According to two late stage trials, Botox, which is popular for smoothing out the wrinkles sold by Allergan Inc., effectively reduced the number of headache days for adults suffering from chronic migraines.

Results from this study were released a year ago but the complete data will be presented for the first time at a meeting of the International Headache Society in Philadelphia.

The trial involved 679 patients complaining of headaches, who were injected with Botox. It was seen that the frequency of their headaches was reduced by 7.8 days every month. This was compared with the results of another group placed on placebo whose headaches were reduced by 6.4 days monthly.

Allergan held a similar trial earlier but missed the primary aim of reducing the number of headache episodes compared with placebo but did meet the goal in the secondary trial.

Allergan plans to file for U. S. Regulatory approval of Botox for treatment of chronic migraine. Around 1.2-3.6 million people are affected with migraine in the United States. An estimate by Biegelsen shows that the market represents a $500 million opportunity for Botox.

Allergan shares went up $1.11 or 2 percent at $ 57.28 in afternoon New York Stock Exchange trading.