Lower Rate of Abacavir Hypersensitivity Reaction among Black Patients Abacavir (Ziagen) is an effective drug for the treatment of HIV infection, but approximately 5% of patients treated with the drug develop a hypersensitivity reaction (HSR) that in rare cases has proved fatal. Abacavir is also a component of the fixed-dose combination pills Trizivir (abacavir/AZT/3TC) and Epzicom (abacavir/3TC). An association between abacavir HSR and carriage of the genetic allele HLA-B*5701 has been reported in several studies. This linkage reaches high statistical significance in Caucasian individuals, but is less significant in Black patients. In multivariate analyses assessing the clinical risk factors for HSR in various studies, black race consistently demonstrated lower odds of experiencing HSR. In the present study, reported at the 46th ICAAC last week in San Francisco, HSR rates from recent randomized controlled clinical trials using abacavir-containing products were reviewed across study populations, comparing self-reported race. Results HSR incidence rates from 5 studies comprising 2800 total subjects from the Americas and Europe are summarized in the table below:
Conclusion The researchers concluded that, "Across 5 randomized controlled trials, there was a consistently low rate of HSR reported among Black subjects. This finding supports previous risk factor findings and recently reported HSR rates in the DART trial (CROI 2006)." "The prevalence of HLA-B*5701 differs among racial groups and is low in people of black race, which may partially explain this finding," they added. "Additional research is underway to more fully address the association of the allele and HSR across racially diverse populations." Researchers are currently developing a genetic test based on HLA-B*5701 to help predict which patients are likely to develop HSR, and thus should avoid abacavir. 10/06/06 Reference
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