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Allergan (AGN, news, msgs) says two large human tests of its Botox drug, best known for smoothing wrinkles, have shown that periodic injections prevent headaches in adults who suffer from chronic migraines.
Though details of the study weren't released, the announcement, which surprised many physicians and investors, sent Allergan's shares surging late last week.
Botox has been used for many years to treat severe headaches, but some researchers have long been skeptical of its effectiveness and had expected the latest studies to fail.
Allergan said it will ask the Food and Drug Administration in a filing next year to expand approval for the drug to cover chronic migraine, a condition that the Irvine, Calif., drug maker said affects between 1.2 million and 3.6 million Americans.
If the FDA were to grant approval, Allergan would be able, for the first time, to market Botox directly to consumers for chronic migraine headaches. That could lead to a sharp increase in sales.
Analysts estimated that Botox sales for migraines are about $50 million but could rise to $400 million a year with regulatory approval.
Physicians are permitted to prescribe drugs for any use once the drugs are approved for one use. Allergan's Botox sales last year were about $1.2 billion, split evenly between cosmetic and therapeutic uses.
Reactions to Allergan's announcement ranged from exuberance to caution.
"These trials clearly showed that the drug worked in patients who are severely disabled with headaches almost every day of their lives -- not the garden-variety kind of migraine," said Stephen Silberstein, an investigator in the study and director of the headache center at Thomas Jefferson University Hospital in Philadelphia.
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A total of 1,384 patients were enrolled in the studies. Injections were given at varying sites around the forehead and the back of the neck.
Unlike in earlier studies, physicians were permitted to inject "where it hurts," said Silberstein, who treated between 40 and 50 patients in the study.
In May, the American Academy of Neurology, a professional group, published guidelines advising physicians that Botox injections weren't effective in the treatment of migraine or chronic tension-type headaches, based on evidence available at the time.
The physician who chaired the guidelines project said it is premature to say whether the guidelines will change. "It appears that at least some of the outcomes were positive. But one could make an argument that the primary outcome for one of the studies was negative," said David Simpson, professor of neurology at Mount Sinai School of Medicine in New York.
In the two studies, patients were randomly assigned to treatment with Botox or placebo injections every 12 weeks.
An analysis was performed at week 24 after two treatment cycles.
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Based on data from the first trial, Allergan changed the primary endpoint in the second study to focus on headache days rather than the number of headaches suffered.
Favorable results were obtained on both measures, the company said.
Allergan said the FDA considers the number of headache days the "preferred efficacy measure," and on that measure both studies were positive.
Scott Whitcup, Allergan's executive vice president of research and development, said that choosing the better measurement was difficult because "this is a new area and there isn't a regulatory pathway."
In retrospect, he says, the FDA was right to suggest measuring headache days because many patients have difficulty in answering a question about when a headache began or ended. However, when asked whether they suffered a headache on any given day, it's more clear-cut.
This article was reported and written by Rhonda L. Rundle for The Wall Street Journal.
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