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High rate of K65R for antiretroviral therapy-naive patients with subtype C HIV infection failing a tenofovir-containing first-line regimen

2012; Lippincott Williams & Wilkins; Volume: 26; Issue: 13 Linguagem: Inglês

10.1097/qad.0b013e328356886d

1473-5571

Henry Sunpath, Baohua Wu, Michelle Gordon, Jane Hampton, Brent A. Johnson, Mahomed‐Yunus S. Moosa, Claudia E. Ordóñez, Daniel R. Kuritzkes, Vincent C. Marconi,

HIV Research and Treatment

We sought to determine the rate of the K65R mutation in patients receiving tenofovir (TDF)-based antiretroviral therapy (ART) with subtype C HIV infection.Retrospective cohort study.All patients initiated on stavudine (d4T) with lamivudine (3TC) or TDF with 3TC and a nonnucleoside reverse transcriptase inhibitor at McCord Hospital in Durban, South Africa had their charts reviewed. All patients with virologic failure, defined as a viral load more than 1000 copies/ml after 5 months of a first ART regimen, had genotypic resistance testing performed prospectively using a validated in-house assay. Important resistance mutations were selected based upon published mutations in subtype B virus in the Stanford HIV Drug Resistance database.A total of 585 patients were initiated on TDF-containing first-line ART from 3 August 2010 to 17 March 2011. Thirty-five (6.0%) of these patients had virologic failure and 23 of 33 (69.7%) of the virologic failure patients had the K65R mutation. The median (interquartile range) for the baseline CD4 cell count was 105 cells/μl (49-209) and viral load at virologic failure was 47 571 copies/ml (20 708-202 000). During the same period, 53 patients were initiated on d4T-containing regimens. Two (3.8%) of these patients had virologic failure and one of the virologic failure patients had the K65R mutation.Preliminary data show very high rates (>65%) of K65R for patients failing TDF-based first-line regimens at McCord Hospital with few additional nucleoside reverse transcriptase inhibitor mutations compared with subtype B. These rates may reflect faster in-vivo selection, longer time on a failing regimen or transmitted drug resistance.