U.S. officials approved on Thursday the first medicine for patients of one specific race, a heart failure treatment that sharply reduced deaths among blacks.

Nitromed Inc.‘s BiDil cut deaths by 43 percent in a company study, but the company’s strategy of marketing it just for one race has generated controversy.

A Nitromed trial of 1,050 people “clearly showed that blacks suffering from heart failure will now have an additional safe and effective option for treating their condition,” Dr. Robert Temple, the Food and Drug Administration’s associate director of medical policy, said in a statement.

“In the future, we hope to discover characteristics that identify people of any race who might be helped by BiDil,” Temple added.

BiDil is the first drug to reach the market for Lexington, Massachusetts-based Nitromed.

The FDA’s clearance of the drug specifically for blacks benefits Nitromed because the company holds patent rights for that use until 2020. The patent for BiDil for general use expires in 2007, a fact that has prompted criticism.

“This approval of BiDil isn’t about personalizing medicine. It’s about exploiting race to make money by extending patent protection,” said Jonathan Kahn, a law professor and ethicist at Hamline University in Minnesota who has studied BiDil’s development.

Kahn and other critics argued BiDil should be approved for all patients, regardless of race, because there is no biological reason blacks should respond differently than others.

Nitromed officials insist their effort is based on solid science and will address a major public health problem. African-Americans are more likely than others to develop heart failure and to die early from the disease, studies have found.

“FDA approval of BiDil represents an important leap forward in addressing this health disparity,” said Dr. Anne Taylor, a NitroMed consultant and lead researcher on the BiDil study.

Future research may identify a genetic variation in people of different races that indicates a good outcome from BiDil, company officials have said.

The drug is a combination of two generic medicines - isosorbide dinitrate and hydralazine - that dilate blood vessels. It was designed to treat congestive heart failure, a progressive weakening that impairs the heart’s ability to pump.

About 750,000 African-Americans have been diagnosed with heart failure, NitroMed said. Half the people with heart failure die within five years of diagnosis.

Tests of BiDil in the 1980s did not show a benefit for patients overall, but researchers said blacks fared better than others.

Nitromed and the Association of Black Cardiologists then studied 1,050 advanced heart failure patients who identified themselves as black, and gave them standard drug therapy plus either BiDil or a placebo.

Deaths were so much lower in the BiDil group that researchers ended the study early so all patients could take BiDil. Fifty-four patients, or 10.2 percent, died in the placebo group, compared with 32 deaths, or 6.2 percent, in the BiDil group. Hospitalizations from heart failure also were reduced.

Even with an approval for blacks only, doctors can prescribe BiDil for anyone they think it might help.