title: Impact of baseline HIV-1 tropism on viral response and CD4 cell count gains in HIV-infected patients receiving first-line antiretroviral therapy.
abstract: BACKGROUND
  Viral tropism influences the natural history of human immunodeficiency type 1 (HIV-1) disease: X4 viruses are associated with faster decreases in CD4 cell count. There is scarce information about the influence of viral tropism on treatment outcomes.
  
  
  METHODS
  Baseline plasma samples from patients recruited to the ArTEN (Atazanavir/ritnoavir vs. Nevirapine on a background of Tenofovir and Emtricitabine) trial were retrospectively tested for HIV-1 tropism using the genotypic tool geno2pheno(FPR=5.75%). ArTEN compared nevirapine with atazanavir-ritonavir, both along with tenofovir-emtricitabine, in drug-naïve patients.
  
  
  RESULTS
  Of 569 ArTEN patients, 428 completed 48 weeks of therapy; 282 of these received nevirapine and 146 of these received atazanavir-ritonavir. Overall, non-B subtypes of HIV-1 were recognized in 96 patients (22%) and X4 viruses were detected in 55 patients (14%). At baseline, patients with X4 viruses had higher plasma HIV RNA levels (5.4 vs 5.2 log copies/mL, respectively; P = .044) and lower CD4 cell counts (145 vs 188 cells/μL, respectively; P < .001) than those with R5 strains. At week 48, virologic responses were lower in patients with X4 viruses than in patients with R5 viruses (77% vs 92%, respectively; P = .009). Multivariate analysis confirmed HIV-1 tropism as an independent predictor of virologic response at week 24 (P = .012). This association was extended to week 48 (P = .007) in clade B viruses. Conversely, CD4 cell count recovery was not influenced by baseline HIV-1 tropism.
  
  
  CONCLUSIONS
  HIV-1 tropism is an independent predictor of virologic response to first-line antiretroviral therapy. In contrast, it does not seem to influence CD4 cell count recovery.
  
  
  BACKGROUND
  NCT00389207.
authors.affiliation: Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Seclén
authors.forename: Vicente
authors.initials: V
authors.lastname: Soriano
authors.forename: María M
authors.initials: MM
authors.lastname: González
authors.forename: Luz
authors.initials: L
authors.lastname: Martín-Carbonero
authors.forename: Holger
authors.initials: H
authors.lastname: Gellermann
authors.forename: Manuel
authors.initials: M
authors.lastname: Distel
authors.forename: Werner
authors.initials: W
authors.lastname: Kadus
authors.forename: Eva
authors.initials: E
authors.lastname: Poveda
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology* / Q000821:virology*; D015497:HIV-1 / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D010949:Plasma / Q000821:virology; D016896:Treatment Outcome; D056189:Viral Tropism
chemical_list: D019380:Anti-HIV Agents