Phenotypic characterization of virological failure following lopinavir/ritonavir monotherapy using full-length Gag-protease genes.

OBJECTIVES: Major protease mutations are rarely observed following first-line failure with PIs and interpretation of genotyping results in this context may be difficult. We performed extensive phenotyping of viruses from five patients failing lopinavir/ritonavir monotherapy in the MONARK study without major PI mutations by standard genotyping. METHODS: Phenotypic susceptibility testing and viral infectivity assessments were performed using a single-cycle assay and fold changes (FC) relative to a lopinavir-susceptible reference strain were calculated. RESULTS: >10-fold reduced baseline susceptibility to lopinavir occurred in two of five patients and >5-fold in another two. Four of five patients exhibited phylogenetic evidence of a limited viral evolution between baseline and failure, with amino acid changes at drug resistance-associated positions in one: T81A emerged in Gag with M36I in the protease gene, correlating with a reduction in lopinavir susceptibility from FC 7 (95% CI 6-8.35) to FC 13 (95% CI 8.11-17.8). Reductions in darunavir susceptibility (>5 FC) occurred in three individuals. DISCUSSION: This study suggests both baseline reduced susceptibility and evolution of resistance could be contributing factors to PI failure, despite the absence of classical PI resistance mutations by standard testing methods. Use of phenotyping also reveals lower darunavir susceptibility, warranting further study as this agent is commonly used following lopinavir failure

Polymorphism in Gag Gene Cleavage Sites of HIV-1 Non-B Subtype and Virological Outcome of a First-Line Lopinavir/Ritonavir Single Drug Regimen

Virological failure on a boosted-protease inhibitor (PI/r) first-line triple combination is usually not associated with the detection of resistance mutations in the protease gene. Thus, other resistance pathways are being investigated. First-line PI/r monotherapy is the best model to investigate in vivo if the presence of mutations in the cleavage sites (CS) of gag gene prior to any antiretroviral treatment might influence PI/r efficacy. 83 patients were assigned to initiate antiretroviral treatment with first-line lopinavir/r monotherapy in the randomised Monark trial. We compared baseline sequence of gag CS between patients harbouring B or non-B HIV-1 subtype, and between those who achieved viral suppression and those who experienced virological failure while on LPV/r monotherapy up to Week 96. Baseline sequence of gag CS was available for 82/83 isolates; 81/82 carried at least one substitution in gag CS compared to HXB2 sequence. At baseline, non-B subtype isolates were significantly more likely to harbour mutations in gag CS than B subtype isolates (p<0.0001). Twenty-three patients experienced virological failure while on lopinavir/r monotherapy. The presence of more than two substitutions in p2/NC site at baseline significantly predicted virological failure (p = 0.0479), non-B subtype isolates being more likely to harbour more than two substitutions in this specific site. In conclusion, gag cleavage site was highly polymorphic in antiretroviral-naive patients harbouring a non-B HIV-1 strain. We show that pre-therapy mutations in gag cleavage site sequence were significantly associated with the virological outcome of a first-line LPV/r single drug regimen in the Monark trial

Predictive Genotypic Algorithm for Virologic Response to Lopinavir-Ritonavir in Protease Inhibitor-Experienced Patients▿

Several genotypic resistance algorithms have been proposed for quantitation of the degree of phenotypic resistance to the human immunodeficiency virus (HIV) protease inhibitor (PI) lopinavir (LPV), including the original LPV mutation score. In this study, we retrospectively evaluated 21 codons in HIV protease known to be associated with PI resistance in a large antiretroviral agent-experienced observational patient cohort, “Autorisation Temporaire d'Utilization” (ATU), to assess whether a more optimal algorithm could be derived by using virologic response data from patients treated with LPV in combination with ritonavir (LPV/r). Five of the 11 mutations constituting the LPV mutation score were not associated with a virologic response, while 4 additional mutations not included in this score demonstrated an association. Therefore, the LPV ATU score, which includes mutations at codons 10, 20, 24, 33, 36, 47, 48, 54, 82, and 84, was constructed and shown in two different types of multivariable analyses of the ATU cohort to be a better predictor of the virologic response than the LPV mutation score. The LPV ATU score was also more strongly associated with a virologic response when it was applied to independent clinical trial populations of PI-experienced patients receiving LPV/r. This study provides the basis for a new genotypic resistance algorithm that is useful for predicting the antiviral activities of LPV/r-based regimens in PI-experienced patients. The refined algorithm may be useful in making clinical treatment decisions and in refining genetic and pharmacologic methods for assessing the activity of LPV/r

Effect of Lopinavir/Ritonavir Monotherapy on Quality of Life and Self-Reported Symptoms among Antiretroviral-Naive Patients: Results of the MONARK Trial

Background Standard-of-care for HIV-infected patients consists of combining three antiretroviral drugs. However, other therapeutic strategies could be beneficial given long-term toxicity and quality of life (QOL) issues associated with taking multiple antiretroviral drugs for many years. In the prospective, open label, randomized, pilot monotherapy antiretroviral Kaletra® (MONARK) trial among antiretroviral-naive patients, lopinavir/ritonavir (LPV/r) monotherapy was found to be less suppressive for HIV RNA than a standard triple-drug therapy of LPV/r plus zidovudine/lamivudine (on-treatment analysis after 48 weeks). We present data from the MONARK trial concerning QOL and patient-reported symptoms. Methods Patient-reported symptoms were collected at baseline and at weeks 4, 12, 24 and 48 using a list of 22 symptoms. QOL was assessed at baseline, week 24 and week 48 using the six-domain World Health Organization QOL short form questionnaire for HIV-infected individuals including an evaluation of global health perception. Results Patients treated with the standard triple-drug therapy reported significantly more symptoms over 48 weeks of treatment than patients treated with LPV/r monotherapy (incidence rate ratio [95% confidence interval] 1.3 [1.1, 1.6] P=0.001 and 1.4 [1.2, 1.7] P=0.0004 for the total number of symptoms and the number of symptoms causing discomfort, respectively). No baseline differences and no significant changes were observed in the six QOL scores. The percentage of patients with a positive perception of their global health status increased significantly in the monotherapy arm from 32% at baseline to 67% at week 48 ( P&lt;0.0001). Conclusions These results suggest that the number of self-reported symptoms could be used as a treatment-sensitive measure of patients’ well-being in clinical trials. </jats:sec

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)&lt;400 copies/ml at week 24 and VL&lt;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&lt;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. </jats:sec

Residual HIV-1 replication may impact immune recovery in patients on first-line lopinavir/ritonavir monotherapy

International audienceBackground: Antiretroviral combination therapy raises issues of long-term adherence and toxicity. Initial treatment simplification based on single-drug therapy was investigated in the MONARK trial, which compared first-line lopinavir/ritonavir monotherapy (arm A) with first-line lopinavir/ritonavir + zidovudine/lamivudine tritherapy (arm B). The MONARK trial is registered as a randomized trial at clinical trials.gov under identifier NCT 00234923.Patients and methods: Immune recovery was compared in patients with undetectable plasma virus (<50 copies/mL) after 60 weeks of treatment (arm A, n = 21; arm B, n = 13).Results: The week 60 CD4 T cell count and CD4 T cell subset distribution did not differ significantly between the treatment arms. Memory CD4 T cell responses to HIV and recall antigens were better with triple therapy than with monotherapy. The frequencies of activated CD8 T cells and anti-HIV CD8 T cell effector responses were similar in the two arms. However, the repertoire of CD8 T cell effector responses was broader and persistent residual viraemia more frequent (by ultrasensitive PCR) in the monotherapy arm.Conclusions: While viral control can be achieved with first-line lopinavir/ritonavir monotherapy, the quality of immune recovery is inferior to that obtained with triple therapy, possibly owing to a higher level of residual viral replication. Thus, the benefits of first-line lopinavir/ritonavir monotherapy in terms of toxicity and adherence might be offset by an increased risk of residual viral replication, which may also fuel latent viral reservoirs

Protease Inhibitor Resistance Analysis in the MONARK Trial Comparing First-Line Lopinavir-Ritonavir Monotherapy to Lopinavir-Ritonavir plus Zidovudine and Lamivudine Triple Therapy▿

The MONARK study was a pilot randomized trial comparing the safety and efficacy of lopinavir-ritonavir (LPV/r) monotherapy to those of LPV/r-zidovudine-lamivudine triple therapy for antiretroviral-naïve human immunodeficiency virus type 1 (HIV-1)-infected patients. Resistance testing was performed at the time of initial screening and at the time of virological failure (defined to include low-level viremia with >50 and <400 HIV-1 virus RNA copies/ml of plasma). Changes from the baseline sequences, including mutations noted on the 2008 International AIDS Society—USA list of resistance-associated protease mutations, were considered. Drug resistance testing was performed for 38 patients (5 of 53 on triple therapy and 33 of 83 on monotherapy). By week 96 (W96), virus samples from 18 of 33 patients in the monotherapy arm showed changes from baseline sequences, and 5 of these patients had viruses with major protease inhibitor (PI) resistance-associated mutations (M46I at W40, L76V at W48, M46I and L76V at W48, L10F and V82A at W72, and L76V at W84). Data on virus phenotypes detected at the time of initial screening and the time of virological failure were available for four patients in whom major PI resistance mutations developed, and these data revealed a mean increase of 2.2-fold (range, 0.75- to 4.6-fold) in the LPV 50% inhibitory concentration. All three patients in whom the L76V PI resistance mutation developed were infected with HIV-1 subtype CRF02_AG. In the triple-therapy group, no major PI resistance mutation was selected among the three patients with protease changes by W48. No association between the baseline CD4 cell count and the viral load, the W4 and final viral loads, or the final LPV trough concentration and the emergence of a major PI resistance mutation was found. Major PI resistance-associated mutations were detected in 5 (6%) of 83 patients treated with LPV/r monotherapy, suggesting that LPV/r monotherapy is an inappropriate first option. The mutation L76V may be considered in further studies of lopinavir resistance