Commentary: Color-Blind Drug Research Is Myopic
Get ready for the fireworks. On June 16, a Food & Drug Administration panel was expected to recommend that the agency approve the heart failure drug BiDil. NitroMed Inc. (NTMD ), which developed it, is asking that the drug be cleared specifically for use by African Americans. The move is stirring up critics who say that the company is simply out to extend its patent life with such a targeted approval -- a charge NitroMed denies. More worrisome, bioethicists warn that greenlighting a drug for only one race sets a dangerous precedent. "This can fuel social conceptions that there are meaningful genetic differences between races," says Jonathan D. Kahn, assistant professor of law at Hamline University in St. Paul, Minn.
Yes, NitroMed's application raises some tough questions. But there should be more -- not less -- study of how people of different races respond to drugs. While ethnicity can be an imperfect measure, understanding the interplay between race and drug efficacy could be a crucial tool in ferreting out the genetic traits that could one day allow researchers to better tailor drugs to individuals.
"It's imperative that we look at racially specific differences," says Dr. Esteban González Burchard, assistant professor at the University of California at San Francisco. "The one-size-fits-all approach to developing drugs is no longer valid." Certainly there is growing evidence that a number of drugs seem to offer different benefits -- or pose different risks -- depending on race. Studies have shown that hypertension drugs called ACE inhibitors are less effective in black patients than in other groups. The lung cancer drug Iressa has shown higher rates of effectiveness in Asians. And when GlaxoSmithKline PLC (GSK ) warned of a possible link between its asthma drug Serevent and life-threatening asthmatic episodes, the problem appeared to be more common in blacks.
In the case of BiDil, critics say that NitroMed hasn't done a study to definitively prove that blacks using the drug have lower death rates than whites. But while the difference in response rates between black and white patients isn't entirely clear, there's no doubt that African Americans, who experienced a 43% decrease in death rate, do benefit from the drug. Dianna S. Wells, a customer service representative in Dallas, says that after taking BiDil she sleeps better and she has more energy: "It has improved my life considerably." Scientists are struggling to understand why many drugs don't work alike in all races. Dr. David B. Goldstein, director of the Center for Population Genomics & Pharmacogenetics at Duke University Medical Center, says his group looked at 42 variations in certain genes that are linked to how people respond to a variety of medications. He says more than two-thirds of those variations occur with differing frequency in people of European ancestry than in those of African ancestry. Still, he says, much more research is needed.
The complex interplay of genes and environment makes understanding race-based differences exceedingly difficult. UCSF's Burchard was part of a study showing that Puerto Rican patients with asthma reacted less well to the drug Albuterol than Mexicans. Yet patients of both nationalities had a gene that previously had been linked to a weaker response to the drug, leading Burchard to suspect other genetic and environmental factors are at work, too.
Until such mysteries are solved, researchers will sometimes have to use the blunt instrument of race to help match patients with the right drugs. And that, ultimately, will help patients of all races. While a gene that makes someone respond positively to a drug may be more common in one race, it will certainly pop up in individuals in other ethnic groups as well. More study -- not less -- is the key to moving toward an era of personalized medicine.
By Amy Barrett