Cerebrospinal fluid drug concentrations and viral suppression in HIV-1-infected patients receiving ritonavir-boosted atazanavir plus lamivudine dual antiretroviral therapy (Spanish HIV/AIDS Research Network, PreEC/RIS 39)

Central nervous system disorders after use of dolutegravir: evidence from preclinical and clinical studies

The evaluation of dolutegravir based on available preclinical and clinical studies reveals a risk of central nervous system (CNS) disorders associated with long-term use of the drug. The available literature on the pharmacokinetics of the drug, including its penetration of the blood-brain barrier, was reviewed, as well as clinical trials assessing the incidence of adverse effects in the CNS and the frequency of its discontinuation. This paper also summarizes the impact of factors affecting the occurrence of CNS disorders and indicates the key role of pharmacovigilance in the process of supplementing knowledge on the safety of drugs, especially those that are newly registered.

Contemporary Antiretroviral Therapy Dysregulates Iron Transport and Augments Mitochondrial Dysfunction in HIV-Infected Human Microglia and Neural-Lineage Cells

HIV-associated cognitive dysfunction during combination antiretroviral therapy (cART) involves mitochondrial dysfunction, but the impact of contemporary cART on chronic metabolic changes in the brain and in latent HIV infection is unclear. We interrogated mitochondrial function in a human microglia (hμglia) cell line harboring inducible HIV provirus and in SH-SY5Y cells after exposure to individual antiretroviral drugs or cART, using the MitoStress assay. cART-induced changes in protein expression, reactive oxygen species (ROS) production, mitochondrial DNA copy number, and cellular iron were also explored. Finally, we evaluated the ability of ROS scavengers or plasmid-mediated overexpression of the antioxidant iron-binding protein, Fth1, to reverse mitochondrial defects. Contemporary antiretroviral drugs, particularly bictegravir, depressed multiple facets of mitochondrial function by 20-30%, with the most pronounced effects in latently infected HIV+ hμglia and SH-SY5Y cells. Latently HIV-infected hμglia exhibited upregulated glycolysis. Increases in total and/or mitochondrial ROS, mitochondrial DNA copy number, and cellular iron accompanied mitochondrial defects in hμglia and SH-SY5Y cells. In SH-SY5Y cells, cART reduced mitochondrial iron-sulfur-cluster-containing supercomplex and subunit expression and increased Nox2 expression. Fth1 overexpression or pre-treatment with N-acetylcysteine prevented cART-induced mitochondrial dysfunction. Contemporary cART impairs mitochondrial bioenergetics in hμglia and SH-SY5Y cells, partly through cellular iron accumulation; some effects differ by HIV latency.

Two-drug regimens for HIV treatment

Combination therapy with three antiretroviral agents has been integral to successful HIV-1 treatment since 1996. Although the efficacy, adverse effects, and toxicities of contemporary three-drug regimens have improved, even the newest therapies have potential adverse effects. The use of two-drug regimens is one way to reduce lifetime exposure to antiretroviral drugs while maintaining the benefits of viral suppression. Multiple large, randomised trials have shown the virological non-inferiority of certain two-drug regimens versus three-drug comparators, including adverse effect differences that reflect known profiles of the antiretroviral drugs in the respective regimens. Two-drug combinations are now recommended in treatment guidelines and include the first long-acting antiretroviral regimen for the treatment of HIV-1. Recommended two-drug regimens differ in their risks for, and factors associated with, virological failure and emergent resistance. The tolerability, safety, metabolic profiles, and drug interactions of two-drug regimens also vary by the constituent drugs. No current two-drug regimen is recommended for people with chronic hepatitis B virus as none include tenofovir. Two-drug regimens have increased options for individualised care.

CNS Considerations in ART Simplification Strategies

PURPOSE OF THE REVIEW

This review summarizes current knowledge on central nervous system (CNS) considerations in ART simplification strategies.

RECENT FINDINGS

Antiretroviral therapies (ART) showing efficacy in plasma will usually show efficacy in the cerebrospinal fluid (CSF). ART simplification may virologically fail if the new regimen has less than two active drugs, the genetic barrier of drugs is not high, and the patient may harbour archived resistance. Dual therapies including a boosted protease inhibitor (PI) or dolutegravir (DTG) are generally effective from the CNS perspective. In cases of related neurotoxicity, switching from either efavirenz (EFV) or DTG to another equally effective drug with better CNS tolerability usually leads to complete resolution of CNS symptoms. However, improvement may be incomplete when factors other than ART that cannot be easily modified are involved.

Dual antiretroviral therapies are effective and safe regimens in the central nervous system of neurologically symptomatic people living with HIV

OBJECTIVE

Aim of this study was to compare cerebrospinal fluid (CSF) virological control, biomarkers and neurocognition of neurologically symptomatic patients on dual antiretroviral therapies (dual therapy) vs. 2 nucleoside reverse transcriptase inhibitors-based three-drug regimens (triple therapy).

DESIGN

Retrospective monocentric cross-sectional study.

METHODS

We analysed data from people living with HIV undergoing lumbar puncture for clinical/research reasons with plasma HIV-RNA less than 200 copies/ml and neurological/neurocognitive symptoms without significant contributing comorbidities. We measured CSF HIV-RNA, inflammation, blood-brain barrier integrity, neuronal damage and astrocytosis biomarkers (five biomarkers by ELISA and five indices by immunoturbidimetry) and recorded the neurocognitive performance (14 tests). CSF escape was defined as any case of CSF HIV-RNA 0.5 Log10 higher than viraemia or any case of detectable CSF HIV-RNA coupled with undetectable viraemia.

RESULTS

A total of 78 patients on triple therapy and 19 on dual therapy were included. Overall, 75.3% male, median age 51 years (46-58), current CD4 count 545 cells/μl (349-735), time on current regimens 18 months (8-29), but length of plasma suppression 32 months (14-94). The two groups did not differ in terms of HIV-associated neurological diagnoses, demographic and viro-immunological features. Undetectable CSF HIV-RNA (73.7% in dual therapy vs. 78.2% in triple therapy, p.67) and CSF escape (21.1% in dual therapy vs. 19.2% in triple therapy, p.86) did not differ. No difference was observed in depression, anxiety, neurocognition (in 63 participants) nor in any tested biomarker.

CONCLUSION

In people living with HIV with neurological/neurocognitive symptoms, peripherally effective dual therapy can show CSF virosuppression, inflammation, neuronal and astrocyte integrity and neurocognition comparable to triple therapy.

Cerebrospinal Fluid and Brain Tissue Penetration of Tenofovir, Lamivudine, and Efavirenz in Postmortem Tissues with Cryptococcal Meningitis

The central nervous system (CNS) is a known HIV reservoir, yet little is known about drug exposure in the brain. Our primary objective was to quantify exposure of three common antiretrovirals in brain tissue and compare exposures to plasma and cerebrospinal fluid (CSF). We also sought to identify pockets of brain most vulnerable to inadequate drug exposures and examine the role of meningitis in drug penetration into the CNS. Tenofovir, lamivudine, and efavirenz concentrations were measured using liquid chromatography and tandem mass spectrometry in plasma and CSF from 14 individuals with HIV, 7 with cryptococcal meningitis. In four individuals (three with meningitis) drug concentrations were also measured in 13 distinct brain tissue regions. In subjects with meningitis, geometric mean ratio (95% confidence interval) of tenofovir CSF to plasma was 66% (7–598%) and 14% (6–31%) in subjects without meningitis. Lamivudine CSF penetration was 100% (25–409%) in subjects with meningitis and 30% (24–37%) in subjects without meningitis. Tenofovir brain tissue concentrations were 36% (14–124%) of plasma and 49% (1–572%) of CSF. Lamivudine brain concentrations were 37% (23–64%) of plasma and 27% (1–104%) of CSF. Efavirenz brain tissue concentrations were 128% (108–179%) of plasma. Tissues collected postmortem provide a unique opportunity to assess drug distribution in tissues difficult to sample in living subjects. CSF is a poor surrogate for drug exposure throughout the CNS. Antiretrovirals differentially penetrate into the CNS and penetration may be enhanced by meningitis.

Switching strategies in the recent era of antiretroviral therapy

INTRODUCTION

Although antiretroviral therapy is highly effective, many patients may benefit from switching strategies. Rapid advances in the development of new antiretroviral drugs could enhance the success of these approaches. In this review, we build on a previous review from 2014 and summarize the current options for switching strategies in virologically suppressed HIV-infected patients. Areas covered: We conduct a critical analysis of scientific evidence for various switching strategies used in the modern era of antiretroviral therapy, as well as reasons for these approaches, other considerations to be taken into account, and alternative strategies. Expert opinion: Current antiretroviral regimens are effective and well tolerated in HIV patients. A number of options may provide benefit to patients, even virologically suppressed patients, possibly enhancing adherence and avoiding adverse effects and toxicities. Cost reduction may also be an important goal of switching strategies. The present scenario is excellent, as many good antiretroviral compounds and regimens allow clinicians to further improve on effective treatments now used in routine practice. Even the current paradigm of triple-drug regimens as the standard of care could change, at least in some patients.

Simplification of combination antiretroviral therapy (cART) and the brain-a real-life experience

Modern antiretroviral combination therapy (cART) has transformed HIV from a life-threatening infection into a chronic disease. However, the life-long treatment has side effects that frequently have a negative impact on patients' quality of life. Thus, there are some efforts to "simplify" therapy, i.e. apply regimens with three or fewer antiretroviral substances. However, neurologists are relatively sceptical towards this cART "simplification", because the capacity of simplified regimens to access the cerebrospinal fluid (CSF) might be too weak to effectively suppress viral load in this compartment. Thus, data of a big Neuro-AIDS cohort of 4992 HIV-positive patients consecutively recruited over three decades were retrospectively analysed in terms of neurocognitive performance of patients switched to simplified therapy regimens. To test whether simplified drug regimens result in new neuropsychological deficits or the worsening of pre-existing ones in HIV+ patients. Three groups of HIV+ patients were switched from triple therapy to three different two drug regimens (n = 177 to lamivudine/PI, n = 37 to INI/PI, and n = 303 to dual PI); three other groups of patients put from one to an alternative triple combination (n = 290 ABC/3TC/PI, n = 244 TDF/FTC/PI, and n = 158 TDF/FTC/NNRTI) for whatever reason served as controls. All patients were followed up over 4 years maximum. Every patient group improved immunologically and virologically after the switch. However, patients who switched to INI/PI combinations remained stable in neuropsychological tests, while a considerable percentage of patients who switched to other treatments demonstrated a decline. Remarkably, a high percentage of the patients switched to "simplified drug regimens" was not well-controlled virologically before the switch. HIV-positive patients with simplified therapy regimens show some benefit in terms of systemic infection surrogate markers (CD4 ± cell count and plasma viral load); however, neurocognitive deficits do not improve, but remain stable in most cases.