Chapter 3: Ethical, Legal, and Social Issues in Pharmacogenomics

INTRODUCTION: NOT AS SIMPLE AS IT SEEMS

Precision medicine, the classification of “individuals into subpopulations that differ in their susceptibility to a particular disease or their response to a specific treatment” so that “preventive or therapeutic interventions can then be concentrated on those who will benefit, sparing expense and side effects for those who will not”¹ is recognized as raising multiple and difficult ethical, legal, and social issues.² Pharmacogenomics (PGx), the study of the relationship between genetic variation among individuals and their drug responses in order to develop new drugs and to inform prescribing practices, is sometimes considered the least ethically challenging domain of precision medicine. Who can reasonably object to precision medicine’s tagline: “the right drug for the right patient at the right time”? Why shouldn’t social policy embrace giving drugs only to those who may benefit, thereby minimizing the risk of adverse drug reactions (ADRs)? What negative sequelae could possibly accompany a revelation of genetic factors related to one’s ability to respond to drugs? While one might worry about living in the shadow of an increased risk for cancer or Alzheimer disease, what shadow is cast by being a rapid or slow metabolizer?

Yet, the title of a 2008 article correctly suggests that PGx is “not as simple as it seems”.³ Some of the PGx-related ethical, legal, and social (ELS) issues differ from those associated with other domains of precision medicine, but some overlap. The issues also differ depending on whether the response-relevant genetic variation is an acquired variant (tissue-specific) or an inherited variant (found in an individual’s genotype). Moreover, different participants in PGx face different ELS challenges as PGx matures and is implemented. These participants include patients, clinicians, pharmacists, researchers, the pharmaceutical industry, and insurers. This chapter will consider the ELS issues of PGx most salient from the different parties’ perspectives.

PATIENTS AND CLINICIANS: OPPORTUNITIES AND CHALLENGES

Risks, Potential Benefits, and Limitations of PGx

Clinical decision making about any intervention, including testing to guide other interventions, is based on the intervention’s risks and potential benefits, weighed in light of the patient’s values and preferences.⁴ The risks of PGx testing are informational risks—risks to privacy, of discrimination, and of psychosocial implications. For patients to realize the benefits of PGx testing, the information must be useful to guide their treatment. To be useful, PGx information must be accurate and available; for it to benefit the individual patient, it must be employed in the patient’s interests.

Pharmacogenomic Information: Entering the Clinic, ...