Precision Medicine

Does pharmacogenomics obviate the need for race-based treatment and screening?

Let’s say that drug A works better for one race than another. Or that disease prevalence is more common for some races than others. Despite the goal to be color-blind in medicine, racial information can prove useful. For instance, sickle cell disease is much more common among African Americans in the US than other races.

However, advances in DNA sequencing may obviate the need for race based screening or treatment procedures. For instance, it could be the case that a given gene increases the risk of a disease or makes a treatment more (or less) effective. If you know genetic information, race-based screening or treatment would be unnecessary.

This is the topic Goodman and Brett (2021) explore in their recent JAMA Viewpoint.

Pharmacogenomics is a field that explores relationships between genes and drug effects, with potential to “personalize” medical therapy. For clinical scenarios in which a genotype is clearly linked to important outcomes, direct genetic testing would appear to obviate the need to use race as a surrogate for genetic predisposition in decision-making.

As the authors note, however, pharmacoeconomics would only eliminate the need for race-based screening or treatment in a world where all people have their genes sequenced.

Universal screening for genetic predisposition to adverse drug reactions would make race-based algorithms unnecessary, but imperatives to use limited resources judiciously may warrant more selective screening, targeted to high-prevalence groups, if such groups can be identified accurately. Although stratifying genetic risk by multigenerational ancestry might seem clinically appealing, race-based or ancestry-based pharmacogenetic decision-making is limited by intrapopulation genetic variation and the fluidity and social construction of racial categories.

The authors also show that geography may be a better predictor of prevalence of genes than race and crude racial categories (e.g., Black, White, Hispanic, Asian) may not be sufficient in a world where genetic sequencing is far less than universal. Some health systems–such as Geisinger–have explored making whole genome sequencing routine care for its patients. Making whole genome sequencing standard of care needs to be available in the not too distant future.

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