Botox Approved to Treat Spasticity in 8 New Arm, Hand Muscles
The U.S. Food and Drug Administration (FDA) has expanded the label for Botox (onabotulinumtoxinA) in adults for the treatment of upper limb spasticity — a common symptom of multiple sclerosis (MS) — to include eight more muscles.
The new approval will allow Botox to be used to treat spasticity in the arms and hands of people with MS.
“Today’s announcement is especially important because spasticity is a disabling neurological condition that can have a significant impact on a patient’s quality of life,” Mitchell F. Brin, MD, senior vice president and chief scientific officer at AbbVie, the drug’s maker, said in a press release.
The new muscles added to the label are several of the elbow and forearm — specifically the brachialis, brachioradialis, pronator teres, and pronator quadratus — and the hands, to include the lumbricals and interossei. Two muscles of the thumb, the flexor pollicis brevis and the opponens pollicis, also are included in the new label.
In addition, the label expansion includes the use of ultrasound as a muscle-locating technique in adult spasticity.
“This label expansion not only adds to our rich history in neurotoxin science, but also reinforces the role of Botox in upper limb spasticity treatment,” Brin said.
“Botox provides an evidence-based dosing strategy to meet the clinical needs of providers and their patients,” he added.
Spasticity, which makes movement difficult, is one of the most common MS symptoms. It can affect walking, balance, and speech, all of which can be hampered by feelings of stiffness and heaviness in the muscles.
In the upper limbs, this often translates to a bent elbow, an arm pressed into the chest, or making a fist with the hand curled inward. These effects can significantly impact a person’s ability to perform daily tasks and worsen an individual’s overall quality of life.
Botox is an injectable preparation of botulinum toxin type A, a toxin naturally made by the bacteria that causes botulism, which blocks nerve activity in the muscles. It is injected directly into the affected muscles, resulting in short-term and localized muscle relaxation.
The treatment is approved for easing upper limb spasticity in patients ages 2 and older. However, it has not been shown to improve an individual’s functional abilities related to their upper extremities, or the range of motion at joints affected by stiffness and rigidity.
The expanded label will allow physicians greater flexibility in treating patients based on their clinical assessments, while staying within the medication’s maximum cumulative adult dose of 400 units in a three-month period.
The most common patient-reported side effects of botox are nausea, fatigue, bronchitis, muscle weakness, and pain in the extremities.
“Botox has demonstrated efficacy and safety for spasticity management at clinically proven doses,” said Kimberly Heckert, MD, director of the spasticity management fellowship at Thomas Jefferson University, in Philadelphia.
“This label expansion offers physicians and their patients living with spasticity another important tool as part of a comprehensive treatment plan for spasticity management,” Heckert said.