Switching to darunavir/ritonavir 800/100 mg once-daily containing regimen maintains virological control in fully suppressed pre-treated patients infected with HIV-1

PrEParing for the unexpected: mechanisms and management of HIV pre-exposure prophylaxis failure

Pre-exposure prophylaxis (PrEP) for HIV is a proven and effective tool for preventing HIV. However, there are instances where individuals taking PrEP have contracted HIV infection. Most of these cases are due to nonadherence to the drug, while other cases of apparent PrEP failure are due to unrecognized HIV infection at baseline. Importantly, there are also now at least three well-documented cases of PrEP failing despite adequate adherence; these are cases of PrEP ‘breakthrough’. This article outlines the potential mechanisms of PrEP failure, as well as how to identify and manage these patients. Finally, we provide a perspective on the future of PrEP as a key tool in preventing HIV worldwide.

Plasma trough concentrations of darunavir/ritonavir and raltegravir in older patients with HIV-1 infection

OBJECTIVES

The aim of the study was to assess plasma concentrations of darunavir/ritonavir and raltegravir in older patients compared with younger patients with HIV-1 infection.

METHODS

In this observational, open-label study, adult HIV-infected out-patients aged ≤ 40 years (younger patients) or ≥ 60 years (older patients) and treated with tenofovir/emtricitabine plus darunavir/ritonavir (800/100 mg daily) or raltegravir (400 mg twice daily) were asked to participate. The trough concentrations (C_trough ) of darunavir/ritonavir and raltegravir were assessed at steady state using a validated high-performance liquid chromatography (HPLC)-tandem mass spectrometry method.

RESULTS

A total of 88 HIV-positive patients were enrolled in the study. Forty-six patients were treated with darunavir/ritonavir, and 42 with raltegravir. The geometric mean plasma C_trough (coefficient of variation) of raltegravir was comparable between the 19 older and 23 younger subjects: 106 ng/mL (151%) and 94 ng/mL (129%), respectively [geometric mean ratio (GMR) 0.85; 95% confidence interval (CI) 0.71-1.57; P = 0.087]. In contrast, the geometric mean plasma C_trough of darunavir was significantly higher among the 21 older patients [2209 ng/mL (139%)] than among the 25 younger patients [1876 ng/mL (162%); GMR 1.56; 95% CI: 1.22-1.88; P = 0.004]. Similarly, the geometric mean C_trough of ritonavir was significantly higher among older than among younger individuals.

CONCLUSIONS

The mean plasma C_trough of darunavir and ritonavir was significantly higher in older patients than in younger patients with HIV-1 infection, while the mean plasma level of raltegravir was comparable in the two groups. However, both regimens showed good tolerability in both younger and older subjects.

Effect of Monotherapy with Darunavir/Ritonavir on Viral Load in Seminal Fluid, and Quality Parameters of Semen in HIV-1-Positive Patients

Patients with human immunodeficiency virus type 1 (HIV-1) who receive antiretroviral therapy (ART) often achieve increased survival and improved quality of life. In this respect, monotherapy with darunavir/ritonavir (mDRV/r) can be a useful treatment strategy. This prospective study analyses the effect of mDRV/r on sperm quality and viral load in a group of 28 patients who had previously been given conventional ART and who had recorded a viral load <20 copies/mL for at least six months. These patients were given mDRV/r at a dose of 800/100 mg for 48 weeks. At baseline (V0), CD4, CD8, FSH, LH and testosterone levels were measured, together with HIV-1 viral load in plasma and semen. In addition, seminal fluid quality was studied before mDRV/r treatment was prescribed. At week 48 (V1), HIV-1 viral load in plasma and semen and the quality of the seminal fluid were again measured. The results obtained indicate that at V0, 10% of the patients with ART had a positive viral load in seminal fluid (>20 copies/ml), and that at V1, after mDRV/r treatment, this figure had fallen to 3%. The quality of seminal fluid was close to normal in 57% of patients at V0 and in 62% at V1. We conclude that, similar to ART, mDRV/r maintains HIV-1 viral load in most patients, and that there is no worsening in seminal fluid quality.

Brief Report: Switch to Ritonavir-Boosted Atazanavir Plus Raltegravir in Virologically Suppressed Patients With HIV-1 Infection: A Randomized Pilot Study

This open-label, multinational, pilot study randomized (1:2 ratio) adults with HIV-1 RNA <40 copies per milliliter and nucleos(t)ide-related safety/tolerability issues to switch to ritonavir-boosted atazanavir (ATV/r) plus tenofovir disoproxil fumarate/emtricitabine (n = 37) or the nucleos(t)ide reverse transcriptase inhibitor-sparing regimen of ATV/r plus raltegravir (RAL) (n = 72). At 24 weeks, 35/37 (94.6%) and 58/72 (80.6%) of patients, respectively, maintained virological suppression, the primary endpoint, and 1 (2.7%) and 7 (9.7%), respectively, experienced virological rebound. Corresponding 48-week proportions were 86.5%, 69.4%, 2.7%, and 12.5%, respectively. Adherence was lower and treatment discontinuation was higher with ATV/r+RAL. In conclusion, switching to ATV/r+RAL resulted in a higher virological rebound rate than switching to ATV/r plus tenofovir disoproxil fumarate/emtricitabine.

Efficacy and safety of once-daily ritonavir-boosted atazanavir or darunavir in combination with a dual nucleos(t)ide analogue backbone in HIV-1-infected combined ART (cART)-naive patients with severe immunosuppression: a 48 week, non-comparative, randomized, multicentre trial (IMEA 040 DATA trial)

OBJECTIVES

Boosted PIs are commonly prescribed in patients presenting with advanced HIV infection. We assessed the efficacy and tolerability of once-daily ritonavir-boosted atazanavir or darunavir plus two NRTIs in HIV-1-infected ART-naive patients with severe immunosuppression, targeting at least an 85% success rate at week 48.

METHODS

This 48 week, open-label, non-comparative, randomized, multicentre trial included ART-naive patients with CD4 cell counts <200 cells/mm(3), with plasma HIV-1 RNA >1000 copies/mL and without genotypic mutations conferring resistance to the study drugs. Patients were randomized (1:1) to receive once-daily atazanavir/ritonavir (300/100 mg) or darunavir/ritonavir (800/100 mg) plus tenofovir disoproxil fumarate/emtricitabine or abacavir/lamivudine. The primary endpoint was treatment success, defined as plasma HIV-1 RNA ≤50 copies/mL at week 48 and no permanent PI/ritonavir discontinuation. The study was registered with ClinicalTrials.gov (NCT01928407).

RESULTS

One hundred and twenty patients were enrolled: 77% were men, 30% were born in Africa and 39% had AIDS. The median baseline CD4 and plasma HIV-RNA values were 69 cells/mm(3) and 5.4 log10 copies/mL. All but four patients received tenofovir disoproxil fumarate/emtricitabine. The week 48 treatment success rate was 66% (95% CI 54%-78%) with atazanavir/ritonavir and 80% (95% CI 68%-89%) with darunavir/ritonavir. The median CD4 cell count increased similarly in the two groups (Δweek 48 to week 0: +194 cells/mm(3)). Adverse events occurred in 23 and 18 patients, respectively.

CONCLUSIONS

Despite good adherence, neither study regimen reached the predefined objective, suggesting a need for more potent regimens for patients with advanced HIV infection.

Darunavir and ritonavir total and unbound plasmatic concentrations in HIV-HCV-coinfected patients with hepatic cirrhosis compared to those in HIV-monoinfected patients

Our objective was to describe the pharmacokinetic (PK) parameters of total and unbound darunavir and ritonavir concentrations in HIV-hepatitis C virus (HCV)-coinfected patients with cirrhosis, as ritonavir-boosted darunavir is mainly metabolized in the liver, and hepatic cirrhosis might modify darunavir-ritonavir concentrations. This was a prospective, case-control, and unicenter study. HIV-HCV-coinfected patients with compensated cirrhosis (cases) and HIV-monoinfected patients with normal liver function (controls) were included. Darunavir-ritonavir was given at 800/100 mg once daily. Patients were followed for 24 weeks to assess safety and efficacy. A steady-state 12-h PK study was performed. Total and unbound concentrations were determined by liquid chromatography-tandem mass spectrometry. The unbound fraction was obtained by ultrafiltration. The plasma area under the concentration-time curve (AUC) and oral clearance (CL/F) were assessed by noncompartmental models. Thirty patients (20 cases and 10 controls) were included. Among cirrhotic patients, the Child-Pugh score was C in 4 cases, B in 1 case, and A in 15 cases; the median (interquartile range) transient elastography values were 20 kPa (14 to 26 kPa), and 5 patients had prior clinical decompensations. There were no significant differences in the darunavir PK parameters between cases and controls except for longer time to maximum plasma concentrations (Tmax) and half-lives in the cirrhotic patients. There were no significant differences in ritonavir total concentrations, but the unbound concentrations were higher in cirrhotic patients. There were significant correlations between the darunavir total and unbound concentrations in both cirrhotic patients and controls. There were no differences in PK parameters based on Child-Pugh score, liver elasticity, gender, or use of concomitant medications. In conclusion, in HIV-HCV-coinfected patients with clinically compensated cirrhosis receiving darunavir-ritonavir at 800/100 mg once daily, the darunavir total and unbound concentrations are similar to those observed in noncirrhotic patients, and dose adjustments are not necessary.

Simplification from twice-daily to once-daily darunavir/ritonavir in a randomized trial among HIV-infected persons with HIV-1 RNA suppression on antiretroviral therapy

BACKGROUND

DRIVESHAFT is a randomized, open-label, 48-week clinical trial that examined virological outcomes and safety of antiretroviral simplification among virologically suppressed, treatment-experienced HIV-infected patients switching from darunavir/ritonavir (DRV/r) twice-daily-based regimens to a once-daily DRV/r component.

METHODS

HIV-infected adults with a stable antiretroviral regimen including DRV/r 600/100 mg twice daily plus a minimum of two other antiretrovirals, <2 historical DRV-associated mutations and HIV RNA<40 copies/ml for at least 12 weeks prior to entry were eligible. Participants were randomized 1:1 to switch DRV/r to 800/100 mg once daily or maintain their current regimen. The primary end point was HIV-1 RNA<40 copies/ml at week 48 using the Snapshot algorithm.

RESULTS

Demographics and baseline characteristics were similar between arms. Virological suppression was greater in the DRV/r once-daily (n=30) versus twice-daily (n=30) arm at week 48 (90.0% versus 83.3%; 95% CI: -11.5, 24.8). Three subjects discontinued the once-daily arm, with four discontinuations and one virological failure in the twice-daily arm. No discontinuations were related to adverse events. Reduction in LDL was significantly greater in the once-daily arm at week 24 (-8.0 mg/dl versus 3.3 mg/dl; P=0.04). There was a trend towards suboptimal adherence <90% to antiretrovirals among subjects taking twice-daily versus once-daily DRV/r by week 48 (12.0% versus 0.0%; P=0.06).

CONCLUSIONS

Switching from twice-daily to once-daily DRV/r in virologically suppressed patients maintains virological control, with greater reduction in LDL cholesterol by 24 weeks. This study provides pilot data that could be used to design a non-inferiority study to definitively answer the question of whether switching from twice-daily to once-daily DRV/r maintains viral suppression. ClinicalTrials.gov number: NCT01423812.

Plasma concentrations of efavirenz, darunavir/ritonavir and raltegravir in HIV-HCV-coinfected patients without liver cirrhosis in comparison with HIV-monoinfected patients

BACKGROUND

The objective of the study was to assess plasma concentrations of efavirenz, darunavir/ritonavir and raltegravir in patients with human immunodeficiency virus-hepatitis C virus (HIV-HCV)-coinfection without liver cirrhosis.

METHODS

In this observational, open-label study, adult HIV-infected outpatients treated with tenofovir/emtricitabine plus efavirenz (600 mg daily), darunavir/ritonavir (800/100 mg daily) or raltegravir (400 mg twice daily) for at least 4 weeks were asked to participate. Subjects with liver cirrhosis were excluded. The trough concentration (C trough) of darunavir/ritonavir and raltegravir and the mid-dose concentration (C12h) of efavirenz were assessed at steady state by a validated high-performance liquid chromatography (HPLC)-tandem mass spectrometry method.

RESULTS

A total of 96 HIV-positive patients were enrolled into the study. Thirty-four patients were treated with efavirenz, 33 with darunavir/ritonavir and 29 with raltegravir. The geometric mean plasma C trough [coefficient of variation (%)] of darunavir was comparable between HIV+/HCV+ and HIV+/HCV- subjects: 2644 ng/ml (155%) and 2491 ng/ml (139%), respectively (geometric mean ratio (GMR) = 0.81; 95% confidence interval (CI) = 0.79-1.56; p = 0.69). These values were comparable for raltegravir: 108 ng/ml (149%) in the HIV+/HCV+ group and 96 ng/ml (161%) in the HIV+/HCV- group (GMR = 0.84; 95% CI = 0.61-1.44; p = 0.72). On the contrary, the geometric mean plasma C12h of efavirenz was significantly higher among the 15 HIV+/HCV+ patients (1915 ng/ml, 159%) than among the 19 HIV+/HCV- patients (1505 ng/ml, 167%; GMR = 1.41; 95% CI = 1.19-1.71; p = 0.009).

CONCLUSIONS

The mean plasma concentration of efavirenz was significantly higher in HCV-positive than in HCV-negative patients without liver cirrhosis, while the mean plasma levels of darunavir/ritonavir and raltegravir were comparable in both groups.

Pharmacokinetics and pharmacodynamics of boosted once-daily darunavir

The ability to dose antiretroviral agents once daily simplifies the often complex therapeutic regimens required for the successful treatment of HIV infection. Thus, once-daily dosing can lead to improved patient adherence to medication and, consequently, sustained virological suppression and reduction in the risk of emergence of drug resistance. Several trials have evaluated once-daily darunavir/ritonavir in combination with other antiretrovirals (ARTEMIS and ODIN trials) or as monotherapy (MONET, MONOI and PROTEA trials) in HIV-1-infected adults. Data from ARTEMIS and ODIN demonstrate non-inferiority of once-daily darunavir/ritonavir against a comparator and, together with pharmacokinetic data, have established the suitability of once-daily darunavir/ritonavir for treatment-naive and treatment-experienced patients with no darunavir resistance-associated mutations. The findings of ARTEMIS and ODIN have led to recent updates to treatment guidelines, whereby once-daily darunavir/ritonavir, given with other antiretrovirals, is now a preferred treatment option for antiretroviral-naive adult patients and a simplified treatment option for antiretroviral-experienced adults who have no darunavir resistance-associated mutations. Once-daily dosing with darunavir/ritonavir is an option for treatment-naive and for treatment-experienced paediatric patients with no darunavir resistance-associated mutations based on the findings of the DIONE trial and ARIEL substudy. This article reviews the pharmacokinetics, efficacy, safety and tolerability of once-daily boosted darunavir. The feasibility of darunavir/ritonavir monotherapy as a treatment approach for some patients is also discussed. Finally, data on a fixed-dose combination of 800/150 mg of darunavir/cobicistat once daily are presented, showing comparable darunavir bioavailability to that obtained with 800/100 mg of darunavir/ritonavir once daily.

Skin rash related to once-daily boosted darunavir-containing antiretroviral therapy in HIV-infected Taiwanese: incidence and associated factor

OBJECTIVES

The study aimed to investigate the incidence of and associated factors with skin rashes among HIV-infected Taiwanese patients who received once-daily darunavir (DRV) boosted by ritonavir (RTV) (800/100 mg) plus 2 nucleoside reverse-transcriptase inhibitors (NRTIs).

METHODS

We reviewed the medical records of HIV-infected patients who switched to once-daily DRV/RTV-containing regimens between January 2012 and November 2013. Patients who switched from 2 NRTIs plus non-NRTI (nNRTI) or other protease inhibitor (PI) to 2 NRTIs plus PIs other than DRV were chosen as comparators.

RESULTS

During the study period, 238 patients who switched to once-daily DRV/RTV-containing regimens (Group A) and 178 patients who switched from 2 NRTIs plus nNRTI or other PI to 2 NRTIs plus PI other than DRV/RTV (Group B) were included. There were no differences between Groups A and B in most of the baseline characteristics. Compared with Group B in which 7 (3.9%) developed rashes after switch to PI other than DRV, 26 patients (10.9%) in Group A developed rashes after a median interval of 14 days of starting DRV/RTV-containing regimens (P = 0.009). In multivariate analysis, patients with a history of rashes related to the previous nNRTI-containing regimens before starting DRV/RTV-containing regimens were more likely to develop rashes with an adjusted odds ratio of 3.53 (95% confidence interval, 1.45-8.62).

CONCLUSIONS

Once-daily regimens containing DRV/RTV is associated with a higher rate of adverse cutaneous reactions than other PI-containing regimens in HIV-infected Taiwanese, especially in those who have a history of rashes to nNRTI-containing regimens before switch to DRV/RTV-containing regimens.