Low-dose ritonavir-boosted darunavir in virologically suppressed HIV-1-infected adults: an open-label trial (ANRS 165 Darulight)

Four days/week antiretroviral maintenance strategy (ANRS 170 QUATUOR): substudies of reservoirs and ultrasensitive drug resistance

BACKGROUND

In a 4 days/week (4/7 days) maintenance strategy (ANRS-170 QUATUOR trial), the virological impact of an intermittent strategy was assessed by ultrasensitive virological analyses of reservoirs and resistance.

METHODS

HIV-1 total DNA, ultra-sensitive plasma viral load (USpVL) and semen VL were measured in the first 121 participants. Sanger and ultra-deep sequencing (UDS) were performed on the HIV-1 genome (Illumina technology) according to the ANRS consensus. A generalized estimation equation with a Poisson distribution was used to compare changes in the proportion of residual viraemia, detectable semen HIV RNA and HIV DNA within and between the two groups over time.

RESULTS

The proportion of participants with residual viraemia at Day 0 (D0) and Week 48 (W48) was 16.7% and 25.0% in the 4/7 days group and 22.4% and 29.7% in the 7/7 days group, respectively (+8.3% versus +7.3%, P = 0.971). The proportion of detectable DNA (>40 copies/106 cells) at D0 and W48 was 53.7% and 57.4% in the 4/7 days group and 56.1% and 51.8% in the 7/7 days group, respectively (+3.7% versus -4.3%, P = 0.358). Semen HIV RNA was detectable (≥100  copies/mL) in 2.2% of participants at D0 and 4.5% at W48 in the 4/7 days group versus 6.1% and 9.1% in the 7/7 days group, respectively (+2.3% versus +3.0%, P = 0.743). Emerging resistance at failure was more frequent in the 4/7 days group detected by Sanger sequencing: 3/6 participants versus 1/4 in the 7/7 days group, and similar with the UDS assay: 5/6 versus 4/4, respectively.

CONCLUSIONS

These findings support the potency of a 4/7 days maintenance strategy on virological suppression at the reservoirs and emergent resistance level, including minority variants.

Exploration of Reduced Doses and Short-Cycle Therapy for Darunavir/Cobicistat in Patients with HIV Using Population Pharmacokinetic Modeling and Simulations

BACKGROUND AND OBJECTIVES

Protease inhibitors such as darunavir are an important therapeutic option in the anti-human immunodeficiency virus arsenal. Current dosage guidelines recommend using cobicistat- or ritonavir-boosted darunavir 800 mg every 24 h (q24h) in protease inhibitor-naïve patients, or ritonavir-boosted darunavir 600 mg q12h in experienced patients. However, darunavir displays a large, poorly characterized, inter-individual pharmacokinetic variability. The objectives of this study were to investigate the pharmacokinetics of darunavir and to elucidate the sources of its inter-individual variability using population pharmacokinetic modeling. Then, to determine the appropriateness of current treatment guidelines and the feasibility of alternative dosing regimens in a representative cohort of adult patients using simulations.

METHODS

Sparse pharmacokinetic samples were collected in 127 patients with human immunodeficiency virus type 1 infection, then supplemented with rich sampling data from a subset of 12 individuals. Data were analyzed using the nonlinear mixed-effects modeling software NONMEM. The effect of reduced doses (600 mg q24h and 400 mg q24h) or reduced frequency of administration (800 mg q24h for 5 days followed by 2 days of treatment interruption) was simulated.

RESULTS

Our model adequately described the pharmacokinetics of darunavir. Predictors of individual exposure were CYP3A5*3 and SLCO3A1 rs8027174 genotypes, sex, and alpha-1 acid glycoprotein level. No relationship was apparent between darunavir area under the curve and treatment efficacy or safety. For reduced dose regimens, darunavir concentrations remained above the protein binding-corrected EC₅₀ in the majority of subjects. More stringent pharmacokinetic targets were not reached in a significant proportion of patients.

CONCLUSIONS

These results add to the growing body of evidence that darunavir-based therapy could be simplified to reduce costs and toxicity, as well as to improve patient compliance. However, the heterogeneity in pharmacokinetic response should be considered when assessing whether individual patients could benefit from a particular regimen, for instance through the use of population pharmacokinetic models.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03101644, date of registration: 5 April, 2017.

Pharmacokinetic modelling of darunavir/ritonavir dose reduction (800/100 to 400/100 mg once daily) in a darunavir/ritonavir-containing regimen in virologically suppressed HIV-infected patients: ANRS 165 DARULIGHT sub-study

Background

In the ANRS 165 DARULIGHT study (NCT02384967) carried out in HIV-infected patients, the use of a darunavir/ritonavir-containing regimen with a switch to a reduced dose of darunavir maintained virological efficacy (≤50 copies/mL) for 48 weeks with a good safety profile.

Objectives

To assess the total and unbound blood plasma pharmacokinetics of darunavir and associated antiretrovirals, and their penetration into semen before and after dose reduction.

Patients and methods

Patients receiving a darunavir/ritonavir (800/100 mg q24h)-containing regimen for >6 months with plasma HIV-RNA ≤50 copies/mL for >12 months were switched to 400/100 mg darunavir/ritonavir q24h at week 0. A 24 h intensive pharmacokinetic blood sampling and a trough seminal sampling were performed before (week 0) and after (week 12) dose reduction. Individual pharmacokinetic parameter estimates were obtained using non-linear mixed-effect modelling for darunavir/ritonavir in blood plasma and used to test for bioequivalence, whereas darunavir/ritonavir in seminal plasma and NRTIs were analysed using a non-compartmental approach.

Results and conclusions

Fifteen patients completed the intensive pharmacokinetic analysis. There was no significant decrease in total and unbound darunavir blood plasma exposure despite a 50% decrease in darunavir daily dose from 800 to 400 mg (AUC0-24 = 65 563 versus 52 518 ng·h/mL; P = 0.25). A decrease in apparent oral clearance (CL/F) of both darunavir and ritonavir at week 12 suggests a modification of the initial darunavir/ritonavir daily dose balance (800/100 to 400/100 mg), in favour of a reduced inducer effect of darunavir on cytochrome P450 and efflux transporters compared with the standard dose.