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HIV viral tropism in vicriviroc VICTOR-E1 trial: correlations with clinical variables
Presented by Jamal Suleiman, Brazil.
Suleiman J.1, Sobhie Diaz R.2, DeJesus E.3, Slim J.4, Dunkle L.5, Alvarez D.5
1Brazilmed Assistencia Medica e Pesquisa S/C Ltda, Sao Paulo, Brazil, 2Laboratorio de Retrovirologia, Sao Paulo, Brazil, 3Orlando Immunology Center, Orlando, United States, 4St. Michael's Medical Center- Infectious Diseases, Newark, United States, 5Schering-Plough Research Institute, Kenilworth, United States
Objectives: Vicriviroc is an investigational small-molecule CCR5 antagonist that is being evaluated in the Phase 2 VICTOR-E1 study in treatment-experienced patients. Here we explored variables associated with HIV-1 tropism in patients screened for this trial.
Methods: Patients were failing on current stable antiretroviral therapy (ART); NRTI-, NNRTI-, PI- and fusion inhibitor experienced; HIV viral load >1,000 copies/mL; ³1 genotypically documented NRTI and one primary PI mutation; and presence of R5-tropic virus with Trofileä. Patients were to be randomized and treated with vicriviroc 20mg, 30mg, or placebo plus an OBT containing a ritonavir-boosted protease inhibitor.
Results: 451 patients were screened and 116 enrolled at 60 sites in 12 countries between June and November 2006, with 67% of patients screened outside of North America. About half of all screened subjects were from Brazil (46%). Screening mean CD4 count was 219 cells/mm3 (median 184 cells/mm3, range 2-1509 cells/mm3), mean viral load was 5.4 log10 copies/ml, and non-B clade accounted for 12% of samples. Approximately 35% of screened patients had dual or mixed (D/M)-tropic HIV, 4% had CXCR4 (X4) virus, 45% had R5 virus; the assay failed in 13% of samples. The proportion of R5 virus was similar between patients from North America and rest of the world (52% and 54%, respectively). D/M- or X4- virus at screening was significantly associated with lower mean CD4 counts than R5 virus (179 vs 228 cells/mm3, P£0.0036), but not associated with viral load, number of resistance mutations, age, sex or non-B clade.
Conclusions: Prevalence of D/M- and X4-tropic virus in patients screened for this study, including a large Latin American population, was consistent with previous studies from other geographies. DM/X4-tropism is associated with lower CD4 counts.
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