FDA Expands Botox Use

The FDA today expanded the indication of Allergan’s onabotulinumtoxinA (Botox), allowing the drug to be used for the treatment of upper limb spasticity in adults.

The label expansion also permits the drug to be injected into the flexor pollicis longus, a muscle in the forearm that flexes the thumb, and the adductor pollicis, a muscle in the hand that helps to adduct the thumb. Additionally, the expansion increases the maximum dose of Botox from 360 units to 400 units when used for the treatment of upper limb spasticity.

With this approval, Botox has become the first and only neurotoxin approved by the FDA for the treatment of this neurological condition, which produces muscle stiffness and can lead to tight muscles in the elbows, wrists, and fingers.

The agency based its nod on 2 studies that evaluated the efficacy and safety of 1-time Botox in a total of 279 patients with upper limb spasticity. In both trials, the researchers found the drug produced a clinically and statistically significant reduction in thumb flexor muscle tone compared with placebo.

“The FDA approval of the expanded Botox indication for upper limb spasticity represents the company's ongoing commitment to research and development in areas of unmet need," said Mitchell F. Brin, MD, Senior Vice President Global Development, in a press release. "Botox continues to provide effective patient care across a broad spectrum of medical conditions."

The most common adverse events reported by trial participants treated for upper limb spasticity included pain in extremities, muscle weakness, fatigue, nausea, and bronchitis.