Telcagepant thumbs up or down?
Migraine is believed to be caused by an interaction between over-excited nerves and blood vessels around the brain. Researchers believe you can effectively treat a migraine by blocking the migraine mechanism in several places along its pathway. The group of migraine drugs called the triptans—like sumatriptan, rizatriptan, zolmitriptan, eletriptan, and almotriptan—work by affecting the nerve part of this pathway. Triptans work on the nerve serotonin receptors.
Telcagepant is a new drug being developed by Merck as an alternative acute migraine treatment.
The exciting thing about telcagepant is that it works on a different migraine mechanism—the vascular side of the mechanism. Telcagepant blocks the calcitonin gene-related peptide receptor. Calcitonin gene-related peptide is important for blood vessels expanding or dilating, which enhances migraine pain signaling.
So, does telcagepant work? The January 2011 issue of the journal Headache includes a series of articles describing research studies designed to ask this very question. If you just read the title of one of the articles—"Excellent tolerability but relatively low initial clinical efficacy"—you might be tempted to read no further and decide this new drug is just a bust. But if you do that, you'll miss the important results of these studies. Here's what the studies show:
- In general, telcagepant is not as effective as the triptan medications.
- After 1 hour, migraine pain was completely gone in 14 percent of patients treated with telcagepant, 18 percent with sumatriptan, and 24 percent with rizatriptan.
- After 2 hours, migraine pain was completely gone in 27 percent of patients treated with telcagepant, 33 percent with sumatriptan, and 40 percent with rizatriptan.
- Telcagepant had very few side effects.
But that study tells only part of the story. A more interesting study in this same journal compared migraine relief with telcagepant or zolmitriptan. They divided people up into those who had previously had good success with a triptan medication and those who did not:
- As you might expect, people who previously responded well to a triptan got good pain relief from zolmitriptan. Migraine pain was completely gone after 2 hours in 44 percent of people previously doing well with a triptan, but only 14 percent of those not having previously found a triptan to be helpful.
- The highest dose of telcagepant tested completely eliminated pain after 2 hours for only 23 percent of people who usually did well with a triptan, and 29 percent of those who didn't find triptans helpful.
So what are the take-home messages? Thumbs up or thumbs down? Well, a little of both.
- Telcagepant probably won't work as well for migraine as the triptans.
- If you're already getting good relief from a triptan and are tolerating it, stick with it. Telcagepant probably won't work better for you.
- But if you haven't found that triptans are the answer for you, this new class may be just what the doctor ordered.
Telcagepant is currently under development and is not yet available for patients.
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