FDA OKs Botox for Adults With Upper Limb Spasticity

Troy Brown, RN

Disclosures

April 21, 2015

The US Food and Drug Administration (FDA) has approved an expanded indication for onabotulinum toxin A (Botox, Actavis) for the treatment of adults with upper limb spasticity, according to a company news release.

The expanded indication now adds two thumb muscles: the flexor pollicis longus, a forearm muscle that flexes the thumb, and the adductor pollicis, a hand muscle that adducts the thumb. The expanded indication increases the maximum dose from 360 to 400 units for the treatment of upper limb spasticity. The FDA also approved an increase to the maximum 3-month cumulative dose from 360 to 400 units in adults treated for one or more indications.

The drug is injected into affected muscles to relieve stiffness. It is unknown whether onabotulinum toxin A is safe or effective in treating upper limb muscles other than those in the elbow, wrist, and fingers or in treating spasticity in lower limb muscles.

"Debilitating Neurological Condition"

Onabotulinum toxin A is the first and only neurotoxin the FDA has approved for the treatment of upper limb spasticity. Upper limb spasticity is a debilitating neurological condition that causes muscle stiffness that can tighten muscles in the wrist, fingers, and thumbs.

More than 1.8 million Americans live with the disorder, which can occur weeks, months, or even years after a stroke.

"Simple tasks such as washing the affected hand or getting dressed can be limiting for patients with the condition, and they're often left to depend on a caregiver to help them," said lead clinical trial investigator Allison Brashear, MD, professor and chair, Department of Neurology, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina, in the company statement.

"It's important for patients experiencing these types of symptoms to talk to their doctor, who can refer them to a neurologist or physiatrist to discuss their treatment options," she added.

The FDA approved onabotulinum toxin A to treat spasticity in the flexor muscles of the elbow, wrist, and fingers in adults in March 2010. Spasticity often occurs after stroke, traumatic brain injury, or the progression of multiple sclerosis.

Studies Support Expanded Indication

The expanded indication follows a discussion of two additional randomized, multicenter, double-blind, placebo-controlled studies that evaluated the safety and efficacy of the drug in those with upper limb spasticity in thumb flexor muscle involvement, according to the company statement.

In the first study, the researchers randomly assigned 170 patients with upper limb spasticity to receive a single injection of onabotulinum toxin A (40 units) or placebo into the thumb flexor muscles. At week 6, the treatment drug caused a clinically and statistically significant reduction in thumb flexor muscle tone of 1.0 Botox vs 0.0 placebo (P < .001), as measured by the modified Ashworth Scale.

In the second study, researchers evaluated the efficacy and safety of a single onabotulinum toxin A injection of 30 or 40 units or placebo into the thumb flexor muscles of 109 patients with upper limb spasticity. The higher dose of the treatment drug caused a clinically and statistically significant reduction in thumb flexor muscle tone, as measured by the modified Ashworth Scale, of 0.5 Botox vs 0.0 placebo (P < .010).

The most commonly reported adverse reactions after injection of the treatment drug for upper limb spasticity include extremity pain, muscle weakness, fatigue, nausea, and bronchitis.

In addition, it has not been demonstrated to assist people in performing certain functions with their upper limbs or to improve movement in joints that are permanently deformed by muscle stiffness.

The most frequent adverse reactions following injection of Botox for upper limb spasticity include pain in extremity, muscle weakness, fatigue, nausea, and bronchitis.

Actavis recently acquired Allergan, the primary supplier of the drug in the United States.

For additional information, patients should refer to the Medication Guide or talk with their physician. Report negative adverse effects of prescription drugs to the FDA at http://www.fda.gov/medwatch or call 1-800-FDA-1088.

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