July 24, 2011
Pharmacogenomics: Paying Attention to Results As Regulation Evolves
The field of pharmacogenomics, in which pharmaceutical treatments are informed by genetic analysis, allows for more individualized therapeutic regimens. This field is also described as personalized medicine. The Public Library of Science hosts an online repository, Evidence on Genomic Tests, that publishes peer-reviewed reports of genomic tests used in clinical practice. These are short, summary reports, which, interestingly, attend to the key attributes that need to be studied in genetic testing: analytic validity, clinical validity, and clinical utility. For more information on these parameters, see the 2008 Report by the HHS Advisory Committee on Genetics, Health and Society on the U.S. oversight of genetic tests. One such report recently studied the Oncotype DX, which is a genetic test that aims to predict the possibility of recurrence for breast cancer patients by analyzing the variations in a discrete 21-gene set which correlate to either lower or higher recurrence risk. The clinical import is that women with lower risks of recurrence, as identified by Oncoptype DX, could receive less aggressive followup treatment, such as adjuvant chemotherapy. The report concluded that, as yet, there is some analytic validity, some clinical validity, but concluded: "There is currently no data clearly demonstrating clinical utility of Oncotype DX in women with lymph node-positive breast cancer." While these phamacogenomic tests have received critical attention, leading to some FDA oversight, it is important to simultaneously monitor how these tests are actually faring in practice. This is key for patients who could be spared unnecessary treatment, but also for patients who might unduly be denied treatment, either conclusions might be drawn from these tests. In addition to frank medical concerns, insurance coverage for these tests varies and presents additional complications. This report reminds us that, as the debates over a proper regulatory framework for genetic testing continue, the scientific evaluation of proposed pharmagenomic modalities is relatively recent, currently ongoing, and far from completed.