Gene-Based Drug Targeting
The next time you walk into the doctor’s office, she or he may take a glance at you and decide in a snap what drugs you should take based on your race. Is race a good proxy for genetic differences?
A growing body of evidence has found that there are race-specific differences in the response to certain medications. For example, African-American children need higher doses of asthma medicine to feel better. Breast cancer tumors in African-American women are less responsive to treatment. (Denver Post, April 19, 2005) And, BiDil, a drug for the treatment of heart failure, is under review by the Federal Drug Administration to be the first drug approved specifically for use in African-Americans.
What kind of trouble might we have if more race-specific drugs are approved?
1. Most people cannot be easily categorized.
2. Some patients will either knowingly or unknowingly misidentify their race.
3. Doctors may be afraid to offer certain drugs for fear of incorrectly identifying the patient’s race and possibly offending the patient.
4. Patients may refuse appropriate but race-specific treatment because they do not want to be identified as that particular race.
5. Patients may not offered or may be denied treatment because it isn’t believed to be effective in their particular racial group.
Instead of using race as a proxy for genetic make-up, a better way of tailoring drugs to individual patients would be to identify specific genetic or biologic markers that indicate drug response. This field of research, known as pharmacogenetics, is making some progress.
1. Hepatitis C – An eighteen gene complex that is believed to play a role in the elimination of the Hepatitis C virus has been found to be overactive in nonresponders to drug therapy. (Medical News Today, May 3, 2005) This finding appeared to be counterintuitive until I realized that the researchers were involved in a fishing expedition.
“We went into this experiment without any hypothesis about what to look for,” said Aled Edwards, a Professor in the Banting and Best Department of Medical Research at University of Toronto with cross appointments in the Departments of Medical Biophysics and Medical Genetics and Microbiology. He is also a senior scientist at the Clinical Genomics Centre at the University Health Network and Director and CEO of the Structural Genomics Consortium. “We cast a very wide net, looking at 19,000 genes of each of the patients.”
Without an a priori hypothesis, researchers studying so many genes and their associations in a small group of 31 patients were bound to get some statistically significant results.
2. Heart Failure – In 61 patients with heart failure, those with a genetic variant of the beta-one adrenergic receptor gene were more likely to require higher doses of beta blocker drugs. (Science Daily, April 22, 2005)
3. Type 2 Diabetes – Polymorphisms in the adiponectin gene are associated with differences in the response to diabetes drug rosiglitazone. (Diabetes Care, May 2005)
Researchers are eager to dissociate themselves from the volatile issue of race.
“This study has nothing to do with race,” said Dr. Eun Seok Kang, one of the lead researchers on the (adiponectin gene and rosiglitazone) study. “It shows us how important pharmacogenetics could be in the future in helping us quickly and efficiently determine the best treatment to give people. If something in our genetic make-up offers clues about how well we will respond to particular medications, this could be a tremendous asset to people with diabetes and other complex diseases. Obviously knowing ahead of time which drugs will work best means we can eliminate the entire trial-and-error process of drugs that don’t work or work poorly for some people. Clearly we have a lot more to learn before we get to that stage, but this is an important first step.”
Moving towards gene-based drug therapy may not go as smoothly as everyone hopes. Being able to accurately predict a person’s risk of disease given their genotype will undoubtedly lead to genetic discrimination (see DNA Stereotyping). When that moment comes, just substitute “genes” for “race” and we’ll have the same troubles all over again.
Actually, self-identification of race is reasonably accurate according to population genetics studies, (See Risch, Shriver, etc.)
So, if your best friend was a black man and he was having a heart attack, would you prefer that Bi-Dil doesn’t exist?
Thank you for your comment. I would disagree that self-identification of race is accurate especially when it comes to the black population. For example, some blacks grow up believing their slave ancestors came from Africa when DNA analysis showed otherwise. A recent Christian Science Monitor article (http://www.csmonitor.com/20...) shows how nebulous our understanding of ancestral origin is:
"The bottom line: We’re not as racially pure as we think we are."
If my best friend were a black man suffering from heart failure, I would hope that he’d be offered BiDil AND whatever other therapies are deemed suitable for him REGARDLESS of his race. And for all my other friends who are not black, I’d also hope that they’d get BiDil if it benefits them.
I see the potential for discrimination. And knowing how well people do at overcoming that tendency, I too think that gene discrimination will become a reality eventually. A lot of people already don’t want to have their DNA analyzed, because of a very real fear that some marker for chronic or terminal illness will be present and they will lose whatever health insurance they may have.
Just looking at people doesn’t indicate race very well. I have a friend who is half African American, who looks Northern European. Would a doctor just looking at her offer her the drugs that would help most based on genetics? Would she be honest when filling out the area that asks for one’s race?
Many people who can "pass" as something other than part of their genetic background they are ashamed of for whatever reason, don’t answer those race questions honestly.
We only have to look at how people with HIV are treated to see how gene discrimination can become a serious problem.
Qadira,
As with sex and race discrimination, we will need to develop a set of clear guildelines of how to deal with genetic discrimination. Let’s hope our law makers aren’t too slow to jump on the bandwagon.
I like it =)
Thank you, Jack!