Rapid and durable antiretroviral effect of the HIV-1 Integrase inhibitor raltegravir as part of combination therapy in treatment-naive patients with HIV-1 infection: results of a 48-week controlled study

Unveiling potent inhibitors for schistosomiasis through ligand-based drug design, molecular docking, molecular dynamics simulations and pharmacokinetics predictions

Schistosomiasis is a neglected tropical disease which imposes a considerable and enduring impact on affected regions, leading to persistent morbidity, hindering child development, diminishing productivity, and imposing economic burdens. Due to the emergence of drug resistance and limited management options, there is need to develop additional effective inhibitors for schistosomiasis. In view of this, quantitative structure-activity relationship studies, molecular docking, molecular dynamics simulations, drug-likeness and pharmacokinetics predictions were applied to 39 Schistosoma mansoni Thioredoxin Glutathione Reductase (SmTGR) inhibitors. The chosen QSAR model demonstrated robust statistical parameters, including an R2 of 0.798, R2adj of 0.767, Q2cv of 0.681, LOF of 0.930, R2test of 0.776, and cR2p of 0.746, confirming its reliability. The most active derivative (compound 40) was identified as a lead candidate for the development of new potential non-covalent inhibitors through ligand-based design. Subsequently, 12 novel compounds (40a-40l) were designed with enhanced anti-schistosomiasis activity and binding affinity. Molecular docking studies revealed strong and stable interactions, including hydrogen bonding, between the designed compounds and the target receptor. Molecular dynamics simulations over 100 nanoseconds and MM-PBSA free binding energy (ΔGbind) calculations validated the stability of the two best-designed molecules. Furthermore, drug-likeness and pharmacokinetics prediction analyses affirmed the potential of these designed compounds, suggesting their promise as innovative agents for the treatment of schistosomiasis.

Advances in Mechanism of HIV-1 Immune Reconstitution Failure: Understanding Lymphocyte Subpopulations and Interventions for Immunological Nonresponders

In individuals diagnosed with AIDS, the primary method of sustained suppression of HIV-1 replication is antiretroviral therapy, which systematically increases CD4+ T cell levels and restores immune function. However, there is still a subset of 10-40% of people living with HIV who not only fail to reach normal CD4+ T cell counts but also experience severe immune dysfunction. These individuals are referred to as immunological nonresponders (INRs). INRs have a higher susceptibility to opportunistic infections and non-AIDS-related illnesses, resulting in increased morbidity and mortality rates. Therefore, it is crucial to gain new insights into the primary mechanisms of immune reconstitution failure to enable early and effective treatment for individuals at risk. This review provides an overview of the dynamics of key lymphocyte subpopulations, the main molecular mechanisms of INRs, clinical diagnosis, and intervention strategies during immune reconstitution failure, primarily from a multiomics perspective.

Chronic Liver Enzyme Elevation and Use of Contemporary ARVs Among People With HIV

Background

While use of some older antiretroviral drugs (ARVs) is associated with chronic liver enzyme elevation (cLEE), the impact of newer ARVs remains unknown.

Methods

People with HIV enrolled in the RESPOND cohort who started an ARV after January 1, 2012 were included (baseline). The primary outcome was first cLEE individuals were censored at first of cLEE, last visit, death, or December 31, 2021. Incidence rates (IRs; events/1000 person-years) were calculated for each ARV overall and by ARV exposure (6-12 months, 1-2 years, and 2+ years). Poisson regression was used to estimate the incidence rate ratio (IRR) of cLEE and its association with individual ARVs and ARV class.

Results

Of 17 106 individuals included contributing 87 924 person-years of follow-up, 1932 (11.3%) experienced cLEE (incidence rate [IR], 22.0; 95% CI, 21.0-23.0). There was no evidence of a cumulative ARV effect on cLEE incidence, (6-12 months: IR, 45.8; 95% CI, 41.4-50.19; 1-2 years: IR, 34.3; 95% CI, 31.5-37.4; and 2+ years: IR, 18.5; 95% CI, 17.4-19.7). Any use (vs no prior use) of non-nucleoside reverse transcriptase inhibitors (NNRTIs) as a class and tenofovir disoproxil fumarate (TDF) was independently associated with an increased IRR of cLEE, and any use of darunavir (DRV) was associated with a decreased risk of cLEE.

Conclusions

cLEE is common and more frequent during the first year after initiating new ARVs. With a >5-year median follow-up, we found no short-term liver safety concerns with the use of INSTIs. Use of NNRTIs and TDF was associated with an increased cLEE risk, while DRV was associated with lower risk.

The Integrase: An Overview of a Key Player Enzyme in the Antiviral Scenario

Integration of a desossiribonucleic acid (DNA) copy of the viral ribonucleic acid (RNA) into host genomes is a fundamental step in the replication cycle of all retroviruses. The highly conserved virus-encoded Integrase enzyme (IN; EC 2.7.7.49) catalyzes such a process by means of two consecutive reactions named 3'-processing (3-P) and strand transfer (ST). The Authors report and discuss the major discoveries and advances which mainly contributed to the development of Human Immunodeficiency Virus (HIV) -IN targeted inhibitors for therapeutic applications. All the knowledge accumulated over the years continues to serve as a valuable resource for the design and development of effective antiretroviral drugs.

EVG/COBI/FTC/TAF Bioequivalence Comparing Whole Tablets with Tablets Dissolved in Tap Water

Medication adherence can be challenging for persons with difficulty swallowing tablets. We investigated the bioequivalence of a dissolved tablet when compared with that of a whole tablet of the fixed-dose combination elvitegravir (EVG)/cobicistat (COBI)/emtricitabine (FTC)/tenofovir (TFV) alafenamide fumarate (TAF). A within-subject fixed-order two-period open-label study was conducted in 12 HIV-negative research participants after obtaining informed consent. Participants took a single dose each of the whole tablet and dissolved tablet under direct observation, separated by a 14-day washout period. The dissolved tablet was prepared by adding one whole EVG/COBI/FTC/TAF tablet to 120 mL tap water and stirring. Both dosage types were taken with a standardized meal. Plasma samples were obtained for 72 h postdose. Plasma EVG, FTC, TAF, and TFV were analyzed with liquid chromatographic-tandem mass spectrometric methods. Peak plasma concentration (Cmax) and the area under the concentration-time curve extrapolated to infinity (AUC0-∞) were estimated using WinNonlin software (v.8.3). The primary outcome was bioequivalence consistent with FDA guidance using the 90% confidence interval or the geometric mean ratio. Of 12 participants, 7 were black (58%) and 5 were white (42%), 4 were women (33%), 8 were men (67%), and the mean age was 43.6 years (23-54). There were no complaints about taste with the dissolved tablet. Bioequivalence was established only for FTC. EVG Cmax and AUC0-∞ were higher by 18% and 12%, respectively, when taking the dissolved compared with the whole tablet. TAF AUC0-∞ and Cmax were both 8% lower, whereas TFV Cmax and AUC0-∞ were 8% and 5% lower, respectively, when taken after dissolution. EVG/COBI/FTC/TAF dissolved rapidly in water and had no unpleasant taste. Increases in EVG and decreases in TAF and TFV concentrations were observed when taking dissolved EVG/COBI/FTC/TAF. These changes were judged to be clinically insignificant. Dissolving EVG/COBI/FTC/TAF in water may be suitable for those with pill swallowing challenges. The trial was registered on (//clinicaltrials.gov NCT03717129).

Analysis of HIV latent infection model with multiple infection stages and different drug classes

Latently infected CD4+ T cells represent one of the major obstacles to HIV eradication even after receiving prolonged highly active anti-retroviral therapy (HAART). Long-term use of HAART causes the emergence of drug-resistant virus which is then involved in HIV transmission. In this paper, we develop mathematical HIV models with staged disease progression by incorporating entry inhibitor and latently infected cells. We find that entry inhibitor has the same effect as protease inhibitor on the model dynamics and therefore would benefit HIV patients who developed resistance to many of current anti-HIV medications. Numerical simulations illustrate the theoretical results and show that the virus and latently infected cells reach an infected steady state in the absence of treatment and are eliminated under treatment whereas the model including homeostatic proliferation of latently infected cells maintains the virus at low level during suppressive treatment. Therefore, complete cure of HIV needs complete eradication of latent reservoirs.

Different Pathways Conferring Integrase Strand-Transfer Inhibitors Resistance

Integrase Strand Transfer Inhibitors (INSTIs) are currently used as the most effective therapy in the treatment of human immunodeficiency virus (HIV) infections. Raltegravir (RAL) and Elvitegravir (EVG), the first generation of INSTIs used successfully in clinical treatment, are susceptible to the emergence of viral resistance and have a high rate of cross-resistance. To counteract these resistant mutants, second-generation INSTI drugs have been developed: Dolutegravir (DTG), Cabotegravir (CAB), and Bictegravir (BIC). However, HIV is also able to develop resistance mechanisms against the second-generation of INSTIs. This review describes the mode of action of INSTIs and then summarizes and evaluates some typical resistance mutations, such as substitution and insertion mutations. The role of unintegrated viral DNA is also discussed as a new pathway involved in conferring resistance to INSTIs. This allows us to have a more detailed understanding of HIV resistance to these inhibitors, which may contribute to the development of new INSTIs in the future.

Synthesis and Biological Activity of 1,3,4-Oxadiazoles Used in Medicine and Agriculture

Biologically active compounds play a key role in the fight against diseases affecting both human and animal living organisms, as well as plants. Finding out about new molecules with a potential biological effect, not yet described in the literature, is one of the most important aspects in the development of medicine and agriculture. Compounds showing desirable biological activity include heterocyclic moieties such as 1,3,4-oxadiazoles. The oxadiazole molecule is composed of two nitrogen atoms and one oxygen atom, forming a five-membered heterocyclic ring. Structures of this type have been successfully used in the treatment of various diseases in humans and animals, and play an important role in modern agriculture. It has been proven that many oxadiazole derivatives exhibit antibacterial, antiviral, blood pressure lowering, antifungal, antineoplastic, anticancer, antioxidant, anti-inflammatory and analgesic properties. In addition, compounds based on 1,3,4-oxadiazole can act as plant protection agents due to their herbicidal, insecticidal and fungicidal activity. Due to the constantly growing interest in heterocyclic systems of this nature, new methods of obtaining complex structures containing oxadiazole rings are sought. This article discusses various methods of synthesis of 1,3,4-oxadiazole derivatives exhibiting biological activity. Based on these techniques, these compounds could be used in the future in medicine and agriculture.

Complex of HIV-1 Integrase with Cellular Ku Protein: Interaction Interface and Search for Inhibitors

The interaction of HIV-1 integrase and the cellular Ku70 protein is necessary for HIV replication due to its positive effect on post-integration DNA repair. We have previously described in detail the Ku70 binding site within integrase. However, the integrase binding site in Ku70 remained poorly characterized. Here, using a peptide fishing assay and site-directed mutagenesis, we have identified residues I72, S73, and I76 of Ku70 as key for integrase binding. The molecular dynamics studies have revealed a possible way for IN to bind to Ku70, which is consistent with experimental data. According to this model, residues I72 and I76 of Ku70 form a "leucine zipper" with integrase residues, and, therefore, their concealment by low-molecular-weight compounds should impede the Ku70 interaction with integrase. We have identified such compounds by molecular docking and have confirmed their capacity to inhibit the formation of the integrase complex with Ku70. Our data demonstrate that the site of IN binding within Ku70 identified in the present work may be used for further search for inhibitors of the integrase binding to Ku70.

Drug Discovery for Mycobacterium tuberculosis Using Structure-Based Computer-Aided Drug Design Approach

Developing new, more effective antibiotics against resistant Mycobacterium tuberculosis that inhibit its essential proteins is an appealing strategy for combating the global tuberculosis (TB) epidemic. Finding a compound that can target a particular cavity in a protein and interrupt its enzymatic activity is the crucial objective of drug design and discovery. Such a compound is then subjected to different tests, including clinical trials, to study its effectiveness against the pathogen in the host. In recent times, new techniques, which involve computational and analytical methods, enhanced the chances of drug development, as opposed to traditional drug design methods, which are laborious and time-consuming. The computational techniques in drug design have been improved with a new generation of software used to develop and optimize active compounds that can be used in future chemotherapeutic development to combat global tuberculosis resistance. This review provides an overview of the evolution of tuberculosis resistance, existing drug management, and the design of new anti-tuberculosis drugs developed based on the contributions of computational techniques. Also, we show an appraisal of available software and databases on computational drug design with an insight into the application of this software and databases in the development of anti-tubercular drugs. The review features a perspective involving machine learning, artificial intelligence, quantum computing, and CRISPR combination with available computational techniques as a prospective pathway to design new anti-tubercular drugs to combat resistant tuberculosis.

Rational Multitargeted Drug Design Strategy from the Perspective of a Medicinal Chemist

The development of multitarget-directed ligands (MTDLs) has become a widely focused research topic, but rational design remains as an enormous challenge. This paper reviews and discusses the design strategy of incorporating the second activity into an existing single-active ligand. If the binding sites of both targets share similar endogenous substrates, MTDLs can be designed by merging two lead compounds with similar functional groups. If the binding sites are large or adjacent to the solution, two key pharmacophores can be fused directly. If the binding regions are small and deep inside the proteins, the linked-pharmacophore strategy might be the only way. The added pharmacophores of second targets should not affect the binding mode of the original ones. Moreover, the inhibitory activities of the two targets need to be adjusted to achieve an optimal ratio.

Targeting SARS-CoV-2: a systematic drug repurposing approach to identify promising inhibitors against 3C-like proteinase and 2'-O-ribose methyltransferase

The recent pandemic associated with SARS-CoV-2, a virus of the Coronaviridae family, has resulted in an unprecedented number of infected people. The highly contagious nature of this virus makes it imperative for us to identify promising inhibitors from pre-existing antiviral drugs. Two druggable targets, namely 3C-like proteinase (3CLpro) and 2'-O-ribose methyltransferase (2'-O-MTase) were selected in this study due to their indispensable nature in the viral life cycle. 3CLpro is a cysteine protease responsible for the proteolysis of replicase polyproteins resulting in the formation of various functional proteins, whereas 2'-O-MTase methylates the ribose 2'-O position of the first and second nucleotide of viral mRNA, which sequesters it from the host immune system. The selected drug target proteins were screened against an in-house library of 123 antiviral drugs. Two promising drug molecules were identified for each protein based on their estimated free energy of binding (ΔG), the orientation of drug molecules in the active site and the interacting residues. The selected protein-drug complexes were then subjected to MD simulation, which consists of various structural parameters to equivalently reflect their physiological state. From the virtual screening results, two drug molecules were selected for each drug target protein [Paritaprevir (ΔG = -9.8 kcal/mol) & Raltegravir (ΔG = -7.8 kcal/mol) for 3CLpro and Dolutegravir (ΔG = -9.4 kcal/mol) and Bictegravir (ΔG = -8.4 kcal/mol) for 2'-OMTase]. After the extensive computational analysis, we proposed that Raltegravir, Paritaprevir, Bictegravir and Dolutegravir are excellent lead candidates for these crucial proteins and they could become potential therapeutic drugs against SARS-CoV-2. Communicated by Ramaswamy H. Sarma.

Brief Report: Integrase Strand Transfer Inhibitors Are Associated With Lower Risk of Incident Cardiovascular Disease in People Living With HIV

BACKGROUND

Several antiretroviral therapy (ART) classes have been associated with increased myocardial infarction (MI) risk. Cardiovascular disease in people living with HIV (PLWH) on integrase strand transfer inhibitors (INSTI) has not been examined. Here we aim to examine this.

SETTING

Retrospective cohort design study.

METHODS

We used the IBMMarketScan databases for U.S. commercially insured and Medicaid covered adults to identify PLWH newly initiated on ART between January 1, 2008 and December 30, 2015. Major adverse cardiac event (MACE), a composite of acute MI, ischemic stroke, coronary artery bypass grafting, and percutaneous coronary intervention was the primary outcome. We used calendar time-specific probability-weighted Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association between INSTI use and MACE. We used propensity score weighting methods to account for potential confounding.

RESULTS

Twenty thousand two hundred forty-two new ART initiators were identified. 5069 (25%) PLWH initiated INSTI-based regimens. 203 MACE events occurred; acute MI 16 (0.32%) vs 66 (0.43%), stroke 24 (0.47%) vs 54 (0.36), coronary artery bypass grafting 2 (0.04%) vs 9 (0.06%), percutaneous coronary intervention 7 (0.14%) vs 25 (0.16%) of INSTI users vs non-users. INSTI-based ART was associated with significantly lower risk of MACE events (hazard ratios 0.79; 95% confidence intervals: 0.64 to 0.96) compared with non-INSTI-based regimens.

CONCLUSION

In this cohort, INSTI-based regimens were associated with a 21% decreased risk of incident cardiovascular disease. These finding require validation in other cohorts and with longer follow-up.

Dual Antiretroviral Therapy-All Quiet Beneath the Surface?

Infection with the human immunodeficiency virus (HIV) is characterized by progressive depletion of CD4+ lymphocytes cells as a result of chronic immune activation. Next to the decreases in the number of CD4+ cells which leads to opportunistic infections, HIV-related immune activation is associated with several prevalent comorbidities in the HIV-positive population such as cardiovascular and bone disease. Traditionally, combination antiretroviral therapy (cART) consists of three drugs with activity against HIV and is highly effective in diminishing the degree of immune activation. Over the years, questions were raised whether virological suppression could also be achieved with fewer antiretroviral drugs, i.e., dual- or even monotherapy. This is an intriguing question considering the fact that antiretroviral drugs should be used lifelong and their use could also induce cardiovascular and bone disease. Therefore, the equilibrium between drug-induced toxicity and immune activation related comorbidity is delicate. Recently, two large clinical trials evaluating two-drug cART showed non-inferiority with respect to virological outcomes when compared to triple-drug regimens. This led to adoption of dual antiretroviral therapy in current HIV treatment guidelines. However, it is largely unknown whether dual therapy is also able to suppress immune activation to the same degree as triple therapy. This poses a risk for an imbalance in the delicate equilibrium. This mini review gives an overview of the current available evidence concerning immune activation in the setting of cART with less than three antiretroviral drugs.

Effect of Pregnancy on Unbound Raltegravir Concentrations in the ANRS 160 RalFe Trial

A population pharmacokinetic model was developed to explore the pharmacokinetics modification of unbound raltegravir during pregnancy. The RalFe ANRS160 study was a nonrandomized, open-label, multicenter trial enrolling HIV-infected pregnant women receiving a combined antiretroviral regimen containing 400 mg raltegravir twice daily. Biological samples were collected during the third trimester of pregnancy (between 30 and 37 weeks of gestational age) and at postpartum (4 to 6 weeks after delivery). A population pharmacokinetic model was developed with Monolix software. A total of 360 plasma samples were collected from 43 women during pregnancy and postpartum. The unbound raltegravir was described by a one-compartment model with a transit compartment with first-order absorption, evolving to bound raltegravir (by a linear binding to albumin) or metabolism to RAL-glucuronide or to a first-order elimination, with a circadian rhythm. During pregnancy, the absorption was decreased and delayed and the raltegravir elimination clearance and glucuronidation increased by 37%. Median total and unbound area under the curve from 0 to 12 h significantly decreased by 36% and 27% during pregnancy. Median total trough concentration (C _trough) decreased significantly in the evening (28%); however, the median total C _trough in the morning, unbound C _trough in the morning, and unbound C _trough in the evening showed a nonsignificant decrease of 16%, 1%, and 15%, respectively, during pregnancy compared to the postpartum period. This is the first study reporting the pharmacokinetics of unbound raltegravir during pregnancy. As unbound C _trough did not significantly decrease during the third trimester, the pregnancy effect on raltegravir unbound concentrations was not considered clinically relevant. (This study has been registered at ClinicalTrials.gov under identifier NCT02099474.).

Integrase Inhibitor-Based Antiretroviral Therapy Among Women Living with HIV: Data from the OPERA Cohort

BACKGROUND

Women face unique complexities in HIV treatment yet are underrepresented in antiretroviral therapy (ART) studies.

OBJECTIVE

This analysis assessed the one-year durability of the first integrase strand transfer inhibitor (INSTI)-based regimens prescribed to women in a large cohort of patients living with HIV in care.

METHODS

Women with HIV who initiated their first INSTI-containing regimen between 08/12/2013 and 11/30/2015 were identified in the OPERA cohort, a collaboration of 79 US outpatient clinics. Discontinuation within the first year of treatment with an INSTI was compared between dolutegravir (DTG), raltegravir (RAL) and elvitegravir (EVG), using multivariable Cox regression and Kaplan- Meier estimates. Virologic response and regimen modifications were described and compared across INSTIs.

RESULTS

A total of 537 treatment-naïve (DTG: 39%, EVG: 48%, RAL: 13%) and 878 treatmentexperienced (DTG: 57%, EVG: 29%, RAL: 13%) women were analyzed. In the first twelve months after initiation, women taking EVG or RAL were more likely to discontinue their initial INSTI than those taking DTG among both treatment-naïve (adjusted hazard ratio EVG vs. DTG: 1.59 (95% CI: 1.09, 2.39); RAL vs. DTG: 2.46 (1.49, 4.05)) and treatment-experienced women (EVG vs. DTG: 1.39 (1.02, 1.88); RAL vs. DTG: 2.17 (1.51, 3.12)). Following discontinuation of the initial INSTI, women commonly switched to a regimen containing a different drug from the INSTI class (treatment-naïve DTG: 34%, RAL: 33% EVG: 41%; treatment-experienced DTG: 23%, RAL: 19% EVG: 41%).

CONCLUSION

In treatment-naïve and treatment-experienced women living with HIV, women taking DTG had the lowest risk for early (≤1 year) discontinuation.

Recent Advances in the Development of Integrase Inhibitors for HIV Treatment

PURPOSE OF THE REVIEW

The complex multistep life cycle of HIV allows it to proliferate within the host and integrate its genome in to the host chromosomal DNA. This provirus can remain dormant for an indefinite period. The process of integration, governed by integrase (IN), is highly conserved across the Retroviridae family. Hence, targeting integration is not only expected to block HIV replication but may also reveal new therapeutic strategies to treat HIV as well as other retrovirus infections.

RECENT FINDINGS

HIV integrase (IN) has gained attention as the most promising therapeutic target as there are no equivalent homologues of IN that has been discovered in humans. Although current nano-formulated long-acting IN inhibitors have demonstrated the phenomenal ability to block HIV integration and replication with extraordinary half-life, they also have certain limitations. In this review, we have summarized the current literature on clinically established IN inhibitors, their mechanism of action, the advantages and disadvantages associated with their therapeutic application, and finally current HIV cure strategies using these inhibitors.

Efficacy and Safety of Raltegravir-Based Dual Therapy in AIDS Patients: A Meta-Analysis of Randomized Controlled Trials

Background: The life expectancy for HIV-infected individuals has improved dramatically because of improvements in antiretroviral therapy (ART). Today, a simplified two-drug regimen enhances adherence and treatment satisfaction by reducing adverse effects. Therefore, we need more evidence to show the benefits and risks of simplified ART regimens from randomized controlled trials (RCTs). We compared the efficacy and safety of raltegravir-based simplified dual therapy (DT) and of traditional triple therapy (TT) for people living with HIV/AIDS (PLWHA). Methods: We carried out a systematic review of RCTs. After using a combination of the key words "HIV," "raltegravir," and "protease inhibitor" to search the English-language electronic databases from January 1, 2004, to September 11, 2019, we pooled data across eligible studies and estimated the summary effect sizes with Review Manager (version 5.3). Results: We included eight RCTs involving 4420 PLWHA: 2187 (49.5%) received raltegravir-based simplified DT, and 2144 (48.5%) received traditional TT. The proportion of viral suppression was 79% at 48 weeks and 74% at 96 weeks in the simplified regimen, and the proportion of viral suppression was 78% at 48 weeks and 71% at 96 weeks in the traditional TT group. Furthermore, the proportion of viral suppression in the simplified DT group was greater than that in the TT group at 24 weeks (risk ratio 1.11, 95% confidence interval 1.02-1.21; p = 0.01). The CD4 cell counts in the simplified DT group were significantly higher at 48 weeks and 96 weeks than those in the group that received the traditional TT. Regarding adverse events and mortality rates, the DT and TT groups were similar. However, there was better adherence in the DT group than in the TT group. Conclusion: We found that the simplified regimen was noninferior to TT regimen in regard to viral suppression. Furthermore, the simplified DT regimen had a better CD4 cell count and lower adverse events than the TT regimen.

Sustained Sexual Behavior Change After Acute HIV Diagnosis in Malawi

BACKGROUND

Identification of acute HIV infection (AHI) allows for important opportunities for HIV prevention through behavior change and biomedical intervention. Here, we evaluate changes in sexual risk behaviors among persons with AHI enrolled in a combined behavioral and biomedical intervention designed to reduce onward transmission of HIV.

METHODS

Participants were randomized to standard HIV counseling, a multisession behavioral intervention, or a multisession behavioral intervention plus antiretrovirals. Sexual behaviors were assessed periodically over 1 year.

RESULTS

Four weeks after diagnosis, the predicted probability of reporting multiple sexual partners decreased from 24% to 9%, and the probability of reporting unprotected sex decreased from 71% to 27%. These declines in sexual risk behaviors were sustained over follow-up irrespective of study arm.

CONCLUSIONS

Diagnosis of AHI alone may be sufficient to achieve immediate and sustained behavior change during this highly infectious period.

Raltegravir-Induced Adaptations of the HIV-1 Integrase: Analysis of Structure, Variability, and Mutation Co-occurrence

The human immunodeficiency virus type 1 (HIV-1) has several proteins of therapeutic importance, many of which are currently used as drug targets in antiretroviral therapy. Among these proteins is the integrase, which is responsible for the integration of the viral DNA into the host genome - a crucial step for HIV-1 replication. Given the importance of this protein in the replication process, three integrase inhibitors are currently used as an option for antiretroviral therapy: Raltegravir, Elvitegravir, and Dolutegravir. However, the crescent emergence of mutations that cause resistance to these drugs has become a worldwide health problem. In this study, we compared the variability of each position of the HIV-1 integrase sequence in clinical isolates of Raltegravir-treated and drug-naïve patients by calculating their Shannon entropies. A co-occurrence network was created to explore how mutations co-occur in patients treated with Raltegravir. Then, by building tridimensional models of the HIV-1 integrase intasomes, we investigated the relationship between variability, architecture, and co-occurrence. We observed that positions bearing some of the major resistance pathways are highly conserved among non-treated patients and variable among the treated ones. The residues involved in the three main resistance-related mutations could be identified in the same group when the positions were clustered according to their entropies. Analysis of the integrase architecture showed that the high-entropy residues S119, T124, and T125, are in contact with the host DNA, and their variations may have impacts in the protein-DNA recognition. The co-occurrence network revealed that the major resistance pathways N155H and Q148HR share more mutations with each other than with the Y143R pathway, this observation corroborates the fact that the N155H pathway is most commonly converted into Q148HRK than into Y143RCH pathway in patients' isolates. The network and the structure analysis also support the hypothesis that the resistance-related E138K mutation may be a mechanism to compensate for mutations in neighbor lysine residues to maintain DNA binding. The present study reveals patterns by which the HIV-1 integrase adapts during Raltegravir therapy. This information can be useful to comprehend the impacts of the drug in the enzyme, as well as help planning new therapeutic approaches.

O papel do dolutegravir na terapia antiretroviral

Os inibidores da integrase são a mais nova classe de antirretroviral aprovada, que agem impedindo a incorporação do DNA do HIV no genoma do linfócito T CD4+ (LTCD4+) do hospedeiro, limitando a propagação do vírus. O Dolutegravir e o inibidor da integrase mais moderno e como os demais inibidores apresenta de alta performance, boa tolerância; alta barreira genética para mutações de resistência, além de apresentar eficácia em pacientes já submetidos a tratamento antirretroviral anterior. Neste contexto o presente estudo trata-se de um estudo de revisão bibliográfica realizada de janeiro a junho de 2018, de artigos científicos de artigos científicos que abordam aspectos exclusivos do dolutegravir na terapia antirretroviral em comparação com outros esquemas terapêuticos. Concluindo que o tratamento com dolutegravir apresenta como principais vantagens à rápida supressão virológica; boa tolerância e alta barreira genética para mutações de resistência.

Bictegravir in a fixed-dose tablet with emtricitabine and tenofovir alafenamide for the treatment of HIV infection: pharmacology and clinical implications

INTRODUCTION

Current antiretroviral therapy is more effective and simpler than in previous times due to the development of new drugs with improved pharmacokinetic and pharmacodynamic profiles and the advent of single pill regimens with low toxicity that facilitate long-term adherence. The recent approval of the novel potent integrase strand-transfer inhibitor bictegravir (BIC) co-formulated with emtricitabine (FTC) and tenofovir alafenamide (TAF) in a fixed daily dose pill, B/F/TAF, adds to the list of single-tablet regimens available to treat HIV infection. Areas covered: This review provides an overview of the pharmacological and clinical information obtained from MEDLINE/PubMed publications and the latest international conferences. Expert opinion: BIC is a potent antiretroviral with an improved resistance profile over previous integrase inhibitors. Its combination with the new tenofovir prodrug TAF and FTC creates an effective regimen B/F/TAF for treatment-naïve patients and for those switching from another successful combination. B/F/TAF's favorable pharmacokinetic profile, simple dose, low pill burden, and few drug-drug interactions or treatment-related adverse events, will make it one of the preferred regimens in the future.

Efficacy and Safety of Raltegravir-Based Dual Therapy in AIDS Patients: A Meta-Analysis of Randomized Controlled Trials

Background: The life expectancy for HIV-infected individuals has improved dramatically because of improvements in antiretroviral therapy (ART). Today, a simplified two-drug regimen enhances adherence and treatment satisfaction by reducing adverse effects. Therefore, we need more evidence to show the benefits and risks of simplified ART regimens from randomized controlled trials (RCTs). We compared the efficacy and safety of raltegravir-based simplified dual therapy (DT) and of traditional triple therapy (TT) for people living with HIV/AIDS (PLWHA). Methods: We carried out a systematic review of RCTs. After using a combination of the key words "HIV," "raltegravir," and "protease inhibitor" to search the English-language electronic databases from January 1, 2004, to September 11, 2019, we pooled data across eligible studies and estimated the summary effect sizes with Review Manager (version 5.3). Results: We included eight RCTs involving 4420 PLWHA: 2187 (49.5%) received raltegravir-based simplified DT, and 2144 (48.5%) received traditional TT. The proportion of viral suppression was 79% at 48 weeks and 74% at 96 weeks in the simplified regimen, and the proportion of viral suppression was 78% at 48 weeks and 71% at 96 weeks in the traditional TT group. Furthermore, the proportion of viral suppression in the simplified DT group was greater than that in the TT group at 24 weeks (risk ratio 1.11, 95% confidence interval 1.02-1.21; p = 0.01). The CD4 cell counts in the simplified DT group were significantly higher at 48 weeks and 96 weeks than those in the group that received the traditional TT. Regarding adverse events and mortality rates, the DT and TT groups were similar. However, there was better adherence in the DT group than in the TT group. Conclusion: We found that the simplified regimen was noninferior to TT regimen in regard to viral suppression. Furthermore, the simplified DT regimen had a better CD4 cell count and lower adverse events than the TT regimen.

Discovery of 4-oxoquinolines, a new chemical class of anti-HIV-1 compounds

Antiretroviral therapy (ART) against HIV-1 infection offers the promise of controlling disease progression and prolonging the survival of HIV-1-infected patients. However, even the most potent ART regimens available today cannot cure HIV-1. Because patients will be exposed to ART for many years, physicians and researchers must anticipate the emergence of drug-resistant HIV-1, potential adverse effects of the current drugs, and need for future drug development. In this study, we screened a small-molecule compound library using cell-based anti-HIV-1 assays and discovered a series of novel anti-HIV-1 compounds, 4-oxoquinolines. These compounds exhibited potent anti-HIV-1 activity (EC₅₀ < 0.1 μM) with high selectivity indexes (CC₅₀/EC₅₀ > 2500) and favorable pharmacokinetic profiles in mice. Surprisingly, our novel compounds have a chemical backbone similar to the clinically used integrase (IN) strand transfer inhibitor (INSTI) elvitegravir, although they lack the crucial 3-carboxylate moiety needed for the common INSTI diketo motif. Indeed, the new 4-oxoquinoline derivatives have no detectable INSTI activity. In addition, various drug-resistant HIV-1 strains did not display cross resistance to these compounds. Interestingly, time-of-addition experiments indicated that the 4-oxoquinoline derivative remains its anti-HIV-1 activity even after the viral integration stage. Furthermore, the compounds significantly suppressed p24 antigen production in HIV-1 latently infected cells exposed with tumor necrosis factor alpha. These findings suggest that our 4-oxoquinoline derivatives with no 3-carboxylate moiety may become novel lead compounds in the development of anti-HIV-1 drugs.

Treatment with a fixed dose combination antiretroviral therapy drug containing tenofovir, emtricitabine and efavirenz is associated with cardioprotection in high calorie diet-induced obese rats

HIV-infection, certain antiretroviral drug classes, especially protease inhibitors (PI), and obesity are associated with increased ischaemic heart disease (IHD) risk. However, the effect of PI-free fixed dose combination (FDC) antiretroviral therapy (ART) on hearts exposed to ischaemia-reperfusion injury (I/R) is unknown, particularly in obesity. This is becoming relevant as World Health Organisation guidelines recommend a FDC ART containing (non-) nucleoside reverse transcriptase inhibitors (tenofovir (TDF), emtricitabine (FTC) and efavirenz (EFV)) as first-line HIV treatment. Additionally, obesity rates are rising in HIV-infected populations, not only in ART-experienced individuals, but also at the time of ART initiation, which may further increase the risk of IHD. Therefore, we investigated the effects of PI-free FDC ART in myocardial I/R-exposed hearts from obese rats. Obesity was induced in male wistar rats via a 16-week high calorie diet. At week 10, treatment with a FDC ART drug containing TDF/FTC/EFV was initiated. Biometric and metabolic parameters, as well as myocardial functional recovery and infract size (IS), and myocardial signalling proteins following I/R were assessed after 16 weeks. Obese rats presented with increased body and intraperitoneal fat mass, elevated triglyceride and TBARS levels, whilst the hearts responded to I/R with impaired functional performance and increased IS. The FDC ART treatment did not alter biometric and metabolic parameters in obese rats. In a novel finding, ART protected obese hearts against I/R as shown by improved functional performance and smaller IS vs. untreated obese hearts. Cardioprotection was underscored by increased myocardial phosphorylated endothelial nitric oxide synthase (eNOS) and reduced AMP-kinase levels. In conclusion, these results demonstrate for the first time, that 6-weeks treatment of obese rats with a FDC ART drug specifically containing TDF/FTC/EFV conferred cardioprotection against I/R. The FDC ART-induced cardioprotection was seemingly unrelated to metabolic changes, but rather due to direct cardiac mechanisms including the up-regulation of myocardial eNOS.

Which antiretrovirals should be prescribed as first-line treatments? Changes over the past 10 years in France

OBJECTIVE

To describe the changes in first-line antiretroviral (ART) regimens in France between 2005 and 2015 and patients' characteristics related to the use of protease inhibitors in 2015.

METHODS

We extracted all patients starting ART between 2005 and 2015 from a large prospective cohort. Regimens were classified as three nucleoside reverse transcriptase inhibitors (NRTI), or two NRTIs with a boosted protease inhibitor (bPI), with a non-nucleoside reverse transcriptase inhibitor (NNRTI), or with an INSTI. Patients' characteristics at the time of initiation were collected. A multinomial logit model was fitted to analyze characteristics related to the choice of regimen in 2015.

RESULTS

We analyzed data from 15,897 patients. The proportion of patients starting with (i) a bPI decreased from 60% before 2014 to 38.1% in 2015; (ii) an NNRTI decreased from 30% to 17.8% in 2015; (iii) an INSTI gradually increased to 39.4% in 2015. In 2015, patients with an initial viral load ˃5 log copies/mL were less likely to receive NNRTI (OR=0.08) or INSTI regimens (OR=0.69) than bPIs. Patients with initial CD4⁺ T cell count ˂200/mm³ were less likely to receive an NNRTI (OR=0.28) or an INSTI regimen (OR=0.52) than a bPI. Women were less likely to receive an NNRTI (OR=0.79) or an INSTI regimen (OR=0.71) than a bPI; although this depended on age.

CONCLUSION

The use of bPI as first-line ART declined sharply in France from 2005 to 2015. bPI remained of preferential use in patients with high viral load, low CD4⁺ T cell count, and in women.

Association of raltegravir use with long-term health outcomes in HIV-infected patients: an observational post-licensure safety study in a large integrated healthcare system

BACKGROUND

Raltegravir became the first integrase inhibitor to gain FDA approval; but with limited evidence documenting long-term risks in real world care, especially for major health outcomes of interest.

OBJECTIVE

Assess raltegravir safety in clinical practice within an integrated health system.

METHODS

We conducted a cohort study of HIV-infected adults within Kaiser Permanente California from 2005 to 2013. We compared patients initiating raltegravir during the study period with two groups; a historical cohort (started new antiretroviral regimen [ART] 2005-2007) and a concurrent cohort that did not initiate raltegravir (2007-2013). We used multivariate Cox proportional hazard regression to obtain hazard ratios (HR) for pre-specified incident health outcomes, employing propensity scores to adjust for potential confounding.

RESULTS

The population included 8,219 HIV-infected adults (raltegravir cohort N = 1,757; 4,798 patient-years), with greater years known HIV-infected among raltegravir patients. The raltegravir cohort had increased HR for AIDS-defining (HR 2.69 [1.53-4.71]; HR 1.85 [1.21-2.82]) and non-AIDS-defining malignancies (HR 2.26 [1.29-3.94]; HR 1.88 [1.26-2.78]) relative to both comparison cohorts. Compared to the historical cohort we found no significant difference in all-cause mortality; the raltegravir cohort experienced increased HR for all-cause mortality compared to concurrent (HR 1.53 [1.02-2.31]). Raltegravir appeared protective of lipodystrophy when compared to the historical cohort but associated with increased incidence compared to concurrent. There were no significant differences in the incidence of hepatic, skin, or cardiovascular events.

CONCLUSIONS

The potentially elevated risk for malignancy and mortality with raltegravir and residual confounding merits further investigation. We demonstrate the value of observational cohorts for monitoring post-licensure medication safety.

Recent advances in the discovery of small-molecule inhibitors of HIV-1 integrase

AIDS caused by the infection of HIV is a prevalent problem today. Rapid development of drug resistance to existing drug classes has called for the discovery of new targets. Within the three major enzymes (i.e., HIV-1 protease, HIV-1 reverse transcriptase and HIV-1 integrase [IN]) of the viral replication cycle, HIV-1 IN has been of particular interest due to the absence of human cellular homolog. HIV-1 IN catalyzes the integration of viral genetic material with the host genome, a key step in the viral replication process. Several novel classes of HIV IN inhibitors have been explored by targeting different sites on the enzyme. This review strives to provide readers with updates on the recent developments of HIV-1 IN inhibitors.

AIDS is an epidemic disease that endangers the lives of millions of people across the world. The AIDS virus, also known as HIV, has developed resistance to the majority of available drugs on the market, thus requiring the need for new drugs. HIV integrase is one of the key viral enzymes required for viral cell proliferation. Since there is no similar enzyme in the human body, major emphasis is being made to develop therapeutics for this novel target. The drugs that are at various stages of development for this target are reviewed here.

Trends in antiretroviral therapy prescription, durability and modification: new drugs, more changes, but less failure

OBJECTIVE

To evaluate the real world durability of contemporary ART for treatment-naïve people living with HIV (PLWH).

DESIGN

A retrospective follow-up study in a multisite cohort.

METHODS

This study of the CNICS (CFAR Network of Integrated Clinical Systems) cohort integrates data from eight Center for AIDS Research (CFARs). PLWH initiating ART between 2007 and 2014 were included. Durability was defined as time from the initiation until discontinuation/modification using Kaplan-Meier survival curves. Cox Proportional Hazards measured associations with various sociodemographic and clinical characteristics.

RESULTS

Among 5373 PLWH, the initial regimen was modified in 2285 (43%) patients. Efavirenz/emtricitabine/tenofovir (n = 2173, 40%) was the most commonly prescribed initial ART regimen; elvitegravir/cobicistat/emtricitabine/tenofovir became more common after 2012. Median durability for all regimens was 48.6 months. There were statistically significant differences in median durability for NNRTI, InSTI, and protease inhibitor-based regimens, which lasted 61, 44, and 32 months, respectively. Female sex (aHR = 1.4; 95% CI 1.2-1.6), intravenous drug use (aHR = 1.6; 95% CI 1.3-1.9), and CD4 cell count less than 200 cells/μl (aHR = 1.2; 95% CI 1.1-1.3) were significantly associated with regimen modification. Compared with InSTI, those receiving an InSTI/protease inhibitor (aHR = 2.7; 95% CI 2.0-3.7) or protease inhibitor-based ART (aHR = 1.9; 95% CI 1.6-2.2) were significantly more likely to be modified; but those receiving NNRTI (aHR = 1.1; 95% CI 0.9-1.3) were not.

CONCLUSION

In treatment-naive PLWH, NNRTI and InSTI-based ART were most durable, relative to protease inhibitor and InSTI/protease inhibitor-based ART, and were least likely to be modified/discontinued. A greater understanding of reasons for regimen modification/discontinuation is needed to analyze contemporary regimen durability.

Virologic suppression and CD4+ cell count recovery after initiation of raltegravir or efavirenz-containing HIV treatment regimens

OBJECTIVE

To explore the effectiveness of raltegravir-based antiretroviral therapy (ART) on treatment response among ART-naive patients seeking routine clinical care.

DESIGN

Cohort study of adults enrolled in HIV care in the United States.

METHODS

We compared virologic suppression and CD4 cell count recovery over a 2.5 year period after initiation of an ART regimen containing raltegravir or efavirenz using observational data from a US clinical cohort, generalized to the US population of people with diagnosed HIV. We accounted for nonrandom treatment assignment, informative censoring, and nonrandom selection from the US target population using inverse probability weights.

RESULTS

Of the 2843 patients included in the study, 2476 initiated the efavirenz-containing regimen and 367 initiated the raltegravir-containing regimen. In the weighted intent-to-treat analysis, patients spent an average of 74 (95% confidence interval: 41, 106) additional days alive with a suppressed viral load on the raltegravir regimen than on the efavirenz regimen over the 2.5-year study period. CD4 cell count recovery was also superior under the raltegravir regimen.

CONCLUSION

Patients receiving raltegravir spent more time alive and suppressed than patients receiving efavirenz, but the probability of viral suppression by 2.5 years after treatment was similar between groups. Optimizing the amount of time spent in a state of viral suppression is important to improve survival among people living with HIV and to reduce onward transmission.

Impact of the HIV-1 genetic background and HIV-1 population size on the evolution of raltegravir resistance

BACKGROUND

Emergence of resistance against integrase inhibitor raltegravir in human immunodeficiency virus type 1 (HIV-1) patients is generally associated with selection of one of three signature mutations: Y143C/R, Q148K/H/R or N155H, representing three distinct resistance pathways. The mechanisms that drive selection of a specific pathway are still poorly understood. We investigated the impact of the HIV-1 genetic background and population dynamics on the emergence of raltegravir resistance. Using deep sequencing we analyzed the integrase coding sequence (CDS) in longitudinal samples from five patients who initiated raltegravir plus optimized background therapy at viral loads > 5000 copies/ml. To investigate the role of the HIV-1 genetic background we created recombinant viruses containing the viral integrase coding region from pre-raltegravir samples from two patients in whom raltegravir resistance developed through different pathways. The in vitro selections performed with these recombinant viruses were designed to mimic natural population bottlenecks.

RESULTS

Deep sequencing analysis of the viral integrase CDS revealed that the virological response to raltegravir containing therapy inversely correlated with the relative amount of unique sequence variants that emerged suggesting diversifying selection during drug pressure. In 4/5 patients multiple signature mutations representing different resistance pathways were observed. Interestingly, the resistant population can consist of a single resistant variant that completely dominates the population but also of multiple variants from different resistance pathways that coexist in the viral population. We also found evidence for increased diversification after stronger bottlenecks. In vitro selections with low viral titers, mimicking population bottlenecks, revealed that both recombinant viruses and HXB2 reference virus were able to select mutations from different resistance pathways, although typically only one resistance pathway emerged in each individual culture.

CONCLUSIONS

The generation of a specific raltegravir resistant variant is not predisposed in the genetic background of the viral integrase CDS. Typically, in the early phases of therapy failure the sequence space is explored and multiple resistance pathways emerge and then compete for dominance which frequently results in a switch of the dominant population over time towards the fittest variant or even multiple variants of similar fitness that can coexist in the viral population.

Association of the HLA-B*53:01 Allele With Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS) Syndrome During Treatment of HIV Infection With Raltegravir

Background

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare, severe adverse event during treatment with raltegravir. The occurrence of DRESS syndrome during treatment with other drugs is strongly associated with particular HLA alleles.

Methods

We performed HLA testing in 3 of the 5 patients previously reported to have developed raltegravir-induced DRESS syndrome and in 1 previously unreported patient. We then used virtual modeling to visualize interactions between raltegravir and the imputed HLA molecule.

Results

Five of the 6 patients who developed raltegravir-induced DRESS syndrome were African, and 1 was Hispanic. HLA typing was performed in 4 patients, all of whom carried both the HLA-B*53 allele and the HLA-C*04 allele to which it is commonly haplotypic. No other HLA alleles were shared by all of the tested patients. Given the approximate prevalence of HLA-B*53 carriage in African (20%) and Hispanic (6%) populations, the probability of all 4 patients being HLA-B*53 carriers, and 2 of 3 African patients being homozygous for HLA-B*53:01, is approximately 0.00002.

Conclusions

These data implicate the prevalent African allele HLA-B*53:01 in the immunopathogenesis of raltegravir-induced DRESS syndrome. Although the immunopathogenic mechanisms are currently unknown, virtual modeling suggests that raltegravir may bind within the antigen binding cleft of the HLA-B*53:01 molecule, but not within the closely related HLA-B*35:01 molecule. Further studies are necessary to confirm the strength of the association between carriage of the HLA-B*53:01 allele and raltegravir-induced DRESS syndrome, and the potential utility of HLA screening before raltegravir treatment.

Oseltamivir-zanamivir combination therapy suppresses drug-resistant H1N1 influenza A viruses in the hollow fiber infection model (HFIM) system

Drug-resistant influenza is a significant threat to global public health. Until new antiviral agents with novel mechanisms of action become available, there is a pressing need for alternative treatment strategies with available influenza antivirals. Our aims were to evaluate the antiviral activity of two neuraminidase inhibitors (oseltamivir and zanamivir) as combination therapy against H1N1 influenza A viruses, as these agents bind to the neuraminidase active site differently: oseltamivir requires a conformational change for binding whereas zanamivir does not. We performed pharmacodynamic studies in the hollow fiber infection model (HFIM) system with oseltamivir (75mg Q12h, t1/2: 8h) and zanamivir (600mg Q12h, t1/2: 2.5h), given as mono- or combination therapy, against viruses with varying susceptibilities to oseltamivir and zanamivir. Each antiviral suppressed the replication of influenza strains which were resistant to the other neuraminidase inhibitor, showing each drug does not engender cross-resistance to the other compound. Oseltamivir/zanamivir combination therapy was as effective at suppressing oseltamivir- and zanamivir-resistant influenza viruses and the combination regimen inhibited viral replication at a level that was similar to the most effective monotherapy arm. However, combination therapy offered a clear benefit by preventing the emergence and spread of drug-resistant viruses. These findings demonstrate that combination therapy with two agents that target the same viral protein through distinctly different binding interactions is a feasible strategy to combat resistance emergence. This is a novel finding that may be applicable to other viral and non-viral diseases for which different classes of agents do not exist.

Risk factors for early mortality on antiretroviral therapy in advanced HIV-infected adults

BACKGROUND

Many HIV-infected individuals present with advanced HIV disease. These patients are at high risk of death after antiretroviral therapy (ART) initiation, but risk factors for death in these patients are unclear.

METHODS

We used data from a multisite randomized trial comparing empiric vs. preventive tuberculosis therapy in HIV-infected adults initiating ART with CD4 T-cell counts less than 50 cells/μl to evaluate risk factors for death within 48 weeks after ART initiation. Cox proportional hazards models were fit to evaluate characteristics present at baseline and at 4 weeks after ART initiation, including the week 4 CD4 T-cell response and new opportunistic infections.

RESULTS

Of 850 enrolled, the median pre-ART CD4 T-cell count was 18 cells/μl and 67 (7.9%) died. Baseline risk factors for death included lymphadenopathy, lower CD4 T-cell count, lower serum albumin, high white blood cell count, elevated neutrophil percentage, and lower hemoglobin. Among 746 participants with data at week 4, the median changes in CD4 T-cell count and viral load for those who died (n = 43) vs. survived were 26 vs. 56 cells/μl and -2.7 vs. -2.7 log10 copies/ml, respectively. Each 20 cell/μl lower change in week 4 CD4 T-cell count was associated with a 20% increased risk of post week-4 mortality (adjusted hazard ratio 1.20, 1.01-1.42, P = .038).

CONCLUSION

Evidence of active infection and suboptimal immunologic response during the first month of ART are associated with death in the first year after ART initiation in those with advanced HIV disease taking tuberculosis preventive therapy. Strategies to reduce early mortality in this population warrant further investigation.

Addition of Etravirine Does Not Enhance the Initial Decline of HIV-1 RNA in Treatment-Experienced Patients Receiving Raltegravir

OBJECTIVE

The importance of an early reduction of HIV-1 RNA as a marker for positive longer term outcome is still under debate. We investigate whether antiretroviral-experienced patients receiving raltegravir plus etravirine have a higher early reduction of HIV-1 RNA compared with patients receiving raltegravir.

DESIGN

An observational study of treatment-experienced patients.

METHODS

The objective is to investigate 349 patients included in a raltegravir resistance study. The early outcome is defined as a reduction of HIV-1 RNA at week 8. The crude method defines all measurements below the limit of quantification to be equal to the limit of quantification provides biased estimates. Such a reduction is censored by the limit of quantification and is subject to selection bias in observational studies.

RESULTS

The crude method showed a significant higher reduction in HIV-1 RNA reduction in patients receiving raltegravir plus etravirine compared with patients receiving raltegravir (mean reduction of 2.1 versus 1.8 log10 copies/mL). However, survival methods adjusted for both censoring, due to the limit of quantification, and confounding factors lead to a nonsignificant difference between the 2 treatment groups (mean reduction of 2.8 versus 2.7 log10 copies/mL).

CONCLUSION

Taking into account censoring and confounding factors, our study did not demonstrate a higher early reduction of HIV-1 RNA in patients receiving raltegravir with versus without etravirine.

Treatment as Prevention: Characterization of Partner Infections in the HIV Prevention Trials Network 052 Trial

HIV Prevention Trials Network 052 demonstrated that antiretroviral therapy (ART) prevents HIV transmission in serodiscordant couples. HIV from index-partner pairs was analyzed to determine the genetic linkage status of partner infections. Forty-six infections were classified as linked, indicating that the index was the likely source of the partner's infection. Lack of viral suppression and higher index viral load were associated with linked infection. Eight linked infections were diagnosed after the index started ART: 4 near the time of ART initiation and 4 after ART failure. Linked infections were not observed when the index participant was stably suppressed on ART.

Virologic outcomes in early antiretroviral treatment: HPTN 052

INTRODUCTION

The HIV Prevention Trials Network (HPTN) 052 trial demonstrated that early antiretroviral therapy (ART) prevented 93% of HIV transmission events in serodiscordant couples. Some linked infections were observed shortly after ART initiation or after virologic failure.

OBJECTIVE

To evaluate factors associated with time to viral suppression and virologic failure in participants who initiated ART in HPTN 052.

METHODS

1566 participants who had a viral load (VL) > 400 copies/mL at enrollment were included in the analyses. This included 832 in the early ART arm (CD4 350-550 cells/mm³ at ART initiation) and 734 in the delayed ART arm (204 with a CD4 < 250 cells/mm³ at ART initiation; 530 with any CD4 at ART initiation). Viral suppression was defined as two consecutive VLs ≤ 400 copies/mL after ART initiation; virologic failure was defined as two consecutive VLs > 1000 copies/mL > 24 weeks after ART initiation.

RESULTS

Overall, 93% of participants achieved viral suppression by 12 months. The annual incidence of virologic failure was 3.6%. Virologic outcomes were similar in the two study arms. Longer time to viral suppression was associated with younger age, higher VL at ART initiation, and region (Africa vs. Asia). Virologic failure was strongly associated with younger age, lower educational level, and lack of suppression by three months; lower VL and higher CD4 at ART initiation were also associated with virologic failure.

CONCLUSIONS

Several clinical and demographic factors were identified that were associated with longer time to viral suppression and virologic failure. Recognition of these factors may help optimize ART for HIV treatment and prevention.

Lack of impact of pre-existing T97A HIV-1 integrase mutation on integrase strand transfer inhibitor resistance and treatment outcome

T97A is an HIV-1 integrase polymorphism associated with integrase strand transfer inhibitor (INSTI) resistance. Using pooled data from 16 clinical studies, we investigated the prevalence of T97A (pre-existing and emergent) and its impact on INSTI susceptibility and treatment response in INSTI-naive patients who enrolled on elvitegravir (EVG)- or raltegravir (RAL)-based regimens. Prior to INSTI-based therapy, primary INSTI resistance-associated mutations (RAMs) were absent and T97A pre-existed infrequently (1.4%; 47 of 3367 integrase sequences); most often among non-B (5.3%) than B (0.9%) HIV-1 subtypes. During INSTI-based therapy, few patients experienced virologic failure with emergent INSTI RAMs (3%; 122 of 3881 patients), among whom T97A emerged infrequently in the presence (n = 6) or absence (n = 8) of primary INSTI RAMs. A comparison between pre-existing and emergent T97A patient populations (i.e., in the absence of primary INSTI RAMs) showed no significant differences in EVG or RAL susceptibility in vitro. Furthermore, among all T97A-containing viruses tested, only 38-44% exhibited reduced susceptibility to EVG and/or RAL (all of low magnitude; <11-fold), while all maintained susceptibility to dolutegravir. Of the patients with pre-existing T97A, 17 had available clinical follow-up: 16 achieved virologic suppression and 1 maintained T97A and INSTI sensitivity without further resistance development. Overall, T97A is an infrequent integrase polymorphism that is enriched among non-B HIV-1 subtypes and can confer low-level reduced susceptibility to EVG and/or RAL. However, detection of T97A does not affect response to INSTI-based therapy with EVG or RAL. These results suggest a very low risk of initiating INSTI-based therapy in patients with pre-existing T97A.

Dolutegravir(DTG, S/GSK1349572) combined with other ARTs is superior to RAL- or EFV-based regimens for treatment of HIV-1 infection: a meta-analysis of randomized controlled trials

Background

The first-generation integrase inhibitors (INIs) raltegravir (RAL) and elvitegravir (EVG) have shown efficacy against HIV infection, but they have the limitations of once-more daily dosing and extensive cross-resistance. Dolutegravir (DTG, S/GSK1349572), a second-generation drug that overcomes such shortcomings, is under spotlight. The purpose of this study is to review the evidence for DTG use in clinical settings, including its efficacy and safety.

Methods

PubMed, EMbase, Ovid, Web of Science, Science Direct, and related websites were screened from establishment until July 2013, and scientific meeting proceedings were manually searched. Two reviewers independently screened 118 citations repeatedly to identify randomized controlled trials comparing the efficacy and safety of DTG-based regimen with those of RAL- or elvitegravir-based regimens. Using the selected studies with comparable outcome measures and indications, we performed a meta-analysis based on modified intention-to-treat (mITT), on-treatment (OT), and as-treated (AT) virological outcome data. Independent data extraction and quality assessment were conducted.

Results

Four unique studies were included with the use of DTG in antiretroviral therapy-naive patients. In therapy-naive patients, DTG combined with abacavir/lamivudine (ABC/3TC) or tenofovir/emtricitabine (TDF/FTC) resulted in a significantly better virological outcome with a mITT relative risk (RR)of 1.07 (95 % confidence interval (95 % CI 1.03–1.12). Evidence further supported use of DTG had a better virological suppression in the 50 mg once daily group (mITT RR 1.07; 95 % CI 1.03–1.12) as well as in the sub-analysis in dolutegravir/efavirenz(DTG/EFV) and dolutegravir/raltegravir (DTG/RAL) groups (RR 1.09, 95 % CI 1.03–1.15; RR 1.06, 95 % CI 0.98–1.15, respectively). In the matter of safety of DTG-based regimen, the risk of any event was RR 0.98 (95 % CI 0.94–1.01), the risk of serious adverse events (AEs) was RR 0.84 (95 % CI 0.62–1.15), and the risk of drug-related serious AEs was RR 0.33 (95 % CI 0.13–0.79).

Conclusion

In general, DTG 50 mg given once daily combined with an active background drug is a better choice in terms of both efficacy and safety.

Comparative efficacy and safety of first-line antiretroviral therapy for the treatment of HIV infection: a systematic review and network meta-analysis

BACKGROUND

New antiretroviral therapy (ART) regimens for HIV could improve clinical outcomes for patients. To inform global guidelines, we aimed to assess the comparative effectiveness of recommended ART regimens for HIV in ART-naive patients.

METHODS

For this systematic review and network meta-analysis, we searched for randomised clinical trials published up to July 5, 2015, comparing recommended antiretroviral regimens in treatment-naive adults and adolescents (aged 12 years or older) with HIV. We extracted data on trial and patient characteristics, and the following primary outcomes: viral suppression, mortality, AIDS defining illnesses, discontinuations, discontinuations due to adverse events, and serious adverse events. We synthesised data using network meta-analyses in a Bayesian framework and included older treatments, such as indinavir, to serve as connecting nodes. We defined network nodes in terms of specific antivirals rather than specific ART regimens. We categorised backbone regimens and adjusted for them through group-specific meta-regression. We used the GRADE framework to interpret the strength of inference.

FINDINGS

We identified 5865 citations through database searches and other sources, of which, 126 articles related to 71 unique trials were included in the network analysis, including 34 032 patients randomly assigned to 161 treatment groups. For viral suppression at 48 weeks, compared with efavirenz, the odds ratio (OR) for viral suppression was 1·87 (95% credible interval [CrI] 1·34-2·64) with dolutegravir and 1·40 (1·02-1·96) with raltegravir; with respect to viral suppression, low-dose efavirenz was similar to all other treatments. Both low-dose efavirenz and integrase strand transfer inhibitors tended to be protective of discontinuations due to adverse events relative to normal-dose efavirenz. The most protective effect relative to efavirenz in network meta-analyses was that of dolutegravir (OR 0·26, 95% CrI 0·14-0·47), followed by low-dose efavirenz (0·39, 0·16-0·92). Owing to insufficient data, we could make no conclusions about serious adverse events. Low event rates also limited the quality of evidence with regard to mortality and AIDS defining illnesses.

INTERPRETATION

The efficacy and safety of ART has substantially improved with the introduction of newer drug classes of antiretrovirals that are now available to patients and HIV care providers. Their improved tolerance could be part of a larger solution to improve retention, which is a challenge, particularly in low-income and middle-income country settings.

FUNDING

The World Health Organization.

P-glycoprotein (ABCB1) activity decreases raltegravir disposition in primary CD4+P-gphigh cells and correlates with HIV-1 viral load

Objectives

To evaluate the role of P-glycoprotein (P-gp) and multidrug-resistant-protein 1 (MRP1) on raltegravir intracellular drug disposition in CD4+ T cells, investigate the effect of HIV-1 infection on P-gp expression and correlate HIV-1 viraemia with P-gp activity in primary CD4+ T cell subsets.

Methods

The cellular accumulation ratio of [³H]raltegravir was quantified in CD4+ T cell lines overexpressing either P-gp (CEM-P-gp) or MRP1 (CEM-MRP1) and in primary CD3+CD4+ T cells with high (P-gp^high) and low P-gp activity (P-gp^low); inhibition of efflux transporters was confirmed by the intracellular retention of calcein-AM. The correlation of P-gp activity with HIV-1 viraemia was assessed in naive and memory T cell subsets from 21 HIV-1-infected treatment-naive subjects.

Results

[³H]Raltegravir cellular accumulation ratio decreased in CEM-P-gp cells (P < 0.0001). XR9051 (a P-gp inhibitor) and HIV-1 PIs reversed this phenomenon. Primary CD4+P-gp^high cells accumulated less raltegravir (38.4% ± 9.6%) than P-gp^low cells, whereas XR9051 also reversed this effect. In vitro HIV-1 infection of PBMCs and stimulation of CD4+ T cells increased P-gp mRNA and P-gp activity, respectively, while primary CD4+P-gp^high T cells sustained a higher HIV-1 replication than P-gp^low cells. A significant correlation between HIV-1 viraemia and P-gp activity was found in different CD4+ T cell subsets, particularly memory CD4+ T cells (r = 0.792, P < 0.0001).

Conclusions

Raltegravir is a substrate of P-gp in CD4+ T cells. Primary CD4+P-gp^high T cells eliminate intracellular raltegravir more readily than P-gp^low cells and HIV-1 viraemia correlates with P-gp overall activity. Specific CD4+P-gp^high T cell subsets could facilitate the persistence of viral replication in vivo and ultimately promote the appearance of drug resistance.

Treatment durability and virological response in treatment-experienced HIV-positive patients on an integrase inhibitor-based regimen: an Australian cohort study

Background: Integrase inhibitors (INSTI) are a newer class of antiretroviral (ARV) drugs that offer additional treatment options for experienced patients. Our aim is to describe treatment durability and virological outcomes in treatment-experienced HIV-positive patients using INSTI-based regimens. Methods: All patients in the Australian HIV Observational Database who had received an INSTI-based regimen ≥ 14 days as well as previous therapy were included in the study. We defined two groups of treatment-experienced patients: (1) those starting a second-line regimen with INSTI; and (2) highly experienced patients, defined as having prior exposure to all three main ARV classes, nucleoside reverse transcriptase inhibitor, nonnucleoside reverse transcriptase inhibitors and protease inhibitors, before commencing INSTI. Survival methods were used to determine time to viral suppression and treatment switch, stratified by patient treatment experience. Covariates of interest included age, gender, hepatitis B and C co-infection, previous antiretroviral treatment time, patient treatment experience and baseline viral load. Results: Time to viral suppression and regimen switching from INSTI initiation was similar for second-line and highly experienced patients. The probability of achieving viral suppression at 6 months was 77.7% for second-line patients and 68.4% for highly experienced patients. There were 60 occurrences of regimen switching away from INSTI observed over 1274.0 person-years, a crude rate of 4.71 (95% CI: 3.66-6.07) per 100 person-years. Patient treatment experience was not a significant factor for regimen switch according to multivariate analysis, adjusting for relevant covariates. Conclusions: We found that INSTI-based regimens were potent and durable in experienced HIV-positive patients receiving treatment outside clinical trials. These results confirm that INSTI-based regimens are a robust treatment option.

The Global Health Impact Index: Promoting Global Health

Millions of people cannot access essential medicines they need for deadly diseases like malaria, tuberculosis (TB) and HIV/AIDS. There is good information on the need for drugs for these diseases but until now, no global estimate of the impact drugs are having on this burden. This paper presents a model measuring companies' key malaria, TB and HIV/AIDS drugs' consequences for global health (global-health-impact.org). It aggregates drugs' impacts in several ways-by disease, country and originator-company. The methodology can be extended across diseases as well as drugs to provide a more extensive picture of the impact companies' drugs are having on the global burden of disease. The study suggests that key malaria, TB and HIV/AIDS drugs are, together, ameliorating about 37% of the global burden of these diseases and Sanofi, Novartis, and Pfizer's drugs are having the largest effect on this burden. Moreover, drug impacts vary widely across countries. This index provides important information for policy makers, pharmaceutical companies, countries, and other stake-holders that can help increase access to essential medicines.

Early HIV RNA decay during raltegravir-containing regimens exhibits two distinct subphases (1a and 1b)

BACKGROUND

We analyzed the early kinetics with integrase inhibitor treatment to gain new insights into viral dynamics.

METHODOLOGY

We analyzed data from 39 HIV-1 infected, treatment-naive, participants: 28 treated with raltegravir (RAL; multiple doses) monotherapy for 9 days, and 11 with RAL 400 mg twice daily and emtricitabine (200 mg daily)/tenofovir disoproxil fumarate (300 mg daily). Plasma HIV-1 RNA was measured frequently; the data was fitted using a mathematical model of viral dynamics distinguishing between infected cells with unintegrated HIV DNA and productively infected cells. Parameters were estimated using mixed-effect models.

RESULTS

RAL treatment led to a biphasic viral decline with a rapid first phase (1a) lasting approximately 5 days followed by a slower phase (1b). Phase 1a is attributed to the rapid elimination of productively infected cells. Phase 1b reflects the loss of infected cells with nonintegrated provirus due to cell loss and integration of HIV DNA. The half-lives of productively infected cells and of infected cells that had completed reverse transcription but had not yet integrated HIV DNA were approximately 19 h and between 3.6 and 5.8 days, respectively. The effectiveness of RAL in preventing proviral integration was 94% and 99.7%, for the combination therapy and monotherapy groups, respectively.

CONCLUSION

We found that the first phase of viral decay with RAL therapy was composed of two subphases corresponding to the half-lives of infected cells with integrated proviruses and with unintegrated HIV-DNA.