Nucleoside reverse transcriptase inhibitor-reducing strategies in HIV treatment: assessing the evidence

Effectiveness and Tolerability of Dual Therapy with Dolutegravir Plus Darunavir/cobicistat in Treatment-Experienced Patients with HIV: A 144-Week Follow-Up

BACKGROUND

A dual regimen with dolutegravir plus cobicistat-boosted darunavir (DTG+DRV/c) is a promising alternative for patients with human immunodeficiency virus (HIV) with resistance or intolerance to nucleoside reverse transcriptase inhibitors, especially those with a history of treatment failure.

MATERIALS AND METHODS

We included all treatment-experienced patients with HIV who switched to the DTG+DRV/c regimen at a tertiary university hospital. We assessed the regimen's effectiveness, safety, and tolerability through serial laboratory data and clinical findings. The primary endpoint was the proportion of patients with plasma HIV-RNA levels <50 copies/mL at week 144 post-switch. The secondary endpoints were safety and tolerability assessments.

RESULTS

Our retrospective analysis involved 40 patients. The leading reasons for switching to DTG+DRV/c were treatment failure in 17 patients (42.5%), simplification after multiple previous regimens in 15 (37.5%), and adverse drug reactions in 8 (20.0%). Among the 17 patients in the treatment failure group, we observed enhanced viral suppression and improved CD4+ T-cell counts after initiating the dual regimen. In the non-treatment failure group (23 patients), viral suppression and CD4+ T-cell levels were consistently maintained. No significant alterations in renal function, liver function, glucose levels, or lipid profiles were observed post-switch. High tolerability was observed, with 34/40 patients (85.0%) responding well to the regimen. However, six patients discontinued treatment before reaching the 144-week mark.

CONCLUSION

Our findings confirm that DTG+DRV/c is an effective and well-tolerated switch therapy regimen for treatment-experienced patients with HIV, with sustained benefits observed for up to 144 weeks of follow-up. This regimen showed adaptability across different patient groups and demonstrated virological and immunological improvements, particularly in patients with a history of treatment failure.

A Review of FDA-Approved Anti-HIV-1 Drugs, Anti-Gag Compounds, and Potential Strategies for HIV-1 Eradication

Acquired immunodeficiency syndrome (AIDS) is an enormous global health threat stemming from human immunodeficiency virus (HIV-1) infection. Up to now, the tremendous advances in combination antiretroviral therapy (cART) have shifted HIV-1 infection from a fatal illness into a manageable chronic disorder. However, the presence of latent reservoirs, the multifaceted nature of HIV-1, drug resistance, severe off-target effects, poor adherence, and high cost restrict the efficacy of current cART targeting the distinct stages of the virus life cycle. Therefore, there is an unmet need for the discovery of new therapeutics that not only bypass the limitations of the current therapy but also protect the body's health at the same time. The main goal for complete HIV-1 eradication is purging latently infected cells from patients' bodies. A potential strategy called "lock-in and apoptosis" targets the budding phase of the life cycle of the virus and leads to susceptibility to apoptosis of HIV-1 infected cells for the elimination of HIV-1 reservoirs and, ultimately, for complete eradication. The current work intends to present the main advantages and disadvantages of United States Food and Drug Administration (FDA)-approved anti-HIV-1 drugs as well as plausible strategies for the design and development of more anti-HIV-1 compounds with better potency, favorable pharmacokinetic profiles, and improved safety issues.

Therapeutic drug monitoring and virological response at week 48 in a cohort of HIV-1-infected patients switching to dolutegravir/rilpivirine dual maintenance therapy (ANRS-MIE-BIRIDER study)

AIMS

Dolutegravir (DTG) and rilpivirine (RPV) dual therapy is now recommended as a switch option in virologically suppressed HIV patients. Literature suggests that virological failure with dual therapy could possibly relate to subtherapeutic drug concentrations. In this study, we aimed at describing the DTG and RPV trough plasma concentrations (Cmin) and plasma HIV-1 RNA viral load (VL) during maintenance dual therapy.

METHODS

We performed a retrospective analysis of DTG and RPV therapeutic drug monitoring in people living with HIV/AIDS (PLWHA) with dual therapy in 9 French centres. DTG and RPV trough plasma concentrations were estimated using a Bayesian approach to predict Cmin. The relationship between the pharmacokinetics of DTG and RPV and VL > 50 copies (cp)/mL was explored using joint nonlinear mixed models. The frequency of subtherapeutic threshold (DTG Cmin below 640 ng/mL and RPV Cmin below 50 ng/mL) were compared between PLWHA presenting VL > 50 cp/mL or not during the study.

RESULTS

At baseline, 209 PLWHA were enrolled in the study. At week 48, 19 people living with HIV/AIDS (9.1%) discontinued their treatment and 15 PLWHA (7.1%) exhibited VL > 50 cp/mL. Six PLWHA out of 15 (40.0%) with VL > 50 cp/mL during the follow-up had at least 1 Cmin below the respective thresholds while only 26/194 patients (13.4%) without virological replication had at least 1 concentration below the threshold (P = .015).

CONCLUSION

A majority of PLWHA receiving DTG/RPV maintenance dual therapy demonstrated VL < 50 cp/mL but virological replication was more frequent in people living with HIV/AIDS with subtherapeutic Cmin.

Synthetic approaches and application of clinically approved small-molecule Anti-HIV drugs: An update

Application of chemotherapeutic agents to inhibit the HIV replication process has brought about a significant metamorphosis in the landscape of AIDS. Substantial declines in morbidity and mortality rates have been attained, accompanied by notable decreases in healthcare resource utilization. However, treatment modalities do not uniformly inhibit HIV replication in every patient, while the emergence of drug-resistant viral strains poses a substantial obstacle to subsequent therapeutic interventions. Furthermore, chronic administration of therapy may lead to the manifestation of toxicities. These challenges necessitate the exploration of novel pharmacological agents and innovative therapeutic approaches aimed at effectively managing the persistent viral replication characteristic of chronic infection. This review examines the role of clinically approved small-molecule drugs in the treatment of HIV/AIDS, which provides an in-depth analysis of the major classes of small-molecule drugs, including nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), integrase inhibitors, entry inhibitors, and pharmacokinetic enhancers. The review mainly discusses the application, synthetic routes, and mechanisms of action of small-molecule drugs employed in the treatment of HIV, as well as their use in combination with antiretroviral therapy, presenting viewpoints on forthcoming avenues in the development of novel anti-HIV drugs.

Utilization of Chemometric-Aided UV Spectrophotometric Methods for Concurrent Assessment of Emtricitabine, Tenofovir Disoproxil Fumarate, Elvitegravir, and Cobicistat in Tablet Formulation

BACKGROUND

Emtricitabine (ETC), tenofovir disoproxil fumarate (TNF), elvitegravir (EVG), and cobicistat (CBS) are antiviral drugs used to treat human immunodeficiency virus (HIV) infections.

OBJECTIVE

To develop chemometric-aided UV spectrophotometric methods for concurrent estimation of the aforementioned drugs used to treat HIV. This method can be used to reduce modification of the calibration model by assessing the absorbance at various points in the zero-order spectra within the selected wavelength range. Additionally, it eliminates interfering signals and provides sufficient resolution in multi-component systems.

METHODS

Two chemometric-assisted UV spectrophotometric methods, namely, partial least-squares (PLS) and principal component regression (PCR) models, were established for the concurrent assessment of EVG, CBS, TNF, and ETC in tablet formulations. The proposed methods were applied to decrease complexity of overlapped spectra and to achieve maximum sensitivity and the lowest error. These approaches were performed in accordance with International Council on Harmonization (ICH) criteria and compared to the reported HPLC method.

RESULTS

The proposed methods were used to assess EVG, CBS, TNF, and ETC in the ranges of 5-30, 5-30 , 5-50, and 5-50 µg/mL, respectively, with an excellent correlation coefficient (r2 ≥ 0.998). The accuracy and precision results were found to be within the acceptable limits. No statistical difference was observed between the proposed and reported studies.

CONCLUSION

The chemometric-aided UV spectrophotometric approaches could be considered as alternatives to chromatographic procedures in the pharmaceutical industry for routine analysis and testing of readily accessible commercial formulations.

HIGHLIGHTS

Novel chemometric-assisted UV spectrophotometric techniques were developed for assessment of multicomponent antiviral combinations in single-tablet formulations. The proposed methods were performed without using harmful solvents, tedious preparation, or expensive instruments. The proposed methods were compared statistically with a reported HPLC method. Assessment of EVG, CBS, TNF, and ETC was performed without interference from excipients in their multicomponent formulations.

Structural and Synthetic Aspects of Small Ring Oxa- and Aza-Heterocyclic Ring Systems as Antiviral Activities

Antiviral properties of different oxa- and aza-heterocycles are identified and properly correlated with their structural features and discussed in this review article. The primary objective is to explore the activity of such ring systems as antiviral agents, as well as their synthetic routes and biological significance. Eventually, the structure-activity relationship (SAR) of the heterocyclic compounds, along with their salient characteristics are exhibited to build a suitable platform for medicinal chemists and biotechnologists. The synergistic conclusions are extremely important for the introduction of a newer tool for the future drug discovery program.

Prevalence and Patterns of Adverse Drug Events Among Adult Patients with Human Immune Virus Infection on Dolutegravir-Based Antiretroviral Drug Regimens in Amhara Comprehensive Specialized Hospitals, Northwest Ethiopia: A Multicenter Retrospective Follow-Up Study

Background

Antiretroviral therapy (ART) refers to any HIV treatment that uses a combination of two or more drugs to suppress viral load and preserve immunofunction. Despite the success of ART, adverse events persist, in particular in patients with baseline viral loads >100,000 copies/mL. Apart from premarketing surveillance, the safety and risk profile of dolutegravir has not been thoroughly researched in Ethiopia. Therefore, this study aimed to assess the prevalence and patterns of adverse drug events among HIV-infected adult patients on dolutegravir-based ART regimens at Amhara comprehensive specialized hospitals, northwest Ethiopia.

Methods

A retrospective follow-up study was conducted from January 1, 2019 to December 31, 2021 at Amhara comprehensive specialized hospitals, with a sample size of 423. Simple random sampling was employed and data collected using kobo tool box software by four trained BSc nurses from March to April, 2022. SPSS 25 was used for analysis. Descriptive summary statistics are used and data presented using tables and text.

Results

A total of 372 patient charts were included in the final analysis, and the prevalence of adverse events associated with dolutegravir was found to be 37.6% (95% CI 32.1%-42.1%). Nearly two-thirds (60.7%) of the participants had neuropsychiatric symptoms, followed by gastrointestinal symptoms (23.6%) and hepatic problems (7.14%). All recorded adverse events were mild.

Conclusion

Dolutegravir adverse events were relatively low compared to previous studies. Common adverse events reported were neuropsychiatric symptoms and gastrointestinal symptoms, followed by hepatic and renal events. All adverse events were mild and none was severe or life-threatening events. Therefore, we recommend the use of dolutegravir in clinical settings.

Associations between plasma nucleoside reverse transcriptase inhibitors concentrations and cognitive function in people with HIV

Objectives

To investigate the associations of plasma lamivudine (3TC), abacavir (ABC), emtricitabine (FTC) and tenofovir (TFV) concentrations with cognitive function in a cohort of treated people with HIV (PWH).

Methods

Pharmacokinetics (PK) and cognitive function (Cogstate, six domains) data were obtained from PWH recruited in the POPPY study on either 3TC/ABC or FTC/tenofovir disoproxil fumarate (TDF)-containing regimens. Association between PK parameters (AUC_0-24: area under the concentration-time curve over 24 hours, C_max: maximum concentration and C_trough: trough concentration) and cognitive scores (standardized into z-scores) were evaluated using rank regression adjusting for potential confounders.

Results

Median (IQR) global cognitive z-scores in the 83 PWH on 3TC/ABC and 471 PWH on FTC/TDF were 0.14 (-0.27, 0.38) and 0.09 (-0.28, 0.42), respectively. Higher 3TC AUC_0-24 and C_trough were associated with better global z-scores [rho = 0.29 (p = 0.02) and 0.27 (p = 0.04), respectively], whereas higher 3TC C_max was associated with poorer z-scores [rho = -0.31 (p<0.01)], independently of ABC concentrations. Associations of ABC PK parameters with global and domain z-scores were non-significant after adjustment for confounders and 3TC concentrations (all p’s>0.05). None of the FTC and TFV PK parameters were associated with global or domain cognitive scores.

Conclusions

Whilst we found no evidence of either detrimental or beneficial effects of ABC, FTC and TFV plasma exposure on cognitive function of PWH, higher plasma 3TC exposures were generally associated with better cognitive performance although higher peak concentrations were associated with poorer performance.

Pharmacokinetics and Drug-Drug Interactions of Long-Acting Intramuscular Cabotegravir and Rilpivirine

Combined antiretroviral treatments have significantly improved the morbidity and mortality related to HIV infection, thus transforming HIV infection into a chronic disease; however, the efficacy of antiretroviral treatments is highly dependent on the ability of infected individuals to adhere to life-long drug combination therapies. A major milestone in HIV treatment is the marketing of the long-acting intramuscular antiretroviral drugs cabotegravir and rilpivirine, allowing for infrequent drug administration, with the potential to improve adherence to therapy and treatment satisfaction. Intramuscular administration of cabotegravir and rilpivirine leads to differences in pharmacokinetics and drug-drug interaction (DDI) profiles compared with oral administration. A notable difference is the long elimination half-life with intramuscular administration, which reaches 5.6-11.5 weeks for cabotegravir and 13-28 weeks for rilpivirine, compared with 41 and 45 h, respectively, with their oral administration. Cabotegravir and rilpivirine have a low potential to cause DDIs, however these drugs can be victims of DDIs. Cabotegravir is mainly metabolized by UGT1A1, and rilpivirine is mainly metabolized by CYP3A4, therefore these agents are susceptible to DDIs with inhibitors, and particularly inducers of drug-metabolizing enzymes. Intramuscular administration of cabotegravir and rilpivirine has the advantage of eliminating DDIs occurring at the gastrointestinal level, however interactions can still occur at the hepatic level. This review provides insight on the intramuscular administration of drugs and summarizes the pharmacology of long-acting cabotegravir and rilpivirine. Particular emphasis is placed on DDI profiles after oral and intramuscular administration of these antiretroviral drugs.

Voltammetric Methods Used in the Determination of Nucleoside Reverse Transcriptase Inhibitors

Background:

The Human Immunodeficiency Virus (HIV) has now been established as the causative agent of the Acquired Immunodeficiency Syndrome (AIDS) and exactly 25 antiretroviral drugs have been formally approved for clinical use in the treatment of AIDS. The life quality and duration of HIV-positive patients have increased with the usage of antiretroviral drugs in the treatment of AIDS. Nucleoside Reverse Transcriptase Inhibitors (NRTIs) are one of the subgroups of antiretroviral.

Objective:

The quantification of drugs is important, as they make positive contributions to dose adjustments in practice. Voltammetric methods are very powerful analytical methods used in the pharmaceutical industry because of the determination of therapeutic agents and/or their metabolites in clinical samples at extremely low concentrations (10-50 ng/ml).

Methods:

This review mainly includes the pharmacological properties and recent determination studies by voltammetric methods from pharmaceutical dosage forms and biological samples of eight NRTIs group antiretroviral drugs (zidovudine, abacavir, adefovir, entecavir, zalcitabine, didanosine, emtricitabine, lamivudine) that are used in the clinic and show electroactive properties, were performed.

Conclusion:

Due to the variety of working electrodes in voltammetric methods, it is possible to choose the electrode that best responds. In this way, the analysis of NRTIs was possible at lower concentrations in pharmaceuticals and biological samples with voltammetric methods in these studies without the necessity for the sample pre-treatment or time-consuming extraction steps. The voltammetric methods provide good stability, repeatability, reproducibility and high recovery for the analysis of the analyte. They could be used for the pharmacokinetic studies as well as for quality control laboratory studies.

Biocatalytic routes to anti-viral agents and their synthetic intermediates

An assessment of biocatalytic strategies for the synthesis of anti-viral agents, offering guidelines for the development of sustainable production methods for a future COVID-19 remedy.

Validation of a UHPLC-MS/MS Method to Quantify Twelve Antiretroviral Drugs within Peripheral Blood Mononuclear Cells from People Living with HIV

Recently, anti-HIV treatment has achieved high efficacy and tolerability. Nevertheless, few data are available about the intracellular penetration of antiretrovirals, partly due to the technical challenges related to intracellular quantification. This work aimed to validate an ultra-high performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method for the simultaneous quantification of maraviroc, nevirapine, rilpivirine, dolutegravir, raltegravir, cobicistat, darunavir, ritonavir, atazanavir, efavirenz, elvitegravir, and etravirine within peripheral blood mononuclear cells (PBMCs) and apply it to samples from patients. PBMCs were isolated by density gradient on cell preparation tubes (CPT). Samples were prepared by addition of internal standards (IS), sonication, centrifugation, and drying. Reconstituted extracts underwent chromatographic separation by reversed phase UHPLC and detection was performed by electrospray ionization and multiple reaction monitoring. Method validation followed FDA and EMA guidelines, showing acceptable accuracy, precision, recovery and IS-normalized matrix effect. The application to 56 samples from patients undergoing antiretroviral treatment provided description of intracellular penetration, showing method eligibility for future studies.

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.

The comparative effectiveness of NRTI-sparing dual regimens in emulated trials using observational data from the Swiss HIV Cohort Study

BACKGROUND

Nucleoside (or nucleotide) reverse transcriptase inhibitors (NRTIs) cause side effects in some patients, prompting the use of either partly or fully NRTI-sparing regimens.

METHODS

We used data from the Swiss HIV Cohort Study to estimate the effectiveness of two new dolutegravir dual regimens relative to the alternative NRTI-sparing dual regimens that our clinicians used previously. We emulated two trials by propensity score matching case patients on the dolutegravir regimen with control patients on an alternative regimen. We analysed the case control sets using a Bayesian Cox model and estimated effectiveness as the percentage still on their trial regimen without virological failure at 48 weeks.

RESULTS

In a comparison of partly NRTI-sparing regimens, 58 cases treated with dolutegravir were matched to 17 controls treated with boosted darunavir (both with lamivudine or emtricitabine). The estimated difference in effectiveness was 15% (95% credible interval [CrI] 2-33) and 12% (95% CrI 0-26) in two sequential analyses 1 year apart. In a comparison of fully NRTI-sparing regimens, 54 cases treated with dolutegravir were matched to 32 controls treated with raltegravir (both with boosted darunavir). The estimated difference in effectiveness was 9% (95% CrI -1-21) and 5% (95% CrI -4-15) in the two sequential analyses.

CONCLUSIONS

Estimates of relative effectiveness suggest that both dolutegravir regimens are not inferior to these alternative regimens. All four regimens seem suitable for patients needing an NRTI-sparing regimen: there were few virological failures and few treatment changes due to toxicity.

Impact of three decades of antiretroviral therapy in a longitudinal population cohort study

BACKGROUND

We have used a comprehensive HIV population to characterize antiretroviral therapy (ART), drug class selection, pill burden, drug costs and health outcomes over the entire span of the HIV epidemic.

METHODS

Antiretroviral (ARV) use (drugs, classes, formulations) and both the laboratory and clinical outcomes (HIV-1 RNA, CD4⁺ T-cell count and mortality) were determined for all patients in Southern Alberta, Canada, at each year-end between 1986 and 2017. Pill burden, cumulative drug exposure and costs were calculated for each year.

RESULTS

The number of ARV-treated patients increased from 29.6% (77/260) in 1989 to 93.4% (1,814/1,943) in 2017. Regimen selection showed continuous adjustments for toxicity, resistance, pill burden and adherence. Dramatic improvements in outcomes were seen. In 1997, 22.4% of treated patients had an undetectable viral load, this has been consistently around 90% since 2010 (92.7% in 2017). While HIV-related annual mortality rate declined from 11.0% in 1994 to 0.1% in 2017, all-cause mortality remained relatively stable from 1997 onwards. ART pill burden escalated in 1997 (12.4/day), then decreased to 2.1/day in 2016. Mean ART cost increased in 1997 (CAN$905/month/regimen in 1997, $1,223 in 2016). Mean cumulative lifetime exposure to protease inhibitors is 5.98 ±4.9 and to nucleoside reverse transcriptase inhibitors 8.8 ±6.2 years.

CONCLUSIONS

Our findings demonstrate not only the immense burden that HIV has imposed on both patients and society, but also the substantial benefit of ART on patient outcomes. They show that research, patient engagement and programme support can with time minimize the harmful long-term effects of HIV-infection.

Continuation of emtricitabine/lamivudine within combination antiretroviral therapy following detection of the M184V/I HIV-1 resistance mutation

OBJECTIVES

The aim of the study was to investigate whether lamivudine (3TC) or emtricitabine (FTC) use following detection of M184V/I is associated with better virological outcomes.

METHODS

We identified people with viruses harbouring the M184V/I mutation in UK multicentre data sets who had treatment change/initiation within 1 year. We analysed outcomes of viral suppression (< 200 HIV-1 RNA copies/mL) and appearance of new major drug resistance mutations (DRMs) using Cox and Poisson models, with stratification by new drug regimen (excluding 3TC/FTC) and Bayesian implementation, and estimated the effect of 3TC/FTC adjusted for individual and viral characteristics.

RESULTS

We included 2597 people with the M184V/I resistance mutation, of whom 665 (25.6%) were on 3TC and 458 (17.6%) on FTC. We found a negative adjusted association between 3TC/FTC use and viral suppression [hazard ratio (HR) 0.84; 95% credibility interval (CrI) 0.71-0.98]. On subgroup analysis of individual drugs, there was no evidence of an association with viral suppression for 3TC (n = 184; HR 0.94; 95% CrI 0.73-1.15) or FTC (n = 454; HR 0.99; 95% CrI 0.80-1.19) amongst those on tenofovir-containing regimens, but we estimated a reduced rate of viral suppression for people on 3TC amongst those without tenofovir use (n = 481; HR 0.71; 95% CrI 0.54-0.90). We found no association between 3TC/FTC and detection of any new DRM (overall HR 0.92; 95% CrI 0.64-1.18), but found inconclusive evidence of a lower incidence rate of new DRMs (overall incidence rate ratio 0.69; 95% CrI 0.34-1.11).

CONCLUSIONS

We did not find evidence that 3TC or FTC use is associated with an increase in viral suppression, but it may reduce the appearance of additional DRMs in people with M184V/I. 3TC was associated with reduced viral suppression amongst people on regimens without tenofovir.

High rates of tenofovir failure in a CRF01_AE-predominant HIV epidemic in the Philippines

BACKGROUND

The Philippines has the fastest growing HIV epidemic in the Asia-Pacific. This increase was accompanied by a shift in the predominant HIV subtype from B to CRF01_AE. Increasing evidence points to a difference in treatment responses between subtypes. We examined treatment failure and acquired drug resistance (ADR) in people living with HIV (PLHIVs) after one year on antiretrovirals (ARVs).

METHODS

PLHIV maintained on ARVs for one year were recruited. Treatment failure was defined as a viral load of ≥1000 copies/mL. Sanger sequencing for genotyping and drug resistance mutation (DRM) detection was performed on patients failing treatment.

RESULTS

513 PLHIV were enrolled. The most common antiretroviral regimens were TDF+3TC + EFV (269) and AZT+3TC + EFV (155). 53 (10.3%) subjects failed treatment. Among these, 48 (90.6%) had DRMs, 84.9% were subtype CRF01_AE. Tenofovir-based regimens performed worse than zidovudine-based regimens (OR 3.28, 95% CI 1.58-7.52 p < 0.001). Higher rates of NRTI, NNRTI, K65R tenofovir resistance, and multi-class resistance were found compared to those reported in literature.

CONCLUSIONS

HIV treatment failure at one year of treatment in the Philippines is 10.3%. We found unusually high tenofovir and multiclass resistance, and optimal ARV regimens may need to be reevaluated for CRF01_AE-predominant epidemics.

Reviewing HIV-1 Gag Mutations in Protease Inhibitors Resistance: Insights for Possible Novel Gag Inhibitor Designs

HIV protease inhibitors against the viral protease are often hampered by drug resistance mutations in protease and in the viral substrate Gag. To overcome this drug resistance and inhibit viral maturation, targeting Gag alongside protease rather than targeting protease alone may be more efficient. In order to successfully inhibit Gag, understanding of its drug resistance mutations and the elicited structural changes on protease binding needs to be investigated. While mutations on Gag have already been mapped to protease inhibitor resistance, there remain many mutations, particularly the non-cleavage mutations, that are not characterized. Through structural studies to unravel how Gag mutations contributes to protease drug resistance synergistically, it is thus possible to glean insights to design novel Gag inhibitors. In this review, we discuss the structural role of both novel and previously reported Gag mutations in PI resistance, and how new Gag inhibitors can be designed.

Randomized study evaluating the efficacy and safety of switching from an an abacavir/lamivudine-based regimen to an elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide single-tablet regimen

OBJECTIVE

To evaluate the efficacy and safety of switching from an abacavir/lamivudine (ABC/3TC)-based regimen to an elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) single-tablet regimen in virologically suppressed, HIV-1-infected adults.

DESIGN

Randomized, open-label, noninferiority study.

METHODS

Participants with HIV-1 RNA levels less than 50 copies/ml receiving ABC/3TC plus a third agent for at least 6 months were randomized 2 : 1 to switch immediately to E/C/F/TAF (immediate-switch group) for 48 weeks or to continue receiving ABC/3TC plus a third agent for 24 weeks followed by E/C/F/TAF for 24 weeks (delayed-switch group). The primary endpoint was HIV-1 RNA less than 50 copies/ml at Week 24 by Food and Drug Administration Snapshot algorithm (-12% noninferiority margin).

RESULTS

Baseline characteristics of 274 participants (183 in immediate-switch group and 91 in delayed-switch group) were similar. Virologic response was maintained at Week 24 by 93.4 and 97.8% of participants in the immediate-switch and delayed-switch groups, respectively, with a treatment difference of -4.4% (95% confidence interval: -9.4 to 1.9%), confirming noninferiority. Adverse events of any grade were similar between groups through Week 24 (66% E/C/F/TAF, 64% ABC/3TC); adverse event-related drug discontinuations occurred in 4% of participants switching to E/C/F/TAF (no discontinuations because of renal events) and no participants continuing ABC/3TC. Renal biomarkers of urine albumin:creatinine and beta-2-microglobulin:creatinine ratios significantly improved on E/C/F/TAF. Self-reported treatment satisfaction was significantly higher with E/C/F/TAF.

CONCLUSION

Switching to E/C/F/TAF was noninferior to continuing ABC/3TC plus a third agent for maintenance of HIV RNA suppression at Week 24. This study supports E/C/F/TAF as an efficacious and well tolerated option for participants switching from ABC/3TC-based regimens.

Evaluating cabotegravir/rilpivirine long-acting, injectable in the treatment of HIV infection: emerging data and therapeutic potential

Cabotegravir and rilpivirine long-acting injectable antiretroviral therapy for the treatment of HIV-1 infection brings promise of a new mode of delivery and potential solutions to some problems of oral therapy, but also new challenges and unanswered questions. Adding to the increasing body of evidence for newer two-drug combinations, phase II and phase III trial data to date demonstrate cabotegravir and rilpivirine combination injectable therapy to be non-inferior to selected oral triple-therapy alternatives. Most importantly, this therapy is reported to be acceptable to individuals taking the 4-weekly or 8-weekly injections, despite frequent injection-site reactions. Key outstanding questions include management of missed or delayed dosing, drug interactions and management of virological failure, as well as the efficacy of cabotegravir and rilpivirine in all HIV-1 subtypes. We describe clinical evidence to date and efficacy and challenges in selected populations, including women; those with prior virological failure; individuals with a history of difficulty adhering to oral therapy and individuals with co-infections. We await real-world data and longer-term evidence while moving forward to this new era of antiretroviral therapy.

Dolutegravir plus rilpivirine as dual regimen in virologically suppressed HIV-1 infected patients in a clinical setting

Objectives: There are scarce data on the combination of dolutegravir (DTG) plus rilpivirine (RPV) in the real world, including patients with hepatitis C virus (HCV) coinfection, toxicity or previous failure, or at risk for severe drug-drug interactions (DDIs). Methods: Prospective cohort study of virologically suppressed HIV-1 infected patients, without resistance to DTG or RPV, switched to this dual regimen because of toxicity or risk of DDIs (NCT02491242). Results: Overall, 102 patients (mean age 54 years, 28% women) were included. Fifty-seven were coinfected with HCV (fibrosis grade 4 in 27 cases, 1 liver transplantation). Seven patients had chronic kidney disease (1 renal transplantation). At week 48, only 1 virologic failure occurred (<1%), and 6 patients (6%) left the regimen (3 with central nervous system adverse events, 1 each due to pregnancy, metformin interaction, and lost to follow up). Thus, the overall treatment success rates were 93% (95% CI, 88%-98%; ITT-e, snapshot analysis) and 96% (95% CI, 92%-99%; per protocol analysis). The CD4/CD8 ratio increased slightly (median, +0.03). Triglycerides levels improved significantly (-18.8%, p < 0.01). The creatinine-based estimated glomerular filtration rate decreased by a mean of -8.4 ml/min/1.73 m², but tubular renal parameters improved. A paired dual X-ray absorptiometry scan showed a mild improvement in spine (mean, +1.15%; -0.57 to +3.3%) and in femoral neck bone mineral density (mean, +0.4%; -3.3% to +2.57%). Conclusions: In the clinical setting, switching to the combination of DTG plus rilpivirine in virologically suppressed HIV-1 patients is effective and safe, and improves lipid, renal and bone evolution.

Does choice of antiretroviral drugs matter for inflammation?

INTRODUCTION

The massive implementation of combination antiretroviral therapy (cART) has forever changed the landscape of HIV infection. This unprecedented success has turned HIV infection into a manageable chronic disease. The increased survival of people living with HIV is, however, shadowed by a high burden of aging-related comorbidities. The pathogenic basis underlying this excess of co-morbid conditions is most likely a persistent inflammatory and immune activation state, despite an optimal control of HIV replication, which in turn has largely been attributed to bacterial or bacterial products translocation from the gut. Area covered: This review is focused on the relationship between cART and the chronic inflammatory and immune activation status in otherwise virologically well-controlled people living with HIV (PLWH). Particular focus will be placed on the differences, if any, between distinct cART modalities, with emphasis on less-drug cART regimens, and especially on dual therapies. Expert opinion: Research to address the increased inflammatory and immune activation status of cART-treated, HIV-infected patients, should focus on adjuvant means of therapy, rather than on the cART regime itself. With current antiretrovirals, no difference between dual and triple regimens has been demonstrated, provided that virological and immunological outcomes be non-inferior.

CD4/CD8 ratio improvement in HIV-1-infected patients receiving dual antiretroviral treatment

The CD4/CD8 ratio is an indirect marker of immune activation, immune senescence, and inflammation in HIV infection. We performed a prospective study of the CD4/CD8 ratio evolution in 245 virally-suppressed (median, 55 months) HIV-infected patients (29% females) who had switched to four dual antiretroviral regimens. At baseline, the median CD4/CD8 ratio was 0.71 (interquartile range, IQR, 0.46-0.97), associated with duration of HIV infection, nadir CD4+ cell count, and AIDS diagnosis. It was lower in the case of hepatitis C virus coinfection and cardiovascular disease (p = 0.09), but the ratio was higher in patients with chronic kidney disease, proteinuria, or osteoporosis. At 48 weeks, the median CD4/CD8 ratio increased by 3% (+0.02; IQR, -0.07, +0.09; p = 0.07); greater improvement was observed in patients with lower baseline ratios and previous AIDS diagnosis. The slope of increase was slower in patients with the highest baseline values. Also, there were no differences in the CD4/CD8 ratio increase according to type of dual regimen, after adjusting for baseline and HIV-related values. In conclusion, CD4/CD8 ratio increase is observed during suppressive dual regimens, and its extent is related to baseline values and previous HIV-related factors. Longer duration on antiretroviral therapy and drug toxicity could affect the evolution of this marker in the presence of comorbidities.

Dolutegravir-rilpivirine coformulation

PURPOSE OF REVIEW

With prolonged life expectancy in HIV-positive patients on combination antiretroviral therapy, the quest for reducing lifelong drug exposure and minimizing or avoiding the toxicities of combination antiretroviral therapy while maintaining viral suppression has emerged when coformulations of antiretroviral agents with improved convenience, and better tolerability and efficacy became available. This review aims to update the current experience with the novel two-drug combination of dolutegravir (DTG) and rilpivirine (RPV) and elucidate the possible applications and limitations of coformulated DTG-RPV in the future.

RECENT FINDINGS

Five observational studies and two randomized, noninferiority trials (SWORD-1 and SWORD-2) evaluated the use of DTG and RPV in treatment-experienced patients. Despite variable inclusion criteria, 95-100% of the included patients maintained plasma HIV RNA load less than 50 copies/ml at the end of 24-48 weeks of observation. Overall, this regimen was well tolerated and only 0.8-7.9% of the patients discontinued the regimen due to adverse events.

SUMMARY

DTG and RPV is a novel two-drug antiretroviral combination regimen that can be effectively and safely used in patients with viral suppression for 6 months or longer. However, its use in patients with a previous history of virological failure and/or antiretroviral resistance warrants further investigation.

Cabotegravir: its potential for antiretroviral therapy and preexposure prophylaxis

PURPOSE OF REVIEW

Analyzing the evidence for the strand transfer integrase inhibitor cabotegravir (CAB; GSK744, GSK1265744), its properties and differences from other compounds in the class, as well as reviewing the preclinical and clinical evidence for its potential in antretroviral therapy and medical HIV prevention.

RECENT FINDINGS

CAB has been investigated both as an oral and an injectable compound. Recent results show that it has promising properties with regards to its potential for parenteral maintenance therapy in combination with other compounds in HIV-infected patients currently suppressed on oral agents, as well as in preexposure prophylaxis.

SUMMARY

The strand transfer integrase inhibitor CAB is currently being investigated as an intramuscular preparation with a long half-life allowing for four to eight-weekly injection intervals, and as an oral preparation. The latter is currently only used in trials for achieving an undetectable viral load in antiretroviral-naive patients, assessing tolerability, and covering phases of suboptimal exposure to the parenteral preparation. Phase 2 trials of a dual regimen of CAB and rilpivirine have demonstrated promising virological activity in oral as well as in parenteral therapy, which are currently investigated in phase three trials. Moreover, CAB protected macaques from experimental simian/human immunodeficiency virus infection and showed promising tolerability in the first trial in humans for preexposure prophylaxis of HIV infection. CAB might, therefore, provide the basis of the new treatment paradigm of parenteral treatment and prevention of HIV infection.

Dolutegravir-rilpivirine: first 2-drug regimen for HIV-positive adults

INTRODUCTION

New strategies for HIV treatment are being investigated to reduce drug-exposure, toxicities, and costs. Dolutegravir (DTG) 50 mg/rilpivirine (RPV) 25 mg was approved in November 2017 by FDA and in May 2018 by the European Medicines Agency (EMA). It is indicated as a complete regimen for HIV-1 infected adults with undetectable plasmatic HIV-RNA for at least 6 months on their current HIV treatment combination. Its approval was based on the data of two randomized, multicenter, non-inferiority trials (SWORD-1 and SWORD-2). Areas covered: We reviewed data from literature about DTG and RPV. We mainly focused on the efficacy and on the safety of this new dual therapy. Its impact on renal function, its bone and cardiovascular profile, its reservoir penetration and its role on inflammation were also evaluated. Expert commentary: Dual therapies may be an attractive alternative to standard triple regimens in terms of tolerability and simplicity. Long-term efficacy of DTG and RPV dual regimen need to be confirmed, where only the extensive use of this new treatment and a longer follow-up will give us the answers.

Biochemical and inflammatory modifications after switching to dual antiretroviral therapy in HIV-infected patients in Italy: a multicenter retrospective cohort study from 2007 to 2015

BACKGROUND

Triple-drug regimens are the gold standard for HIV therapy. Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) reducing regimens are used to decrease drugs toxicity, exposure and costs. Aim of our study was to evaluate trends of biochemical and inflammatory indices in patients switching to dual therapy (DT).

METHODS

We included patients that a) switched to a DT from 2007 to 2015 from a tenofovir/abacavir-based triple regimen b) previously maintained a triple and c) subsequently a dual regimen for 12 months with virological suppression. We retrieved data measured at 5 points (at the switch, 6 and 12 months before and after switch). We used platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR) and CD4/CD8 ratio as inflammatory indices. We assessed temporal trends of viro-immunological, biochemical and inflammatory parameters.

RESULTS

Overall, 364 and 65 patients switched from a tenofovir- and an abacavir-triple regimen, respectively. In the tenofovir-reducing group, creatinine clearance and lipids raised after the switch. There was a significant increase in both CD4+ cells and CD4/CD8. CD8+ cells rose after the switch, while opposite trend was found for PLR. In the abacavir-reducing group total lipids showed a decrease during the first 6 months after the switch and then stabilized. An increase of CD4+ and a decrease of CD8+ cells was observed during the study period, although not statistically significant. While CD4/CD8 remained stable after simplification, PLR decreased significantly after 6 months, then returning to baseline. CD8+ cells increased in the tenofovir-reducing group despite a viro-immunological response. Intriguingly, PLR decreased, maintaining this trend for 12 and 6 months after tenofovir and abacavir interruption respectively.

CONCLUSIONS

Increased PLR has been linked to hypercholesterolemia and metabolic-syndrome, while high CD8+ cells count to increased risk of non-AIDS-related events regardless of CD4 T-cell recovery and to virological failure. Whether these findings may have clinical implications, and which role DT plays on the immune system and on inflammation should be further investigated.

Role of tenofovir alafenamide (TAF) in the treatment and prophylaxis of HIV and HBV infections

Tenofovir (TFV) is the cornerstone of the treatment and prophylaxis of HIV infections. It has been routinely used in its prodrug form TDF (tenofovir disoproxil fumarate) combined with emtricitabine ((-)FTC) and other antiretroviral agents. TDF has now been replaced by TAF (tenofovir alafenamide) which allows better uptake by the lymphoid tissue. In combination with elvitegravir (E), cobicistat (C), emtricitabine (F), TAF can be advocated as an STR (single tablet regimen, Genvoya®) for the treatment of HIV infections. In this combination, E and C may in the future be replaced by bictegravir. The prophylaxis of HIV infection is momentarily based upon Truvada®, the combination of F with TDF, which in the future may also be replaced by TAF. TAF (Vemlidy®) has also replaced TDF (Viread®) for the treatment of hepatitis B virus (HBV) infections. Both TDF and TAF offer little or no risk for virus-drug resistance. As compared to TDF, TAF limits the risk for nephrotoxicity and loss of bone mineral density. What remains to be settled, however, before the universal use of TAF could be recommended, is its safety during pregnancy and its applicability in the treatment of tuberculosis, in combination with rifampicin.