Prognostic factors for virological response in antiretroviral therapy-naive patients in the MONARK Trial randomized to ritonavir-boosted lopinavir alone.
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.
Flandre
Philippe
P
INSERM U 943, Paris, France. pflandre@ccde.chups.jussieu.fr
Delaugerre
Constance
C
Ghosn
Jade
J
Chaix
Marie Laure
ML
Horban
Andrzej
A
Girard
Pierre-Marie
PM
Gladysz
Andrzej
A
Cohen-Codar
Isabelle
I
Van
Philippe Ngo
PN
Taburet
Anne-Marie
AM
Rouzioux
Christine
C
Delfraissy
Jean-François
JF