Broad antiretroviral activity and resistance profile of the novel human immunodeficiency virus integrase inhibitor elvitegravir (JTK-303/GS-9137)

Hazards of antiviral contamination in water: Dissemination, fate, risk and their impact on fish

Antiviral drugs are a cornerstone in the first line of antiviral therapy and their demand rises consistently with increments in viral infections and successive outbreaks. The drugs enter the waters due to improper disposal methods or via human excreta following their consumption; consequently, many of them are now classified as emerging pollutants. Hereby, we review the global dissemination of these medications throughout different water bodies and thoroughly investigate the associated risk they pose to the aquatic fauna, particularly our vertebrate relative fish, which has great economic and dietary importance and subsequently serves as a major doorway to the human exposome. Our risk assessment identifies eleven such drugs that presently pose high to moderate levels of risk to the fish. The antiviral drugs are likely to induce oxidative stress, alter the behaviour, affect different physiological processes and provoke various toxicological mechanisms. Many of the compounds exhibit elevated bioaccumulation potential, while, some have an increased tendency to leach through soil and contaminate the groundwater. Eight antiviral medications show a highly recalcitrant nature and would impact the aquatic life consistently in the long run and continue to influence the human exposome. Thereby, we call for urgent ecopharmacovigilance measures and modification of current water treatment methods.

Clinical Outcomes of Integrase Strand Transfer Inhibitors Containing Antiretroviral Therapy in HIV-2: A Narrative Review

The human immunodeficiency virus type 2 (HIV-2) is a particular subtype of HIV, which is endemic in West Africa and is characterized by a more indolent course than HIV-1. As people living with HIV-2 (PWH-2) are at risk for the development of acquired immunodeficiency syndrome and can transmit the virus, antiretroviral therapy is usually indicated. However, the optimal treatment of HIV-2 is unknown and historically the protease inhibitors (PIs) were a regular part of therapy. Nowadays, the use of integrase strand transfer inhibitors (INSTIs) in HIV-2 is increasing but the evidence supporting this approach is limited. In this narrative review, we outline the clinical data on the use of INSTI-containing antiretroviral therapy in HIV-2. We found that in the setting of treatment-naïve PWH-2, the use of INSTIs is successful, but also noted large heterogeneity in reported outcomes and that most cohorts are small with limited follow-up time. There is a lack of studies comparing the efficacy of INSTIs to other first-line options. For treatment-experienced PWH-2, the efficacy of INSTI is highly variable.

HIV-1 Integrase Inhibitor, Dihydroobionin B, and the Investigation of Its Extraordinary Specific Rotation

Dihydroobionin B (1), a chiral congener of known obionin B, was isolated from Pseudocoleophoma sp. KT4119, a freshwater fungus collected from a submerged wood block in Kochi Prefecture, Japan, in 2020. The planar structure of 1 was characterized by mass and NMR spectral analysis and confirmed by density functional theory (DFT)-based chemical shift calculations. Its absolute structure was determined by electronic circular dichroism spectral analysis. Notably, 1 exhibited an extraordinarily large specific rotation [[α]20D +1080 (c 0.056, CHCl3)], which was verified by DFT-based specific rotation calculations. However, these calculations indicated that the sign of the specific rotation based on static analysis was insufficient to determine the absolute configuration in this case. Furthermore, Pseudocoleophoma KT4119 produced coleophomapyrones A (2) and B (3) and coleophomaldehyde A (4). While this is the first report of 2 isolated from a natural source, it has also been prepared previously using a synthetic approach. Compound 1 potently inhibited HIV type 1 integrase (IC50 = 0.44 μM) without significant cytotoxicity. Finally, docking experiments were conducted to propose a plausible mechanism for the behavior of 1.

Recent Updates on Viral Oncogenesis: Available Preventive and Therapeutic Entities

Human viral oncogenesis is a complex phenomenon and a major contributor to the global cancer burden. Several recent findings revealed cellular and molecular pathways that promote the development and initiation of malignancy when viruses cause an infection. Even, antiviral treatment has become an approach to eliminate the viral infections and prevent the activation of oncogenesis. Therefore, for a better understanding, the molecular pathogenesis of various oncogenic viruses like, hepatitis virus, human immunodeficiency viral (HIV), human papillomavirus (HPV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV), could be explored, especially, to expand many potent antivirals that may escalate the apoptosis of infected malignant cells while sparing normal and healthy ones. Moreover, contemporary therapies, such as engineered antibodies antiviral agents targeting signaling pathways and cell biomarkers, could inhibit viral oncogenesis. This review elaborates the recent advancements in both natural and synthetic antivirals to control viral oncogenesis. The study also highlights the challenges and future perspectives of using antivirals in viral oncogenesis.

Transmitted Drug Resistance Against Integrase Strand Transfer Inhibitors in Iranian HIV-Infected Naïve Patients

Background

Human Immunodeficiency Virus (HIV) has claimed the lives of millions of people during the past decades. While several antiretroviral drugs like Integrase Strand Transfer Inhibitors (INSTIs) have been introduced to control HIV, Transmitted Drug Resistance (TDR) in HIV genome caused failure in treatment. This study aimed to investigate TDR and natural occurring mutations (NOPs) in HIV integrase gene in Iranian HIV patients.

Methods

In this cross-sectional study, blood samples of 30 HIV-positive patients who had never taken integrase inhibitors were considered for CD4 T cell count, RT real-time PCR, and, Nested PCR. The sequencing results were analyzed by CLC sequence viewer software and Stanford University HIV Drug Resistance Database.

Results

In all samples, nine NOPs with a high prevalence were found; however, we did not find any drug resistance mutations, except for a mutation in one sample, which showed a low resistance level. Subtype A1 was dominant in all samples.

Conclusion

Based on the findings and compared to our previous study, all patients were sustainable to main integrase inhibitors, including bictegravir, raltegravir, bictegravir, elvitegravir and dolutegravir. It seems the resistant mutation pattern attributed to integrase inhibitors was not diffent among studied patients; hence, the prescription of such inhibitors helps physicians to control HIV infection in Iranian HIV-infected patients.

Integrasone Derivatives Isolated from Lepteutypa sp. KT4162 and Their Anti-HIV-1 Integrase Activity

Five integrasone derivatives, integrasone C (1), isointegrasone C (2), integrasone D1 (3), integrasone D2 (4), and integrasone E (5), were isolated from the culture broth of Lepteutypa sp. KT4162. Neither conventional NMR analyses nor DFT (density functional theory)-based computationally assisted chemical shift discussions were sufficient to elucidate the relative configuration of the 1,4-epoxydiol moiety. A combined analysis using the calculated ⁿJ_CH values and HMBC spectra was helpful to establish the relative configuration. The absolute configurations of 1-5 were determined using DFT-based ECD (electronic circular dichroism) spectral analysis. Biological assays of these compounds revealed that 2 potently inhibits HIV-1 integrase without cytotoxicity.

Structure of a HIV-1 IN-Allosteric inhibitor complex at 2.93 Å resolution: Routes to inhibitor optimization

HIV integrase (IN) inserts viral DNA into the host genome and is the target of the strand transfer inhibitors (STIs), a class of small molecules currently in clinical use. Another potent class of antivirals is the allosteric inhibitors of integrase, or ALLINIs. ALLINIs promote IN aggregation by stabilizing an interaction between the catalytic core domain (CCD) and carboxy-terminal domain (CTD) that undermines viral particle formation in late replication. Ongoing challenges with inhibitor potency, toxicity, and viral resistance motivate research to understand their mechanism. Here, we report a 2.93 Å X-ray crystal structure of the minimal ternary complex between CCD, CTD, and the ALLINI BI-224436. This structure reveals an asymmetric ternary complex with a prominent network of π-mediated interactions that suggest specific avenues for future ALLINI development and optimization.

A phase I study to assess safety, pharmacokinetics, and pharmacodynamics of a vaginal insert containing tenofovir alafenamide and elvitegravir

Background

New multi-purpose prevention technology (MPT) products are needed to prevent human immunodeficiency virus (HIV) and herpes simplex virus type 2 (HSV2). In this study, we evaluated a fast-dissolve insert that may be used vaginally or rectally for prevention of infection.

Objective

To describe the safety, acceptability, multi-compartment pharmacokinetics (PK), and in vitro modeled pharmacodynamics (PD) after a single vaginal dose of an insert containing tenofovir alafenamide (TAF) and elvitegravir (EVG) in healthy women.

Methods

This was a Phase I, open-label, study. Women (n=16) applied one TAF (20mg)/EVG (16mg) vaginal insert and were randomized (1:1) to sample collection time groups for up to 7 days post dosing. Safety was assessed by treatment-emergent adverse events (TEAEs). EVG, TAF and tenofovir (TFV) concentrations were measured in plasma, vaginal fluid and tissue, and TFV-diphosphate (TFV-DP) concentration in vaginal tissue. PD was modeled in vitro by quantifying the change in inhibitory activity of vaginal fluid and vaginal tissue against HIV and HSV2 from baseline to after treatment. Acceptability data was collected by a quantitative survey at baseline and post treatment.

Results

The TAF/EVG insert was safe, with all TEAEs graded as mild, and acceptable to participants. Systemic plasma exposure was low, consistent with topical delivery, while high mucosal levels were detected, with median TFV vaginal fluid concentrations exceeding 200,000 ng/mL and 1,000 ng/mL for up to 24 hours and 7 days post dosing, respectively. All participants had vaginal tissue EVG concentrations of > 1 ng/mg at 4 and 24 hours post dosing. The majority had tissue TFV-DP concentrations exceeding 1000 fmol/mg by 24 - 72 hours post dosing. Vaginal fluid inhibition of HIV-1 and HSV-2 in vitro significantly increased from baseline and was similarly high at 4 and 24 hours post dosing. Consistent with high tissue TFV-DP concentrations, p24 HIV antigen production from ectocervical tissues infected ex vivo with HIV-1 significantly decreased from baseline at 4 hours post dosing. HSV-2 production from tissue also decreased post treatment.

Conclusions

A single dose of TAF/EVG inserts met PK benchmarks, with PK data supporting an extended window of high mucosal protection. PD modeling supports mucosal protection against both HIV-1 and HSV-2. The inserts were safe and highly acceptable.

Clinical trial registration

ClinicalTrials.gov, identifier NCT03762772.

High Instantaneous Inhibitory Potential of Bictegravir and the New Spiro-β-Lactam BSS-730A for HIV-2 Isolates from RAL-Naïve and RAL-Failing Patients

Integrase inhibitors (INIs) are an important class of drugs for treating HIV-2 infection, given the limited number of drugs active against this virus. While the clinical efficacy of raltegravir and dolutegravir is well established, the clinical efficacy of bictegravir for treating HIV-2 infected patients has not been determined. Little information is available regarding the activity of bictegravir against HIV-2 isolates from patients failing raltegravir-based therapy. In this study, we examined the phenotypic and matched genotypic susceptibility of HIV-2 primary isolates from raltegravir-naïve and raltegravir-failing patients to raltegravir, dolutegravir, and bictegravir, and to the new spiro-β-lactam BSS-730A. The instantaneous inhibitory potential (IIP) was calculated to help predict the clinical activity of bictegravir and BSS-730A. Isolates from raltegravir-naïve patients were highly sensitive to all INIs and BSS-730A. Combined integrase mutations E92A and Q148K conferred high-level resistance to raltegravir, and E92Q and T97A conferred resistance to raltegravir and dolutegravir. The antiviral activity of bictegravir and BSS-730A was not affected by these mutations. BSS-730A displayed strong antiviral synergism with raltegravir. Mean IIP values at Cmax were similar for all INIs and were not significantly affected by resistance mutations. IIP values were significantly higher for BSS-730A than for INIs. The high IIP values of bictegravir and BSS-730A for raltegravir-naïve and raltegravir-resistant HIV-2 isolates highlight their potential value for treating HIV-2 infection. Overall, the results are consistent with the high clinical efficacy of raltegravir and dolutegravir for HIV-2 infection and suggest a promising clinical profile for bictegravir and BSS-730A.

Comprehensive Review on Different Analytical Techniques for HIV 1- Integrase Inhibitors: Raltegravir, Dolutegravir, Elvitegravir and Bictegravir

The advent of HIV-Integrase inhibitors (IN) has marked a significant impact on the lives of HIV patients. Since the launch of the first anti retro-viral drug "Azidothymidine" to the recent advances of IN inhibitors, about 27.4 million people benefit by antiretroviral therapy (ART). The path had been challenging due to many crossroads, leading to the discovery of newer targets. One such recent ART target is Integrase. Use of Integrase inhibitors has surpassed the usage of all other ART owing to a strong barrier to resistance and have been reported to be the first-line therapy. Raltegravir, Elvitegravir, Dolutegravir and Bictegravir are US FDA approved IN inhibitors. The high usage of ART created an opportunity to study various analytical techniques for IN inhibitors. Hitherto, no review encompassing all IN inhibitors is presented. Herein, this review describes the analytical techniques employed for IN inhibitors estimation and quantification reported in the literature and official compendia. Literature suggests that most studies focus on LC-MS/MS and HPLC methods for drug estimation, and few reports suggest spectrophotometric, spectrofluorimetric and electrochemical methods. Furthermore, the review presents the techniques that describe the quantification of integrase drugs in various matrices. Although, antiretroviral drugs are extensively used but data suggests that limited studies have been conducted for determination of impurity profile and stability. This therefore, presents a scope to detect and validate impurities in order to meet ICH guidelines for their limits and further to improve the quality and safety of antiretroviral drugs.

N-4 Alkyl Cytosine Derivatives Synthesis: A New Approach

The selective N-4 alkylation of cytosine plays a critical role in the synthesis of biologically active molecules. This work focuses on the development of practical reaction conditions toward a regioselective synthesis of N-4-alkyl cytosine derivatives. The sequence includes a direct and selective sulfonylation at the N-1 site of the cytosine, followed by the alkylation of the amino site using KHMDS in CH2Cl2/THF mixture, providing a fast and efficient approach consistent with pyrimidine-based drug design.

Antiviral Activity and Resistance Profile of the Novel HIV-1 Non-Catalytic Site Integrase Inhibitor, JTP-0157602

HIV-1 integrase (IN) is an essential enzyme for viral replication. Non-catalytic site integrase inhibitors (NCINIs) are allosteric HIV-1 IN inhibitors and a potential new class of antiretrovirals. In this report, we identified a novel NCINI, JTP-0157602, with an original scaffold. JTP-0157602 exhibited potent antiviral activity against HIV-1 and showed a serum-shifted EC₉₀ of 138 nM, which is comparable to the FDA-approved IN strand transfer inhibitors (INSTIs). This compound was fully potent against a wide range of recombinant viruses with IN polymorphisms, including amino acids 124/125, a hot spot of IN polymorphisms. In addition, JTP-0157602 retained potent antiviral activity against a broad panel of recombinant viruses with INSTI-related resistant mutations, including multiple substitutions that emerged in clinical studies of INSTIs. Resistance selection experiments of JTP-0157602 led to the emergence of A128T and T174I mutations, which are located at the lens epithelium-derived growth factor/p75 binding pocket of IN. JTP-0157602 inhibited HIV-1 replication mainly during the late-phase of the replication cycle, and HIV-1 virions produced by reactivation from HIV-1 latently-infected Jurkat cells in the presence of JTP-0157602 were non-infectious. These results suggest that JTP-0157602 and analog compounds can be used to treat HIV-1 infectious diseases. IMPORTANCE Non-catalytic site integrase inhibitors (NCINIs) are allosteric HIV-1 integrase (IN) inhibitors that bind to the lens epithelium-derived growth factor (LEDGF)/p75 binding pocket of IN. NCINIs are expected to be a new class of anti-HIV-1 agents. In this study, we present a novel NCINI, JTP-0157602, which has potent activity against a broad range of HIV-1 strains with IN polymorphisms. Furthermore, JTP-0157602 shows strong antiviral activity against IN strand transfer inhibitor-resistant mutations, suggesting JTP-0157602 and its analogs are potential agents to treat HIV-1 infections. Structural modeling indicated that JTP-0157602 binds to the LEDGF/p75 binding pocket of IN, and the results of in vitro resistance induction revealed the JTP-0157602-resistance mechanism of HIV-1. These data shed light on developing novel NCINIs, which exhibit potent activity against HIV-1 with broad IN polymorphisms and multi-drug resistant HIV-1 variants.

HIV-1 drug resistance and genetic diversity in a cohort of people with HIV-1 in Nigeria

OBJECTIVE

This study was designed to provide information on the genetic diversity of HIV-1 and drug resistance mutations in Nigeria, as there is limited understanding of variants circulating in the country.

METHODS

We used an advanced next-generation sequencing platform, Primer ID, to: investigate the presence of high and low abundance drug resistance mutations; characterize preexisting Integrase Strand Transfer Inhibitor (INSTI) mutations in antiretroviral therapy (ART)-experienced but dolutegravir-naive individuals; detect recent HIV-1 infections and characterize subtype diversity from a cohort of people with HIV-1 (PWH).

RESULTS

HIV-1 subtype analysis revealed the predominance of CRF02_AG and subtype G in our study population. At detection sensitivity of 30% abundance, drug resistance mutations (DRMs) were identified in 3% of samples. At a sensitivity level of 10%, DRMs were identified in 27.3% of samples. We did not detect any major INSTI mutation associated with dolutegravir-resistance. Only one recent infection was detected in our study population.

CONCLUSION

Our study suggests that dolutegravir-containing antiretroviral regimens will be effective in Nigeria. Our study also further emphasizes the high genetic diversity of HIV-1 in Nigeria and that CRF02_AG and subtype G are the dominant circulating forms of HIV-1 in Nigeria. These two circulating forms of the virus are largely driving the epidemic in the country.

Advances in the development of HIV integrase strand transfer inhibitors

HIV-1 integrase (IN) is a key enzyme in viral replication that catalyzes the covalent integration of viral cDNA into the host genome. Currently, five HIV-1 IN strand transfer inhibitors (INSTIs) are approved for clinical use. These drugs represent an important addition to the armamentarium for antiretroviral therapy. This review briefly illustrates the development history of INSTIs. The characteristics of the currently approved INSTIs, as well as their future perspectives, are critically discussed.

Selective elimination of host cells harboring replication-competent human immunodeficiency virus reservoirs: a promising therapeutic strategy for HIV cure

ABSTRACT

Many seminal advances have been made in human immunodeficiency virus (HIV)/AIDS research over the past four decades. Treatment strategies, such as gene therapy and immunotherapy, are yielding promising results to effectively control HIV infection. Despite this, a cure for HIV/AIDS is not envisioned in the near future. A recently published academic study has raised awareness regarding a promising alternative therapeutic option for HIV/AIDS, referred to as "selective elimination of host cells capable of producing HIV" (SECH). Similar to the "shock and kill strategy," the SECH approach requires the simultaneous administration of drugs targeting key mechanisms in specific cells to efficiently eliminate HIV replication-competent cellular reservoirs. Herein, we comprehensively review the specific mechanisms targeted by the SECH strategy. Briefly, the suggested cocktail of drugs should contain (i) latency reversal agents to promote the latency reversal process in replication-competent reservoir cells, (ii) pro-apoptotic and anti-autophagy drugs to induce death of infected cells through various pathways, and finally (iii) drugs that eliminate new cycles of infection by prevention of HIV attachment to host cells, and by HIV integrase inhibitor drugs. Finally, we discuss three major challenges that are likely to restrict the application of the SECH strategy in HIV/AIDS patients.

Algae-mediated processes for the treatment of antiretroviral drugs in wastewater: Prospects and challenges

The prevalence of pharmaceuticals (PCs), especially antiretroviral (ARV) drugs in various aquatic ecosystems has been expansively reported, wherein wastewater treatment plants (WWTPs) are identified as the primary point source. Consequently, the occurrence, ecotoxicity and treatment of ARV drugs in WWTPs have drawn much attention in recent years. Numerous studies have shown that the widely employed activated sludge-based WWTPs are incapable of removing ARV drugs efficiently from wastewater. Recently, algae-based wastewater treatment processes have shown promising results in PCs removal from wastewater, either completely or partially, through different processes such as biosorption, bioaccumulation, and intra-/inter-cellular degradation. Algal species have also shown to tolerate high concentrations of ARV drugs than the reported concentrations in the environmental matrices. In this review, emphasis has been given on discussing the current status of the occurrence of ARV drugs in the aquatic environment and WWTPs. Besides, the current trends and future perspectives of PCs removal by algae are critically reviewed and discussed. The potential pathways and mechanisms of ARV drugs removal by algae have also been discussed.

Clinical Safety Considerations of Integrase Strand Transfer Inhibitors in the Older Population Living with HIV

There are approximately 40 million people living with HIV globally, and 21% (7.9 million) are older adults (aged > 50 years) as of 2019. The average age of HIV-positive patients is predicted to increase to 58 by 2035. The favorable clinical efficacy of integrase strand transfer inhibitors has led to high rates of viral suppression and have now become the preferred agents by the AIDS guideline when initiating antiretroviral therapy. There are concerns of increasing adverse effects from HIV medications, such as integrase strand transfer inhibitors, as a result of changes in pharmacodynamic and pharmacokinetic parameters within the older population. The authors aim to describe the safety concerns of the current integrase strand transfer inhibitors based upon a narrative literature review, including recommendations for drug-drug interactions, and relevant comorbidities to consider for selection of the most appropriate integrase strand transfer inhibitor for older people living with HIV. Raltegravir is a well-tolerated option with minor adverse events; however, adherence to a twice-daily regimen may be difficult in older patients who are also taking many other medications for various comorbidities. Elvitegravir is also well tolerated with limited adverse effects, but has many drug-drug interactions that may pose problems for older patients with polypharmacy. Dolutegravir has been associated with more frequent adverse events, such as neuropsychiatric disorders.

Clinical Features and Outcomes of Coronavirus Disease 2019 Among People With Human Immunodeficiency Virus in the United States: A Multicenter Study From a Large Global Health Research Network (TriNetX)

Background

Human immunodeficiency virus infection (HIV) is a presumed risk factor for severe coronavirus disease 2019 (COVID-19), yet little is known about COVID-19 outcomes in people with HIV (PWH).

Methods

We used the TriNetX database to compare COVID-19 outcomes of PWH and HIV-negative controls aged ≥18 years who sought care in 44 healthcare centers in the United States from January 1 to December 1, 2020. Outcomes of interest were rates of hospitalization (composite of inpatient non-intensive care [ICU] and ICU admissions), mechanical ventilation, severe disease (ICU admission or death), and 30-day mortality.

Results

Of 297 194 confirmed COVID-19 cases, 1638 (0.6%) were HIV-infected, with >83% on antiretroviral therapy (ART) and 48% virally suppressed. Overall, PWH were more commonly younger, male, African American or Hispanic, had more comorbidities, were more symptomatic, and had elevated procalcitonin and interleukin 6. Mortality at 30 days was comparable between the 2 groups (2.9% vs 2.3%, P = .123); however, PWH had higher rates hospitalization (16.5% vs 7.6%, P < .001), ICU admissions (4.2% vs 2.3%, P < .001), and mechanical ventilation (2.4% vs 1.6%, P < .005). Among PWH, hospitalization was independently associated with male gender, being African American, integrase inhibitor use, and low CD4 count; whereas severe disease was predicted by older age (adjusted odds ratio [aOR], 8.33; 95% confidence interval [CI], 1.06-50.00; P = .044) and CD4 <200 cells/mm³ (aOR, 8.33; 95% CI, 1.06-50.00; P = .044).

Conclusions

People with HIV had higher rates of poor COVID-19 outcomes but were not more at risk of death than their non-HIV-infected counterparts. Older age and low CD4 count predicted adverse outcomes.

HIV-1 Integrase Inhibitors with Modifications That Affect Their Potencies against Drug Resistant Integrase Mutants

Integrase strand transfer inhibitors (INSTIs) block the integration step of the retroviral lifecycle and are first-line drugs used for the treatment of HIV-1/AIDS. INSTIs have a polycyclic core with heteroatom triads, chelate the metal ions at the active site, and have a halobenzyl group that interacts with viral DNA attached to the core by a flexible linker. The most broadly effective INSTIs inhibit both wild-type (WT) integrase (IN) and a variety of well-known mutants. However, because there are mutations that reduce the potency of all of the available INSTIs, new and better compounds are needed. Models based on recent structures of HIV-1 and red-capped mangabey SIV INs suggest modifications in the INSTI structures that could enhance interactions with the 3′-terminal adenosine of the viral DNA, which could improve performance against INSTI resistant mutants. We designed and tested a series of INSTIs having modifications to their naphthyridine scaffold. One of the new compounds retained good potency against an expanded panel of HIV-1 IN mutants that we tested. Our results suggest the possibility of designing inhibitors that combine the best features of the existing compounds, which could provide additional efficacy against known HIV-1 IN mutants.

HIV-1 Integrase Inhibitors with Modifications That Affect Their Potencies against Drug Resistant Integrase Mutants

Integrase strand transfer inhibitors (INSTIs) block the integration step of the retroviral lifecycle and are first-line drugs used for the treatment of HIV-1/AIDS. INSTIs have a polycyclic core with heteroatom triads, chelate the metal ions at the active site, and have a halobenzyl group that interacts with viral DNA attached to the core by a flexible linker. The most broadly effective INSTIs inhibit both wild-type (WT) integrase (IN) and a variety of well-known mutants. However, because there are mutations that reduce the potency of all of the available INSTIs, new and better compounds are needed. Models based on recent structures of HIV-1 and red-capped mangabey SIV INs suggest modifications in the INSTI structures that could enhance interactions with the 3'-terminal adenosine of the viral DNA, which could improve performance against INSTI resistant mutants. We designed and tested a series of INSTIs having modifications to their naphthyridine scaffold. One of the new compounds retained good potency against an expanded panel of HIV-1 IN mutants that we tested. Our results suggest the possibility of designing inhibitors that combine the best features of the existing compounds, which could provide additional efficacy against known HIV-1 IN mutants.

Quinolinonyl Non-Diketo Acid Derivatives as Inhibitors of HIV-1 Ribonuclease H and Polymerase Functions of Reverse Transcriptase

Novel anti-HIV agents are still needed to overcome resistance issues, in particular inhibitors acting against novel viral targets. The ribonuclease H (RNase H) function of the reverse transcriptase (RT) represents a validated and promising target, and no inhibitor has reached the clinical pipeline yet. Here, we present rationally designed non-diketo acid selective RNase H inhibitors (RHIs) based on the quinolinone scaffold starting from former dual integrase (IN)/RNase H quinolinonyl diketo acids. Several derivatives were synthesized and tested against RNase H and viral replication and found active at micromolar concentrations. Docking studies within the RNase H catalytic site, coupled with site-directed mutagenesis, and Mg²⁺ titration experiments demonstrated that our compounds coordinate the Mg²⁺ cofactor and interact with amino acids of the RNase H domain that are highly conserved among naïve and treatment-experienced patients. In general, the new inhibitors influenced also the polymerase activity of RT but were selective against RNase H vs the IN enzyme.

Long-Acting Cabotegravir for HIV/AIDS Prophylaxis

The retrovirus HIV-1 is the etiological agent of the decades-long AIDS pandemic. Although vaccination is the most common preexposure route to prevent acquisition of viral disease, scalable efficacious vaccination strategies have yet to be developed for HIV-1. By contrast, small molecule inhibitors of the HIV-1 enzymes reverse transcriptase, integrase, and protease have been developed that effectively block virus replication. Three different drug compounds are commonly prescribed for people living with HIV as once-daily oral tablets. Once-daily pills composed of two different reverse transcriptase inhibitors are moreover approved as preexposure prophylaxis (PrEP) treatment for virus naïve individuals who may partake in behaviors associated with increased risk of HIV-1 acquisition such as unprotected sex or injection drug use. Long-acting (LA) injectable HIV-1 enzyme inhibitors are at the same time being developed to sidestep adherence noncompliance issues that can arise from self-administered once-daily oral dosing regimens. Cabotegravir (CAB)-LA, which inhibits integrase strand transfer activity, has in recent clinical trials been shown to prevent HIV-1 acquisition more effectively than once-daily oral dosed reverse transcriptase inhibitors. In this Perspective, we examine bench to bedside aspects of CAB-LA treatment and development, starting from the biochemical basis of HIV-1 integration and pharmacological inhibition of integrase catalysis. We also review the results of recent clinical trials that evaluated CAB-LA, as well as the promises and challenges that surround its use for HIV/AIDS PrEP.

Interaction analysis of statistically enriched mutations identified in Cameroon recombinant subtype CRF02_AG that can influence the development of Dolutegravir drug resistance mutations

BACKGROUND

The Integrase (IN) strand transfer inhibitor (INSTI), Dolutegravir (DTG), has been given the green light to form part of first-line combination antiretroviral therapy (cART) by the World Health Organization (WHO). DTG containing regimens have shown a high genetic barrier against HIV-1 isolates carrying specific resistance mutations when compared with other class of regimens.

METHODS

We evaluated the HIV-1 CRF02_AG IN gene sequences from Cameroon for the presence of resistance-associated mutations (RAMs) against INSTIs and naturally occurring polymorphisms (NOPs), using study sequences (n = 20) and (n = 287) sequences data derived from HIV Los Alamos National Laboratory database. The possible impact of NOPs on protein structure caused by HIV-1 CRF02_AG variations was addressed within the context of a 3D model of the HIV-1 IN complex and interaction analysis was performed using PyMol to validate DTG binding to the Wild type and seven mutant structures.

RESULTS

We observed 12.8% (37/287) sequences to contain RAMs, with only 1.0% (3/287) of the sequences having major INSTI RAMs: T66A, Q148H, R263K and N155H. Of these,11.8% (34/287) of the sequences contained five different IN accessory mutations; namely Q95K, T97A, G149A, E157Q and D232N. NOPs occurred at a frequency of 66% on the central core domain (CCD) position, 44% on the C-terminal domain (CTD) position and 35% of the N-terminal domain (NTD) position. The interaction analysis revealed that DTG bound to DNA, 2MG ions and DDE motif residues for T66A, T97A, Q148H, N155H and R263K comparable to the WT structure. Except for accessory mutant structure E157Q, only one MG contact was made with DTG, while DTG had no MG ion contacts and no DDE motif residue contacts for structure D232N.

CONCLUSIONS

Our analysis indicated that all RAM's that resulted in a change in the number of interactions with encompassing residues does not affect DTG binding, while accessory mutations E157Q and D232N could affect DTG binding leading to possible DTG resistance. However, further experimental validation is required to validate the in silico findings of our study.

Integrase strand transfer inhibitor (INSTI)-resistance mutations for the surveillance of transmitted HIV-1 drug resistance

BACKGROUND

Integrase strand transfer inhibitors (INSTIs) are expected to be widely adopted globally, requiring surveillance of resistance emergence and transmission.

OBJECTIVES

We therefore sought to develop a standardized list of INSTI-resistance mutations suitable for the surveillance of transmitted INSTI resistance.

METHODS

To characterize the suitability of the INSTI-resistance mutations for transmitted HIV-1 drug resistance (TDR) surveillance, we classified them according to their presence on published expert lists, conservation in INSTI-naive persons, frequency in INSTI-treated persons and contribution to reduced in vitro susceptibility. Mutation prevalences were determined using integrase sequences from 17302 INSTI-naive and 2450 INSTI-treated persons; 53.3% of the INSTI-naive sequences and 20.0% of INSTI-treated sequences were from non-B subtypes. Approximately 10% of sequences were from persons who received dolutegravir alone or a first-generation INSTI followed by dolutegravir.

RESULTS

Fifty-nine previously recognized (or established) INSTI-resistance mutations were present on one or more of four published expert lists. They were classified into three main non-overlapping groups: 29 relatively common non-polymorphic mutations, occurring in five or more individuals and significantly selected by INSTI treatment; 8 polymorphic mutations; and 22 rare mutations. Among the 29 relatively common INSTI-selected mutations, 24 emerged as candidates for inclusion on a list of INSTI surveillance drug-resistance mutations: T66A/I/K, E92G/Q, G118R, F121Y, E138A/K/T, G140A/C/S, Y143C/H/R/S, S147G, Q148H/R/K, N155H, S230R and R263K.

CONCLUSIONS

A set of 24 non-polymorphic INSTI-selected mutations is likely to be useful for quantifying INSTI-associated TDR. This list may require updating as more sequences become available from INSTI-experienced persons infected with HIV-1 non-subtype B viruses and/or receiving dolutegravir.

Integrase Strand Transfer Inhibitors Are Effective Anti-HIV Drugs

Integrase strand transfer inhibitors (INSTIs) are currently recommended for the first line treatment of human immunodeficiency virus type one (HIV-1) infection. The first-generation INSTIs are effective but can select for resistant viruses. Recent advances have led to several potent second-generation INSTIs that are effective against both wild-type (WT) HIV-1 integrase and many of the first-generation INSTI-resistant mutants. The emergence of resistance to these new second-generation INSTIs has been minimal, which has resulted in alternative treatment strategies for HIV-1 patients. Moreover, because of their high antiviral potencies and, in some cases, their bioavailability profiles, INSTIs will probably have prominent roles in pre-exposure prophylaxis (PrEP). Herein, we review the current state of the clinically relevant INSTIs and discuss the future outlook for this class of antiretrovirals.

Structural Insights to Human Immunodeficiency Virus (HIV-1) Targets and Their Inhibition

Human immunodeficiency virus (HIV) is a deadly virus that attacks the body's immune system, subsequently leading to AIDS (acquired immunodeficiency syndrome) and ultimately death. Currently, there is no vaccine or effective cure for this infection; however, antiretrovirals that act at various phases of the virus life cycle have been useful to control the viral load in patients. One of the major problems with antiretroviral therapies involves drug resistance. The three-dimensional structure from crystallography studies are instrumental in understanding the structural basis of drug binding to various targets. This chapter provides key insights into different targets and drugs used in the treatment from a structural perspective. Specifically, an insight into the binding characteristics of drugs at the active and allosteric sites of different targets and the importance of targeting allosteric sites for design of new-generation antiretrovirals to overcome complex and resistant forms of the virus has been reviewed.

Evidence for Disruption of Mg2+ Pair as a Resistance Mechanism Against HIV-1 Integrase Strand Transfer Inhibitors

HIV-1 integrase is the enzyme responsible for integrating the viral DNA into the host genome and is one of the main targets for antiretroviral therapy; however, there are documented cases of resistance against all the currently used integrase strand transfer inhibitors (INSTIs). While some resistance-related mutations occur near the inhibitor’s binding site, the mutation N155H occurs on the opposite side of the drug-interacting Mg²⁺ ions, thus, not interacting directly with the drug molecules and currently lacking an explanation for its resistance mechanism. Moreover, mutation N155H and the resistance-related mutation Q148H are mutually exclusive for unknown reasons. In the present study, we use molecular dynamics simulations to understand the impact of the N155H mutation in the HIV-1 integrase structure and dynamics, when alone or in combination with Q148H. Our findings suggest that the Mg²⁺ ions of the active site adopt different orientations in each of the mutants, causing the catalytic triad residues involved in the ion coordination to adapt their side-chain configurations, completely changing the INSTIs binding site. The change in the ion coordination also seems to affect the flexibility of the terminal viral DNA nucleotide near the active site, potentially impairing the induced-fit mechanism of the drugs. The explanations obtained from our simulations corroborate previous hypotheses drawn from crystallographic studies. The proposed resistance mechanism can also explain the resistance caused by other mutations that take place in the same region of the integrase and help uncover the structural details of other HIV-1 resistance mechanisms.

Sc(OTf)3-Catalyzed Synthesis of Symmetrical Dithioacetals and Bisarylmethanes Using Nitromethane as a Methylene Source

Use of nitromethane as an electrophilic methylene source for the synthesis of symmetrical dithioacetals and bisarylmethanes has been showcased using Sc(OTf)₃ as a catalyst. The procedure allows straightforward access to the densely functionalized dithioacetals and bisarylmethanes under mild conditions. Additionally, the method has been applied for the synthesis of antimalarial tetramethyl mellotojaponin C and anticancer dimeric phloroglucinol derivative.

Resistance to integrase inhibitors: a national study in HIV-1-infected treatment-naive and -experienced patients

OBJECTIVES

To describe integrase strand transfer inhibitor (INSTI) resistance profiles and factors associated with resistance in antiretroviral-naive and -experienced patients failing an INSTI-based regimen in clinical practice.

METHODS

Data were collected from patients failing an INSTI-containing regimen in a multicentre French study between 2014 and 2017. Failure was defined as two consecutive plasma viral loads (VL) >50 copies/mL. Reverse transcriptase, protease and integrase coding regions were sequenced at baseline and failure. INSTI resistance-associated mutations (RAMs) included in the Agence Nationale de Recherches sur le SIDA genotypic algorithm were investigated.

RESULTS

Among the 674 patients, 359 were failing on raltegravir, 154 on elvitegravir and 161 on dolutegravir therapy. Overall, 90% were experienced patients and 389 (58%) patients showed no INSTI RAMs at failure. The strongest factors associated with emergence of at least one INSTI mutation were high VL at failure (OR = 1.2 per 1 log10 copies/mL increase) and low genotypic sensitivity score (GSS) (OR = 0.08 for GSS ≥3 versus GSS = 0-0.5). Patients failing dolutegravir also had significantly fewer INSTI RAMs at failure than patients failing raltegravir (OR = 0.57, P = 0.02) or elvitegravir (OR = 0.45, P = 0.005). Among the 68 patients failing a first-line regimen, 11/41 (27%) patients on raltegravir, 7/18 (39%) on elvitegravir and 0/9 on dolutegravir had viruses with emergent INSTI RAMs at failure.

CONCLUSIONS

These results confirmed the robustness of dolutegravir regarding resistance selection in integrase in the case of virological failure in routine clinical care.

Quinolines-Based SARS-CoV-2 3CLpro and RdRp Inhibitors and Spike-RBD-ACE2 Inhibitor for Drug-Repurposing Against COVID-19: An in silico Analysis

The novel coronavirus SARS-CoV-2 disease “COVID-19” emerged in China and rapidly spread to other countries; due to its rapid worldwide spread, the WHO has declared this as a global emergency. As there is no specific treatment prescribed to treat COVID-19, the seeking of suitable therapeutics among existing drugs seems valuable. The structure availability of coronavirus macromolecules has encouraged the finding of conceivable anti-SARS-CoV-2 therapeutics through in silico analysis. The results reveal that quinoline,1,2,3,4-tetrahydro-1-[(2-phenylcyclopropyl)sulfonyl]-trans-(8CI) and saquinavir strongly interact with the active site (Cys-His catalytic dyad), thereby are predicted to hinder the activity of SARS-CoV-2 3CLpro. Out of 113 quinoline-drugs, elvitegravir and oxolinic acid are able to interact with the NTP entry-channel and thus interfere with the RNA-directed 5′-3′ polymerase activity of SARS-CoV-2 RdRp. The bioactivity-prediction results also validate the outcome of the docking study. Moreover, as SARS-CoV-2 Spike-glycoprotein uses human ACE2-receptor for viral entry, targeting the Spike-RBD-ACE2 has been viewed as a promising strategy to control the infection. The result shows rilapladib is the only quinoline that can interrupt the Spike-RBD-ACE2 complex. In conclusion, owing to their ability to target functional macromolecules of SARS-CoV-2, along with positive ADMET properties, quinoline,1,2,3,4-tetrahydro-1-[(2-phenylcyclopropyl)sulfonyl]-trans-(8CI), saquinavir, elvitegravir, oxolinic acid, and rilapladib are suggested for the treatment of COVID-19.

Design, Synthesis, Docking Studies and Biological Activities Novel 2,3- Diaryl-4-Quinazolinone Derivatives as Anti-HIV-1 Agents

BACKGROUND

Although major efforts have been devoted to the effective treatment of HIV-1 infection, it has remained one of the leading causes of deaths around the world. So, development of anti-HIV-1 agents featuring novel structure is essential.

OBJECTIVE

To synthesize novel quinazolinone derivatives and evaluate their anti-HIV-1 activity.

METHOD

In this study, we designed and synthesized a series of novel 2,3-diaryl-4-quinazolinone derivatives using a one-pot multicomponent reaction. Then, the resulting derivatives were evaluated for anti-HIV-1 activity using Hela cell-based single-cycle replication assay.

RESULTS

Most of the compounds showed efficacy against HIV-1 replication and the compound 9c exhibited the highest activity with EC50 value of 37 μM. Docking studies indicated that synthesized compounds can interact with the key residues of the HIV-1 integrase active site. Binding of the most active compound was consistent with the HIV-1 integrase inhibitors.

CONCLUSION

Based on our results, these derivatives represent novel lead compounds for the development of new promising anti-HIV-1 agents.

Quantum-Chemistry Based Design of Halobenzene Derivatives With Augmented Affinities for the HIV-1 Viral G4/C16 Base-Pair

The HIV-1 integrase (IN) is a major target for the design of novel anti-HIV inhibitors. Among these, three inhibitors which embody a halobenzene ring derivative (HR) in their structures are presently used in clinics. High-resolution X-ray crystallography of the complexes of the IN-viral DNA transient complex bound to each of the three inhibitors showed in all cases the HR ring to interact within a confined zone of the viral DNA, limited to the highly conserved 5′CpA 3′/5′TpG 3′ step. The extension of its extracyclic CX bond is electron-depleted, owing to the existence of the “sigma-hole.” It interacts favorably with the electron-rich rings of base G₄. We have sought to increase the affinity of HR derivatives for the G₄/C₁₆ base pair. We thus designed thirteen novel derivatives and computed their Quantum Chemistry (QC) intermolecular interaction energies (ΔE) with this base-pair. Most compounds had ΔE values significantly more favorable than those of the HR of the most potent halobenzene drug presently used in clinics, Dolutegravir. This should enable the improvement in a modular piece-wise fashion, the affinities of halogenated inhibitors for viral DNA (vDNA). In view of large scale polarizable molecular dynamics simulations on the entirety of the IN-vDNA-inhibitor complexes, validations of the SIBFA polarizable method are also reported, in which the evolution of each ΔE(SIBFA) contribution is compared to its QC counterpart along this series of derivatives.

The crosstalk between antiretrovirals pharmacology and HIV drug resistance

INTRODUCTION

The clinical development of antiretroviral drugs has been followed by a rapid and concomitant development of HIV drug resistance. The development and spread of HIV drug resistance is due on the one hand to the within-host intrinsic HIV evolutionary rate and on the other to the wide use of low genetic barrier antiretrovirals.

AREAS COVERED

We searched PubMed and Embase on 31 January 2020, for studies reporting antiretroviral resistance and pharmacology. In this review, we assessed the molecular target and mechanism of drug resistance development of the different antiretroviral classes focusing on the currently approved antiretroviral drugs. Then, we assessed the main pharmacokinetic/pharmacodynamic of the antiretrovirals. Finally, we retraced the history of antiretroviral treatment and its interconnection with antiretroviral worldwide resistance development both in , and middle-income countries in the perspective of 90-90-90 World Health Organization target.

EXPERT OPINION

Drug resistance development is an invariably evolutionary driven phenomenon, which challenge the 90-90-90 target. In high-income countries, the antiretroviral drug resistance seems to be stable since the last decade. On the contrary, multi-intervention strategies comprehensive of broad availability of high genetic barrier regimens should be implemented in resource-limited setting to curb the rise of drug resistance.

De novo design based identification of potential HIV-1 integrase inhibitors: A pharmacoinformatics study

In the present study, pharmacoinformatics paradigms include receptor-based de novo design, virtual screening through molecular docking and molecular dynamics (MD) simulation are implemented to identify novel and promising HIV-1 integrase inhibitors. The de novodrug/ligand/molecule design is a powerful and effective approach to design a large number of novel and structurally diverse compounds with the required pharmacological profiles. A crystal structure of HIV-1 integrase bound with standard inhibitor BI-224436 is used and a set of 80,000 compounds through the de novo approach in LigBuilder is designed. Initially, a number of criteria including molecular docking, in-silico toxicity and pharmacokinetics profile assessments are implied to reduce the chemical space. Finally, four de novo designed molecules are proposed as potential HIV-1 integrase inhibitors based on comparative analyses. Notably, strong binding interactions have been identified between a few newly identified catalytic amino acid residues and proposed HIV-1 integrase inhibitors. For evaluation of the dynamic stability of the protein-ligand complexes, a number of parameters are explored from the 100 ns MD simulation study. The MD simulation study suggested that proposed molecules efficiently retained their molecular interaction and structural integrity inside the HIV-1 integrase. The binding free energy is calculated through the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) approach for all complexes and it also explains their thermodynamic stability. Hence, proposed molecules through de novo design might be critical to inhibiting the HIV-1 integrase.

Recent Advances in the Development of Integrase Inhibitors for HIV Treatment

PURPOSE OF THE REVIEW

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

RECENT FINDINGS

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

A three-component reaction of phosphorus ylides with isocyanates: facile synthesis of 2-amino-3-carboxylate-4-quinolones

A three-component reaction between one molecule of phosphorus ylides (P-ylides) and two molecules of isocyanates for the rapid assembly of 2-amino-3-carboxylate-4-quinolones is described. The mechanism may involve the addition of a P-ylide to an isocyanate followed by 1,3-H shift to form a carbamoyl stabilized P-ylide. The intermediate then reacts with another aryl isocyanate via Wittig/ketenimine-ketene rearrangement/6π-electrocyclization/1,3-H shift to finally afford the 4-quinolones.

Access to 2-Alkyl/Aryl-4-(1H)-Quinolones via Orthogonal "NH3" Insertion into o-Haloaryl Ynones: Total Synthesis of Bioactive Pseudanes, Graveoline, Graveolinine, and Waltherione F

An efficient one-pot synthesis of 4-(1H)-quinolones through an orthogonal engagement of diverse o-haloaryl ynones with ammonia in the presence of Cu(I), involving tandem Michael addition and ArCsp₂-N coupling, is presented. The substrate scope of this convenient protocol, wherein ammonium carbonate acts as both an in situ ammonia source and a base toward diverse 2-substituted 4-(1H)-quinolones, has been mapped and its efficacy validated through concise total synthesis of bioactive natural products pseudanes (IV, VII, VIII, and XII), graveoline, graveolinine, and waltherione F.

N-arylnaphthylamines as inhibitors of human immunodeficiency virus integrase - lens epithelium-derived growth factor interactions: theoretical studies

Presented work reports a comprehensive theoretical study on the inhibitory nature of N-arylnaphthylamines in Human Immunodeficiency Virus Integrase (HIV IN) - Lens Epithelium-Derived Growth Factor (LEDGF/p75) complexes. Factors influencing the inhibition efficiency in AlphaScreen% assay are evaluated and explained through the structure- and ligand-based studies; including molecular docking, molecular dynamics calculations, and quantitative structure-activity relationship (QSAR) approach. It has been shown that N-arylnaphthylamines possess a wide variety of binding poses. Three QSAR models have been developed using structural descriptors and descriptors derived from docking calculations. The activity of untested N-arylnaphthylamines have been predicted using the most successful model. Proposed here technique could become a useful tool for ligand selection, accelerating the development of a new generation of anti-HIV medications. [Formula: see text] Communicated by Ramaswamy H. Sarma.

Synthesis, Molecular Modelling and Biological Studies of 3-hydroxypyrane- 4-one and 3-hydroxy-pyridine-4-one Derivatives as HIV-1 Integrase Inhibitors

BACKGROUND

Despite the progress in the discovery of antiretroviral compounds for treating HIV-1 infection by targeting HIV integrase (IN), a promising and well-known drug target against HIV-1, there is a growing need to increase the armamentarium against HIV, for avoiding the drug resistance issue.

OBJECTIVE

To develop novel HIV-1 IN inhibitors, a series of 3-hydroxy-pyrane-4-one (HP) and 3- hydroxy-pyridine-4-one (HPO) derivatives have been rationally designed and synthesized.

METHODS

To provide a significant characterization of the novel compounds, in-depth computational analysis was performed using a novel HIV-1 IN/DNA binary 3D-model for investigating the binding mode of the newly conceived molecules in complex with IN. The 3D-model was generated using the proto-type foamy virus (PFV) DNA as a structural template, positioning the viral polydesoxyribonucleic chain into the HIV-1 IN homology model. Moreover, a series of in vitro tests were performed including HIV-1 activity inhibition, HIV-1 IN activity inhibition, HIV-1 IN strand transfer activity inhibition and cellular toxicity.

RESULTS

Bioassay results indicated that most of HP analogues including HPa, HPb, HPc, HPd, HPe and HPg, showed favorable inhibitory activities against HIV-1-IN in the low micromolar range. Particularly halogenated derivatives (HPb and HPd) offered the best biological activities in terms of reduced toxicity and optimum inhibitory activities against HIV-1 IN and HIV-1 in cell culture.

CONCLUSION

Halogenated derivatives, HPb and HPd, displayed the most promising anti-HIV profile, paving the way to the optimization of the presented scaffolds for developing new effective antiviral agents.

Update on Adverse Effects of HIV Integrase Inhibitors

PURPOSE OF REVIEW

The goal of this paper is to provide an up-to-date review of adverse events related to the class of integrase strand transfer inhibitors (INSTIs), which became the class of choice in few years. We sought answers specifically to issues pertaining to neuropsychiatric adverse events, as well as weight gain, which were the two most important categories of adverse events raised in recent studies based on real-life experience. The primary focus of this paper is on adults with a brief summary on pregnant women and children/adolescents.

RECENT FINDINGS

Dolutegravir (DTG) bears the heaviest burden of neuropsychiatric side effects. Weight gain was reported with all INSTIs, although there are methodological caveats in the analyses and the findings need to be interpreted with caution.Moreover, due to recent findings on neural tube defects in infants exposed to dolutegravir during their peri-conception period, its use is not recommended for women of childbearing age without proper birth control method, while raltegravir remains the only drug which may be prescribed without caution. Given the importance of cognitive and metabolic co-morbidities in people living with HIV in regard to their quality of life, future research needs to focus on long-term effects of INSTIs in relation to these adverse events. Pharmacogenetics seems to be a promising tool. Safety during pregnancy is also another important issue to further clarify.

SUMMARY

INSTIs are a generally well-tolerated class of antiretrovirals (ARV), and has a higher antiviral potency compared to other classes of ARV.Clinicians and patients need however to be aware of some red flags when starting with and monitoring patients on INSTIs.All INSTIs can lead to mild increases in creatinine levels, usually without clinical significance, but caution is needed in patients with low eGFR (<30ml/min), when using other nephrotoxic drugs, such as as tenofovir disoproxil.Neuro-psychiatric (NP) effects are to be monitored with INSTIs, especially with DTG (though reports are at times contradictory); clinicians might want to avoid DTG for patients with history of severe NP symptoms, until clarity is provided.Weight gain was reported with all INSTIs, especially with DTG, with possible differential effects according to sex and ethnicity (female and non-white patients being at increased risk). This is worrying since patients from African descent are at higher risk of cardio-vascular events and increased body mass index (BMI) can cause further increase metabolic risk. There is possibly an additional effect of tenofovir alafenamide (TAF) on weight increase.Discrepancies between clinical trials - with low rates of adverse events - and reports from real-life settings might be due partly to under-representation of some groups of patients in clinical trials, and/or the short duration of follow-up, since some adverse effects may only occur after prolonged exposure.Preliminary data on safety of bictegravir (BIC), from clinical trials and non-trial settings, are very reassuring and seem to show lower rates of adverse events compared to DTG.Elvitegravir/cobicistat (EVG/cobi) need to be used with caution in patients with other co-morbidities given potential for polypharmacy, as it is the case for aging patients, because of the high potential of drug-drug interactions due to effects of the cobicistat booster.We are awaiting the release of cabotegravir (CAB), which could represent a good option for patients struggling with adherence, despite injection site reactions.Pharmacogenetics is a promising way to explore adverse effects occurrence in the INSTI class.

Discovery and Development of Anti-HIV Therapeutic Agents: Progress Towards Improved HIV Medication

The history of the human immunodeficiency virus (HIV)/AIDS therapy, which spans over 30 years, is one of the most dramatic stories of science and medicine leading to the treatment of a disease. Since the advent of the first AIDS drug, AZT or zidovudine, a number of agents acting on different drug targets, such as HIV enzymes (e.g. reverse transcriptase, protease, and integrase) and host cell factors critical for HIV infection (e.g. CD4 and CCR5), have been added to our armamentarium to combat HIV/AIDS. In this review article, we first discuss the history of the development of anti-HIV drugs, during which several problems such as drug-induced side effects and the emergence of drug-resistant viruses became apparent and had to be overcome. Nowadays, the success of Combination Antiretroviral Therapy (cART), combined with recently-developed powerful but nonetheless less toxic drugs has transformed HIV/AIDS from an inevitably fatal disease into a manageable chronic infection. However, even with such potent cART, it is impossible to eradicate HIV because none of the currently available HIV drugs are effective in eliminating occult “dormant” HIV cell reservoirs. A number of novel unique treatment approaches that should drastically improve the quality of life (QOL) of patients or might actually be able to eliminate HIV altogether have also been discussed later in the review.

Meta-analysis and systematic review of the efficacy and resistance for human immunodeficiency virus type 1 integrase strand transfer inhibitors

Integrase strand transfer inhibitors (INSTIs) are the most recent class of antiretroviral drugs with potent and durable antiviral activity used to treat human immunodeficiency virus type 1 (HIV-1) infection. However, development of drug resistance increases the risk of treatment failure, disease progression and mortality. A better understanding of drug efficacy and resistance against INSTIs is crucial for their efficient use and the development of new antiretrovirals. A meta-analysis of studies reporting efficacy and resistance data on INSTI use in HIV-infected patients was performed. Odds ratios (ORs) of efficacy outcome data favouring INSTI use in different clinical settings demonstrated that INSTIs have higher efficacy compared with drugs of other classes. For combination antiretroviral therapy-naïve patients and virologically-suppressed patients who switched to INSTI-based therapy, the OR was 1.484 (95% CI 1.229-1.790) and 1.341 (95% CI 0.913-1.971), respectively. ORs of resistance data indicated decreased treatment-emergent resistance development to dolutegravir (DTG) upon virological failure than to non-INSTIs (OR = 0.081, 95% CI 0.004-1.849), whereas the opposite was observed for raltegravir (RAL) (OR = 3.137, 95% CI 1.827-5.385) and elvitegravir (EVG) (OR = 1.886, 95% CI 0.569-6.252). Pooled analysis of resistance data indicated that development of resistance to DTG and bictegravir was rare, whereas EVG and RAL had low genetic barriers to resistance and the intensive cross-resistance between them limits INSTI efficiency. Efficient means of monitoring the emergence of resistance to INSTIs and the development of drugs with high genetic barriers are clear paths for future research.

HIV‑1 integrase inhibitors targeting various DDE transposases: Retroviral integration versus RAG‑mediated recombination (Review)

Transposases are ubiquitous mobile genetic elements responsible for genome development, driving rearrangements, such as insertions, deletions and translocations. Across species evolution, some transposases are tamed by their host and are made part of complex cellular systems. The proliferation of retroviruses is also dependent on transposase related enzymes termed integrases. Recombination-activating gene protein (RAG)1 and metnase are just two examples of transposase domestication and together with retroviral integrases (INs), they belong to the DDE polynucleotidyl transferases superfamily. They share mechanistic and structural features linked to the RNase H-like fold, harboring a DDE(D) metal dependent catalytic motif. Recent antiretroviral compounds target the catalytic domain of integrase, but they also have the potential of inhibiting other related enzymes. In this review, we report the activity of different classes of integrase inhibitors on various DDE transposases. Computational simulations are useful to predict the extent of off-target activity and have been employed to study the interactions between RAG1 recombinase and compounds from three different pharmacologic classes. We demonstrate that strand-transfer inhibitors display a higher affinity towards the RAG1 RNase H domain, as suggested by experimental data compared to allosteric inhibitors. While interference with RAG1 and 2 recombination is associated with a negative impact on immune function, the inhibition of metnase or HTLV-1 integrase opens the way for the development of novel therapies for refractory cancers.

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

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

Multifaceted HIV integrase functionalities and therapeutic strategies for their inhibition

Antiretroviral inhibitors that are used to manage HIV infection/AIDS predominantly target three enzymes required for virus replication: reverse transcriptase, protease, and integrase. Although integrase inhibitors were the last among this group to be approved for treating people living with HIV, they have since risen to the forefront of treatment options. Integrase strand transfer inhibitors (INSTIs) are now recommended components of frontline and drug-switch antiretroviral therapy formulations. Integrase catalyzes two successive magnesium-dependent polynucleotidyl transferase reactions, 3' processing and strand transfer, and INSTIs tightly bind the divalent metal ions and viral DNA end after 3' processing, displacing from the integrase active site the DNA 3'-hydroxyl group that is required for strand transfer activity. Although second-generation INSTIs present higher barriers to the development of viral drug resistance than first-generation compounds, the mechanisms underlying these superior barrier profiles are incompletely understood. A separate class of HIV-1 integrase inhibitors, the allosteric integrase inhibitors (ALLINIs), engage integrase distal from the enzyme active site, namely at the binding site for the cellular cofactor lens epithelium-derived growth factor (LEDGF)/p75 that helps to guide integration into host genes. ALLINIs inhibit HIV-1 replication by inducing integrase hypermultimerization, which precludes integrase binding to genomic RNA and perturbs the morphogenesis of new viral particles. Although not yet approved for human use, ALLINIs provide important probes that can be used to investigate the link between HIV-1 integrase and viral particle morphogenesis. Herein, I review the mechanisms of retroviral integration as well as the promises and challenges of using integrase inhibitors for HIV/AIDS management.