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BiDil to Become First Drug Marketed to a Specific Racial Group

June 20, 2005

In an unprecedented move, the US Food and Drug Administration (FDA) cardiovascular drug advisory panel has voted 9:0 to recommend approval of cardiac drug BiDil to treat heart failure in Black patients. BiDil was developed by NitroMed of Lexington, Massachusetts, and contains the active ingredients isosorbide dinitrate and hydralazine.

"The Committee's recommendation to approve BiDil represents an important step forward in our ability to make this treatment available," says Dr. Manuel Worcel, Chief Medical Officer at NitroMed. "We believe that, if approved by the FDA, BiDil will provide new hope to Black heart failure patients who suffer a disproportionate burden of this disease."

BiDil has sparked controversy because of attempts to classify it as a race-specific drug. More than twice as many African Americans suffer from heart disease compared with white Americans, and some evidence exists to support different treatments for heart failure based on ethnicity. For example, ACE inhibitors are commonly prescribed in heart failure, but research suggests that their efficacy is lower among Black versus white patients.

Because of its mechanism of action, BiDil may play a particularly significant role when used to treat Black patients. BiDil's combination of isosorbide dinitrate (used to relieve heart pain) and hydralazine (used to ease blood pressure) raises nitric oxide levels in the blood. Nitric oxide is found at lower levels within the Black population and plays a variety of roles in maintaining good cardiac health.

Although BiDil has shown particular promise among Black people with heart failure, the FDA group roundly affirmed that the drug may have wider health applications among the general public.

BiDil's Background: Early Studies and "A-HeFT"

An early study of BiDil included over 1,000 individuals from many races, but at that time the FDA rejected the medication because, overall, participants showed little improvement. However, results from the same study also suggested that Black participants might receive more benefit than other participants. Therefore, NitroMed decided to conduct a second trial to test BiDil exclusively on African Americans. This second trial was called the African American Heart Failure Trial, abbreviated as "A-HeFT".

The A-HeFT study included 1,050 self-identified African American/Black patients with heart disease, half of whom received standard heart medications plus BiDil, and the other half of whom received standard medications along with placebo.

The results were significant: after about two years, 6.2% of participants receiving BiDil had died, versus 10.2% of participants receiving placebo. Moreover, 16.4% of those receiving BiDil were hospitalized for heart failure, versus 24.4% of those on placebo. BiDil's primary side effects, dizziness and headache, caused some participants to withdraw from the study.

The Future of BiDil

The FDA will use the advisory committee's findings to evaluate the A-HeFt study and decide whether or not to grant NitroMed permission to sell the drug. Although it is not required to follow the committee's recommendations, the FDA normally relies strongly on their findings to make their decisions.

Interestingly, two of nine FDA advisors who support the approval for BiDil believe that the drug label should not be race-specific. Moreover, some researchers have queried the findings of the original study of BiDil and believe that further investigation into BiDil's wider applications among the general population may be warranted.

NitroMed completed its resubmission of a new drug application for BiDil in December 2004 for the treatment of Black people with heart failure. According to goal-action dates set by FDA under the Prescription Drug User Fee Act (PDUFA), NitroMed expects a response from the FDA by June 23, 2005.

Posted: June 2005