From rxpgnews.com

Pharmacology
BiDil to be Reviewed for Heart Failure Indication in African Americans
By FDA Advisory Committe
Apr 30, 2005, 08:12

NitroMed's BiDil will be reviewed by FDA's Cardiovascular & Renal Drugs Advisory Committee on June 16 for treatment of heart failure based on the African American Heart Failure Trial.

BiDil (hydralazine/isosorbide) could be the first FDA drug approval specifically for African Americans.

The dual vasodilator drug has been 'approvable' at FDA since March 2001. The agency requested results from the A-HeFT study be added to the application. The NDA was resubmitted in on Dec. 23, 2004, giving the antihypertensive a June 23 user fee deadline.

The 1,050-patient study was initiated in June 2001 and halted July 19, 2004 when preliminary results showed a significant survival benefit; top-line results were published in the Nov. 11, 2004 issue of the New England Journal of Medicine.

Investigators reported that adding BiDil to standard heart failure therapy provided a 43% improvement in survival compared to patients taking standard therapy plus placebo. BiDil also yielded a significant benefit for the primary endpoint, a composite score of death, first hospitalization and quality of life.

BiDil reduced mortality from 10.2% for placebo patients to 6.2% and the rate of first heart failure-related hospitalization from 22.4% to 16.4%. There was also an improvement in quality of life score from 2.7 to 5.6.

Researchers believe that African Americans may be more prone to nitric oxide deficiency than other populations.

In A-HeFT, 'one of the reasons [BiDil] may have worked is that the isosorbide dinitrate gives nitrate oxide, which is the vasodilating substance. The hydralazine, which is also a vasodilator, is also an anti-oxidant, and may help the body maintain the nitric oxide which was donated by the nitrate.'

"Hydralazine, by reducing oxidative stress, may enhance the effects of nitric oxide derived from nitric oxide donors as well as from endogenous sources," the NEJM authors hypothesized. "This study, however, does not establish that these mechanisms explain the clinical benefit of isosorbide dinitrate plus hydralazine in heart failure."

The authors conclude that A-HeFT's results "lend credence to the concept that the average effects in heterogeneous populations may obscure therapeutic efficacy in some subgroups and the lack of such efficacy in others".

NitroMed has predicted Bidil could be a $1 bil. market opportunity. There are approximately 750,000 African American heart failure patients in the U.S., NitroMed estimates.

The committee will also meet on June 15 to discuss class labeling of antihypertensive drugs based on the proximity of their data to outcome trials.

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