Abacavir Pharmacogenetics – From Initial Reports to Standard of Care


  • Supported by Predoctoral Training Grant GM-07175 from the National Institutes of Health and U01 GM61390, also from the National Institutes of Health.

For questions or comments, contact Deanna L. Kroetz, Department of Bioengineering and Therapeutic Sciences, 1550 4th Street, Box 2911, San Francisco, CA 94158-2911, USA; e-mail: deanna.kroetz@ucsf.edu.


Abacavir is a nucleoside analogue reverse transcriptase inhibitor indicated for the treatment of human immunodeficiency virus infection as part of a multidrug, highly active antiretroviral therapy regimen. Despite its efficacy, approximately 5% of individuals who receive abacavir develop an immune-mediated hypersensitivity reaction (HSR) that warrants immediate discontinuation of abacavir and switching to an alternative antiretroviral regimen. Abacavir HSR is associated with individuals who carry the *57:01 variant in the human leukocyte antigen B (HLA-B) gene. There is a large volume of evidence to show that those who carry HLA-B*57:01 are at significantly increased risk of developing HSR and should not receive abacavir. Pharmacogenetic screening to ensure individuals who carry HLA-B*57:01 do not receive abacavir can reduce the incidence of HSR and is now considered the standard of care before prescribing abacavir. Genetic testing to prevent abacavir HSR is currently one of the best examples of integrating pharmacogenetic testing into clinical practice.