NitroMed

(NTMD)

will unveil data Monday on its heart drug BiDil that will reveal for the first time just how much it benefits African-Americans suffering from heart failure.

In July, shares of the Lexington, Mass.-based drugmaker

soared when it halted a late-stage clinical study of BiDil after an independent monitoring board said the drug provided a statistically significant survival benefit. The benefit was so compelling, the monitoring board said, that it would have been unethical to keep the drug away from patients taking a placebo.

But while BiDil clearly works, final analysis of data from the study was kept under wraps -- until now. NitroMed will present this data from the BiDil study at the American Heart Association Scientific Sessions, which kick off this weekend in New Orleans.

NitroMed shares closed Thursday down 47 cents, at $23.73 -- that's up more than 300% since the company announced the BiDil study was stopped on July 19. NitroMed is expected to file BiDil with the Food and Drug Administration before year-end, which would allow the agency to approve the drug for marketing in the second half of 2005.

BiDil is not a novel, groundbreaking drug. It's actually a combination of two generic products, isosorbide dinitrate and hydralazine, neither of which are approved for heart failure. Previous studies of BiDil failed to show any benefit in a general population of heart-failure patients, but NitroMed re-analyzed the data and discovered that the drug seemed to help African-Americans. This led the company to conduct another phase III trial, the African American Heart Failure Trial, or A-HeFT, enrolling 1,000 African-Americans in 170 sites across the U.S.

At the American Heart meeting Monday, researchers will disclose for the first time the magnitude of the mortality benefit in the A-HeFT study that caused it to be halted early. Mortality benefit is defined as a percentage, calculated as the mortality benefit of those patients taking BiDil compared with patients given a placebo.

Generally speaking, a 30% to 40% mortality benefit in favor of BiDil is expected by Wall Street. J.P. Morgan analyst Cory Davis, who has an overweight rating on NitroMed, said in a September report that he would "classify anything in the neighborhood of 40% mortality improvement as 'very significant,' especially since all of the patients also had to be on at least digoxin, diuretics and beta-blockers," referring to other, commonly used drugs to treat heart failure. (J.P. Morgan has a banking relationship with NitroMed.)

The actual primary endpoint of the A-HeFT study is a composite of mortality, time until first hospitalization for heart failure and quality of life. Given that it's already known that BiDil produced a statistically significant mortality benefit, it's widely expected that this broader primary endpoint will be positive as well.

Since BiDil is made from two generic drugs, there has been some concern that doctors will bypass a branded product and simply prescribe the two generic components separately. But generic substitution is complicated by the precise dosing of the two individual drugs, as well as the large number of pills that patients would need to take.

NitroMed may also face intellectual property challenges. The company does have several method-of-use patents for BiDil's use as a heart-failure treatment in African-Americans expiring in 2020, but it doesn't have composition-of-matter patents, which are generally considered stronger and harder to break.

But if BiDil is approved, it will likely qualify for three years of marketing exclusivity under the Hatch-Waxman Act; after that, any generic competitor would have to fight NitroMed's patents in court.