The Food and Drug Administration has expanded the indication of abobotulinumtoxinA (Dysport) for upper-limb spasticity to include patients aged 2 years and older, according to a release from Ipsen. This botulinum toxin product received approval for this indication in adults in 2015 and approval for lower-limb spasticity in patients aged 2 years and older in 2016. Notably, Orphan Drug Exclusivity prevents it from being indicated for patients with cerebral palsy because another botulinum toxin product, onabotulinumtoxinA (Botox), already was approved for the indication in June 2019.
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Spasticity affects the muscles and joints of extremities, especially in growing children, and is usually caused by nerve damage, such as head trauma or spinal cord injury. The degree of spasticity can vary from mild muscle stiffness to severe, painful, and uncontrollable muscle spasms.
AbobotulinumtoxinA was evaluated for upper-limb spasticity in a phase 3, randomized, double-blind, low-dose controlled, multicenter study; the study enrolled 210 children aged 2-17 years with the condition and a Modified Ashworth Scale grade 2 or greater for elbow and wrist flexors. The children were randomized 1:1:1 to injections of either 8 units/kg, 16 units/kg, or 2 units/kg into the elbow flexors and wrist flexors. At 6 weeks, there were statistically significant improvements in Modified Ashworth Scale grade, the primary endpoint, with least-square mean changes from baseline of –2.0, –2.3, and –1.6, respectively.
AbobotulinumtoxinA and all other botulinum toxin products carry a boxed warning, the most serious warning the FDA issues. This warning refers to risk of botulism-like symptoms caused by the botulinum toxin spreading away from the injection area; these symptoms can included sometimes life-threatening difficulty swallowing or breathing. AbobotulinumtoxinA is contraindicated in patients with known hypersensitivity to any botulinum toxin or any of the components, those with presence of infection at proposed injection site(s), and those with known allergy to cow’s milk protein. It is also important to note that botulinum toxin preparations are not interchangeable; the potency units of one are not the same as those of another. Full prescribing information can be found on the Ipsen website.