Merck issued positive results from a phase III pivotal clinical trial of telcagepant, a calcitonin gene-related peptide (CGRP) antagonists for the treatment of migraine headaches. Merck stated the company plans to file for FDA approval in the U.S. in 2009.

"These findings provide further support for the development of telcagepant as a potential new acute migraine treatment based on its novel mechanism of action targeting CGRP," said Paul Winner, D.O., F.A.A.N., study investigator and director of Premiere Research Institute and Palm Beach Headache Center, West Palm Beach, Florida. "Based on this initial large study, the investigational compound telcagepant relieved migraine pain and migraine associated symptoms comparable to a triptan medication but with fewer side effects."

The randomized, double-blind, placebo-controlled trial enrolled 1,380 adult subjects who had experienced a single moderate or severe migraine attack.

The subjects received either telcagepant (as a gel capsule) at doses of either 150 mg or 300 mg or zolmitriptan 5 mg or placebo. Five primary endpoints were analyzed at two hours post-dose. The 300 mg dose of telcagepant was significantly greater than placebo for all five primary endpoints in the study (p=

The studies results for each of the endpoints are as follows:

Two-hour pain relief: 55% of subjects who received telcagepant reported their pain had been reduced at two hours compared to 56% for zolmitriptan and 28% for placebo.

Two-hour pain freedom: 27% of subjects in the telcagepant arm reported being pain free at two hours compared to 31% for zolmitriptan and 10% for placebo.

Absence of phonophobia: 58% of subjects who received telcagepant reported they were not experiencing sensitivity to noise at two hours compared to 55% for zolmitriptan and 37% for placebo.

Absence of photophobia: 51% of subjects in the telcagepant arm reported they were not experiencing sensitivity to light compared to 50% for zolmitriptan and 29% for placebo.

Th absence of nausea was reported in 65% of subjects who received telcagepant, 71% for zolmitriptan and 55% for placebo. All secondary endpoints were reached as well.

Migraine headaches affect about 35 million Americans and tend to be more common in women than men.