Switching to darunavir/ritonavir monotherapy vs. triple-therapy on body fat redistribution and bone mass in HIV-infected adults: the Monarch randomized controlled trial

Metabolic profiles of individuals switched to second-line antiretroviral therapy after failing standard first-line therapy for treatment of HIV-1 infection in a randomized, controlled trial

BACKGROUND

To investigate metabolic changes associated with second-line antiretroviral therapy (ART) following virological failure of first-line ART.

METHODS

SECOND-LINE was an open-label randomized controlled trial. Participants were randomized 1:1 to receive ritonavir-boosted lopinavir (LPV/r) with 2-3 nucleoside/nucleotide reverse transcriptase inhibitors (N[t]RTI group) or raltegravir (RAL group). 210 participants had a dual energy X-ray absorptiometry (DXA)-scan at baseline, week 48 and 96. We categorized participants according to second-line ART backbone: thymidine analogue (ta-NRTI) + lamivudine/emtricitabine (3[F]TC; ta-NRTI group); tenofovir (TDF)+3(F)TC (TDF group); TDF+ta-NRTI ±3(F)TC (TDF+ta-NRTI group); RAL. Changes in fasted total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, TC/HDL-cholesterol ratio, triglycerides and glucose from baseline to week 96 were examined. We explored the association between metabolic and DXA-assessed soft-tissue changes. Linear regression methods were used.

RESULTS

We analysed 454 participants. Participants in RAL group had greater TC increases, TC (adjusted mean difference [aMD]=0.65, 95% CI 0.33, 0.96), LDL-c (aMD=0.38, 95% CI 0.15, 0.61) and glucose (aMD=0.47, 95% CI -0.01, 0.92) compared to TDF group, and had greater increases in TC (aMD=0.65, 95% CI 0.28, 1.03), HDL-c (aMD=0.12, 95% CI 0.02, 0.23) and LDL-c (aMD=0.41, 95% CI 0.13, 0.69) compared to TDF+ta-NRTI group. TC/HDL ratio and triglycerides increased in all groups without significant differences between groups. A 1 kg increase in trunk fat mass was associated with an increase in TC.

CONCLUSIONS

We observed metabolic changes of limited clinical significance in the relatively young population enrolled in this study. However, the metabolic changes observed may have greater clinical significance in older people living with HIV or those with other concomitant cardiovascular risks.

Effect of monotherapy with darunavir/cobicistat on viral load and semen quality of HIV-1 patients

Many patients previously using darunavir/ritonavir (DRV/r) (800/100mg) have switched to darunavir/cobicistat (DRV/C) (800/150 mg) either as part of triple therapy (ART) or as monotherapy with DRV (mDRV). The latter approach continues to be used in some countries for patients receiving long-term treatment. However, to date, the behaviour of DRV/C in the seminal compartment has not been analysed. This study explores how the combination behaves in monotherapy, with respect to the control of viral load and seminal quality. To this end, we studied 20 patients who were treated with mDRV/C after previous treatment with mDRV/r for at least 24 weeks. A viral load control in seminal plasma similar to that published in the literature was observed after 24 weeks of treatment with mDRV/C (viral load positivity in 20% of patients). Similarly, semen quality was confirmed (70% normozoospermic) in patients treated with this formulation, as has previously been reported for ART and mDRV/r. The DRV levels measured in seminal plasma were above EC50, regardless of whether the seminal viral load was positive or negative. We conclude that this mDRV/C co-formulation behaves like mDRV/r in seminal plasma in terms of viral load control and semen quality.

HIV-1 resistance rarely observed in patients using darunavir once-daily regimens across clinical studies

BACKGROUND

Darunavir 800 mg once daily (QD) is indicated for HIV-1-infected treatment-naïve and treatment-experienced (without darunavir resistance-associated mutations [RAMs]) individuals, and has been evaluated in phase 2/3 studies with durations between 48 and 192 weeks.

OBJECTIVE

To summarize the development (or identification) of post-baseline resistance (RAMs and antiretroviral phenotypic susceptibility) among patients receiving darunavir QD dosing.

METHODS

Seven phase 2/3 studies with available genotypes/phenotypes for subjects treated with ritonavir- or cobicistat-boosted darunavir 800 mg QD regimens were assessed: ARTEMIS (NCT00258557; n = 343), GS-US-299-0102 (NCT01565850; n = 153), GS-US-216-0130 (NCT01440569; n = 313), ODIN (NCT00524368; n = 294), INROADS (NCT01199939; n = 54), MONET (NCT00458302; n = 256), and PROTEA (NCT01448707; n = 273). Genotypic analyses were conducted at baseline (except switch studies enrolling virologically suppressed subjects [MONET, PROTEA]). Criteria for post-baseline resistance testing and evaluation of the development (or identification [switch studies]) of RAMs (respective IAS-USA mutations) varied slightly across studies.

RESULTS

Among 1686 subjects treated with darunavir 800 mg QD regimens, 184 had protocol-defined virologic failure; 182 had post-baseline genotypes analyzed. Overall, 4/1686 (0.2%) developed (or had identified [switch studies]) primary protease inhibitor and/or darunavir RAMs (ARTEMIS, n = 1; GS-US-216-0130, n = 1; ODIN, n = 1; MONET, n = 1). Only 1/1686 (<0.1%) subject lost darunavir phenotypic susceptibility (ODIN; possibly related to prior ritonavir-boosted lopinavir virologic failure). Among 1103 subjects using a nucleos(t)ide reverse transcriptase inhibitor (N[t]RTI) backbone, 10 (0.9%) developed ≥ 1 N(t)RTI RAM (8 had the emtricitabine RAM M184I/V).

CONCLUSIONS

Darunavir has a high genetic barrier to resistance. Across a diverse population of HIV-1-infected subjects treated with darunavir 800 mg QD regimens, the development of darunavir resistance was rare (<0.1%).

Bone Loss in HIV Infection

Human immunodeficiency virus (HIV) infection is an established risk factor for low bone mineral density (BMD) and subsequent fracture, and treatment with combination antiretroviral therapy (cART) leads to additional BMD loss, particularly in the first 1-2 years of therapy. The prevalence of low BMD and fragility fracture is expected to increase as the HIV-infected population ages with successful treatment with cART. Mechanisms of bone loss in the setting of HIV infection are likely multifactorial, and include viral, host, and immune effects, as well as direct and indirect effects of cART, particularly tenofovir disoproxil fumarate (TDF) and the protease inhibitors (PIs). Emerging data indicate that BMD loss following cART initiation can be mitigated by prophylaxis with either long-acting bisphosphonates or vitamin D and calcium supplementation. In addition, newer antiretrovirals, particularly the integrase strand transfer inhibitors and tenofovir alafenamide (TAF), are associated with less intense bone loss than PIs and TDF. However, further studies are needed to establish optimal bone sparing cART regimens, appropriate screening intervals, and preventive measures to address the rising prevalence of fragility bone disease in the HIV population.

The protease inhibitors and HIV-associated bone loss

PURPOSE OF REVIEW

HIV infection is an established risk factor for osteoporosis and bone fracture. Combination antiretroviral therapy (cART) increases bone resorption leading to an additional 2-6% bone mineral density (BMD) loss within the first 1-2 years of therapy. Although tenofovir disoproxil fumarate is often blamed for antiretroviral drug-associated bone loss, evidence abounds to suggest that other agents, including the protease inhibitors (PIs), have adverse bone effects. In the current review, we examine bone loss associated with protease inhibitor use, describing the relative magnitude of bone loss reported for individual protease inhibitors. We also review the potential mechanisms associated with protease inhibitor-induced bone loss.

RECENT FINDINGS

As a class, protease inhibitors contribute to a greater degree of bone loss than other anchor drugs. HIV disease reversal and the associated immune reconstitution following cART initiation play an important role in protease inhibitor-mediated bone loss in addition to plausible direct effects of protease inhibitors on bone cells.

SUMMARY

Protease inhibitors remain an important component of cART despite their adverse effects on bone. A better understanding of factors that drive HIV/cART-induced bone loss is needed to stem the rising rate of fracture in the HIV-infected population.

Efficacy of protease inhibitor monotherapy vs. triple therapy: meta-analysis of data from 2303 patients in 13 randomized trials

OBJECTIVES

The aim of this analysis was to review the evidence and update a meta-analysis evaluating the efficacy and safety results from randomized controlled trials of ritonavir-boosted protease inhibitor (PI/r) monotherapy.

METHODS

A PubMed/EMBASE search was conducted to find randomized trials of PI/r monotherapy vs. triple therapy in patients with HIV-1 RNA suppression at baseline (<50 HIV-1 RNA copies/mL). Rates of virological suppression were analysed using switch-equals-failure and intensification-included endpoints [intent-to-treat (ITT)]. The rate of treatment-emergent resistance mutations, neurocognitive function endpoints, and cerebrospinal fluid (CSF) HIV-1 RNA were also analysed by treatment arm.

RESULTS

There were 2303 patients from 13 different randomized clinical trials of darunavir/r monotherapy (n = 784: MONET, MONOI, Monarch and PROTEA), lopinavir/r monotherapy (n = 829: OK pilot, OK-04, KalMo, KALESOLO, KRETA, MOST and DREAM), atazanavir/r monotherapy (n = 103: MODAT), or all three (n = 587: PIVOT). HIV-1 RNA plasma suppression was lower in the PI/r monotherapy arm compared with the triple therapy arm in the switch-equals-failure analysis [difference -8.3%; 95% confidence interval (CI) -11.9 to -4.8%], but not when intensification was included (difference 0.5%; 95% CI -2.5 to 3.6%). Rates of resistance mutations were similar between arms, as was overall neurocognitive function.

CONCLUSIONS

PI/r monotherapy showed a higher risk of plasma HIV-1 RNA elevations. However, there was no increased risk of treatment-emergent drug resistance, neurocognitive endpoints did not differ, and HIV-1 RNA suppression rates after intensification were similar between PI/r monotherapy and triple therapy.

Darunavir/cobicistat for the treatment of HIV-1: a new era for compact drugs with high genetic barrier to resistance

INTRODUCTION

Cobicistat-boosted darunavir is a boosted protease inhibitor in a fixed-dose combination to be approved for the treatment of human immunodeficiency virus type1 infection. It contains darunavir, a well-known protease inhibitor with a good efficacy and safety profile, and the new pharmacokinetic enhancer cobicistat. The convenience of this combination in a single pill makes this compound easier to take, thus improving adherence.

AREAS COVERED

PubMed and www.clinicaltrials.gov were searched with the term "darunavir/cobicistat" for all clinical trials conducted up to date, as well as for those ongoing and to be opened in the near future as well as for pharmacology data. A review of abstracts from major infectious diseases (particularly those dedicated to human immunodeficiency disease) and pharmacology conferences from 2010 to 2015 was also conducted.

EXPERT OPINION

improving adherence, particularly by minimizing pill burden with convenient formulations (i.e., fixed-dose combination), is one of the major objectives of modern antiretroviral treatment of patients with human immunodeficiency virus disease. Cobicistat is an alternative agent to ritonavir for boosting plasma drug levels for several antiretrovirals. Darunavir co-administered with low-dose ritonavir, in combination with other antiretrovirals, is recommended in several guidelines for treatment of patients with human immunodeficiency disease. Darunavir/cobicistat fixed-dose combination allows for a once-daily treatment regimen with a reduced pill burden. This new co formulation makes this compound easier to take, thus improving adherence.

Effects on vitamin D, bone and the kidney of switching from fixed-dose tenofovir disoproxil fumarate/emtricitabine/efavirenz to darunavir/ritonavir monotherapy: a randomized, controlled trial (MIDAS)

BACKGROUND

Efavirenz (EFV) has been associated with reductions in vitamin D (25[OH]D) and tenofovir (TDF) with increased bone turnover, reductions in bone mineral density (BMD) and renal tubular dysfunction. We hypothesized that switching from fixed-dose TDF/emtricitabine (FTC)/EFV to darunavir/ritonavir monotherapy (DRV/r) might increase 25(OH)D and BMD, and improve renal tubular function.

METHODS

Subjects with HIV RNA <50 copies/ml on TDF/FTC/EFV for ≥6 months were randomized 1:1 to ongoing TDF/FTC/EFV or DRV/r (800/100 mg once daily) for 48 weeks. The primary end point was change from baseline in 25(OH)D at week 48. Secondary end points included changes in BMD, bone turnover markers and renal tubular function.

RESULTS

A total of 64 subjects (86% male, 66% white, mean [sd] CD4(+) T-cell count 537.3 [191.5]/mm(3)) were analysed. After adjustment for baseline 25(OH)D and demographics, at week 48 DRV/r monotherapy was associated with a +3.6 (95% CI 0.6, 6.6) ng/ml increase in 25(OH)D compared to TDF/FTC/EFV (P=0.02). DRV/r monotherapy was associated with an increase in BMD (+2.9% versus -0.003% at the neck of femur and +2.6% versus +0.008% at the lumbar spine for DRV/r versus TDF/FTC/EFV; P<0.05 for all) and reductions in bone biomarkers compared with those remaining on TDF/FTC/EFV. No significant difference in renal tubular function was observed. Reasons for discontinuation in the DRV/r arm included side effects (n=4) and viral load rebound (n=3), all of which resolved with DRV/r discontinuation or regimen intensification.

CONCLUSIONS

Switching from TDF/FTC/EFV to DRV/r in patients with suppressed HIV RNA resulted in significant improvements in 25(OH)D and bone biomarkers, and a 2-3% increase in BMD.

An update on the pharmacological strategies in the treatment of HIV-1-associated adipose redistribution syndromes

INTRODUCTION

With the introduction of combination antiretroviral therapy (ART) for HIV infection in the mid-1990s, descriptions of morphological changes and metabolic disturbances in treated patients began to emerge. HIV-1/highly active ART-associated lipodystrophy syndrome (HALS) involves metabolic abnormalities and diverse forms of anomalous fat distribution. The current review focuses on the pathophysiological basis and the clinical evidence for the use of several medical strategies in the management of HALS.

AREAS COVERED

We have covered the most relevant studies related to the pharmacological strategies in the treatment of HALS, with attention to the current and novel antiretroviral agents.

EXPERT OPINION

The most commonly used strategies for HALS reversion have included modification of host-dependent factors, including those related to HIV-1 infection and those associated with ART. Preventive and medical strategies have been associated with moderate success. The only intervention that offers an immediate aesthetical improvement for patients with HALS so far has been plastic surgery.

HIV-associated lipodystrophy: impact of antiretroviral therapy

In the late 1990s, reports of unusual changes in body fat distribution named 'lipodystrophy' (LD) began to appear in HIV patients mitigating the enormous enthusiasm about improvement of survival and quality of life provided by the combinations of antiretroviral (ARV) drug classes, the so-called highly active antiretroviral therapy (HAART), which had just become available at that time. The objective of this paper is to critically review the literature on LD and to discuss the impact of newer ARV agents, namely atazanavir, darunavir and raltegravir, as well as strategies of the late HAART era, including single-tablet regimens and nucleoside-sparing regimens. Studies in which LD was measured by dual-energy x-ray absorptiometry or by abdominal computed tomography or magnetic resonance imaging scan only, were included. We were unable to identify studies depicting a negative impact of drugs or ARV regimens on limb fat loss. On the contrary, a few studies identified a negative impact of atazanavir/ritonavir or darunavir/ritonavir on trunk fat increase. It should be noted that this anthropometric measure is a poor instrument since it cannot distinguish between subcutaneous and visceral fat. We conclude that presumably the body fat changes currently observed in HIV-infected patients is the net result of competing phenomena: on one side the natural history of lipohypertrophy as a result of HIV and HAART impact, and on the other side the physiological body fat changes observed in the aging population.

Boosted protease inhibitor monotherapy in HIV-infected adults: outputs from a pan-European expert panel meeting

While the introduction of combination highly active antiretroviral therapy (HAART) regimens represents an important advance in the management of human immunodeficiency virus (HIV)-infected patients, tolerability can be an issue and the use of several different agents may produce problems. The switch of combination HAART to ritonavir-boosted protease inhibitor (PI) monotherapy may offer the opportunity to maintain antiviral efficacy while reducing treatment complexity and the risks of toxicity. Current European AIDS Clinical Society (EACS) guidelines recognise ritonavir-boosted PI monotherapy with twice-daily lopinavir/ritonavir or once-daily darunavir/ritonavir as a possible option in patients who have intolerance to nucleoside reverse transcriptase inhibitors, or for treatment simplification. Clinical trials data for PI boosted monotherapy are encouraging, showing substantial efficacy in the majority of patients; however, further data are required before this approach can be recommended as a routine treatment. Available data indicate that the most suitable candidates for the use of boosted PI monotherapy are long-term virologically suppressed patients who have demonstrated good adherence to antiretroviral therapy, who do not have chronic hepatitis B, have no history of treatment failure on PIs and are able to tolerate low-dose ritonavir.

New strategies for lowering the costs of antiretroviral treatment and care for people with HIV/AIDS in the United Kingdom

In the UK, the annual cost of treatment and care for people with human immunodeficiency virus (HIV)/acquired immune deficiency virus (AIDS) rose by over 600% from £104 million in 1997 to £762 million in 2010; approximately two-thirds of the £762 million cost of treatment and care in 2010 was for the procurement of antiretrovirals and other related drugs. The number of people accessing care for HIV/AIDS rose from 22,000 in 2000 to 65,000 in 2009. Adoption of "test and treat" guidelines for treating all HIV-infected people with antiretrovirals would further increase the burden of costs. Given the current economic situation, there is now a new focus on strategies for treatment and care of people with HIV-1 infection which can maintain efficacy but at a lower cost. In this review, we propose three strategies which could potentially lower the costs of treatment and care, ie, stopping testing CD4 counts for patients with full HIV RNA suppression on antiretroviral treatment and recent CD4 counts above 350 cells/μL; more widespread use of generic antiretrovirals as replacements for patients currently taking patented versions; and use of darunavir-ritonavir monotherapy as a switch option for patients with full HIV RNA suppression on other antiretrovirals and no history of virological failure. However, it is important that high standards of clinical care are maintained despite cost-saving measures. Antiretrovirals with generic alternatives may have toxicity issues, eg, zidovudine and nevirapine. There could be ethical issues in starting patients on these drugs if they are currently tolerating other treatments. The use of darunavir-ritonavir monotherapy is not consistently recommended in international HIV treatment guidelines.