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First-line HAART guided by genotypic resistance testing - long-term follow-up data from the RESINA-study
Presented by Stefan Reuter, Germany.
S. Reuter1, M. Oette1, R. Kaiser2, M. Daeumer3, G. Fätkenheuer4, J. Rockstroh5, T. Lengauer6, D. Haeussinger1, RESINA study group
1University Hospital Duesseldorf, Gastroenterology, Hepatology and Infectious Diseases, Duesseldorf, Germany, 2University Hospital Cologne, Virology, Cologne, Germany, 3Institute of Immunology and Genetics, Kaiserslautern, Germany, 4University Hospital Cologne, Hematology, Oncology and Infectious Diseases, Cologne, Germany, 5University Hospital Bonn, Bonn, Germany, 6Max Planck Institute for Informatics, Saarbruecken, Germany
Background: Primary drug resistance in untreated HIV-infected patients is associated with suboptimal virological outcome of first-line HAART. Preliminary data suggested equal efficacy of HAART guided by resistance testing in patients with resistance compared to patients with wild-type virus. The aim of this study was to validate this approach in the long-term follow-up.
Methods: In this prospective multicenter study in Germany, genotypic resistance testing was performed in chronically HIV-infected individuals before initiation of first-line HAART. Resistance was classified according to AIDS 2007;21:215. Expert interpretation was provided using the geno2pheno® tool. Treatment was monitored for 96 weeks.
Results: From 2001 to 2005, HAART was initiated in 677 individuals. 78% were males, mean age was 39.6 years (standard deviation (SD): 10.3), 36% were at clinical stage of AIDS, mean CD4-cell count was 197 /µl (SD: 167), mean viral load was 5.3 log/ml (SD: 5.5). Overall prevalence of primary drug resistance was 9.7% (95%-CI, 7.5-12.0). In intent to treat-analysis, a viral load below 50 copies/ml (VL<50) at 48 weeks was seen in 66.7% of patients with resistance and in 72.3% without (p=0.39). At week 96, VL<50 was seen in 60.9% of patients with resistance and 64.0% without (p=0.75). In on-treatment-analysis, VL<50 at 48 weeks was found in 80.8% of patients with resistance and in 86.0% without (p=0.23). At week 96, VL<50 was seen in 85.5% of patients with resistance and 87.7% without (p=1.0). In univariate and multivariate analyses, primary resistance was not associated with virological efficacy.
Conclusions: The prevalence of primary HIV drug resistance was about 10%. In the long-term follow-up of this large cohort, application of resistance testing resulted in equal efficacy of HAART in cases showing resistant virus as compared to cases with wild-type virus. Thus, genotypic resistance testing should be strongly taken into account for tailoring the first-line HAART.
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