title: HIV RNA in plasma rebounds within days during structured treatment interruptions.
abstract: OBJECTIVE
  To evaluate time to viral rebound in patients undergoing repeated structured treatment interruptions (STI).
  
  
  METHODS
  Fourteen chronically HIV-infected patients enrolled in the Swiss-Spanish Intermittent Treatment Trial (SSITT) underwent frequent blood sampling. Patients underwent four cycles of 2-week STI, followed by 8-week retreatment with the identical antiretroviral treatment (HAART) used before STI. At the fifth cycle, treatment was stopped for a longer period. Before each new STI, plasma viral load (VL) had to reach < 50 copies/ml. VL was measured during day 0 (last day on HAART) and on days 4, 8 and 14 during all five STI.
  
  
  RESULTS
  During the first cycle, plasma HIV RNA increased to > 50 copies/ml (range, 67-88) in five patients at day 4, in eight patients (> 100 copies/ml) at day 8 and in 12 patients (> 100 copies/ml) at day 14. Cumulative analysis of the frequency of detectable HIV RNA at days 4, 8 and 14 compared with day 0 for all five cycles revealed nine patients with VL > 50 copies/ml [13 of 54 samples tested (24.1%); = 0.14] at day 4, 11 patients [33 of 58 samples tested (56.9%); < 0.0001] at day 8 and 12 patients [53 of 65 samples tested (81.5%); < 0.0001] at day 14.
  
  
  CONCLUSIONS
  Significant viral replication can be induced during 1 week STI, and this may increase the risk of the emergence of drug resistance during long-term cycling. Therefore, short-term cycling strategies such as 1-week-on, 1-week-off treatment, although conceptually intriguing, should still be regarded as investigational and should be restricted to rigorously controlled clinical trials ideally involving patients who have never failed treatment before.
authors.affiliation: Division of Infectious Diseases, University Hospital of Zürich, Switzerland.
authors.forename: Marek
authors.initials: M
authors.lastname: Fischer
authors.forename: Roland
authors.initials: R
authors.lastname: Hafner
authors.forename: Christine
authors.initials: C
authors.lastname: Schneider
authors.forename: Alexandra
authors.initials: A
authors.lastname: Trkola
authors.forename: Beda
authors.initials: B
authors.lastname: Joos
authors.forename: Helen
authors.initials: H
authors.lastname: Joller
authors.forename: Bernard
authors.initials: B
authors.lastname: Hirschel
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
authors.forename: Huldrych F
authors.initials: HF
authors.lastname: Günthard
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D004334:Drug Administration Schedule; D006678:HIV / Q000502:physiology*; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D012367:RNA, Viral / Q000097:blood*; D014766:Viremia / Q000821:virology; D017735:Virus Latency; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral