title: Prognostic factors for virological response in antiretroviral therapy-naive patients in the MONARK Trial randomized to ritonavir-boosted lopinavir alone.
abstract: BACKGROUND
  MONARK is a pilot randomized trial comparing the safety and efficacy of lopinavir/ritonavir (LPV/r) monotherapy to a standard triple-drug regimen as initial therapy. The primary endpoint was virological response (VR) defined as viral load (VL)<400 copies/ml at week 24 and VL<50 copies/ml at week 48. The objective of this study was to determine prognostic factors of VR in patients receiving LPV/r monotherapy.
  
  
  METHODS
  Baseline characteristics, including demographics, HIV type-1 (HIV-1) subtype (B versus non-B), early VR up to week 4, LPV trough concentrations and compliance were investigated as prognostic factors for VR in patients receiving LPV/r monotherapy. Logistic regression was used to search for variables significantly associated with the occurrence of VR.
  
  
  RESULTS
  VR was achieved in 53 out of 83 patients randomized to the LPV/r arm. The on-treatment analysis, using a multivariate model, indicated that having VL<400 copies/ml at week 4 and harbouring HIV-1 subtype B were independently associated with an increased probability of VR. No difference in early VL reduction was evidenced between patients harbouring B or non-B subtypes. The latter patients had more difficulty in adherence to therapy than the former patients. The intention-to-treat analysis showed similar results.
  
  
  CONCLUSIONS
  HIV-1 RNA measured at baseline or at week 4 and HIV-1 subtype (B versus non-B) were independent predictive factors of VR in patients starting therapy with LPV/r alone. Although based on a small sample size, results of this study showed that adherence to therapy is lower in patients harbouring non-B subtypes and appears to be a key factor of VR in the context of protease inhibitor monotherapy.
authors.affiliation: INSERM U 943, Paris, France. pflandre@ccde.chups.jussieu.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Flandre
authors.forename: Constance
authors.initials: C
authors.lastname: Delaugerre
authors.forename: Jade
authors.initials: J
authors.lastname: Ghosn
authors.forename: Marie Laure
authors.initials: ML
authors.lastname: Chaix
authors.forename: Andrzej
authors.initials: A
authors.lastname: Horban
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Girard
authors.forename: Andrzej
authors.initials: A
authors.lastname: Gladysz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cohen-Codar
authors.forename: Philippe Ngo
authors.initials: PN
authors.lastname: Van
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Taburet
authors.forename: Christine
authors.initials: C
authors.lastname: Rouzioux
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Delfraissy