The heart failure drug BiDil (search) was approved Thursday by government regulators for use by blacks. It will be the first medication marketed for a specific racial group.

The Food and Drug Administration (search) called the approval a step toward "the promise of personalized medicine."

Studies showed that blacks benefited from the drug while the general population did not.

The drug is marketed by NitroMed Inc. (search) of Lexington, Mass.

"The information presented to the FDA clearly showed that blacks suffering from heart failure will now have an additional safe and effective option for treating their condition," said Dr. Robert Temple, the agency's associate director of medical policy. "In the future, we hope to discover characteristics that identify people of any race who might be helped by BiDil."

A study indicated that the drug led to a 43 percent reduction in deaths from heart failure among the blacks who took it. Research was stopped early after scientist realized the benefits of the drug so the data could be presented for the drug's approval.

BiDil is a combination of two older drugs, hydralazine and isosorbide dinitrate, neither approved for heart failure. Some common side effects with the drug are headache and dizziness.

Temple said the success of the drug in blacks was a "striking example of how a treatment can help some patients even if it does not help all patients."

In addition to the reduction in deaths, the FDA cited a 39 percent decrease in hospitalizations for those who took the drug compared with those who took a placebo.

While the favorable results of the study is good news for blacks, some health care experts said the company won't have financial incentive to do larger trials for the general population now that they have a product patented for blacks only. While, others worry that blacks will automatically be prescribed the pill based on their skin color, even if it may not be the best choice.

Messages left with Lawrence E. Bloch, NitroMed chief financial officer and chief business officer, weren't immediately returned.