Merck & Co., Inc. announced that, in a Phase III clinical trial, telcagepant (formerly MK-0974), its investigational oral calcitonin gene-related peptide (CGRP) receptor antagonist, significantly improved relief of migraine pain and migraine-associated symptoms two hours after dosing compared to placebo. In addition, the efficacy results for telcagepant 300 mg were similar to the highest recommended dose of zolmitriptan,1 an approved migraine therapy, with a lower incidence of adverse events associated with telcagepant in this study. The new data were presented here at the American Headache Society (AHS) annual meeting.

This trial is part of an ongoing Phase III program evaluating telcagepant. While Phase II and Phase III trials have used a liquid-fill capsule (including the study presented here), telcagepant has been successfully reformulated into a solid tablet that is being evaluated in ongoing trials. Merck continues to anticipate filing a New Drug Application (NDA) for telcagepant with the U.S. Food and Drug Administration 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., clinical study investigator and director of both 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."

Nearly 1,400 patients treated for migraine attack in this trial

The reported findings are from a randomized, double-blind, placebo- and active-controlled Phase III study in patients with migraine. A total of 1,380 adult patients who experienced a single moderate or severe migraine attack, as defined by the International Headache Society criteria, were treated with either telcagepant (as a liquid-filled soft gel capsule) at doses of either 150 mg (n=333) or 300 mg (n=354) or zolmitriptan 5 mg (n=345) or placebo (348). Patients enrolled were primarily women (85 percent) with an average age of 43 years.

Overall treatment effect was assessed by analyzing five primary endpoints at two hours post-dose: pain relief (reduction to mild or none); pain freedom (reduction to no pain); absence of sensitivity to sound (phonophobia); absence of sensitivity to light (photophobia); and absence of nausea. Sustained pain freedom from two to 24 hours (defined as those with no pain at two hours who remain free of pain during the two-24 hour period with no use of optional second study dose or rescue medication); total migraine freedom (TMF) (defined as no pain and absence of nausea, photophobia and phonophobia) at two hours post-dose; and TMF from two-24 hours were secondary endpoints of the study. The study was not designed to show equivalence or non-inferiority of telcagepant versus zolmitriptan.

Telcagepant relieved migraine pain and migraine associated symptoms in study

The treatment effect of the 300 mg dose of telcagepant was significantly greater than placebo for all five primary endpoints in the study (p=