VANCOUVER -- Guidelines for the use of botulinum toxin in various neurological disorders are getting an update, with the best evidence supporting the use of some formulations in spasticity and chronic migraine, researchers reported here.
All three botulinum toxin type A formulations are supported by level A evidence for use in upper limb spasticity, and onabotulinumtoxinA (Botox) received a level A recommendation in chronic migraine, although the magnitude of the benefit is small, according to David Simpson, MD, of Icahn School of Medicine at Mount Sinai in New York, and colleagues.
The new guidance, which is the first since 2008, was published online in Neurology and reported here at the American Academy of Neurology meeting.
There are four types of botulinum toxin available on the U.S. market: three type A and one type B. Type A botulinum toxins include abobotulinumtoxinA (Dysport), incobotulinumtoxinA (Xeomin), onabotulinumtoxinA (Botox), and the lone Type B product is rimabotulinumtoxinB (Myobloc).
Simpson and colleagues reviewed the evidence for botulinum toxin in four conditions: cervical dystonia, blephrospasm, limb spasticity, and headache.
"We chose these diseases because we had a sense that there were sufficient data to show they were going to change in particular ways," Mark Hallett, MD, of the National Insitute of Neurological Disorders and Stroke, a co-author of the guideline, said during a press briefing. "We already had a feeling for what we were going to find, but we had to prove it carefully."
All three botulinum toxin type A drugs had level-A evidence supporting their use in upper limb spasticity, and abobotulinumtoxinA and onabotulinumtoxinA had level A evidence behind their use in lower limb spasticity, the researchers reported.
There was also strong level-A evidence that onabotulinumtoxinA works in chronic migraine, since the drug had been approved by the FDA in 2010 for this condition -- although the magnitude of benefit was small, Simpson said, with a 15% reduction in headache days per month compared with placebo.