Effectiveness of Once/Day Dolutegravir Plus Boosted Darunavir as a Switch Strategy in Heavily Treated Patients with Human Immunodeficiency Virus

STUDY OBJECTIVE

Dual therapy with once/day dolutegravir (DTG) plus boosted darunavir (DRV/b) may be a suitable and effective strategy with a high genetic barrier to resistance in patients infected with human immunodeficiency virus (HIV). Our aim was to evaluate the effectiveness of DTG plus DRV/b (DTG+DRV/b) as a switch strategy in HIV-infected patients, irrespective of their history of virologic failure (VF).

DESIGN

Multicenter retrospective cohort study.

SETTING

Human immunodeficiency outpatient treatment clinics at three university hospitals in Spain.

PATIENTS

Fifty HIV-infected adults who had a stable antiretroviral treatment (ART) regimen and an undetectable viral load for at least 6 months, and whose ART was switched to once/day DTG+DRV/b between January 2015 and January 2018 were included in the analysis. Historical genotype at the time of VF was available in 44 patients.

MEASUREMENTS AND MAIN RESULTS

Patients were followed until VF or treatment discontinuation for any reason. The primary outcome was the percentage of patients with a viral load of 50 copies/mL or lower at the last follow-up visit. Secondary outcomes included changes in CD4⁺ cell count, lipid profile, and renal function. Of the 50 patients included, median time of viral suppression was 52 months (interquartile range [IQR] 18-103 mo) and nadir CD4⁺ 89 cells/mm³ (IQR 37-241 cells/mm³ ). Patients had a history of a median of 8 ART combinations (IQR 4-11 combinations) and 3 VFs (IQR 2-8 VFs). The historical genotypes from 44 patients showed 41 patients (93.2%) with nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs), 32 (72.7%) with nonnucleoside reverse transcriptase inhibitor (NNRTI) RAMs, and 12 (27.3%) with primary protease inhibitor (PI) RAMs; 7 (15.9%) had darunavir RAMs, and no patients had baseline integrase strand transfer inhibitor RAMs. Thirty-seven patients (84.1%) had resistance to at least two antiretroviral classes. After a median of 25 months (IQR 17-28 mo) of follow-up, 49 patients (98%) maintained a viral load of 50 copies/mL or lower, and 1 patient (2%) had VF. No new RAMs emerged at VF. At week 4, serum creatinine concentration increased a median of 0.12 mg/dl (0.03-0.23 mg/dl). At last visit, total cholesterol and low-density lipoprotein cholesterol levels increased by a median of 9 mg/dl (IQR -18 to 40 mg/dl) and 16 mg/dl (IQR -9 to 40 mg/dl), respectively, whereas CD4⁺ cell count remained stable (median +13 cell/mm³ ).

CONCLUSION

In this cohort of heavily treated HIV-infected patients with virologic suppression, switching to the combination of DTG+DRV/b was a convenient regimen that was highly effective and had good tolerability.

Real-life study of dual therapy based on dolutegravir and ritonavir-boosted darunavir in HIV-1-infected treatment-experienced patients

BACKGROUND

Dual therapy based on dolutegravir and ritonavir-boosted darunavir (DTG/DRV/r) is a combination of well-known drugs with a high genetic barrier to HIV resistance.

METHOD

A retrospective analysis of all HIV-1 infected treatment-experienced patients who switched to DTG/DRV/r from May 2014 till March 2017 in 4 Polish centres-results of a 48-week treatment.

RESULTS

The study group consisted of 59 men and 17 women. Median baseline parameters were: age- 42.7 years, CD4 cells count- 560.5 cells/μl, CD4 cells nadir- 150 cells/μl, number of prior antiretroviral regimens- 3. The introduction of dual therapy was primarily due to virologic failure (30 patients), adverse events on previous regimens (17 patients) and therapy simplification (27 patients). At week 48 the treatment was continued in 70/76 of patients and the median CD4 cells count increased from 560.5 to 641.0 cells/μl. The therapy was discontinued in six patients (1 -virologic failure, 1 -decrease of estimated glomerular filtration rate (eGFR), 1 -myalgia, 3 -lost to follow-up). At week 48 six patients had detectable viremia, but only in one patient viremia was higher than 200 copies/ml. At week 48 the level of serum total cholesterol of the investigated subjects was statistically significantly higher than at the moment of dual therapy introduction (185.8 mg/dl vs. 174.8 mg/dl- p<0.05). However, in patients previously not treated with TDF, there were no changes in lipid parameters during therapy. Proteinuria was observed in 13.2% of patients before the switch to dual therapy and in 7.1% of patients at week 48.

CONCLUSIONS

The investigated dual therapy was effective and safe. The observed increase in lipid parameters only concerned the patients who had used a TDF-based regimen prior to analysed dual treatment.

Supramolecular combinations of humic polyanions as potent microbicides with polymodal anti-HIV-activities

Anti-HIV potency of humic PAs is governed by scaffolds diversity.

Physiological Mg2+ Conditions Significantly Alter the Inhibition of HIV-1 and HIV-2 Reverse Transcriptases by Nucleoside and Non-Nucleoside Inhibitors in Vitro

Reverse transcriptases (RTs) are typically assayed in vitro with 5-10 mM Mg²⁺, whereas the free Mg²⁺ concentration in cells is much lower. Artificially high Mg²⁺ concentrations used in vitro can misrepresent different properties of human immunodeficiency virus (HIV) RT, including fidelity, catalysis, pausing, and RNase H activity. Here, we analyzed nucleoside (NRTIs) and non-nucleoside RT inhibitors (NNRTIs) in primer extension assays at different concentrations of free Mg²⁺. At low concentrations of Mg²⁺, NRTIs and dideoxynucleotides (AZTTP, ddCTP, ddGTP, and 3TCTP) inhibited HIV-1 and HIV-2 RT synthesis less efficiently than they did with large amounts of Mg²⁺, whereas inhibition by the "translocation-defective RT inhibitor" EFdA (4'-ethynyl-2-fluoro-2'-deoxyadenosine) was unaffected by Mg²⁺ concentrations. Steady-state kinetic analyses revealed that the reduced level of inhibition at low Mg²⁺ concentrations resulted from a 3-9-fold (depending on the particular nucleotide and inhibitor) less efficient incorporation (based on k_cat/K_m) of these NRTIs under this condition compared to incorporation of natural dNTPs. In contrast, EFdATP was incorporated with an efficiency similar to that of its analogue dATP at low Mg²⁺ concentrations. Unlike NRTIs, NNRTIs (nevirapine, efavirenz, and rilviripine), were approximately 4-fold (based on IC₅₀ values) more effective at low than at high Mg²⁺ concentrations. Drug-resistant HIV-1 RT mutants also displayed the Mg²⁺-dependent difference in susceptibility to NRTIs and NNRTIs. In summary, analyzing the efficiency of inhibitors under more physiologically relevant low-Mg²⁺ conditions yielded results dramatically different from those from measurements using commonly employed high-Mg²⁺ in vitro conditions. These results also emphasize differences in Mg²⁺ sensitivity between the translocation inhibitor EFdATP and other NRTIs.

Free Energy-Based Virtual Screening and Optimization of RNase H Inhibitors of HIV-1 Reverse Transcriptase

We report the results of a binding free energy-based virtual screening campaign of a library of 77 α-hydroxytropolone derivatives against the challenging RNase H active site of the reverse transcriptase (RT) enzyme of human immunodeficiency virus-1. Multiple protonation states, rotamer states, and binding modalities of each compound were individually evaluated. The work involved more than 300 individual absolute alchemical binding free energy parallel molecular dynamics calculations and over 1 million CPU hours on national computing clusters and a local campus computational grid. The thermodynamic and structural measures obtained in this work rationalize a series of characteristics of this system useful for guiding future synthetic and biochemical efforts. The free energy model identified key ligand-dependent entropic and conformational reorganization processes difficult to capture using standard docking and scoring approaches. Binding free energy-based optimization of the lead compounds emerging from the virtual screen has yielded four compounds with very favorable binding properties, which will be the subject of further experimental investigations. This work is one of the few reported applications of advanced-binding free energy models to large-scale virtual screening and optimization projects. It further demonstrates that, with suitable algorithms and automation, advanced-binding free energy models can have a useful role in early-stage drug-discovery programs.

Nanodrug formulations to enhance HIV drug exposure in lymphoid tissues and cells: clinical significance and potential impact on treatment and eradication of HIV/AIDS

Although oral combination antiretroviral therapy effectively clears plasma HIV, patients on oral drugs exhibit much lower drug concentrations in lymph nodes than blood. This drug insufficiency is linked to residual HIV in cells of lymph nodes. While nanoformulations improve drug solubility, safety and delivery, most HIV nanoformulations are intended to extend plasma levels. A stable nanodrug combination that transports, delivers and accumulates in lymph nodes is needed to clear HIV in lymphoid tissues. This review discusses limitations of current oral combination antiretroviral therapy and advances in anti-HIV nanoformulations. A 'systems approach' has been proposed to overcome these limitations. This concept has been used to develop nanoformulations for overcoming drug insufficiency, extending cell and tissue exposure and clearing virus for treating HIV/AIDS.

227 Views of RNA: Is RNA Unique in Its Chemical Isomer Space?

Ribonucleic acid (RNA) is one of the two nucleic acids used by extant biochemistry and plays a central role as the intermediary carrier of genetic information in transcription and translation. If RNA was involved in the origin of life, it should have a facile prebiotic synthesis. A wide variety of such syntheses have been explored. However, to date no one-pot reaction has been shown capable of yielding RNA monomers from likely prebiotically abundant starting materials, though this does not rule out the possibility that simpler, more easily prebiotically accessible nucleic acids may have preceded RNA. Given structural constraints, such as the ability to form complementary base pairs and a linear covalent polymer, a variety of structural isomers of RNA could potentially function as genetic platforms. By using structure-generation software, all the potential structural isomers of the ribosides (BC5H9O4, where B is nucleobase), as well as a set of simpler minimal analogues derived from them, that can potentially serve as monomeric building blocks of nucleic acid-like molecules are enumerated. Molecules are selected based on their likely stability under biochemically relevant conditions (e.g., moderate pH and temperature) and the presence of at least two functional groups allowing the monomers to be incorporated into linear polymers. The resulting structures are then evaluated by using molecular descriptors typically applied in quantitative structure-property relationship (QSPR) studies and predicted physicochemical properties. Several databases have been queried to determine whether any of the computed isomers had been synthesized previously. Very few of the molecules that emerge from this structure set have been previously described. We conclude that ribonucleosides may have competed with a multitude of alternative structures whose potential proto-biochemical roles and abiotic syntheses remain to be explored.

Visualizing nucleic acid metabolism using non-natural nucleosides and nucleotide analogs

Nucleosides and their corresponding mono-, di-, and triphosphates play important roles in maintaining cellular homeostasis. In addition, perturbations in this homeostasis can result in dysfunctional cellular processes that cause pathological conditions such as cancer and autoimmune diseases. This review article discusses contemporary research areas applying nucleoside analogs to probe the mechanistic details underlying the complexities of nucleoside metabolism at the molecular and cellular levels. The first area describes classic and contemporary approaches used to quantify the activity of nucleoside transporters, an important class of membrane proteins that mediate the influx and efflux of nucleosides and nucleobases. A focal point of this section is describing how biophotonic nucleosides are replacing conventional assays employing radiolabeled substrates to study the mechanism of these proteins. The second section describes approaches to understand the utilization of nucleoside triphosphates by cellular DNA polymerases during DNA synthesis. Emphasis here is placed on describing how novel nucleoside analogs such as 5-ethynyl-2'-deoxyuridine are being used to quantify DNA synthesis during normal replication as well as during the replication of damaged DNA. In both sections, seminal research articles relevant to these areas are described to highlight how these novel probes are improving our understanding of these biological processes. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions.

Synthesis and antiviral evaluation of 2-amino-6-carbamoylpurine dioxolane nucleoside derivatives and their phosphoramidates prodrugs

The synthesis of 9-(β-d-1,3-dioxolan-4-yl)2,6-diaminopurine nucleoside phosphoramidate prodrugs as well as various 2-amino-6-carbamoylpurine dioxolane derivatives and their phosphoramidates prodrugs is reported. Their ability to block HIV and HBV replication along with their cytotoxicity toward HepG2, human lymphocyte, CEM and Vero cells was also assessed.

Development of a population simulation model for HIV monotherapy virological outcomes using lamivudine

Current highly active antiretroviral therapy (HAART) requires the use of combinations of three drugs to minimize the early emergence of drug-resistant HIV strains. Therefore, long-term monotherapy data with new agents are unavailable. However, the development of computer models for Monte-Carlo-type simulations of antiviral monotherapy, which incorporate HIV infection dynamic distributions from previously studied populations, together with pharmacokinetics and pharmacodynamic parameters of the new agent, could serve as an important tool. The nucleoside lamivudine (3TC) was used as a representative drug to standardize an improved pharmacodynamic and infection dynamic monotherapy model. 3TC plasma concentration versus time profiles was used to drive the cellular accumulation of 3TC-triphosphate (TP) in primary human lymphocytes in the model, over a 16 week period. The fraction of HIV reverse transcription inhibited was calculated using the median inhibitory concentration and intracellular 3TC-TP levels. Virus loads and activated CD4+ T-cell counts were generated for 2,200 theoretical individuals and compared with the outcomes of an actual 3TC monotherapy trial at the same dose. Pharmacokinetic variance alone did not account for the interindividual HIV-load variability. However, selection of appropriate distributions of the various pharmacokinetic and infection dynamics parameters produced a similar range of virus load reductions to actual observations. Therefore, once parameter and variance distributions are standardized, this modelling approach could be helpful in planning clinical trials and predicting the antiviral contribution of each agent in a HAART modality.

Nucleoside Analogue-Sparing Strategy for the Treatment of Chronic HIV Infection: Potential Interest and Clinical Experience

Nucleoside analogue-sparing antiretroviral combinations may be interesting as first-line therapies as they spare a complete class of drugs that will remain fully active for later use and prevent the risk of mitochondrial toxicity related to exposure to nucleoside reverse transcriptase inhibitors (NRTIs). This strategy is also used in patients failing NRTIs with cross-resistance to compounds in this class. Different combinations of antiretroviral drugs are theoretically available. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) associated with protease inhibitor (PI) and boosted double-PI combinations have been studied through small, non-comparative clinical studies and preliminary results suggest that they are efficient and often well-tolerated. However, NNRTIs and PIs are extensively metabolized in the liver through cytochrome P450, leading to pharmacokinetic interactions; a good knowledge of the interactions between NNRTIs and PIs, or between PIs, is helpful in assisting physicians in clinical practice in choosing drugs and doses. Access to a therapeutic drug monitoring service to confirm that appropriate drug exposures are achieved is useful when using such regimens. Some negative kinetic interactions may lead to complicated combinations with a high pill burden that reduces their applicability. Gastrointestinal toxicity often remains a limiting factor in the use of boosted double-PI combinations. Non-comparative studies have allowed selection of NRTI-sparing options that now need to be compared with the current standard of care in comparative clinical trials before being considered as valuable options. Other NRTI-sparing therapeutic strategies are emerging: PI monotherapy with lopinavir/ritonavir has been evaluated in a small group of naive patients and appears promising. Drugs belonging to new classes currently under investigation, such as entry inhibitors, might be included early in the antiretroviral treatment of patients as soon as compounds with a convenient route of administration are available, increasing the number of therapeutic combinations without NRTIs.