NEW ORLEANS – A two-drug combination pill dramatically reduced deaths among blacks with heart failure, a landmark finding that is expected to lead to government approval of the first medication marketed for a specific race.

The nationwide study is the largest ever done solely on blacks with heart failure. The findings were reported Monday at an American Heart Association meeting in New Orleans and will be published Thursday in the New England Journal of Medicine. The drug’s maker plans to seek Food and Drug Administration approval by the end of the year.

Heart failure affects 5 million Americans, but blacks are 21/2 times more likely to develop it. It happens when the heart is too weak to pump effectively, causing fluid to back up in the lungs and leaving people weak and short of breath. Half die within five years of diagnosis.

Earlier research suggested that standard heart-failure drugs called ACE inhibitors do not work as well in blacks, and that blacks may have lower amounts of nitric oxide, which plays many roles in heart health, in their blood.

Two chemicals – isosorbide dinitrate and hydralazine – boost this substance, but administering the right dose is complicated when they are prescribed separately. A Massachusetts biotechnology company, NitroMed, developed a combination pill, BiDil, that gets around this problem, but the FDA refused to license it as a new drug because earlier studies involving mostly white patients who got the chemicals separately showed no benefit.

But there were tantalizing signs that BiDil helped the few blacks in the studies, and NitroMed won a patent to use it just in that minority group.

The company then launched a study of 1,050 blacks. Half of them got standard heart failure drugs; the other half got those drugs plus BiDil.

After about two years’ use, only 6.2 percent of the patients who took BiDil had died vs. 10.2 percent who got only standard heart failure drugs. That translates to a 43 percent reduction in deaths, said Dr. Anne Taylor of the University of Minnesota, one of the study’s leaders.

Only 16.4 percent on BiDil required hospitalization for heart failure, vs. 24.4 percent of the rest.

BiDil had substantial side effects – 47.5 percent on it had headaches, compared with 19.2 of the others. Dizziness occurred in 29.3 percent on the drug and 12.3 percent on placebos.