We designed, synthesized, and characterized a novel nucleoside analog, (1
,3
,5
)-3-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-5-hydroxy-1-(hydroxymethyl)-2-methylene-cyclopentanecarbonitrile, or ...4'-cyano-methylenecarbocyclic-2'-deoxyguanosine (CMCdG), and evaluated its anti-hepatitis B virus (anti-HBV) activity, safety, and related features. CMCdG's
activity was determined using quantitative PCR and Southern blotting assays, and its cytotoxicity was determined with a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, while its
activity and safety were determined in human liver-chimeric mice infected with wild-type HBV genotype Ce (HBV
) and an entecavir (ETV)-resistant HBV variant containing the amino acid substitutions L180M, S202G, and M204V (HBV
). CMCdG potently inhibited HBV production in HepG2.2.15 cells (50% inhibitory concentration IC
, ∼30 nM) and HBV
plasmid-transfected Huh7 cells (IC
, 206 nM) and efficiently suppressed ETV-resistant HBV
(IC
, 2,657 nM), while it showed no or little cytotoxicity (50% cytotoxic concentration, >500 μM in most hepatocytic cells examined). Two-week peroral administration of CMCdG (1 mg/kg of body weight/day once a day q.d.) to HBV
-infected human liver-chimeric mice reduced the level of viremia by ∼2 logs. CMCdG also reduced the level of HBV
viremia by ∼1 log in HBV
-infected human liver-chimeric mice, while ETV (1 mg/kg/day q.d.) completely failed to reduce the viremia. None of the CMCdG-treated mice had significant drug-related changes in body weights or serum human albumin levels. Structural analyses using homology modeling, semiempirical quantum methods, and molecular dynamics revealed that although ETV triphosphate (TP) forms good van der Waals contacts with L180 and M204 of HBV
reverse transcriptase (RT), its contacts with the M180 substitution are totally lost in the HBV
RT complex. However, CMCdG-TP retains good contacts with both the HBV
RT and HBV
RT complexes. The present data warrant further studies toward the development of CMCdG as a potential therapeutic for patients infected with drug-resistant HBV and shed light on the further development of more potent and safer anti-HBV agents.
To evaluate the efficacy, safety and virologic resistance profile of etravirine (TMC125), a next-generation nonnucleoside reverse transcriptase inhibitor, over 48 weeks in treatment-experienced ...adults infected with HIV-1 strains resistant to a nonnucleoside reverse transcriptase inhibitor and other antiretrovirals.
DUET-1 (NCT00254046) and DUET-2 (NCT00255099) are two identically designed, randomized, double-blind phase III trials.
Patients received twice-daily etravirine 200 mg or placebo, each plus a background regimen of darunavir/ritonavir, investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors and optional enfuvirtide. Eligible patients had documented nonnucleoside reverse transcriptase inhibitor resistance, at least three primary protease inhibitor mutations at screening and were on a stable but virologically failing regimen for at least 8 weeks, with plasma viral load more than 5000 copies/ml. Pooled 48-week data from the two trials are presented.
Patients (1203) were randomized and treated (n = 599, etravirine; n = 604, placebo). Significantly more patients in the etravirine than in the placebo group achieved viral load less than 50 copies/ml at week 48 (61 vs. 40%, respectively; P < 0.0001). Significantly fewer patients in the etravirine group experienced at least one confirmed or probable AIDS-defining illness/death (6 vs. 10%; P = 0.0408). Safety and tolerability in the etravirine group was comparable to the placebo group. Rash was the only adverse event to occur at a significantly higher incidence in the etravirine group (19 vs. 11%, respectively, P < 0.0001), occurring primarily in the second week of treatment.
At 48 weeks, treatment-experienced patients receiving etravirine plus background regimen had statistically superior and durable virologic responses (viral load less than 50 copies/ml) than those receiving placebo plus background regimen, with comparable tolerability and no new safety signals reported since week 24.
Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor used in first-line combination antiretroviral therapy (cART). It is usually administered with nucleoside reverse transcriptase ...inhibitors (NRTI), many of which are substrates of OCT uptake solute carriers (SLC22A) and MATE (SLC47A), P-gp (MDR1, ABCB1), BCRP (ABCG2), or MRP2 (ABCC2) efflux transporters. The aim of this study was to evaluate the inhibitory potential of efavirenz towards these transporters and investigate its effects on the pharmacokinetics and tissue distribution of a known Oct/Mate substrate, lamivudine, in rats. Accumulation and transport assays showed that efavirenz inhibits the uptake of metformin by OCT1-, OCT2- and MATE1-expressing MDCK cells and reduces transcellular transport of lamivudine across OCT1/OCT2- and MATE1-expressing MDCK monolayers. Only negligible inhibition of MATE2-K was observed in HEK-MATE2-K cells. Efavirenz also reduced the efflux of calcein from MDCK-MRP2 cells, but had a rather weak inhibitory effect on Hoechst 33342 accumulation in MDCK-MDR1 and MDCK-BCRP cells. An in vivo pharmacokinetic interaction study in male Wistar rats revealed that intravenous injection of efavirenz or the control Oct/Mate inhibitor cimetidine significantly reduced the recovery of lamivudine in urine and greatly increased lamivudine retention in the renal tissue. Co-administration with efavirenz or cimetidine also increased the AUC0-∞ value and reduced total body clearance of lamivudine. These data suggest that efavirenz is a potent inhibitor of OCT/Oct and MATE/Mate transporters. Consequently, it can engage in drug-drug interactions that reduce renal excretion of co-administered substrates and enhance their retention in the kidneys, potentially compromising therapeutic safety.
The human T-lymphotropic virus type 1 (HTLV-1) infects millions of people globally and is endemic to various resource-limited regions. Infections persist for life and are associated with increased ...susceptibility to opportunistic infections and severe diseases including adult T cell leukemia/lymphoma and HTLV-1-associated myelopathy-tropical spastic paraparesis. No HTLV-1-specific anti-retrovirals have been developed and it is unclear whether existing anti-retrovirals developed for treatment of human immunodeficiency virus (HIV) have efficacy against HTLV-1. To understand the structural basis for therapeutic binding, homology modelling and machine learning were used to develop a structural model of the HTLV-1 reverse transcriptase. With this, molecular docking experiments using a panel of FDA-approved inhibitors of viral reverse transcriptases to assess their capacity for binding, and in turn, inhibition. Importantly, nucleoside/nucleotide reverse transcriptase inhibitor but not non-nucleoside reverse transcriptase inhibitors were predicted to bind the HTLV-1 reverse transcriptase, with similar affinity to HIV-1 reverse transcriptase. By strengthening the rationale for clinical testing of therapies such as tenofovir alafenamide, zidovudine, lamivudine, and azvudine for treatment of HTLV-1, this study has demonstrated the power of in silico structural biology approaches in drug design and therapeutic testing.
Tenofovir (TFV) is the active form of the prodrugs tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), both clinically prescribed as HIV reverse transcriptase inhibitors. The ...biophysical interactions between these compounds and human serum albumin (HSA), the primary carrier of exogenous compounds in the human bloodstream, have not yet been thoroughly characterized. Thus, the present study reports the interaction profile between HSA and TFV, TDF, and TAF via UV-Vis, steady-state, and time-resolved fluorescence techniques combined with isothermal titration calorimetry (ITC) and in silico calculations. A spontaneous interaction in the ground state, which does not perturb the microenvironment close to the Trp-214 residue, is classified as weak. In the case of HSA/TFV and HSA/TDF, the binding is both enthalpically and entropically driven, while for HSA/TAF, the binding is only entropically dominated. The binding constant (
) and thermodynamic parameters obtained via ITC assays agree with those obtained using steady-state fluorescence quenching measurements, reinforcing the reliability of the data. The small internal cavity known as site I is probably the main binding pocket for TFV due to the low steric volume of the drug. In contrast, most external sites (II and III) can better accommodate TAF due to the high steric volume of this prodrug. The cross-docking approach corroborated experimental drug-displacement assays, indicating that the binding affinity of TFV and TAF might be impacted by the presence of different compounds bound to albumin. Overall, the weak binding capacity of albumin to TFV, TDF, and TAF is one of the main factors for the low residence time of these antiretrovirals in the human bloodstream; however, positive cooperativity for TAF and TDF was detected in the presence of some drugs, which might improve their residence time (pharmacokinetic profile).
Justicia gendarussa, a medicinal plant collected in Vietnam, was identified as a potent anti-HIV-1 active lead from the evaluation of over 4500 plant extracts. Bioassay-guided separation of the ...extracts of the stems and roots of this plant led to the isolation of an anti-HIV arylnaphthalene lignan (ANL) glycoside, patentiflorin A (1). Evaluation of the compound against both the M- and T-tropic HIV-1 isolates showed it to possess a significantly higher inhibition effect than the clinically used anti-HIV drug AZT. Patentiflorin A and two congeners were synthesized, de novo, as an efficient strategy for resupply as well as for further structural modification of the anti-HIV ANL glycosides in the search for drug leads. Subsequently, it was determined that the presence of a quinovopyranosyloxy group in the structure is likely essential to retain the high degree of anti-HIV activity of this type of compounds. Patentiflorin A was further investigated against the HIV-1 gene expression of the R/U5 and U5/gag transcripts, and the data showed that the compound acts as a potential inhibitor of HIV-1 reverse transcription. Importantly, the compound displayed potent inhibitory activity against drug-resistant HIV-1 isolates of both the nucleotide analogue (AZT) and non-nucleotide analogue (nevaripine). Thus, the ANL glycosides have the potential to be developed as novel anti-HIV drugs.
Objectives
The aim of the review was to elucidate the adverse effects of chronic treatment with the main subclasses of highly active antiretroviral therapy (HAART).
Methods
A systematic review was ...carried out using the methods recommended in the Preferred Reporting Items for Systematic Review and Meta‐analysis Protocols (PRISMA‐P). Searches of articles in MEDLINE, SCIELO, Web of Science and LILACS were conducted from January to October 2018 based on the following descriptors and keywords: ‘HIV’ AND; ‘AIDS’ OR; ‘HAART’ AND; ‘Highly Active Antiretroviral Therapy’ OR; ‘Adverse Effects’ AND. All articles selected described the biochemical changes produced by, and the main adverse effects of, using one or more of the following HAART subclasses: nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and other new drugs. The selected articles included patients living with HIV (PLWH) initiating or continuing any type of HAART. The results are presented qualitatively and discussed.
Results
Twenty‐one articles found in the searches were selected for the review, and they included a total of 5626 participants. Seven of the studies investigated mainly NRTIs, three studies mainly NNRTIs, eight studies predominantly PIs, and three studies other antiretroviral drugs as the main treatment. The most common adverse effects on biochemical parameters were the emergence of anaemia for NRTIs as well as NNRTIs and PIs, and plasma lipid alterations caused by their prolonged use. In general, it was found that biological differences among individuals can cause differences in adverse effects, such as virological and treatment failure.
Conclusions
One or more occurrences of adverse effects of the chronic utilization of drugs were found for all subclasses of HAART, and certain combinations of drugs from different subclasses were also found to be associated with adverse events.
Efavirenz is a highly effective HIV-1 antiretroviral; however, it is also frequently associated with neuropsychiatric adverse events (NPAE) that include abnormal dreams, sleep disturbances, ...nervousness, anxiety, depression, and dizziness. The incidence of NPAEs upon initiation of treatment with efavirenz-containing medications is high, exceeding 50% in most studies. Although the NPAEs tend to decrease after the first month in many patients, they persist for long periods of time in others. Efavirenz-based treatment is generally well-tolerated in children, although some experience persistent concentration problems, as well as sleep disturbances, psychotic reactions, and seizures. In an effort to link basic with clinical research, parameters associated with efavirenz brain exposure are discussed, and factors that increase efavirenz levels are explored in depth as they are expected to contribute to NPAE risk. These include the role of modifiable and nonmodifiable risk factors such as diet, weight, and drug-drug interactions and sex, age, and ethnicity/pharmacogenetics. In addition to NPAEs, this review explores what is known about antiretroviral (ARV) drugs being used for recreational purposes. Although multiple ARV drugs are covered, special attention is devoted to efavirenz given that the majority of reports of NPAEs and illicit use of ARV drugs concern efavirenz. The evolving molecular mechanistic basis of NPAEs and abuse of efavirenz point to a complex and polymodal receptor pharmacology. Animal studies to date primarily point to a serotonergic mechanism of action. Recently emerging associations between HIV-associated neurocognitive disorder and efavirenz use, and possible contributions of the mitochondrial-immune-inflammatory-redox cascade are explored in the context of the signaling mechanisms that appear to be involved.
HIV is the causative agent of Acquired Immunodeficiency Syndrome (AIDS), an infectious disease with increasing incidence worldwide. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) play an ...important role in the treatment of AIDS. Although, many compounds are already being used as anti-HIV drugs, research for the development of new inhibitors continues as the virus develops resistant strains.
The best features of available NNRTIs were taken into account for the design of novel inhibitors. PASS (Prediction of activity spectra for substances) prediction program and molecular docking studies for the selection of designed compounds were used for the synthesis. Compounds were synthesized using conventional and microwave irradiation methods and HIV RT inhibitory action was evaluated by colorimetric photometric immunoassay.
The evaluation of HIV-1 RT inhibitory activity revealed that seven compounds have significantly lower ΙC
values than nevirapine (0.3 μΜ). It was observed that the activity of compounds depends not only on the nature of substituent and it position in benzothiazole ring but also on the nature and position of substituents in benzene ring.
Twenty four of the tested compounds exhibited inhibitory action lower than 4 μΜ. Seven of them showed better activity than nevirapine, while three of the compounds exhibited IC
values lower than 5 nM. Two compounds 9 and 10 exhibited very good inhibitory activity with IC50 1 nM.
ABSTRACT
The retrovirus HIV‐1 has been a major health issue since its discovery in the early 80s. In 2017, over 37 million people were infected with HIV‐1, of which 1.8 million were new infections ...that year. Currently, the most successful treatment regimen is the highly active antiretroviral therapy (HAART), which consists of a combination of three to four of the current 26 FDA‐approved HIV‐1 drugs. Half of these drugs target the reverse transcriptase (RT) enzyme that is essential for viral replication. One class of RT inhibitors is nucleoside reverse transcriptase inhibitors (NRTIs), a crucial component of the HAART. Once incorporated into DNA, NRTIs function as a chain terminator to stop viral DNA replication. Unfortunately, treatment with NRTIs is sometimes linked to toxicity caused by off‐target side effects. NRTIs may also target the replicative human mitochondrial DNA polymerase (Pol γ), causing long‐term severe drug toxicity. The goal of this work is to understand the discrimination mechanism of different NRTI analogues by RT. Crystal structures and kinetic experiments are essential for the rational design of new molecules that are able to bind selectively to RT and not Pol γ. Structural comparison of NRTI‐binding modes with both RT and Pol γ enzymes highlights key amino acids that are responsible for the difference in affinity of these drugs to their targets. Therefore, the long‐term goal of this research is to develop safer, next generation therapeutics that can overcome off‐target toxicity.
PDB Code(s): 6OR7, 6OTZ, 6OUN, 6P2G, 6P1X, 6P1I
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