Allergan says Botox works on chronic migraines

By Debra Sherman

CHICAGO (Reuters) - Allergan Inc said on Thursday that its popular Botox facial wrinkle-smoother worked as a treatment for adults suffering from chronic migraines, according to late-stage clinical data.

Shares of Allergan, which had been under pressure amid concerns the trial would fail, rallied as much as 13 percent, even as the broad market stumbled.

Botox, or botulinum toxin type A, is the first therapy being investigated for chronic migraine, which affects an estimated 1.2 million to 3.6 million people in the United States, according to the company.

Irvine, California-based Allergan, which also makes breast implants and eye-care products, said data from its Phase III clinical trials showed a significantly greater decrease in headache days among patients receiving Botox, compared with those receiving a placebo.

Injections at fixed-sites in varying locations, including the forehead, temples and potentially extending into the neck muscles, were well tolerated, it said.

"This is positive, there's no question about it," said Jefferies & Co analyst Peter Bye. "The question is, how positive? The devil is in the details here."

The first Phase III trial missed its primary goal of a reduction in the number of headache episodes compared with placebo, but did demonstrate a statistically significant benefit on the secondary goal of a reduction in headache days versus placebo.

DAYS VS. EPISODES

According to Allergan, the U.S. Food and Drug Administration considered the number of headache days as a preferred measure of effectiveness.

Based on the data from the first Phase III trial, Allergan changed the primary goal of the second Phase III study to number of headache days from number of headache episodes.

In the second Phase III study, the primary goal and secondary goal showed a statistically significant benefit for Botox over placebo.

"At this point, it is unclear to us if Allergan will be successful in obtaining a headache indication as we cannot think of a drug that received an indication after missing the primary endpoint in one study and switching the primary endpoint in the second study," Wachovia analyst Larry Biegelsen wrote in a research note.

He said he expects the FDA to conduct an Advisory Committee meeting, which could be to Allergan's advantage since Botox appears to be effective in treating migraine.

"Without seeing the actual clinical data, it is unclear to us if the results were clinically relevant," Biegelsen said.

Without an indication, the company could not promote the data as the U.S. Department of Justice is already investigating the off-label promotion of Botox for migraine, he noted.