The roughly five million Americans who suffer from heart failure, a chronic and deadly disease, could be part of a radical change in the practice of medicine later this year. Cardiologists across the country will likely begin to prescribe a new, and by most accounts highly promising, drug based on an unusual criterion: whether the patient is black or white – or, to be more precise, whether the person identifies him- or herself as an African American.
Sometime by midyear, the U.S. Food and Drug Administration will decide whether to approve BiDil, a heart failure medicine developed by NitroMed, a small pharmaceutical company in Lexington, MA. Experts say that the drug, if approved, will be the first pharmacuetical targeted exclusively at a specific racial group. While physicians often prescribe medicines differently for white and black patients, the new pill could mark a change in how drugs are clinically tested, reviewed by the FDA, and marketed. And its arrival has set off a heated debate among physicians, geneticists, and social scientists over the biological justification for and social ramifications of so-called race-based medicines – and over how drug developers should handle information about genetic variations in the world’s different populations.
At the core of the controversy is a disagreement over whether lumping people into a few broad racial categories has any medical value as a shortcut to more-detailed genetic analysis. The debate is particularly urgent because biomedical researchers have begun to identify subtle genetic differences among population groups and are finding preliminary but provocative clues as to why populations often react differently to drugs. Most notably, the International HapMap Project, a consortium of leading genomic researchers, is cataloguing genetic variations by examining the frequency with which certain blocks of DNA occur in different groups around the world (see “Genes, Medicine, and the New Race Debate,” June 2003, p. 40). One goal of the HapMap project and related research is to give physicians and drugmakers the tools needed to more accurately predict how different patients will respond to drugs. But fully fleshing out the genomic variations among population groups – and relating them to differences in drug responses – will take years.
Enter NitroMed and BiDil, a pill that, literally, reduces group differences in drug response to black and white. Some argue that it is a form of high-tech racial marketing done by a pharmaceutical industry eager to sell to well-defined groups of consumers. Others, including many physicians, counter that BiDil and other potential race-specific drugs represent a shortcut, albeit a crude one, to using genetic variation to more effectively and safely prescribe medicines. According to this argument, considering the race of a patient is simply a commonsense approach until using more-detailed genomic information becomes practical.
“There are extraordinary opportunities in the tailoring of medicines. It is plainly the future,” says M. Gregg Bloche, a physician and law professor at Georgetown University. But using race as a shortcut to that future, he says, “presents all sorts of risks.”
The problem, say critics of BiDil, is that while genetic patterns are related to a population’s shared ancestries and geographic histories, what are conventionally called races are socially constructed categories that have little basis in biology or genetics. Marketing BiDil only to black patients “is a bad idea,” says Charles Rotimi, an epidemiologist and acting director of the National Human Genome Center at Howard University in Washington, DC. The problem, he says, “is in using a social label that we know is not directly related to genetics” to categorize responses to a drug. That practice, says Rotimi, ignores the complexities and subtleties of population genomics, conflating genetics and race.
Making the debate over BiDil even more contentious is the convincing evidence that the drug is, for many heart failure patients, a lifesaver. Of the five million Americans suffering from heart failure, about 725,000 are African American. And there is evidence that, as a group, African Americans tend not to respond as well to some conventional heart failure drugs, such as angiotensin-converting enzyme (ACE) inhibitors. By nearly all accounts, BiDil could help a significant portion of these African-American patients.
Indeed, NitroMed’s clinical trial of BiDil in African Americans – a 1,050-patient study called A-HeFT – was halted last year because results indicated that the drug was helping patients dramatically, and experts considered it unethical to continue denying the benefits of the drug to those trial participants receiving placebos. While the patients in the study were already taking a number of conventional heart failure medicines – some as many as a dozen – adding BiDil to that mix decreased their mortality rate by 43 percent. “When a drug reduces the risk of death by that much,” says Clyde Yancy, a cardiologist at the University of Texas Southwestern Medical Center at Dallas and an A-HeFT investigator, “it gets the attention of the medical community. It’s a significant opportunity for treating an important disease.”