With all the talk about Obamacare recently, I'm beginning to get a headache, though probably not as big as the whopping migraine that members of Congress probably have.
Despite good efficacy data in its phase 2 trial yesterday at the International Headache Congress in Philadelphia, Merck said it's killing its backup compound, MK-3207, because patients in the phase 1 trial experienced liver-test abnormalities after going off the drug.
The lead compound, telcagepant, also looks pretty good on the efficacy side. The drug works just as well as AstraZeneca's
More importantly, there are fewer heart problems in patients taking telcagepant than in those who take Merck's current migraine drug, Maxalt. Drugs such as Maxalt, Zomig, and GlaxoSmithKline's
Unfortunately, while the heart data looks good, telcagepant may share some issues with its little brother, MK-3207. When taken daily, the drug appears to raise liver enzyme levels in patients -- an early sign of potential liver damage. Sure, Merck will ask the Food and Drug Administration to approve it for intermittent use, but the FDA will probably be worried that patients will take it more often than prescribed.
Compounds in the same class often exhibit similar side effects, and investors (and patients!) would be wise to pay attention to them. But it's also important to remember that there's often a spectrum of side effects in each class -- Merck's Vioxx was removed from the market, but Pfizer's
While telcagepant's liver side effects seem less severe than MK-3207's, it's not clear whether the difference is enough to get the drug on the market. All we investors can do right now is wait, and waiting is often not the worst choice to make.
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