Preclinical characterization of a non-peptidomimetic HIV protease inhibitor with improved metabolic stability.

Protease inhibitors (PIs) remain an important component of antiretroviral therapy for the treatment of HIV-1 infection due to their high genetic barrier to resistance development. Nevertheless, the two most commonly prescribed HIV PIs, atazanavir and darunavir, still require co-administration with a pharmacokinetic boosting agent to maintain sufficient drug plasma levels which can lead to undesirable drug-drug interactions. Herein, we describe GS-9770, a novel investigational non-peptidomimetic HIV PI with unboosted once-daily oral dosing potential due to improvements in its metabolic stability and its pharmacokinetic properties in preclinical animal species. This compound demonstrates potent inhibitory activity and high on-target selectivity for recombinant HIV-1 protease versus other aspartic proteases tested. In cell culture, GS-9770 inhibits Gag polyprotein cleavage and shows nanomolar anti-HIV-1 potency in primary human cells permissive to HIV-1 infection and against a broad range of HIV subtypes. GS-9770 demonstrates an improved resistance profile against a panel of patient-derived HIV-1 isolates with resistance to atazanavir and darunavir. In resistance selection experiments, GS-9770 prevented the emergence of breakthrough HIV-1 variants at all fixed drug concentrations tested and required multiple protease substitutions to enable outgrowth of virus exposed to escalating concentrations of GS-9770. This compound also remained fully active against viruses resistant to drugs from other antiviral classes and showed no in vitro antagonism when combined pairwise with drugs from other antiretroviral classes. Collectively, these preclinical data identify GS-9770 as a potent, non-peptidomimetic once-daily oral HIV PI with potential to overcome the persistent requirement for pharmacological boosting with this class of antiretroviral agents.

FMO-guided design of darunavir analogs as HIV-1 protease inhibitors.

The prevalence of HIV-1 infection continues to pose a significant global public health issue, highlighting the need for antiretroviral drugs that target viral proteins to reduce viral replication. One such target is HIV-1 protease (PR), responsible for cleaving viral polyproteins, leading to the maturation of viral proteins. While darunavir (DRV) is a potent HIV-1 PR inhibitor, drug resistance can arise due to mutations in HIV-1 PR. To address this issue, we developed a novel approach using the fragment molecular orbital (FMO) method and structure-based drug design to create DRV analogs. Using combinatorial programming, we generated novel analogs freely accessible via an on-the-cloud mode implemented in Google Colab, Combined Analog generator Tool (CAT). The designed analogs underwent cascade screening through molecular docking with HIV-1 PR wild-type and major mutations at the active site. Molecular dynamics (MD) simulations confirmed the assess ligand binding and susceptibility of screened designed analogs. Our findings indicate that the three designed analogs guided by FMO, 19-0-14-3, 19-8-10-0, and 19-8-14-3, are superior to DRV and have the potential to serve as efficient PR inhibitors. These findings demonstrate the effectiveness of our approach and its potential to be used in further studies for developing new antiretroviral drugs.

Enteral administration of crushed rilpivirine in a patient with HIV: A case report.

Antiretroviral therapy administration is challenging in patients with HIV requiring enteral nutrition. There are limited pharmacokinetic data available regarding the absorption of crushed rilpivirine (RPV) and its impact on drug bioavailability, plasma concentrations and, consequently, the efficacy of treatment. We present the case of a 60-year-old woman with HIV diagnosed with squamous cell carcinoma who needed enteral administration of antiretroviral therapy following the insertion of a gastrotomy tube in September 2018. Initially, the patient was treated with a daily dose of RPV 25 mg, dolutegravir 50 mg and emtricitabine 200 mg. The treatment was later intensified with darunavir boosted with ritonavir. RPV and dolutegravir were crushed, dissolved in water and administered via a percutaneous endoscopic gastrostomy tube. Therapeutic drug and viral load monitoring determined the adequacy of enteral antiretroviral dosing. RPV plasma concentrations remained within the expected therapeutic range of 43-117 ng/mL, with only 1 below the currently used 50 ng/mL efficacy threshold. After the treatment intensification with darunavir boosted with ritonavir, the patient achieved an undetectable viral load. While we observed satisfactory RPV plasma concentrations, it is essential to maintain strict monitoring of administration method, plasma concentrations and virological responses when initiating treatment with crushed RPV. Hence, additional pharmacokinetic data are necessary to ensure the effective enteral administration of RPV and to establish the best antiretroviral dosing regimens.

Identification of Darunavir Derivatives for Inhibition of SARS-CoV-2 3CLpro.

The effective antiviral agents that treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed around the world. The 3C-like protease (3CLpro) of SARS-CoV-2 plays a pivotal role in virus replication; it also has become an important therapeutic target for the infection of SARS-CoV-2. In this work, we have identified Darunavir derivatives that inhibit the 3CLpro through a high-throughput screening method based on a fluorescence resonance energy transfer (FRET) assay in vitro. We found that the compounds 29# and 50# containing polyphenol and caffeine derivatives as the P2 ligand, respectively, exhibited favorable anti-3CLpro potency with EC50 values of 6.3 µM and 3.5 µM and were shown to bind to SARS-CoV-2 3CLpro in vitro. Moreover, we analyzed the binding mode of the DRV in the 3CLpro through molecular docking. Importantly, 29# and 50# exhibited a similar activity against the protease in Omicron variants. The inhibitory effect of compounds 29# and 50# on the SARS-CoV-2 3CLpro warrants that they are worth being the template to design functionally improved inhibitors for the treatment of COVID-19.

Beyond darunavir: recent development of next generation HIV-1 protease inhibitors to combat drug resistance.

We report our recent development of a conceptually new generation of exceptionally potent non-peptidic HIV-1 protease inhibitors that displayed excellent pharmacological and drug-resistance profiles. Our X-ray structural studies of darunavir and other designed inhibitors from our laboratories led us to create a variety of inhibitors incorporating fused ring polycyclic ethers and aromatic heterocycles to promote hydrogen bonding interactions with the backbone atoms of HIV-1 protease as well as van der Waals interactions with residues in the S2 and S2' subsites. We have also incorporated specific functionalities to enhance van der Waals interactions in the S1 and S1' subsites. The combined effects of these structural templates are critical to the inhibitors' exceptional potency and drug-like properties. We highlight here our molecular design strategies to promote backbone hydrogen bonding interactions to combat drug-resistance and specific design of polycyclic ether templates to mimic peptide-like bonds in the HIV-1 protease active site. Our medicinal chemistry and drug development efforts led to the development of new generation inhibitors significantly improved over darunavir and displaying unprecedented antiviral activity against multidrug-resistant HIV-1 variants.

Two Novel Precursors of the HIV-1 Protease Inhibitor Darunavir Target the UPR/Proteasome System in Human Hepatocellular Carcinoma Cell Line HepG2.

Background: Several pre-clinical and clinical reports suggest that HIV-1 protease inhibitors, in addition to the antiretroviral properties, possess pleiotropic pharmacological effects including anticancer action. Therefore, we investigated the pro-apoptotic activity in tumor cells of two molecules, RDD-19 and RDD-142, which are hydroxyethylamine derivatives' precursors of darunavir and several HIV-1 protease inhibitors. Methods: Three hepatoma cell lines and one non-pathological cell line were treated with RDD-19 and RDD-142, and cell viability was assessed. The expression levels of several markers for ER stress, autophagy, cellular ubiquitination, and Akt activation were quantified in HepG2 cells treated with RDD-19 and RDD-142 to evaluate apoptotic and non-apoptotic cell death. Results: RDD-19 and RDD-142 showed a greater dose-dependent cytotoxicity towards the hepatic tumor cell line HepG2 compared to the non-pathological hepatic cell line IHH. Both molecules caused two types of cell death, a caspase-dependent apoptosis, which was ascertained by a series of biochemical and morphological assays, and a caspase-independent death that was characterized by the induction of ER stress and autophagy. The strong increase of ubiquitinated proteins inside the cells suggested that the target of these molecules could be the proteasome and in silico molecular docking analysis that was used to support the plausibility of this hypothesis. Furthermore, cells treated with the two compounds displayed decreased levels of p-AKT, which interferes with cell survival and proliferation. Conclusions: These findings demonstrate that two compounds, RDD-19 and RDD-142, have pleiotropic effects and that they may represent promising anticancer candidates.

Inhibiting HTLV-1 Protease: A Viable Antiviral Target.

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that can cause severe paralytic neurologic disease and immune disorders as well as cancer. An estimated 20 million people worldwide are infected with HTLV-1, with prevalence reaching 30% in some parts of the world. In stark contrast to HIV-1, no direct acting antivirals (DAAs) exist against HTLV-1. The aspartyl protease of HTLV-1 is a dimer similar to that of HIV-1 and processes the viral polyprotein to permit viral maturation. We report that the FDA-approved HIV-1 protease inhibitor darunavir (DRV) inhibits the enzyme with 0.8 µM potency and provides a scaffold for drug design against HTLV-1. Analogs of DRV that we designed and synthesized achieved submicromolar inhibition against HTLV-1 protease and inhibited Gag processing in viral maturation assays and in a chronically HTLV-1 infected cell line. Cocrystal structures of these inhibitors with HTLV-1 protease highlight opportunities for future inhibitor design. Our results show promise toward developing highly potent HTLV-1 protease inhibitors as therapeutic agents against HTLV-1 infections.

Darunavir: A comprehensive profile.

Darunavir: (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl [(2S,3R)-4-{[(4-aminophenyl)sulfonyl] (isobutyl)amino}-3-hydroxy-1-phenyl-2-butanyl]carbamate is a synthetic non-peptide protease inhibitor. On June 2006, it was first approved by the Food and Drug administration (FDA) for treatment of resistant type-1 of the human immunodeficiency virus (HIV). In July 2016, the FDA expanded the approval for use of darunavir in pregnant women with HIV infection. Darunavir prevents the replication of HIV virus by inhibiting the catalytic activity of the HIV-1 protease enzyme, and selectively inhibits the cleavage of HIV encoded Gag-Pol polyproteins in virus-infected cells, which prevents the formation of mature infectious virus particles. Darunavir is unique among currently available protease inhibitors because it maintains antiretroviral activity against a variety of multidrug-resistant HIV strains. This article discusses, by a critical extensive review of the literature, the description of darunavir in terms of its names, formulae, elemental composition, appearance, and use in the treatment of HIV-infected patients. The article also discusses the methods for preparation of darunavir, its physical-chemical properties, analytical methods for its determination, pharmacological properties, and dosing information.

Darunavir-Resistant HIV-1 Protease Constructs Uphold a Conformational Selection Hypothesis for Drug Resistance.

Multidrug resistance continues to be a barrier to the effectiveness of highly active antiretroviral therapy in the treatment of human immunodeficiency virus 1 (HIV-1) infection. Darunavir (DRV) is a highly potent protease inhibitor (PI) that is oftentimes effective when drug resistance has emerged against first-generation inhibitors. Resistance to darunavir does evolve and requires 10-20 amino acid substitutions. The conformational landscapes of six highly characterized HIV-1 protease (PR) constructs that harbor up to 19 DRV-associated mutations were characterized by distance measurements with pulsed electron double resonance (PELDOR) paramagnetic resonance spectroscopy, namely double electron-electron resonance (DEER). The results show that the accumulated substitutions alter the conformational landscape compared to PI-naïve protease where the semi-open conformation is destabilized as the dominant population with open-like states becoming prevalent in many cases. A linear correlation is found between values of the DRV inhibition parameter Ki and the open-like to closed-state population ratio determined from DEER. The nearly 50% decrease in occupancy of the semi-open conformation is associated with reduced enzymatic activity, characterized previously in the literature.

Drug binding dynamics of the dimeric SARS-CoV-2 main protease, determined by molecular dynamics simulation.

We performed molecular dynamics simulation of the dimeric SARS-CoV-2 (severe acute respiratory syndrome corona virus 2) main protease (Mpro) to examine the binding dynamics of small molecular ligands. Seven HIV inhibitors, darunavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir, were used as the potential lead drugs to investigate access to the drug binding sites in Mpro. The frequently accessed sites on Mpro were classified based on contacts between the ligands and the protein, and the differences in site distributions of the encounter complex were observed among the ligands. All seven ligands showed binding to the active site at least twice in 28 simulations of 200 ns each. We further investigated the variations in the complex structure of the active site with the ligands, using microsecond order simulations. Results revealed a wide variation in the shapes of the binding sites and binding poses of the ligands. Additionally, the C-terminal region of the other chain often interacted with the ligands and the active site. Collectively, these findings indicate the importance of dynamic sampling of protein-ligand complexes and suggest the possibilities of further drug optimisations.

Computational Determination of Potential Inhibitors of SARS-CoV-2 Main Protease.

The novel coronavirus (SARS-CoV-2) has infected several million people and caused thousands of deaths worldwide since December 2019. As the disease is spreading rapidly all over the world, it is urgent to find effective drugs to treat the virus. The main protease (Mpro) of SARS-CoV-2 is one of the potential drug targets. Therefore, in this context, we used rigorous computational methods, including molecular docking, fast pulling of ligand (FPL), and free energy perturbation (FEP), to investigate potential inhibitors of SARS-CoV-2 Mpro. We first tested our approach with three reported inhibitors of SARS-CoV-2 Mpro, and our computational results are in good agreement with the respective experimental data. Subsequently, we applied our approach on a database of ∼4600 natural compounds, as well as 8 available HIV-1 protease (PR) inhibitors and an aza-peptide epoxide. Molecular docking resulted in a short list of 35 natural compounds, which was subsequently refined using the FPL scheme. FPL simulations resulted in five potential inhibitors, including three natural compounds and two available HIV-1 PR inhibitors. Finally, FEP, the most accurate and precise method, was used to determine the absolute binding free energy of these five compounds. FEP results indicate that two natural compounds, cannabisin A and isoacteoside, and an HIV-1 PR inhibitor, darunavir, exhibit a large binding free energy to SARS-CoV-2 Mpro, which is larger than that of 13b, the most reliable SARS-CoV-2 Mpro inhibitor recently reported. The binding free energy largely arises from van der Waals interaction. We also found that Glu166 forms H-bonds to all of the inhibitors. Replacing Glu166 by an alanine residue leads to ∼2.0 kcal/mol decreases in the affinity of darunavir to SARS-CoV-2 Mpro. Our results could contribute to the development of potential drugs inhibiting SARS-CoV-2.

An in silico pharmacological approach toward the discovery of potent inhibitors to combat drug resistance HIV-1 protease variants.

Protease inhibitors (PIs) are crucial drugs in highly active antiretroviral therapy for human immunodeficiency virus-1 (HIV-1) infections. However, resistance owing to mutations challenge the long-term efficacy in the medication of HIV-1-infected individuals. Lopinavir (LPV) and darunavir (DRV), two second-generation drugs are the most potent among PIs, hustling the drug resistance when mutations occur in the active and nonactive site of the protease (PR). Herein, we strive for compounds that can stifle the function of wild-type (WT) HIV-1 PR along with four major single mutants (I54M, V82T, I84V, and L90M) instigating resistance to the PIs using in silico approach. Six common compounds are retrieved from six databases using combined pharmacophore-based and structure-based virtual screening methodology. LPV and DRV are docked and the binding free energy is calculated to set the cut-off value for selecting compounds. Further, to gain insight into the stability of the complexes the molecular dynamics simulation (MDS) is carried out, which uncovers two lead molecules namely NCI-524545 and ZINC12866729. Both the lead molecules connect with WT and mutant HIV-1 PRs through strong and stable hydrogen bond interactions when compared with LPV and DRV throughout the trajectory analysis. Interestingly, NCI-524545 and ZINC12866729 exhibit direct interactions with I50/50' by replacing the conserved water molecule as evidenced by MDS, which indicates the credible potency of these compounds. Hence, we concluded that NCI-524545 and ZINC12866729 have great puissant to restrain the role of drug resistance HIV-1 PR variants, which can also show better activity through in vivo and in vitro conditions.

Double trouble? Gag in conjunction with double insert in HIV protease contributes to reduced DRV susceptibility.

HIV protease is essential for processing the Gag polyprotein to produce infectious virions and is a major target in antiretroviral therapy. We have identified an unusual HIV-1 subtype C variant that contains insertions of leucine and asparagine (L38↑N↑L) in the hinge region of protease at position 38. This was isolated from a protease inhibitor naïve infant. Isothermal titration calorimetry showed that 10% less of L38↑N↑L protease was in the active conformation as compared with a reference strain. L38↑N↑L protease displayed a ±50% reduction in KM and kcat The catalytic efficiency (kcat/KM) of L38↑N↑L protease was not significantly different from that of wild type although there was a 42% reduction in specific activity for the variant. An in vitro phenotypic assay showed the L38↑N↑L protease to be susceptible to lopinavir (LPV), atazanavir (ATV) and darunavir in the context of an unrelated Gag. However, in the presence of the related Gag, L38↑N↑L showed reduced susceptibility to darunavir while remaining susceptible to LPV and ATV. Furthermore, a reduction in viral replication capacity (RC) was observed in combination with the related Gag. The reduced susceptibility to darunavir and decrease in RC may be due to PTAPP duplication in the related Gag. The present study shows the importance of considering the Gag region when looking at drug susceptibility of HIV-1 protease variants.

Darunavir-cobicistat-emtricitabine-tenofovir alafenamide: safety and efficacy of a protease inhibitor in the modern era.

A fixed-dose combination consisting of darunavir (Drv), cobicistat (Cobi), emtricitabine (2',3'-dideoxy-5-fluoro-3'-thiacytidine [FTC]), and tenofovir alafenamide (Taf) has been recently approved by the European Medicines Agency for the treatment of HIV infection, and is the first ever protease-inhibitor-based single-tablet regimen. This article provides a detailed description of its pharmacokinetic, efficacy, and safety profile. The pharmacokinetics of single compounds were analyzed, with a special focus on contrasts between Drv/Cobi and Drv/ritonavir (Rtv). When comparing Cobi and Rtv, multiple interactions must be taken into account: in comparison to Rtv, Cobi is a more selective CYP3A4 inhibitor and has no clinical effect on other isoenzymes inhibited by Rtv (eg, 2C8 and 2C9). Moreover, unlike Cobi, Rtv shows in vivo induction activity on some CYP isoenzymes (eg, 1A2, 2C19, 2C8, 2C9, and 2B6), glucuronyltransferases (eg, UGT1A4), and Pgp. Drv-Cobi-FTC-Taf has recently been demonstrated to be of equal efficacy to Drv-Rtv and other protease inhibitors in both experienced (EMERALD study) and naïve (AMBER study) patients. Moreover, kidney and bone safety profiles have been shown to be good, as has central nervous system tolerance. Total cholesterol:low-density-lipoprotein cholesterol and total cholesterol:high-density-lipoprotein cholesterol ratios are generally high in Drv-Cobi-FTC-Taf vs Rtv-Drv-FTC + tenofovir disoproxil fumarate. An unlikely role of Drv in influencing cardiovascular risk in HIV infection has also been reported. Kidney safety profile is influenced by Cobi, with an increase in creatinine plasma concentration of 0.05-0.1 mg/dL and a parallel glomerular filtration-rate reduction of 10 mL/min within the first 4 weeks after Cobi introduction, which remains stable during treatment. Bone and central nervous system safety profiles were found to be good in randomized clinical trials of both experienced and naïve patients. The efficacy and safety of Drv/Cobi/FTC/Taf are comparable to other drug regimens recommended for HIV treatment.

Blood Telomere Length Changes After Ritonavir-Boosted Darunavir Combined With Raltegravir or Tenofovir-Emtricitabine in Antiretroviral-Naive Adults Infected With HIV-1.

Background: Tenofovir is a potent inhibitor of human telomerase. The clinical relevance of this inhibition is unknown. Methods: NEAT001/ANRS143 is a randomized trial that showed noninferiority over 96 weeks of ritonavir-boosted darunavir plus raltegravir versus tenofovir disoproxil fumarate/emtricitabine in 805 antiretroviral antiretrovrial-naive HIV-infected adults. We compared changes in whole-blood telomere length measured with quantitative polymerase chain reaction in 201 randomly selected participants (104 raltegravir and 97 tenofovir disoproxil fumarate/emtricitabine). We performed multivariable estimative and predictive linear regression. Results: At week 96, participants receiving tenofovir disoproxil fumarate/emtricitabine had a statistically significant higher gain in telomere length than participants receiving raltegravir. Difference in mean telomere length change between groups (tenofovir disoproxil fumarate/emtricitabine minus raltegravir) from baseline to week 96 adjusted by baseline telomere length was 0.031 (P = .009). This difference was not significantly confounded by age, gender, known duration of HIV infection, CD4 (baseline/nadir), CD8 cells, CD4/CD8 ratio, HIV viral load (baseline/week 96), tobacco and alcohol consumption, statins, or hepatitis C. Conclusion: Antiretroviral-naive HIV-infected adults receiving ritonavir-boosted darunavir and tenofovir disoproxil fumarate/emtricitabine had a significant higher gain in blood telomere length than those receiving ritonavir-boosted darunavir and raltegravir, suggesting a better initial recovery from HIV-associated immunosenescence.

Darunavir alleviates irinotecan-induced intestinal toxicity in Vivo.

Irinotecan (CPT-11) is used to treat various cancers but side effects such as delayed diarrhea restrict its use. Darunavir (DRV) is an antiretroviral drug used to treat and prevent human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS), but whether DRV is protective against CPT-11-induced intestinal toxicity is unclear. An CPT-11-induced intestinal toxicity model was produced using uninterrupted CPT-11 (ip) for 4 d in mice. Enzyme-linked immuno sorbent assay (ELISA), fecal occult blood test (FOBT), Western blot, histopathological evaluation, and immunohistochemistry staining assays were used to document toxicity. DRV treatment attenuated CPT-11-induced intestinal toxicity via decreasing fecal occult blood and mitigating delayed-onset diarrhea, as well as reducing weight loss, reduced food intake, and pathomorphologic changes without inhibiting ß-glucuronidase (ß-GLU) activity. The high mobility group box-1 protein (HMGB1)-toll-like receptor 4 (TLR4) pathway induced inflammation and tight junction protein (occludin and zonular occluden-1) reduction in the colon was inhibited by DRV. Hepatotoxicity induced by CPT-11 was diminished after treatment with DRV, and activation of the NOD-like receptor 3 inflammasome (NLRP3) was prevented in colon tissue. In addition, DRV didn't reduce the concentration of CPT-11 and 7-ethyl-10-hydroxycamptothecin (SN-38) in plasma at the same dose of irinotecan with DRV. DRV has anti-inflammatory and intestinal-protective properties and may be used to manage CPT-11-induced intestinal toxicity.

GRL-079, a Novel HIV-1 Protease Inhibitor, Is Extremely Potent against Multidrug-Resistant HIV-1 Variants and Has a High Genetic Barrier against the Emergence of Resistant Variants.

We identified four novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs), GRL-078, -079, -077, and -058, containing an alkylamine at the C-5 position of P2 tetrahydropyrano-tetrahydrofuran (Tp-THF) and a P2' cyclopropyl (Cp) (or isopropyl)-aminobenzothiazole (Abt) moiety. Their 50% effective concentrations (EC50s) were 2.5 to 30 nM against wild-type HIV-1NL4-3, 0.3 to 6.7 nM against HIV-2EHO, and 0.9 to 90 nM against laboratory-selected PI-resistant HIV-1 and clinical HIV-1 variants resistant to multiple FDA-approved PIs (HIVMDR). GRL-078, -079, -077, and -058 also effectively blocked the replication of HIV-1 variants highly resistant to darunavir (DRV) (HIVDRVrp51), with EC50s of 38, 62, 61, and 90 nM, respectively, while four FDA-approved PIs examined (amprenavir, atazanavir, lopinavir [LPV], and DRV) had virtually no activity (EC50s of >1,000 nM) against HIVDRVrp51 Structurally, GRL-078, -079, and -058 form strong hydrogen bond interactions between Tp-THF modified at C-5 and Asp29/Asp30/Gly48 of wild-type protease, while the P2' Cp-Abt group forms strong hydrogen bonds with Asp30'. The Tp-THF and Cp-Abt moieties also have good nonpolar interactions with protease residues located in the flap region. For selection with LPV and DRV by use of a mixture of 11 HIVMDR strains (HIV11MIX), HIV11MIX became highly resistant to LPV and DRV over 13 to 32 and 32 to 41 weeks, respectively. However, for selection with GRL-079 and GRL-058, HIV11MIX failed to replicate at >0.08 µM and >0.2 µM, respectively. Thermal stability results supported the highly favorable anti-HIV-1 potency of GRL-079 as well as other PIs. The present data strongly suggest that the P2 Tp-THF group modified at C-5 and the P2' Abt group contribute to the potent anti-HIV-1 profiles of the four PIs against HIV-1NL4-3 and a wide spectrum of HIVMDR strains.

Influence of Ethanol on Darunavir Hepatic Clearance and Intracellular PK/PD in HIV-Infected Monocytes, and CYP3A4-Darunavir Interactions Using Inhibition and in Silico Binding Studies.

PURPOSE: Although the prevalence of alcohol consumption is higher in HIV+ people than general public, limited information is available on how alcohol affects the metabolism and bioavailability of darunavir (DRV). METHODS: DRV was quantified by using LC-MS/MS method. All in vitro experiments were performed using human liver microsomes and HIV-infected monocytic cells. CYP3A4 and DRV/Ritonavir (RTV) docking was performed using GOLD suite 5.8. RESULTS: Ethanol (20 mM) significantly decreased apparent half-life and increased degradation rate constant of RTV-boosted DRV but not for DRV alone. Similarly, ethanol exposure increased hepatic intrinsic clearance for RTV-boosted DRV with no significant influence on DRV alone. Ethanol showed a limited influence on intracellular total DRV exposure in the presence of RTV without altering maximum concentration (Cmax) values in HIV-infected monocytic cells. Ethanol alone elevated HIV replication but this effect was nullified with the addition of DRV or DRV + RTV. Additionally, inhibitory potency of DRV was significantly reduced in the presence of ethanol. Our docking results projected that ethanol increases the average distance between DRV and CYP3A4 heme, and alter the orientation of DRV-CYP3A4 binding. CONCLUSIONS: Collectively these findings suggest that DRV metabolism is primarily influenced by ethanol in the liver, but has minor effect in HIV-residing monocytes.

A Modified P1 Moiety Enhances In Vitro Antiviral Activity against Various Multidrug-Resistant HIV-1 Variants and In Vitro Central Nervous System Penetration Properties of a Novel Nonpeptidic Protease Inhibitor, GRL-10413.

We report here that GRL-10413, a novel nonpeptidic HIV-1 protease inhibitor (PI) containing a modified P1 moiety and a hydroxyethylamine sulfonamide isostere, is highly active against laboratory HIV-1 strains and primary clinical isolates (50% effective concentration [EC50] of 0.00035 to 0.0018 µM), with minimal cytotoxicity (50% cytotoxic concentration [CC50] = 35.7 µM). GRL-10413 blocked the infectivity and replication of HIV-1NL4-3 variants selected by use of atazanavir, lopinavir, or amprenavir (APV) at concentrations of up to 5 µM (EC50 = 0.0021 to 0.0023 µM). GRL-10413 also maintained its strong antiviral activity against multidrug-resistant clinical HIV-1 variants isolated from patients who no longer responded to various antiviral regimens after long-term antiretroviral therapy. The development of resistance against GRL-10413 was significantly delayed compared to that against APV. In addition, GRL-10413 showed favorable central nervous system (CNS) penetration properties as assessed with an in vitro blood-brain barrier (BBB) reconstruction system. Analysis of the crystal structure of HIV-1 protease in complex with GRL-10413 demonstrated that the modified P1 moiety of GRL-10413 has a greater hydrophobic surface area and makes greater van der Waals contacts with active site amino acids of protease than in the case of darunavir. Moreover, the chlorine substituent in the P1 moiety interacts with protease in two distinct configurations. The present data demonstrate that GRL-10413 has desirable features for treating patients infected with wild-type and/or multidrug-resistant HIV-1 variants, with favorable CNS penetration capability, and that the newly modified P1 moiety may confer desirable features in designing novel anti-HIV-1 PIs.

Antileishmanial activity of antiretroviral drugs combined with miltefosine.

Co-infection of Leishmaniasis, a neglected tropical disease, with human immunodeficiency virus (HIV) has hindered treatment efficacy. In this study, we aim to evaluate the antileishmanial activity of two protease inhibitors (darunavir and atazanavir) and four reverse transcriptase inhibitors (tenofovir, efavirenz, neviraprine, and delavirdine mesylate) on Leishmania infantum. The activity of different antiretrovirals combinations and of antiretroviral with miltefosine, a drug used on leishmaniasis treatment, was also evaluated. Only two non-nucleoside reverse transcriptase inhibitors (NNRTIs) were active on L. infantum. Efavirenz showed the best antileishmanial activity on promastigotes cells with IC50 value of 26.1 µM followed by delavirdine mesylate with an IC50 value of 136.2 µM. Neviraprine, tenofovir, atazanavir, and darunavir were not active at the concentrations tested (IC50 > 200 µM). The efavirenz also showed high antileishmanial activity on intramacrophage amastigotes with IC50 of 12.59 µM. The interaction of efavirenz with miltefosine improved antileishmanial activity on promastigotes and intracellular amastigotes (IC50 values of 11. 8 µM and 8.89 µM, respectively). These results suggest that combined-therapy including efavirenz and miltefosine could be alternative options for treating Leishmaniasis and Leishmania/HIV co-infections.