On
pages 67-68, Moalem briefly discusses pharmacogenetics, the study of producing
pharmaceutical treatments based on a population’s specific genetic variation. The
pharmaceutical industry recognizes that certain populations do not respond to
treatments as well as other populations. Moalem mentions BiDil, a new drug
meant to treat self-identified black patients who suffer from hypertension. BiDil
was produced because African Americans with heart failure were not responding
to certain heart failure treatments. There was much controversy when the FDA
approved BiDil.
Research
another population-specific drug. Discuss the disease or disorder the drug is
meant to treat as well as the population for which the drug was created. Why is
a personalized treatment required for this population? Was there any
controversy related to this drug? Connect your response to anything you learned
about personalized medicine from Sam Rhine. Be sure to also connect your
response to Big Idea 1 (The process of evolution drives the diversity and unity
of life).
(Christine Fanning, cfannin4@students.d125.org)
Although pharmacogenetics is a new field of research, it is predicted to gain significant prevalence and success within the next 10-20 years, according to experts at Dartmouth University. Pharmacogenetics is the study of how genetic variations can affect one’s drug metabolism and response. This research coincides with recent scientific findings about common diseases. Genetics expert Sam Rhine explained that common diseases, such as diabetes, heart disease, and ADHD, are the hardest to study due to the fact that they are not simply caused by a single genetic mutation, but rather various factors and complex genetic traits. Each patient of a common disease is different and falls on a different place in the spectrum of the severity of their condition, and therefore should be treated with medicine personalized to their genetic profile. This is where pharmacogenetics steps in to create medication that delivers the highest potency to specific populations. The latest advancements in genetics make this possible, such as new imaging and molecular technology that give further insight into a patient’s physiological and pathological conditions, and allow for quicker and cheaper genotyping.
ReplyDeleteHypertension, or high blood pressure, is a common disease that has been an interesting case for pharmacogeneticists. When doctors realized that hypertension is twice as common among African Americans as the rest of the American population, they were even more fascinated to discover that these high rates of hypertension do not occur in Africans living in Africa (Moalem 64). How did scientists account for this? Moalem explains on page 65 that high levels of salt is linked to hypertension, but salt is also a vital part of survival. Scientists hypothesize that when Africans were taken slave trade ships to America, they were held under poor conditions of scarce food and water, so the slaves that had the ability to retain higher levels of salt were selected for in this environment. Since salt is important in fluid regulation, this advantage of retaining higher levels of salt aided them in survival by allowing them to preserve water in their bodies and avoid dehydration. The Africans with a higher propensity for salt that survived the voyage were favored and able to survive and reproduce. As the survivors passed on this trait, the ability to retain salt increased among America’s black population, which is the basis of Big Idea 1 (The process of evolution drives the diversity and unity of life). We see how a certain variation is selected for based on the environmental pressures present, which favors the reproductive success of certain organisms over others and drives the evolution of a given population. This survival tactic, however, proved to be dangerous when combined with the modern American diet that is rich in sodium. An abundance of salt coupled with the ability to preserve salt in the body is what accounts for the large population of black hypertension patients in the U.S.
Statistics have shown that the African American population experiences nearly double the amount of heart attacks and has a 10% higher rate of cancer compared to Europeans and Asian Americans. (Moalem 65). There are many genetic differences among population groups due to the fact that each population has a unique history, diet, health care, environment, lifestyle, etc, which has exposed them to varying selection pressures and driven their evolution in different directions The pharmaceutical industry has realized that these genetic differences play a large part in the way certain people respond to medication. For example, typical hypertension treatments have proven to be less effective for African Americans. This led to the creation of the drug BiDil, which is a heart failure treatment specifically designed for self identified African Americans. Controversy followed the release of BiDil. Some believed pharmacogenetics was simply about “exploiting race to obtain quicker, cheaper FDA approval for drugs, some didn’t believe that race had anything to do with the effectiveness of drugs, and others thought it was degrading to create “black” drugs or “white” drugs and that the only category should be “human being.”
ReplyDeleteA similar example of personalized medicine is Herceptin. Herceptin was one of the first cases of personalized medicine, although it is not designed specifically for a certain racial group. It is a drug for breast cancer, geared towards the 30% of female patients that have a form of the disease in which the protein HER2 is over-expressed. Excessive HER2 makes this form unresponsive to standard breast cancer treatment. The drug was approved in 1998, and in studies conducted in 2005, the rates of recurrence were reduced by 52% when Herceptin medication was combined with chemotherapy. The controversy that revolved around this drug was deciding who would qualify for the treatment. Due to its large costs, only about 5000 women who met the clinical criteria for Herceptin would be able to receive it. Some people were unhappy with the fact that the availability of the drug is limited by costs, which appeared to put “money over life.” Other issues included the potential link between Herceptin and heart problems.
SOURCES:
http://www.dartmouth.edu/~dmsheart/genetics/pharm/pharm.html
McCarthy, Alun D., James L. Kennedy, and Lefkos T. Middleton. "Pharmacogenetics in Drug Development." Philosophical Transactions of the Royal Society B: Biological Sciences .JSTOR. Web
Hood, E. “Pharmacogenomics: The Promise of Personalized Medicine”
Environmental Health Perspectives. Vol. 111, No. 11 (Aug., 2003), pp. A580-A589. JSTOR. Web
Christensen, D. “Targeted Therapies” Science News , Vol. 162, No. 11 (Sep. 14, 2002), pp. 171-172. JSTOR. Web.
Kahn, J. “Exploiting Race in Drug Development: BiDil's Interim Model of Pharmacogenomics” Social Studies of Science , Vol. 38, No. 5, Race, Genomics, and Biomedicine (Oct., 2008), pp. 737-758. JSTOR.
(Michelle Liang, mliang4@students.d125.org)