Structure-based design of diarylpyrimidines and triarylpyrimidines as potent HIV-1 NNRTIs with improved metabolic stability and drug resistance profiles.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are an important component of anti-acquired immunodeficiency syndrome treatment regimen. In the present work, with the previously reported compound K-16c as lead, a series of novel 2,4,5-trisubstituted pyrimidine derivatives were designed based on the cocrystal structure of K-16c/RT, with the aim to improve the anti-human immunodeficiency virus type-1 (HIV-1) activities and metabolic stability properties. Compound 11b1 exhibited the most potent antiviral activity against wild-type (WT) and a panel of single mutant HIV-1 strains (EC50 = 2.4-12.4 nM), being superior to or comparable to those of the approved drug etravirine. Meanwhile, 11b1 exhibited moderate cytotoxicity (CC50 = 4.96 µM) and high selectivity index (SI = 1189) toward HIV-1 WT strain. As for HIV-1 RT inhibition test, 11b1 possessed excellent inhibitory potency (IC50 = 0.04 µM) and confirmed its target was RT. Moreover, the molecular dynamics simulation was performed to elucidate the improved drug resistance profiles. Moreover, 11b1 was demonstrated with favorable safety profiles and pharmacokinetic properties in vivo, indicating that 11b1 is a potential anti-HIV-1 drug candidate worthy of further development.

Tri-substituted 1,3,5-triazine-based analogs as effective HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs): A systematic review.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) have significantly impacted the HIV-1 wild-type due to their high specificity and superior potency. As well as different combinations of NNRTIs have been used on clinically approved combining highly active antiretroviral therapy (HAART) to resist the growth of HIV-1 and decrease the mortality rate of HIV/AIDS. Although the feeble strength against the drug-resistant mutant strains and the long-term damaging effects have been reducing the effectiveness of HAART, it could be a crucial challenge to develop novel Anti-HIV leads with a vital mode of action and the least side effects. The extensive chemical reactivity and the diverse chemotherapeutic applications of the 1,3,5-triazine have provided a wide scope of research in medicinal chemistry via a structural modification. In this review, we focused on the Anti-HIV profile of the tri-substituted s-triazine derivatives with structure-based features and also discussed the active mode of action to evaluate the significant findings. The tri-substituted 1,3,5-triazine derivatives have been found more promising to inhibit the growth of the drug-sensitive and drug-resistant variants of HIV-1, especially HIV-1 wild-type, HIV-1 K103N/Y181C, and HIV-1 Tyr181Cys. It has been observed that these derivatives have interacted with the enzyme protein residues via a significant π $\pi $ - π $\pi $ interaction and hydrogen bonding to resist the proliferation of the viral genomes. Further, the SAR and the active binding modes are critically described and highlight the role of structural variations with functional groups along with the binding affinity of targeted enzymes, which may be beneficial for rational drug discovery to develop highly dynamic Anti-HIV agents.

CD4/CD8 Ratio Outcome According to the Class of the Third Active Drug in Antiretroviral Therapy Regimens: Results From the Quebec Human Immunodeficiency Virus Cohort Study.

BACKGROUND: The impact of different therapeutic classes of drugs in antiretroviral therapy (ART) regimens on the CD4/CD8 ratio is not well documented in people treated for HIV. The objective of this study was to analyze the long-term effect of exposure to integrase strand transfer inhibitor (INSTI) on CD4/CD8 ratio compared with nonnucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) among ART-treated persons with HIV (PWH). METHODS: Data from the Quebec HIV Cohort collected from 31 August 2017 were used. Our analysis included all patients in the cohort who received a first or subsequent ART regimen composed of 2 nucleoside reverse transcriptase inhibitors (NRTIs) and a third active drug of a different class (NNRTI, PI, or INSTI) for at least 16 weeks. Marginal structural Cox models were constructed to estimate the effect of different therapeutic classes on the CD4/CD8 ratio outcome. RESULTS: Among the 3907 eligible patients, 972 (24.9%), 1996 (51.1%), and 939 (24.0%) were exposed to an ART regimen whose third active agent was an NNRTI, PI, or INSTI, respectively. The total follow-up time was 13 640.24 person-years. The weighted hazard ratio for the association between the third active class and CD4/CD8 ratio ≥1 was .56 (95% confidence interval [CI]: .48-.65) for patients exposed to NNRTI + 2 NRTIs and .41 (95% CI: .35-.47) for those exposed to PI + 2 NRTIs, compared with those exposed INSTI + 2 NRTIs. CONCLUSIONS: For people treated for HIV, INSTI-based ART appears to be associated with a higher CD4/CD8 ratio than NNRTI and PI-based ART.

No Meaningful Drug-Drug Interactions Are Associated with the Coadministration of ACC007, Lamivudine, and Tenofovir Disoproxil Fumarate.

ACC007 is a new-generation nonnucleoside reverse transcriptase inhibitor (NNRTI) with favorable pharmacokinetic and safety profiles. NNRTIs are typically administered in combination with two nucleoside reverse transcriptase inhibitors as first-line recommended regimens in several guidelines. Therefore, this open-label, randomized, single-period, parallel-cohort study aimed to assess the drug-drug interactions (DDIs) and safety profiles of ACC007 in combination with tenofovir disoproxil fumarate (TDF) and lamivudine (3TC) in healthy subjects. All 24 screened subjects were randomly assigned to group A or B. On days 1 to 17, 3TC at 300 mg and TDF at 300 mg were taken orally by group A, and ACC007 at 300 mg was coadministered on days 8 to 17. On days 1 to 17, 300 mg of ACC007 was taken orally by group B, and 300 mg 3TC and 300 mg TDF were coadministered on days 8 to 17. When we compared 3TC-TDF versus 3TC-TDF-ACC007 DDIs, the geometric mean ratios (GMRs, with 90% confidence intervals [CIs] in parentheses) of the maximum concentration at steady state (Cmax,ss) and area under the concentration-time curve from 0 h to infinity (i.e., at steady state; AUCss) values for TDF were 108.14% (95.68 to 122.22%) and 89.90% (82.67 to 97.76%) (P = 0.344); for 3TC, these values were 113.48% (91.45 to 140.82%) and 95.33% (83.61 to 108.7%) (P = 0.629). When ACC007 alone was compared to the combination 3TC-TDF-ACC007, the GMRs (90% CIs) of the Cmax,ss and AUCss values for ACC007 were 89.00% (76.35 to 103.74%) and 82.57% (73.27 to 93.05%) (P = 0.375). The coadministration of 3TC-TDF-ACC007 did not significantly affect the time to maximum concentration of any of the drugs in terms of P values. ACC007 combined with 3TC-TDF was generally well tolerated during daily dosing for 17 days with no serious adverse events. Overall, ACC007 and 3TC-TDF had no significant or meaningful interactions and a favorable safety profile, which supports the use of the combination regimen.

Trend over time of HIV-1 drug resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and their drivers: A cohort study from Antiviral Response Cohort Analysis (ARCA).

The rise of HIV-1 drug resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) threatens the long-term success of NNRTI-based therapies. Our study aims to describe the circulation of major resistance-associated mutations (RAMs) for NNRTIs in people living with HIV (PLWH) in Italy from 2000 to 2020. We included 5982 naïves and 28 505 genotypes from 9387 treatment-experienced PLWH from the Antiviral Response Cohort Analysis (ARCA) cohort. Transmitted drug resistance (TDR) was found in 12.5% and declined from 17.3% in 2000-2003 to 10.9% in 2016-2020 (p = 0.003). Predictors of TDR were viral subtype B [vs. non-B, adjusted odds ratio (aOR) = 1.94, p < 0.001], zenith viral load (VL) (per 1 log10 higher, aOR = 0.86, p = 0.013), nadir CD4 cell count (per 100 cells/µL increase aOR = 0.95, p = 0.013). At least one RAM for NNRTIs among treatment experienced PLWH was detected in 33.2% and pre-treatment drug resistance (PDR) declined from 43.4% in 2000-2003 to 20.9% in 2016-2020 (p < 0.001). Predictors of PDR were sexual transmission route (vs. others, aOR = 0.78, p < 0.001), time since HIV diagnosis (per 1 month longer, aOR = 1.002, p < 0.001), viral subtype B (vs. non B, aOR = 1.37, p < 0.001), VL (per 1 log10 higher, aOR = 1.12, p < 0.001), nadir CD4 count (per 100 cells/µL increase, aOR = 0.91, p < 0.001), previous exposure to any NNRTI (aOR = 2.31, p < 0.001) and a more recent calendar year sequence (any time span > 2008 vs. 2000-2003, any aOR <1, p < 0.001). Circulation of RAMs to NNRTIs declined during the last 20 years in Italy. NNRTIs remain pivotal drugs for the management of HIV-1 due to safety concerns and long-acting options.

In situ click chemistry-based discovery of 1,2,3-triazole-derived diarylpyrimidines as novel HIV-1 NNRTIs by exploiting the tolerant region I in binding pocket.

HIV-1 reverse transcriptase (RT) is considered as one of the most significant targets for the anti-HIV-1 drug design due to their determined mechanism and well-decoded crystal structure. As a part of our continuous efforts towards the development of potent HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) by exploiting the tolerant region I of NNRTIs binding pocket (NNIBP), the miniaturized parallel synthesis via CuAAC click chemistry reaction followed by in situ biological screening have been performed in this work. The in situ enzyme inhibition screening results showed that 14 compounds exhibited higher or equivalent inhibitory activity compared to the lead K-5a2 and ETR. Anti-HIV-1 activity results indicated that C1N51 displayed the most potent activity (EC50 = 0.01-0.26 µM) against wild-type and a panel of NNRTIs-resistant strains. Moreover, the molecular simulation demonstrated that the newly introduced triazole ring could develop new hydrogen bonds with Lys103 and Pro236, which explained the feasibility of introducing triazole in the tolerant region I of the RT binding pocket.

Structure-directed linker optimization of novel HEPTs as non-nucleoside inhibitors of HIV-1 reverse transcriptase.

1-[(2-Hydroxyethoxy)methyl]-6-(phenylthio)thymines (HEPTs) have been previously described as an important class of HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs). In our continuously pursuing HEPT optimization efforts, a series of novel HEPTs, featuring -C(OH)CH2R, -CC, or -CHCH2R linker at the benzylic α-methylene unit, were developed as NNRTIs. Among these new HEPTs, the compound C20 with -CHCH3 group at the benzylic α-methylene unit conferred the highest potency toward WT HIV-1 and selectivity (EC50 = 0.23 µM, SI = 150.20), which was better than the lead compound HEPT (EC50 = 7 µM, SI = 106). Also, C20 was endowed with high efficacy against clinically relevant mutant strains (EC50(L100I) = 1.07 µM; EC50(K103N) = 4.33 µM; EC50(Y181C) = 5.57 µM; EC50(E138K) = 1.06 µM; EC50(F227L+V106A) = 5.45 µM) and wild-type HIV-1 reverse transcriptase (RT) with an IC50 value of 0.55 µM. Molecular docking and molecular dynamics simulations, as well as preliminary structure-activity relationship (SAR) analysis of these new compounds, provided a deeper insight into the key structural features of the interactions between HEPT analogs and HIV-1 RT and laid the foundation for further modification on HEPT scaffold.

4-Phenylcoumarin derivatives as new HIV-1 NNRTIs: Design, synthesis, biological activities, and computational studies.

A series of 4-phenylcoumarin derivatives was synthesized and evaluated for their cellular anti-HIV-1 and HIV-2 activities as well as their inhibitory effects against HIV-1 reverse transcriptase (RT). The hydrazone compound 8b and the ethylthiosemicarbazide derivative 4c showed the best inhibition activity against wild-type (WT) HIV-1. The promising compounds were further evaluated against HIV-1 RT and exhibited significant inhibitory activity with compound 8b showing comparable effect to the reference NNRTI Efavirenz (IC50 = 9.01 nM). Structure activity relationship study revealed the importance of 6-chloro and 4-phenyl substituents for optimum activity, as well as the 5-atoms linker (=N-NH-CO-CH2-O-) at position 7 of coumarin scaffold that can support the rotation and flexibility of compound 8b to fit well in the binding pocket. The molecular docking of compound 8b demonstrated a typical seahorse binding mode with better binding interactions that covered more residues when compared to Efavirenz.

Synthesis and biological profile of benzoxazolone derivatives.

The benzoxazolone nucleus is an ideal scaffold for drug design, owing to its discrete physicochemical profile, bioisosteric preference over pharmacokinetically weaker moieties, weakly acidic behavior, presence of both lipophilic and hydrophilic fragments on a single framework, and a wider choice of chemical modification on the benzene and oxazolone rings. These properties apparently influence the interactions of benzoxazolone-based derivatives with their respective biological targets. Hence, the benzoxazolone ring is implicated in the synthesis and development of pharmaceuticals with a diverse biological profile ranging from anticancer, analgesics, insecticides, anti-inflammatory, and neuroprotective agents. This has further led to the commercialization of several benzoxazolone-based molecules and a few others under clinical trials. Nevertheless, the SAR exploration of benzoxazolone derivatives for the identification of potential "hits" followed by the screening of "leads" provides a plethora of opportunities for further exploration of the pharmacological profile of the benzoxazolone nucleus. In this review, we aim to present the biological profile of different derivatives based on the benzoxazolone framework.

Synthesis and anti-HIV activity of non-nucleoside reverse-transcriptase inhibitor DB02 phosphate derivatives based on water-soluble optimization.

To improve the water solubility of anti-human immunodeficiency virus (HIV) agent DB02, an excellent non-nucleoside reverse-transcriptase inhibitor (NNRTI) obtained in our previous efforts, we designed and synthesized four phosphate derivatives of DB02 based on the molecular model of DB02 with RT. Here, the antiviral activity of these four derivatives was detected, leading to the discovery of compound P-2, which possessed a superior potency to the lead compound DB02 against wild-type HIV-1 and a variety of HIV-resistant mutant viruses significantly. Furthermore, the water solubility of P-2 was nearly 17 times higher than that of DB02, and the pharmacokinetic test in rats showed that P-2 demonstrate significantly improved oral bioavailablity of 14.6%. Our study showed that the introduction of a phosphate ester group at the end of the C-2 side chain of DB02 was beneficial to the improvement of its antiviral activity and pharmacokinetic properties, which provided a promising lead for the further development of S-DACOs type of NNRTIs.

Covalently Targeted Highly Conserved Tyr318 to Improve the Drug Resistance Profiles of HIV-1 NNRTIs: A Proof-of-Concept Study.

This study presents proof of concept for designing a novel HIV-1 covalent inhibitor targeting the highly conserved Tyr318 in the HIV-1 non-nucleoside reverse transcriptase inhibitors binding pocket to improve the drug resistance profiles. The target inhibitor ZA-2 with a fluorosulfate warhead in the structure was found to be a potent inhibitor (EC50 = 11-246 nM) against HIV-1 IIIB and a panel of NNRTIs-resistant strains, being far superior to those of NVP and EFV. Moreover, ZA-2 was demonstrated with lower cytotoxicity (CC50 = 125 µM). In the reverse transcriptase inhibitory assay, ZA-2 exhibited an IC50 value of 0.057 µM with the ELISA method, and the MALDI-TOF MS data demonstrated the covalent binding mode of ZA-2 with the enzyme. Additionally, the molecular simulations have also demonstrated that compounds can form covalent binding to the Tyr318.

Targeting HIV-1 Reverse Transcriptase Using a Fragment-Based Approach.

Human immunodeficiency virus type I (HIV-1) is a retrovirus that infects cells of the host's immune system leading to acquired immunodeficiency syndrome and potentially death. Although treatments are available to prevent its progression, HIV-1 remains a major burden on health resources worldwide. Continued emergence of drug-resistance mutations drives the need for novel drugs that can inhibit HIV-1 replication through new pathways. The viral protein reverse transcriptase (RT) plays a fundamental role in the HIV-1 replication cycle, and multiple approved medications target this enzyme. In this study, fragment-based drug discovery was used to optimize a previously identified hit fragment (compound B-1), which bound RT at a novel site. Three series of compounds were synthesized and evaluated for their HIV-1 RT binding and inhibition. These series were designed to investigate different vectors around the initial hit in an attempt to improve inhibitory activity against RT. Our results show that the 4-position of the core scaffold is important for binding of the fragment to RT, and a lead compound with a cyclopropyl substitution was selected and further investigated. Requirements for binding to the NNRTI-binding pocket (NNIBP) and a novel adjacent site were investigated, with lead compound 27-a minimal but efficient NNRTI-offering a starting site for the development of novel dual NNIBP-Adjacent site inhibitors.

Indolylarylsulfones bearing phenylboronic acid and phenylboronate ester functionalities as potent HIV­1 non-nucleoside reverse transcriptase inhibitors.

To explore the chemical space around the entrance channel of the HIV-1 reverse transcriptase (RT) binding pocket, we innovatively designed and synthesized a series of novel indolylarylsulfones (IASs) bearing phenylboronic acid and phenylboronate ester functionalities at the indole-2-carboxamide as new HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) through structure-based drug design. All the newly synthesized compounds exhibited excellent to moderate potency against wild-type (WT) HIV-1 with EC50 values ranging from 6.7 to 42.6 nM. Among all, (3-ethylphenyl)boronic acid substituted indole-2-carboxamide and (4-ethylphenyl) boronate ester substituted indole-2-carboxamide were found to be the most potent inhibitors (EC50 = 8.5 nM, SI = 3310; EC50 = 6.7 nM, SI = 3549, respectively). Notably, (3-ethylphenyl)boronic acid substituted indole-2-carboxamide maintained excellent activities against the single HIV-1 mutants L100I (EC50 = 7.3 nM), K103N (EC50 = 9.2 nM), as well as the double mutant V106A/F227L (EC50 = 21.1 nM). Preliminary SARs and molecular modelling studies are also discussed in detail.

Structure-Based design of [(2-Hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives as nonnucleoside HIV-1 reverse transcriptase Inhibitors: From HEPTs to Sulfinyl-substituted HEPTs.

The [(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) analogs were reported to be a kind of promising lead compounds as nonnucleoside HIV-1 reverse transcriptase inhibitors. In this work, a series of novel sulfinyl-substituted analogs were designed by structure-based design strategy with the purpose of improving the activity of HEPT, followed by evaluating their anti-HIV-1 activity in MT-4 cells. Most of the final compounds had moderate to strong activity against wild-type HIV-1 strain (IIIB) with EC50 values in the range of 0.21-1.91 µM, which were around 4 âˆ¼ 32-fold better than the reference compound HEPT. Some of them showed higher sensitivity toward clinically relevant mutant L100I and E138K viruses than NVP. Selected compounds were further evaluated for their activity against wild-type reverse transcriptase (RT), and most of them exhibited nanomolar activity, suggesting a good correlation with the cell-based activity. The compounds 11h, 11l, and 11ab displayed the best anti-HIV-1 activity against wild-type HIV-1 strain (EC50 = 0.280, 0.209, and 0.290 µM) and nanomolar activity against mutant strains (L100I and E138K), superior to HEPT and NVP. Molecular modeling studies were also performed to elucidate the biological activity, providing a structural insight for follow-up research on HEPT optimization.

C6-structural optimizations of 2-aryl-1H-pyrazole-S-DABOs: From anti-HIV to anti-DENV activity.

Both HIV and DENV are serious threats to human life, health and social economy today. So far, no vaccine for either HIV or DENV has been developed successfully. The research on anti-HIV or DENV drugs is still of great significance. In this study we developed a series of novel 2-Aryl-1H-pyrazole-S-DABOs with C6-strucutral optimizations as potent NNRTIs, among which, 8 compounds had low cytotoxicity and EC50 values in the range of 0.0508 âˆ¼ 0.0966 µM, and their selectivity index was SI > 1415 âˆ¼ 3940. In particular, two compounds 4a and 4b were identified to have good inhibitory effects on DENV of four serotypes. The EC50 of compound 4a and 4b against DENV-II (13.2 µM and 9.23 µM, respectively) were better than that of the positive control ribavirin (EC50 = 40.78 µM). In addition, the effect of C-6 substituents on the anti-HIV or anti-DENV activity of these compounds was also discussed.

Analytical Assessment of the Vela Diagnostics NGS Assay for HIV Genotyping and Resistance Testing: The Apulian Experience.

Drug-resistance monitoring is one of the hardest challenges in HIV management. Next-generation sequencing (NGS) technologies speed up the detection of drug resistance, allowing the adjustment of antiretroviral therapy and enhancing the quality of life of people living with HIV. Recently, the NGS Sentosa® SQ HIV Genotyping Assay (Vela Diagnostics) received approval for in vitro diagnostics use. This work is the first Italian evaluation of the performance of the Vela Diagnostics NGS platform, assessed with 420 HIV-1 clinical samples. A comparison with Sanger sequencing performance is also reported, highlighting the advantages and disadvantages of the Sentosa® NGS assay. The precision of the technology was studied with reference specimens, while intra- and inter-assay reproducibility were evaluated for selected clinical samples. Vela Diagnostics' NGS assay reached an 87% success rate through 30 runs of analysis in a real-world clinical context. The concordance with Sanger sequencing outcomes was equal to 97.2%. Several detected mismatches were due to NGS's superior sensitivity to low-frequency variants. A high accuracy was observed in testing reference samples. Repeatability and reproducibility assays highlighted the good performance of the NGS platform. Beyond a few technical issues that call for further optimization, the key improvement will be a better balance between costs and processing speed. Once these issues have been solved, the Sentosa® SQ HIV Genotyping Assay will be the way forward for HIV resistance testing.

Identification of Boronate-Containing Diarylpyrimidine Derivatives as Novel HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors.

In this study, privileged boronic acid ester was introduced into the right wing of etravirine (ETR) to obtain a series of novel boronate-containing derivatives. These newly synthesized derivatives were evaluated for their anti-HIV potency in MT-4 cells using the MTT method, and their inhibitory activity to HIV-1 reverse transcriptase (RT) was assayed by the ELISA method. Most of the synthesized compounds displayed promising antiviral activity against the wild-type and a wide range of HIV-1 mutant strains. In particular, 4a exhibited the most potent activity against the wild-type and a panel of single mutations (L100I, K103N, Y181C, and E138K) with EC50 values ranging from 0.005 to 0.648 µM, which were much superior to those of nevirapine (EC50 = 0.151 µM). Moreover, 4b turned out to be an effective inhibitor against the double-mutant strains F227L + V106A and RES056 with EC50 values of 3.21 and 2.30 µM, respectively. RT inhibition activity and molecular docking were also investigated.

Clinical Impact of Pretreatment Human Immunodeficiency Virus Drug Resistance in People Initiating Nonnucleoside Reverse Transcriptase Inhibitor-Containing Antiretroviral Therapy: A Systematic Review and Meta-analysis.

BACKGROUND: Increased access to antiretroviral therapy (ART) has resulted in rising levels of pretreatment human immunodeficiency virus drug resistance (PDR). This is the first systematic review and meta-analysis to assess the impact of PDR on treatment outcomes among people initiating nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, including the combination of efavirenz (EFV), tenofovir (TDF), and lamivudine or emtricitabine (XTC). METHODS: We systematically reviewed studies and conference proceedings comparing treatment outcomes in populations initiating NNRTI-based ART with and without PDR. We conducted subgroup analyses by regimen: (1) NNRTIs + 2 nucleoside reverse transcriptase inhibitors (NRTIs), (2) EFV + 2 NRTIs, or (3) EFV/TDF/XTC; by population (children vs adults); and by definition of resistance (PDR vs NNRTI PDR). RESULTS: Among 6197 studies screened, 32 were analyzed (31 441 patients). We found that individuals with PDR initiating NNRTIs across all the subgroups had increased risk of virological failure compared to those without PDR. Risk of acquisition of new resistance mutations and ART switch was also higher in people with PDR. CONCLUSIONS: This review shows poorer treatment outcomes in the presence of PDR, supporting the World Health Organization's recommendation to avoid using NNRTIs in countries where levels of PDR are high.

Increased acquired protease inhibitor drug resistance mutations in minor HIV-1 quasispecies from infected patients suspected of failing on national second-line therapy in South Africa.

BACKGROUND: HIV-1C has been shown to have a greater risk of virological failure and reduced susceptibility towards boosted protease inhibitors (bPIs), a component of second-line combination antiretroviral therapy (cART) in South Africa. This study entailed an evaluation of HIV-1 drug resistance-associated mutations (RAMs) among minor viral populations through high-throughput sequencing genotypic resistance testing (HTS-GRT) in patients on the South African national second-line cART regimen receiving bPIs. METHODS: During 2017 and 2018, 67 patient samples were sequenced using high-throughput sequencing (HTS), of which 56 samples were included in the final analysis because the patient's treatment regimen was available at the time of sampling. All patients were receiving bPIs as part of their cART. Viral RNA was extracted, and complete pol genes were amplified and sequenced using Illumina HiSeq2500, followed by bioinformatics analysis to quantify the RAMs according to the Stanford HIV Drug Resistance Database. RESULTS: Statistically significantly higher PI RAMs were observed in minor viral quasispecies (25%; 14/56) compared to non-nucleoside reverse transcriptase inhibitors (9%; 5/56; p = 0.042) and integrase inhibitor RAM (4%; 2/56; p = 0.002). The majority of the drug resistance mutations in the minor viral quasispecies were observed in the V82A mutation (n = 13) in protease and K65R (n = 5), K103N (n = 7) and M184V (n = 5) in reverse transcriptase. CONCLUSIONS: HTS-GRT improved the identification of PI and reverse transcriptase inhibitor (RTI) RAMs in second-line cART patients from South Africa compared to the conventional GRT with ≥20% used in Sanger-based sequencing. Several RTI RAMs, such as K65R, M184V or K103N and PI RAM V82A, were identified in < 20% of the population. Deep sequencing could be of greater value in detecting acquired resistance mutations early.

Novel indolylarylsulfone derivatives as covalent HIV-1 reverse transcriptase inhibitors specifically targeting the drug-resistant mutant Y181C.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are widely used in combination therapies against HIV-1. However, emergent and transmitted drug resistance compromise their efficacy in the clinical setting. Y181C is selected in patients receiving nevirapine, etravirine and rilpivirine, and together with K103N is the most prevalent NNRTI-associated mutation in HIV-infected patients. Herein, we report on the design, synthesis and biological evaluation of a novel series of indolylarylsulfones bearing acrylamide or ethylene sulfonamide reactive groups as warheads to inactivate Cys181-containing HIV-1 RT via a Michael addition reaction. Compounds I-7 and I-9 demonstrated higher selectivity towards the Y181C mutant than against the wild-type RT, in nucleotide incorporation inhibition assays. The larger size of the NNRTI binding pocket in the mutant enzyme facilitates a better fit for the active compounds, while stacking interactions with Phe227 and Pro236 contribute to inhibitor binding. Mass spectrometry data were consistent with the covalent modification of the RT, although off-target reactivity constitutes a major limitation for further development of the described inhibitors.