Bristol-Myers Squibb Corp. and Sanofi-Aventis SA blood pressure drug Avapro failed in a large study to show a benefit among patients with a common and difficult to treat form of heart failure.

Avapro, known generically as irbesartan, is a member of a class of blood-pressure drugs called angiotensin-receptor blockers or ARBs. It was thought that Avapro could improve patients with preserved ejection fraction heart failure who tend to have high blood pressure, but the study showed no such benefit.

“We were particularly disappointed because we still have large numbers of patients that still don’t have a good treatment” said Dr. Barry Massie, who presented the data at the American Heart Association scientific meeting on Tuesday.

Preserved ejection fraction heart failure, in which the heart has a reduced ability to pump blood, appears to affect women and the elderly. About 50 percent of the 5.3 million US citizens with heart failure have it.

 The 4-1/2 year-study involved 4,128 patients in 25 countries. The participants were given either their usual medicines and Avapro, or a placebo on top of their other treatments, such as hypertension drugs like ace inhibitors and beta blockers. After the follow-up period ended, there was no statistically significant difference between the composites rates of heart attack, heart failure or stroke in each group.

Some 742 patients in the Avapro group, or 36 percent, experienced these events, versus 763, or 37 percent, in the placebo group, the study showed. Also, there were similar rates of serious adverse events between the treatment groups, such as low blood pressure and kidney failure.

The findings were published online by The New England Journal of Medicine.