title: HIV monotherapy with ritonavir-boosted protease inhibitors: a systematic review.
abstract: OBJECTIVE
  To assess the efficacy of ritonavir-boosted protease inhibitor monotherapy.
  
  
  METHODS
  Systematic review of all protease inhibitor-monotherapy studies published in peer-reviewed journals or presented at conferences to date. Data of randomized controlled trials were pooled to yield common odds ratios.
  
  
  RESULTS
  Twenty-two protease inhibitor-monotherapy studies were identified. In the intent-to-treat analysis, 395 out of 582 (67.9%) patients had undetectable HIV-RNA at the end of follow-up. In the six randomized controlled trials (all lopinavir/ritonavir monotherapy), the risk of therapy failure was greater on monotherapy: 121 out of 364 (33.2%) patients on monotherapy against 64 out of 280 (22.9%) patients on HAART [pooled odds ratio 1.48 (95% confidence interval 1.02-2.13, P = 0.037)]. Regarding patients with successfully resuppressed HIV-RNA upon (re-)introducing nucleoside reverse transcriptase inhibitors (NRTIs) as nonfailures, the risk of therapy failure was comparable: 98 out of 364 (26.9%) against 64 out of 280 (22.9%) patients [odds ratio 1.05 (95% confidence interval 0.72-1.53, P = 0.81)].
  
  
  CONCLUSIONS
  The overall efficacy of ritonavir-boosted protease inhibitor monotherapy is inferior to HAART. The efficacy improves in patients started on monotherapy after suppressed HIV-RNA for at least 6 months. Ten percent of patients have viral rebound with HIV-RNA levels between 50 and 500 copies/ml. Possible explanations are lack of HIV suppression in particular cells or compartments, alternative resistance mechanisms, and nonadherence. Once proven that reintroduction of NRTIs, in patients with loss of viral suppression, is safe and effective, a broader use of simplification of HAART to protease inhibitor monotherapy might be justified. This review supports that the majority of patients with prolonged viral suppression on HAART can successfully be treated with protease inhibitor monotherapy. Arguments for this strategy are NRTI/NNRTI side effects, NRTI/NNRTI resistance, and costs.
authors.forename: Wouter F W
authors.initials: WF
authors.lastname: Bierman
authors.forename: Michiel A
authors.initials: MA
authors.lastname: van Agtmael
authors.forename: Monique
authors.initials: M
authors.lastname: Nijhuis
authors.forename: Sven A
authors.initials: SA
authors.lastname: Danner
authors.forename: Charles A B
authors.initials: CA
authors.lastname: Boucher
mesh_terms: D000069446:Atazanavir Sulfate; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000627:therapeutic use*; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D019469:Indinavir / Q000627:therapeutic use; D061466:Lopinavir; D009842:Oligopeptides / Q000627:therapeutic use; D011725:Pyridines / Q000627:therapeutic use; D011744:Pyrimidinones / Q000627:therapeutic use; D012367:RNA, Viral / Q000097:blood; D019438:Ritonavir / Q000627:therapeutic use*; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D017320:HIV Protease Inhibitors; D009842:Oligopeptides; D011725:Pyridines; D011744:Pyrimidinones; D012367:RNA, Viral; D061466:Lopinavir; D000069446:Atazanavir Sulfate; D019469:Indinavir; D019438:Ritonavir