Pharmacogenomics: History, Barriers, and Regulatory Solutions
![handle is hein.journals/foodlj69 and id is 293 raw text is: Pharmacogenomics: History, Barriers,
and Regulatory Solutions
SARAH BLANKSTEIN*
I. INTRODUCTION
A patient comes to the hospital with a blood clot, and his physician prescribes the
blood thinner Coumadin' (warfarin). The physician knows that people process warfarin
differently and that she must tailor the dosage to her individual patient. A decade ago, the
physician had to adjust the patient's warfarin dosage by trial and error over the course of
many months. During that time the patient risked excessive bleeding from too high a dose
or further blood clots from too low a dose. Today, though, the physician orders a simple
genetic test which she can then use to tailor the warfarin dosage more quickly to her
patient's individual genetic makeup.I The use of genetic testing to determine how a drug
should be administered to an individual patient is an example of pharmacogenomics.
Pharmacogenomics is the branch of pharmacology which looks at the influence of
genetic variation on drug response, connecting particular genetic markers with the
effectiveness or safety of a drug.2 Pharmacogenomics deals with variations in both
DNA and RNA, encompassing within it the field of pharmacogenetics, which focuses
only on the effect of variations in DNA sequence on drug response.' The application of
pharmacogenomic and other genetic or environmental tools to the management of an
individual patient's medical care is referred to as personalized medicine.4
Many pathways exist for developing a pharmacogenomic product. In most cases,
though, the process begins when researchers discover a genetic link in people's response
to a particular drug. They then use that knowledge to develop a genetic test called
a companion diagnostic, which the drug's labeling indicates should be used before
administering the drug. Based on the results of the genetic test, clinicians may predict
whether an individual patient will benefit from that drug, have an adverse response, or
have no response at all.' Such information can then be used in selecting and deselecting
. Sarah Faye Blankstein received her J.D. from Harvard Law School in 2013 and her B.A. from
Harvard College in 2008. This article was written in conjunction with Peter Barton Hutt's 2012 Food and
Drug Law course at Harvard Law School. Sarah is currently an associate at Ropes & Gray LLP. This article
was submitted in conjunction with the FDLI Austem Writing competition and is published as submitted.
1 Coumadin@ (warfarin) Prescribing Information, Dosing Recommendations with Consideration of
Genotype (Oct. 2011).
2 T. P. Aneesh et al., Pharmacogenomics: The Right Drug to the Right Person, I J. Clinical Med.
Research 191, 191 (2009). The Food and Drug Administration (FDA) defines pharmacogenomics as the study
of variations of DNA and RNA characteristics as related to drug response. FDA, Guidance for Industry: EI5
Definitions for Genomic Biomarkers, Pharmacogenomics, Pharmacogenetics, Genomic Data and Sample
Coding Categories, 3 (Apr. 2008) [hereinafter Guidance: E15 Definitions].
Guidance: E15 Definitions, supra note 2, at 3. This paper will use the terms pharmacogenomics and
pharmacogenetics interchangeably.
4 C. Lee Ventola, Pharmacogenomics in Clinical Practice: Reality and Expectations, 36 Pharmacy
& Therapeutics 412, 412 (2011).
5 J. Cohen et al., Clinical and Economic Challenges Facing Pharmacogenomics, Pharmacogenomics
J. 1. 1 (2012).
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Pharmacogenomics: History, Barriers, and Regulatory Solutions
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