The cost-effectiveness of HLA-B*5701 genetic screening to guide initial antiretroviral therapy for HIV

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Abstract
Objective: To evaluate the clinical impact and cost-effectiveness of HLA-B*5701 testing to guide selection of first-line HIV regimens in the United States. Design: Cost-effectiveness analysis using a simulation model of HIV disease. The prevalence of HLA-B*5701 and the probabilities of confirmed and unconfirmed severe systemic hypersensitivity reaction among patients taking abacavir testing HLA-B*5701 positive and negative were from the Prospective Randomized Evaluation of DNA Screening in a Clinical Trial study. The monthly costs of abacavir-based and tenofovir-based regimens were $1135 and $1139, respectively; similar virologic efficacy was assumed and this assumption was varied in sensitivity analysis. Patients: Simulated cohort of patients initiating HIV therapy. Interventions: The interventions are first-line abacavir, lamivudine, and efavirenz without pretreatment HLA-B*5701 testing; the same regimen with HLA-B*5701 testing; and first-line tenofovir, emtricitabine, and efavirenz. Main outcome measures: Quality-adjusted life years and lifetime medical costs discounted at 3% per annum, cost-effectiveness ratios ($/QALY). Results: Abacavir-based treatment without HLA-B*5701 testing resulted in a projected 30.93 years life expectancy, 16.23 discounted quality-adjusted life years, and $472 200 discounted lifetime cost per person. HLA-B*5701 testing added 0.04 quality-adjusted months at an incremental cost of $110, resulting in a cost-effectiveness ratio of $36 700/QALY compared with no testing. Initiating treatment with a tenofovir-based regimen increased costs without improving quality-adjusted life expectancy. HLA-B*5701 testing remained the preferred strategy only if abacavir-based treatment had equal efficacy and cost less per month than tenofovir-based treatment. Results were also sensitive to the cost of HLA-B*5701 testing and the prevalence of HLA-B*5701. Conclusion: Pharmacogenetic testing for HLA-B*5701 is cost-effective only if abacavir-based treatment is as effective and costs less than tenofovir-based treatment.