injection site; or in patients known to be allergic to cow’s milk protein. The potency units of Dysport are specific to the preparation and assay method used. They are not interchangeable with other preparations of botulinum toxin products.
Source: Ipsen Biopharmaceuticals; August 1, 2016.