Interestingly, in September 1999, right around the same time as the Human Genome Project a retrospective study was published in the Journal of Cardiac Failure by Carson et al titled, "Racial differences in response to therapy for heart failure: Analysis of the vasodilator-heart failure trials." In this study, they analyzed data from two previous trials studying the use of ACE inhibitors, isosorbide, and hydralazine in the treatment of congestive heart failure. When the data was split apart by race, there was a statistically significant decrease in the response of African American patients to the drug enalapril, and a statistically significant decrease in the effectiveness of hydralazine/isosorbide in white patients. The conclusion of the analysis was that certain drugs respond better for some races than others. In response to this study, the drug carvediol was studied specifically in the African American and white populations to say conclusively that it benefited both groups equally, and this became a marketing point for the pharmaceutical company that manufactures carvediol.
This Wikipedia article has a little more info:
Isosorbide dinitrate/hydralazine is a fixed dose combination drug treatment specifically indicated for black people with congestive heart failure. It is a combination of hydralazine (an antihypertensive) and isosorbide dinitrate (a vasodilator). It is the first race-based prescription drug in the United States. The combination preparation is marketed in the United States by Nitromed under the trade name BiDil.
Originally rejected by the Food and Drug Administration (FDA) in 1997, the combination preparation was approved by the FDA in June 2005 for black use only based on the results of a clinical study. It was already known that black individuals with congestive heart failure (CHF) respond less effectively to conventional CHF treatments (particularly ACE inhibitors) than Caucasians. The study by Taylor et al. demonstrated that isosorbide dinitrate with hydralazine reduced mortality by 43%, reduced hospitalizations by 39%, and quality of life markers in black patients with CHF.