Feng, Xiaodong_ Xie, Hong-Guang - Applying pharmacogenomics in therapeutics-CRC Press (2016)

Pharmacoeconomics of Pharmacogenomics
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efficacy and safety, which results in substantial economic savings by decreasing
costs associated with therapy failure or drug toxicity to be avoided by genotyping,
PGx cannot be assumed to be cost-effective if any economic evaluation is not
available for a certain PGx intervention. To determine whether PGx technologies
or interventions are implemented in a cost-effective manner, all costs and benefits
resulting from a PGx intervention should be properly evaluated according to the
basic principles and practice of pharmacoeconomics. 5,7–10 In this chapter, a novel
term— pharmacoeconogenomics—is coined to better describe the marriage of pharmacoeconomics
and PGx in patient care. In other words, pharmacoeconogenomics
is the study of economic evaluation of PGx interventions. Through this chapter, the
readers can better follow the basic principles of pharmacoeconomics and some welldefined
examples in the PGx research field, and further understand how the PGx
component is incorporated into pharmacoeconomics, and why not all patients benefit
more from a cost-effective perspective, using only genotype-guided medications.
PRINCIPLES OF PHARMACOECONOGENOMICS
The term cost is defined as the value of resource input relative to “charge,” which
is the amount charged to the payer. The direct costs refer to all costs where funds
are paid out as a consequence of the intervention, whereas indirect costs refer to all
other costs not categorized as direct costs. On the other hand, healthcare outcomes or
outputs of these costs are measured in different ways in pharmacoeconomic evaluation,
such as cost per quality-adjusted life years (QALY) gained, quality of lifeadjusted
life expectancy, the number and severity of medical events, the number
of deaths averted, or the costs saved by prevention of hospitalization of a patient
with adverse drug reaction events after use of an alternative medication or another
intervention, and so on. Therefore, measurement and assessment of the outcomes
produced by the resource inputs is the key for a pharmacoeconomic study—in particular,
PGx-based strategies. 11
PGx is the study of how genetic differences affect variation in response to medication,
and thus testing of a patient’s genetic make-up has the potential to predict
intended or undesired responses to the medication in patient care. How such tests
can best be performed and applied in a cost-effective way is the key to guide an economic
evaluation of PGx testing in clinical settings. Therefore, the major principles
and methodologies of pharmacoeconomic analyses are also applied to relevant PGx
studies.
Cost-Effectiveness Analysis
Cost-effectiveness analysis (CEA) is a widely used tool to measure and assess the
value of new healthcare interventions relative to empiric or current conventional
therapy with standard dosing, and also a quantitative method to systematically
compare the costs and healthcare outcomes of competing healthcare technologies
or interventions. By definition, CEA can use various outcomes, including
clinical events or life years saved. In fact, CEA is a specific type of economic
evaluation that measures costs in relation to all types of the outcomes gained,