A global pharmaceutical company, Actavis plc, which recently completed the acquisition of Allergan, has received the United States Food and Drug Administration (FDA) approval for expansion of the Botox (onabotulinumtoxinA) label to treat adults with upper limb spasticity.

The expanded label now includes the addition of two thumb muscles: flexor pollicis longus, a muscle in the forearm that flexes the thumb; and adductor pollicis, a muscle in the hand that functions to adduct the thumb; increasing the maximum dose from 360 to 400 units for the treatment of upper limb spasticity.

The FDA also approved an increase to the maximum Botox cumulative dose within three months from 360 to 400 units in adults treated for one or more indications.

Botox is the first and only neurotoxin approved by the FDA for the treatment of upper limb spasticity—a debilitating neurological condition, producing muscle stiffness that can result in tight muscles in the elbow, wrist and fingers including thumb.

This FDA approval expands the therapy's previous approval in 2010. In patients 18 years and older with upper limb spasticity, Botox, a prescription medicine, is injected into muscles and used to treat increased muscle stiffness in elbow, wrist and finger muscles.

It is not known whether Botox is safe or effective to treat increased stiffness in upper limb muscles other than those in the elbow, wrist and fingers, or to treat increased stiffness in lower limb muscles. It has not been shown to help people perform task-specific functions with their upper limbs or increase movement in joints that are permanently fixed in position by stiff muscles.

Treatment with Botox is not meant to replace existing physical therapy or other rehabilitation prescribed by a doctor.

"It's critical for patients who suspect they may be experiencing upper limb spasticity in the elbow, wrist and fingers including thumb to seek a consultation with a physician specifically trained to treat upper limb spasticity, such as a neurologist or physical medicine and rehabilitation (PM&R) specialist. Often, even if the person has been suffering with the condition for years, there are ways to manage upper limb spasticity effectively," said Mitchell F. Brin, M.D., senior vice president, Global Development and chief scientific officer, Botox.

 "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. Botox continues to provide effective patient care across a broad spectrum of medical conditions."

More than 1.8 million Americans live with upper limb spasticity, which can occur weeks, months or even years after a stroke. The condition can manifest after a patient has stopped seeing a specialist for follow-up care.

"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, M.D., professor and chair, Department of Neurology at Wake Forest Baptist Medical Center in Winston-Salem, NC.

"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."

This expanded label approval for the two thumb flexor muscles is based on two additional randomized, multi-center, double-blind, placebo-controlled studies evaluating the efficacy and safety of Botox in patients with upper limb spasticity.

In the first study, the efficacy and safety of one-time Botox injections in 170 patients with upper limb spasticity were evaluated. Patients received a single treatment of Botox (40 units) or placebo into thumb flexor muscles. This study investigated the median change from baseline to week 6 in thumb flexor tone measured by the modified Ashworth Scale. Results showed that Botox neurotoxin produced a clinically and statistically significant reduction of 1.0 Botox 0.0 placebo (p< 0.001).

The second trial evaluated the efficacy and safety of one-time Botox injections in 109 patients with upper limb spasticity. Patients received a single treatment with lower dose (30 units) or higher dose (40 units) of Botox or placebo into thumb flexor muscles.

The study found that the higher dose of Botox produced a clinically and statistically significant reduction in thumb flexor muscle tone on the modified Ashworth Scale of 0.5 Botox vs 0.0 placebo (p< 0.010).

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