Questions Linger on Pfizer Drug

Nissen and fellow authors say "careful consideration" should be given to the theory that good cholesterol produced by the Pfizer drug was "dysfunctional," causing some of the side effects. It's also possible, they say, that the Pfizer drug molecule had "unique" toxic effects.

"It is difficult to determine the extent to which the failure of torcetrapib was the result of dysfunctional [good cholesterol], properties that increased blood pressure, or other toxic effects specific to this agent," the authors say.

CETP inhibitors work differently than several other good-cholesterol-raising drugs on the market, including Niaspan, an extended release form of niacin, and TriCor. Both are sold by Abbott(ABT Quote).

The New England Journal says TriCor and similar drugs can raise good cholesterol "modestly," usually by 7% to 15% vs. the 61% gain for torcetrapib. The journal says large doses of niacin can raise good cholesterol by 25% or more, but this compound can cause flushing of the skin, occasional liver toxicity and an increase in blood-sugar levels.