Impact of lopinavir-ritonavir exposure in HIV-1 infected children and adolescents in Madrid, Spain during 2000-2014

Background

The most-used protease-inhibitor in children is Lopinavir-ritonavir (LPV/r), which provides durable suppression of viral load and increases CD4+T-counts. This study describes the virological outcome of the HIV-1-infected paediatric population exposed to LPV/r during 15 years in Spain.

Methodology

Patients from the Madrid Cohort of HIV-1-infected-children and adolescents exposed to LPV/r as different line therapy during 2000–2014 were selected. The baseline epidemiological-clinical features, viral suppression, changes in CD4+T-CD8+T cell counts and drug susceptibility were recorded before and during LPV/r exposure. Drug resistance mutations (DRM) were identified in viruses from samples collected until 2011. We predicted drug susceptibility to 19 antiretrovirals among those carrying DRM using the Stanford′s HIVdb Algorithm.

Results

A total of 199 (37.3%) of the 534 patients from the cohort were exposed to LPV/r during 2000–2014 in first (group 1), second (group 2) or more line-therapies (group 3). Patients were mainly Spaniards (81.9%), perinatally infected (96.5%) with subtype-B (65.3%) and HIV-diagnosed before year 2000 (67.8%). The mean age at first LPV/r exposure was 9.7 years. After protease-inhibitor exposure, viral suppression was higher in groups 1 and 2 than in group 3. Viral suppression occurred in 87.5%, 68.6% and 64.8% patients from groups 1, 2 and 3, respectively. Among the 64 patients with available resistance data during LPV/r treatment, 27(42.3%) carried DRM to protease-inhibitor, 28 (58.3%) to reverse-transcriptase-inhibitors and 21 (43.7%) to non-reverse-transcriptase-inhibitors. Darunavir/ritonavir, atazanavir-ritonavir and tipranavir/ritonavir presented the highest susceptibility and nelfinavir the lowest.

Conclusions

A better lymphocyte recovering occurred when protease-inhibitor was taken as part of a first-line regimen and a higher number of patients reached viral suppression. The least compromised antiretrovirals for rescue antiretroviral regimens, according to DRM in the LPV/r-exposed-paediatric cohort, were mainly the new protease inhibitors.

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

BACKGROUND

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.

Plasma Concentrations of the HIV-Protease Inhibitor Lopinavir are Suboptimal in Children Aged 2 Years and Below

Background

Lopinavir/ritonavir (LPV/r) has been licensed for the treatment of HIV-infected children >6 months in the US and >2 years in the EU. Limited LPV paediatric pharmacokinetic data are available. We studied LPV pharmacokinetics to determine whether the recommended dose (230/57.5 mg/m2 twice daily) results in optimal LPV exposure in all age groups. Virological efficacy was a secondary objective.

Methods

HIV-1-infected children who started treatment with LPV/r and two nucleoside reverse transcriptase inhibitors underwent a 12-h pharmacokinetic curve. LPV plasma concentrations were determined with a validated HPLC method with UV detection. If Cmin was <1.0 mg/l LPV/r dose was increased by 33%. Plasma trough levels were drawn subsequently. HIV-1 RNA was followed-up until week 48.

Results

A total of 23 children were included (seven girls; 16 boys), with a median (range) age of 5.6 (0.4–13.2) years. Mean (±SD) AUC0–12h, Cmax and Cmin of LPV were 75.3 (±33.7) mg/l.h, 9.33 (±3.27) mg/l and 3.68 (±2.48) mg/l, respectively, which is similar to previously published data. Interindividual variability was large. Cmin was inadequate in 7/23 children. Significantly more children <2 years had inadequate Cmin compared with children >2 years. Dose increase to ±300/75 mg/m2 LPV/r led to Cmin >1.0 mg/l. The studied regimen provided excellent viral suppression for naive and pretreated patients.

Conclusions

Mean LPV pharmacokinetic parameters in these HIV-infected children are similar to published data, but exposure is significantly reduced in children <2 years. Prospective pharmacokinetic studies using 300/75 mg/m2 LPV/r in this age population are urgently warranted.