HLA-B*5701 Screening for Hypersensitivity to Abacavir
ABSTRACT Hypersensitivity reaction to abacavir is strongly associated with the presence of the HLA-B*5701 allele. This study was designed to establish the effectiveness of prospective HLA-B*5701 screening to prevent the hypersensitivity reaction to abacavir.
This double-blind, prospective, randomized study involved 1956 patients from 19 countries, who were infected with human immunodeficiency virus type 1 and who had not previously received abacavir. We randomly assigned patients to undergo prospective HLA-B*5701 screening, with exclusion of HLA-B*5701-positive patients from abacavir treatment (prospective-screening group), or to undergo a standard-of-care approach of abacavir use without prospective HLA-B*5701 screening (control group). All patients who started abacavir were observed for 6 weeks. To immunologically confirm, and enhance the specificity of, the clinical diagnosis of hypersensitivity reaction to abacavir, we performed epicutaneous patch testing with the use of abacavir.
The prevalence of HLA-B*5701 was 5.6% (109 of 1956 patients). Of the patients receiving abacavir, 72% were men, 84% were white, and 18% had not previously received antiretroviral therapy. Screening eliminated immunologically confirmed hypersensitivity reaction (0% in the prospective-screening group vs. 2.7% in the control group, P<0.001), with a negative predictive value of 100% and a positive predictive value of 47.9%. Hypersensitivity reaction was clinically diagnosed in 93 patients, with a significantly lower incidence in the prospective-screening group (3.4%) than in the control group (7.8%) (P<0.001).
HLA-B*5701 screening reduced the risk of hypersensitivity reaction to abacavir. In predominantly white populations, similar to the one in this study, 94% of patients do not carry the HLA-B*5701 allele and are at low risk for hypersensitivity reaction to abacavir. Our results show that a pharmacogenetic test can be used to prevent a specific toxic effect of a drug. (ClinicalTrials.gov number, NCT00340080.)
- SourceAvailable from: Andrew Rowland
03/2014; 5(2):62-66. DOI:10.1177/2042098613520030
- "One example of an RCT where participants were randomised to use of a pharmacogenomic marker was with the antiretroviral abacavir. Abacavir was plagued by hypersensitivity reactions in up to 6% of treated patients, and in this study screening for the HLA-B*5701 allele eliminated these hypersensitivity reactions [Mallal et al. 2008]. Prior to this trial the association between HLA-B*5701 and abacavir hypersensitivity had been identified by two independent groups and observed in several noncontrolled environments, but retrospective methodologies, lack of control populations and racial diversification, small sample sizes and issues of overdiagnosis had led to uncertainty about its clinical utility. "
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- "An example of good value is the use of HLA‐B Ã 57:01 genotyping prior to initiation of the anti‐retroviral medication abacavir. Presence of this genotype drastically increases the risk for developing a severe hypersensitivy reaction leading to significant morbidity and mortality [Mallal et al., 2008]. Cost‐ effectiveness analysis of genotyping prior to use of abacavir has been shown to be cost saving under a broad range of assumptions [Kauf et al., 2010] thus would fit solidly in the upper left hand sector (Fig. 1 Box A). "
ABSTRACT: Genomic Medicine is beginning to emerge into clinical practice. The National Human Genome Research Institute's Genomic Medicine Working Group consists of organizations that have begun to implement some aspect of genomic medicine (e.g., family history, systematic implementation of Mendelian disease program, pharmacogenomics, whole exome/genome sequencing). This article concisely reviews the working group and provides a broader context for the articles in the special issue including an assessment of anticipated provider needs and ethical, legal, and social issues relevant to the implementation of genomic medicine. The challenges of implementation of innovation in clinical practice and the potential value of genomic medicine are discussed. © 2014 Wiley Periodicals, Inc.American Journal of Medical Genetics Part C Seminars in Medical Genetics 03/2014; 166(1). DOI:10.1002/ajmg.c.31394 · 3.54 Impact Factor
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- "Pharmacogenomics is introducing SNP profiling into clinical practice. Fifty percent of individuals with HLA-B ⁄ 5701 gene variants found in 5.8% of Caucasians are hypersensitive to abacivir versus none without . A trial in 4877 people showed identification of HLA-B ⁄ 1502 allele carriers (7.7%) eliminated carbamazepine induced toxicity . "
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