An experimental drug from Roche raised "good" HDL cholesterol substantially without increasing blood pressure, the problem that sank a rival treatment from Pfizer, researchers said on Sunday.
The data from a relatively small Phase II trial may increase confidence in the high-risk project, although the key test of whether dalcetrapib saves lives in heart patients will not be known until a large Phase III trial finishes in late 2012, with results likely in 2013.
Dr. Thomas Luescher, of University Hospital Zurich, said the new drug was generally well tolerated and did not produce any significant increase in blood pressure. Nor did it impair the flow rate in blood vessels.
After 36 weeks, dalcetrapib had increased high-density cholesterol (HDL) levels by an average 31 percent and no safety problems were seen. The study involved 476 patients who received either dalcetrapib or placebo.
In contrast to another small study of the drug, details of which were released a week ago, there was no difference in the number of adverse cardiovascular events seen between patients on dalcetrapib and those on a placebo.
However, neither of the two studies was large enough to detect significant differences in such outcomes.
It is still early days for dalcetrapib, and medical experts remain wary following the high-profile failure of a similar drug from Pfizer, called torcetrapib, in 2006.
Dr. Keith Fox from the University of Edinburgh, who was not involved in the Roche-sponsored research, said the limited size of the trial meant it might not reveal all potential problems.
There is also a lack of evidence -- so far at least -- that raising HDL with drugs actually stops heart attacks and strokes.
Nonetheless, the research presented at the European Society of Cardiology annual meeting is encouraging and may also a boost the broader field, which includes another experimental HDL-boosting drug from Merck & Co.
"I think we can say it is safe and has no untoward effects and it does the job as far as the lipid (cholesterol) profile is concerned," lead researcher Luescher told reporters.
"It's a bit less potent than torcetrapib, which increased HDL by about 60 to 70 percent, but maybe that is even an advantage.
"It was a bit disappointing that vascular (blood vessel) function wasn't improved -- it wasn't worsened, but it wasn't improved."
NO PROOF YET
Dr. Heinz Drexel, a cardiologist at the Private University in the Principality of Liechtenstein who was not involved in the study, said it was encouraging that the problems with the earlier Pfizer drug had been avoided.
But while there is strong evidence from epidemiological studies that low HDL is linked to heart problems, the jury is still out on whether Roche's new drug will make a difference.
"It's promising, but it's no proof that it will reduce outcomes," Drexel said of the latest data.
Industry analysts believe dalcetrapib, which Roche bought from Japan Tobacco, could become a multibillion-dollar-a-year seller if it proves itself in final-stage Phase III tests, which are now under way.
Tim Race of Deutsche Bank said he saw theoretical peak sales of 10 billion Swiss francs ($10 billion) but was adjusting this by 75 percent for risk to 1.2 billion by 2016.
If it succeeds, dalcetrapib would become a major product for Roche and one that would start to diversify its focus firmly beyond cancer treatments, where it is the market leader.
Dalcetrapib and Merck's anacetrapib -- like torcetrapib -- belong to a class of drugs called CETP inhibitors.
Some doctors currently prescribe a different product called niacin, a B vitamin that can boost heart-protective HDL. But niacin is not widely used because it causes uncomfortable facial flushing.
Adding to uncertainty about the role of drugs in HDL, U.S. government researchers reported in May that giving niacin to heart patients already taking a cholesterol-lowering statin did nothing more to prevent heart attacks and strokes.