October 16, 2010 — The US Food and Drug Administration (FDA) has approved onabotulinumtoxinA (Botox; Allergan Inc) for headache prophylaxis in patients with adult chronic migraine who suffer headaches on 15 or more days per month, each lasting more than 4 hours.
"Chronic migraine is one of the most disabling forms of headache," said Russell Katz, MD, director of the Division of Neurology Products in the FDA's Center for Drug Evaluation and Research, in a statement. "Patients with chronic migraine experience a headache more than 14 days of the month. This condition can greatly affect family, work, and social life, so it is important to have a variety of effective treatment options available."
To treat chronic migraine, onabotulinumtoxinA is given approximately every 12 weeks as multiple injections around the head and neck "to try to dull future headache symptoms," the FDA statement notes. It has not been shown to work for the treatment of episodic migraine headaches that occur 14 days or fewer per month, or for other forms of headache, it adds.
The most common adverse reactions reported by patients being treated with onabotulinumtoxinA for chronic migraine were neck pain and headache.
Marketed as Botox and Botox Cosmetic, onabotulinumtoxinA has a boxed warning that the effects of the botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism, the FDA statement adds. Symptoms include swallowing and breathing difficulties that can be life-threatening.
"There has not been a confirmed serious case of spread of toxin effect when Botox has been used at the recommended dose to treat chronic migraine, severe underarm sweating, blepharospasm, or strabismus, or when Botox Cosmetic has been used at the recommended dose to improve frown lines," the FDA notes.
The approval for chronic migraine was based on results of the phase 3 Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) program, which was made up of 2 double-blind, placebo-controlled clinical trials that included 1384 adults from 122 centers in North America and Europe, a statement from Allergan notes.
In both of these studies, patients receiving onabotulinumtoxinA had a significantly greater decrease in the frequency of headache days from baseline compared with placebo at 24 weeks, 7.8 and 9.2 fewer days for the treated groups vs 6.4 and 6.9 days for the placebo groups, respectively.
Treated patients also had a total cumulative reduction in headache hours by 107 and 134 hours, respectively, compared with 70 and 95 hours for the placebo groups.
Adverse reactions reported by greater than 2% of treated patients and more frequent than in placebo patients included headache, migraine and facial paresis, eyelid ptosis, bronchitis, musculoskeletal and connective tissue disorders including neck pain, musculoskeletal stiffness, muscular weakness, myalgia, musculoskeletal pain and muscle spasms, injection site pain, and hypertension.
Severe worsening of migraine requiring hospitalization occurred in approximately 1% of patients treated with onabotulinumtoxinA in both studies, usually within the first week of treatment, compared with 0.3% of patients receiving placebo (Cephalagia. 2010;30:793-803, 804-813).
OnabotulinumtoxinA was first approved by the FDA 21 years ago for the treatment of strabismus and blepharospasm, and it is now approved for a variety of indications including upper limb spasticity, cervical dystonia, as well as severe primary hyperhidrosis, and in lower doses, to temporarily improve the look of moderate to severe frown lines between the eyebrows, called glabellar lines.
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Cite this: Botox Approved for Headache Prophylaxis in Chronic Migraine - Medscape - Oct 16, 2010.