Fate of New Migraine Drug Is Uncertain
Researchers Say Telcagepant May Help Treat Migraines, but Safety Issues Remain
April 21, 2010 -- An experimental migraine drug could help many patients who can't take or don't respond to current treatments, but questions remain about its safety.
Studies suggest that the drug telcagepant works in many people whose headache pain is not relieved with triptans, which are considered the most effective currently available drugs for treating migraines.
As many as a third of migraine sufferers fall into this category, according to one research analysis.
Since triptans cause the blood vessels to constrict, they may not be considered appropriate for use in people with heart disease or angina, history of stroke, uncontrolled high blood pressure, or pregnant women.
Telcagepant is a new type of migraine drug that blocks the calcitonin-gene-related peptide (CGRP) receptor.
In a review of investigational migraine treatments published today in The Lancet, migraine researchers Lars Edvinsson, MD, and Mattias Linde, MD, write that CGRP-targeting drugs may prove to be an important advance in migraine treatment.
But it is not clear if drugmaker Merck & Co., which developed telcagepant, will pursue regulatory approval for the drug due to concerns about its potential toxic effect on the liver.
Last spring, a phase II trial of telcagepant for the prevention of migraines was stopped early after several patients developed elevated liver enzymes indicative of possible liver damage.
When the treatment was stopped, liver enzyme levels returned to normal.
After meeting with regulatory authorities, Merck agreed to conduct an additional safety study of the drug.
Until that trial is completed, the company will not decide whether to seek approval for telcagepant as a migraine treatment, Merck spokeswoman Pam Eisele tells WebMD.
Edvinsson tells WebMD that with the exception of the unresolved questions about liver safety, the CGRP receptor blockers seem to have fewer troublesome side effects than triptans.
Patients who take triptans often complain of nausea, dizziness, abnormal skin sensations like numbness or tingling, or throat or chest tightness.
Some 28 million Americans have some experience with migraines, including 25% of women and 8% of men, according to the National Headache Foundation.
In some people, symptoms are limited to severe headache. In others, headaches are accompanied by nausea and vomiting, sensitivity to light and noise or visual displays preceding or during attacks known as aura.