…The main question: Is the problem limited to torcetrapib or is the whole category faulty?
The picture isn't clear, but some experts say the new torcetrapib data suggest CETP inhibitors might be a valid approach to heart care. If that thesis holds up, it would be good news for Pfizer, Merck & Co. and Roche Holding AG, which are developing other CETP inhibitors.
It is possible something unique to torcetrapib -- such as its tendency to raise blood pressure -- contributed to its failure, rather than a class effect. Other experimental CETP inhibitors haven't been associated with elevated blood pressure in studies so far.
"You don't want to abandon a class where the first drug you studied had unique toxicities," said Steven Nissen, head of cardiovascular medicine at the Cleveland Clinic and lead author of one of the torcetrapib studies. "We just don't know if we'll see that in the other compounds."
However, further development of CETP inhibitors could be prolonged. Dr. Nissen suggested that other compounds in the class should first undergo studies using imaging techniques, followed by trials to test whether the drugs reduce deaths, heart attacks and other events. That could delay the introduction of a CETP to the market for several years. For torcetrapib, imaging and outcomes trials were being conducted concurrently.
"Today's data certainly will raise significant doubts about these agents and will slow their development as well," said A.G. Edwards analyst Joseph Tooley. Results of the torcetrapib studies were presented at the annual meeting of the American College of Cardiology in New Orleans. The results also were published online by the New England Journal of Medicine.
Doctors and analysts say they'll get a better idea of why torcetrapib failed when Pfizer releases results of the 15,000-patient study that was halted in December due to the increased death rate. That will show what caused the higher death rate in the torcetrapib arm. Pfizer still is analyzing the results of the aborted trial.
Pfizer's other experimental CETP compounds remain in development, Steve Ryder, a senior vice president, said. But Pfizer's priority is to analyze as much data about torcetrapib as possible, to learn what implications it may hold for all CETP inhibitors, he said.
…Merck, Whitehouse Station, N.J., reiterated yesterday that no adverse effect on blood pressure was seen in early studies of its CETP inhibitor, MK-0859. Merck is pursuing another way to raise HDL: a combination of extended-release niacin and a compound designed to minimize a skin-related side effect of niacin that has limited niacin's use. Abbott Laboratories, Abbott Park, Ill., sells a prescription version of niacin and is also working on a version designed to reduce the side effect.
Roche said yesterday that it continues to investigate its CETP inhibitor, R-1658, and expects to submit it for regulatory approval after 2010. <<
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