title: Treatment interruption of highly active antiretroviral therapy in patients with nadir CD4 cell counts >200 cells/mm3.
abstract: BACKGROUND
  The goal of the present study was to characterize outcome and predictors of outcome of treatment interruption (TI) in highly active antiretroviral therapy (HAART)-treated patients.
  
  
  METHODS
  A systematic chart/database review was conducted to identify patients with nadir CD4 cell counts >200 cells/mm(3) and without acquired immunodeficiency syndrome-defining illnesses who underwent a TI. Collected data included duration and reason for TI, demographic characteristics, CD4 cell count, and plasma viral load. Human immunodeficiency virus (HIV) envelope (V3) loop genotyping was performed on plasma HIV RNA. The presence of basic residues at aa 11 and/or 25 (the "11/25" genotype) was a further possible prognostic variable of interest. Cox proportional hazards models were used to assess characteristics associated with time to HAART reinitiation after TI.
  
  
  RESULTS
  A total of 208 of 4461 (4.7%) patients underwent TI. The study group consisted of 197 (94.7%) of 208 participants for whom V3 genotyping was successful. The median CD4 cell count at time of the initiation of TI was 620 cells/mm(3). A total of 59 (29.9%) patients reinitiated HAART after a median of 15 months. At the time of the reinitiation of HAART, the median plasma viral load was >100,000 copies/mL, and the median CD4 cell count was 260 cells/mm(3). Among the 197 study patients, there were 6 deaths, none of which was attributable to the TI. A total of 81% had plasma viral loads <50 copies/mL by 15 months of follow-up after reinitiation of HAART. In multivariate analysis, a nadir CD4 cell count < or =250 cells/mm(3) (risk ratio [RR], 2.79 [95% confidence interval [CI], 1.60-4.86]; P < .001) and the presence of the 11/25 genotype (RR, 2.07 [95% CI, 1.07-4.02]; P = .031) were positively and independently associated with faster time to HAART reinitiation, after adjusting for age and plasma virus load at the start of TI.
  
  
  CONCLUSIONS
  Our study suggests that TI is a viable option for HIV-positive adults with nadir CD4 cell counts >250 cells/mm(3). A nadir CD4 cell count of 200-250 cells/mm(3) and the 11/25 viral genotype were found to be associated with a faster HAART reinitiation.
authors.affiliation: BC Centre for Excellence in HIV/AIDS, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Adrienne R
authors.initials: AR
authors.lastname: Toulson
authors.forename: Richard
authors.initials: R
authors.lastname: Harrigan
authors.forename: Katherine
authors.initials: K
authors.lastname: Heath
authors.forename: Benita
authors.initials: B
authors.lastname: Yip
authors.forename: Zabrina L
authors.initials: ZL
authors.lastname: Brumme
authors.forename: Marianne
authors.initials: M
authors.lastname: Harris
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hogg
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D016896:Treatment Outcome