Plausible mechanism of drug resistance and side-effects of COVID-19 therapeutics: a bottleneck for its eradication

BACKGROUND

COVID-19 pandemic has turned our world upside down by meddling with our normal lives. While there is no definitive drug against SARS-CoV-2, antiviral drugs that are already in the market, are being repurposed against it, could now complete long-term as well as all age-specific investigations, and they are successful in saving millions of lives. Nevertheless, side-effects are emergingly seen in the patients undergoing treatment, and ineffectiveness is increasingly found due to the emerging notorious variants of the virus. Many of them are also facing serious co-infections including black fungus, Zika, and H1N1 virus to name a few.

OBJECTIVES

Therefore, this review highlights both drug resistance, their side-effects, and the significance for proper and long-term clinical trials of all age groups including children.

METHODS

We have explored and proposed the mechanisms of drug resistance that may arise due to the misuse or overuse of drugs based on available experimental reports.

RESULTS

The review provides solutions to the aforesaid issues of drug-resistance and side-effects by providing combination therapies, ancillary treatments, and other preventive strategies that can be useful in preventing drawbacks thereby curbing COVID-19 or similar future infections to maintain our normal lives.

CONCLUSION

COVID-19 and its long-term effects, if any, can be eradicated with strategic and mindful use of related therapeutics in a controlled manner.

Diastereodivergent and Regioselective Synthesis of Tetrahydrofuro[2,3-b]furans with Four Consecutive Stereocenters

Base-catalyzed diastereodivergent and regioselective domino processes of triketone enones with arylacetaldehydes for the synthesis of tetrahydrofuro[2,3-b]furans with four consecutive stereocenters are reported. Good yields and diastereoselectivities are obtained when DBU is employed as a catalyst; in contrast, Et3N delivers a different diastereomer in excellent diastereoselectivity. This work offers many advantages, including switchable diastereoselectivity, cheap base catalysts, and a simple operation.

Structural and Synthetic Aspects of Small Ring Oxa- and Aza-Heterocyclic Ring Systems as Antiviral Activities

Antiviral properties of different oxa- and aza-heterocycles are identified and properly correlated with their structural features and discussed in this review article. The primary objective is to explore the activity of such ring systems as antiviral agents, as well as their synthetic routes and biological significance. Eventually, the structure-activity relationship (SAR) of the heterocyclic compounds, along with their salient characteristics are exhibited to build a suitable platform for medicinal chemists and biotechnologists. The synergistic conclusions are extremely important for the introduction of a newer tool for the future drug discovery program.

Updates on drug designing approach through computational strategies: a review

The drug discovery and development (DDD) process in pursuit of novel drug candidates is a challenging procedure requiring lots of time and resources. Therefore, computer-aided drug design (CADD) methodologies are used extensively to promote proficiency in drug development in a systematic and time-effective manner. The point in reference is SARS-CoV-2 which has emerged as a global pandemic. In the absence of any confirmed drug moiety to treat the infection, the science fraternity adopted hit and trial methods to come up with a lead drug compound. This article is an overview of the virtual methodologies, which assist in finding novel hits and help in the progression of drug development in a short period with a specific medicinal solution.

Multi-modality attribute learning-based method for drug-protein interaction prediction based on deep neural network

Identification of active candidate compounds for target proteins, also called drug-protein interaction (DPI) prediction, is an essential but time-consuming and expensive step, which leads to fostering the development of drug discovery. In recent years, deep network-based learning methods were frequently proposed in DPIs due to their powerful capability of feature representation. However, the performance of existing DPI methods is still limited by insufficiently labeled pharmacological data and neglected intermolecular information. Therefore, overcoming these difficulties to perfect the performance of DPIs is an urgent challenge for researchers. In this article, we designed an innovative 'multi-modality attributes' learning-based framework for DPIs with molecular transformer and graph convolutional networks, termed, multi-modality attributes (MMA)-DPI. Specifically, intermolecular sub-structural information and chemical semantic representations were extracted through an augmented transformer module from biomedical data. A tri-layer graph convolutional neural network module was applied to associate the neighbor topology information and learn the condensed dimensional features by aggregating a heterogeneous network that contains multiple biological representations of drugs, proteins, diseases and side effects. Then, the learned representations were taken as the input of a fully connected neural network module to further integrate them in molecular and topological space. Finally, the attribute representations were fused with adaptive learning weights to calculate the interaction score for the DPIs tasks. MMA-DPI was evaluated in different experimental conditions and the results demonstrate that the proposed method achieved higher performance than existing state-of-the-art frameworks.

Aryl glyoxal: a prime synthetic equivalent for multicomponent reactions in the designing of oxygen heterocycles

The category of bifunctional building blocks overrides many others because of their fascinating wide applicability in synthetic chemistry. Aryl glyoxal is one of the key molecules that has been extensively used in heterocyclic chemistry to afford nearly all types of five- and six-membered heterocycles, which are the structural constituents of many natural products. The multicomponent reaction is a practical strategy to utilize this wonderful moiety with different types of starting materials to obtain numerous diverse oxygen heterocycles. This review covers the advancement of aryl glyoxal as a prime synthetic equivalent in recent years for the synthesis of oxygen heterocycles.

Analysis of virological response to therapy and resistance profile in treatment-experienced and naive HIV-1 infected Romanian patients receiving regimens containing darunavir boosted with ritonavir or cobicistat

77% of Romanians infected with HIV receive antiretroviral therapy, with the challenge of maintaining long-term therapeutic success (the viral load becoming/remaining undetectable). The main purpose of this study was to provide comparative analysis of the long-term virological response to therapeutic regimens containing pharmacokinetically enhanced darunavir (DRV) with ritonavir (RTV) or cobicistat (COBI). The second aim was to evaluate the viral resistance profile to therapy, by number/type/frequency of viral mutations. This retrospective study was conducted on 462 patients infected with subtype F HIV-1, registered at the "Matei Bals" National Institute of Infectious Diseases, between 2018 and 2021: 384 patients received (among other ARV) DRV 600 mg, enhanced with RTV 100 mg (twice daily) and 78 patients received DRV 800 mg boosted with COBI 150 mg (once daily). The virological response was measured by determining the viral load (HIV-1 RNA copies/mL), while the incidence of viral resistance to therapy was assessed by genotyping tests. Comparing the patients with undetectable viremia, from the 1st visit to the 3rd one, the outcomes showed that at the last visit, 84.6% subjects in the DRV/c group achieved virological efficiency over those from DRV/r group (76.8%). The differences observed between this time points are statistically significant p < 0.05. DRV/c administered in combination with other ARV, in subtype F HIV-1 infected patients, proved to be more virologically effective, maintaining a favorable long-time result. When comparing the outcomes of the two groups, a statistically significant difference of p < 0.05 was obtained. 32 patients (27 from DRV/r group and 5 from DRV/c group) were evaluated with persistent HIV-1 ARN plasma load > 1000 copies/mL, during all 3 clinical visits. They formed a research sub-group evaluated in terms of resistance to therapy and were reported as virological failures. 28.12% of the sub-group with persistent HIV-1 RNA > 1000 copies/mL were from the DRV/r group and only 3.12% from the DRV/c group. Drug mutations (DRM) involved in antiretroviral resistance/sensitivity occurred both in the protease gene, and in the reverse transcriptase gene, with the involved ARV classes being protease inhibitors, nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors. 16 different types of mutations were evaluated in the PR gene and 20 mutations were evaluated in RT gene.

A rare complication of coronary vasospasm associated with concomitant use of ergotamine, cobicistat, and darunavir

Ergotism is a rare cause of peripheral vasoconstriction with varying presentation depending on the affected vessels. Coronary vasospasm is a rare, potentially fatal manifestation of ergotism. Cytochrome P-450 isoenzyme CYP3A metabolizes ergot alkaloids and their derivatives; thus, concomitant use of ergotamine and CYP3A inhibitors significantly increases ergotism risk. The antiretroviral drug darunavir boosted with cobicistat potently inhibits CYP3A. A few deleterious interactions are described in the literature when combining ergotamine with boosted human immunodeficiency virus protease inhibitors. Herein, we describe a patient who presented to the emergency department with profound coronary vasospasm arising from ergotamine’s interaction with darunavir and cobicistat. Emergency coronary angiography revealed no critical atherosclerotic stenosis, but prolonged coronary artery spasm. After prompt cardiopulmonary resuscitation, intravenous vasodilator treatment, and 14-day extracorporeal membrane oxygenation application, the patient fully recovered and was discharged. Concomitant use of ergot alkaloids and their derivatives could be disastrous for patients treated with cobicistat-boosted darunavir.

Prevalence and evolution of transmitted HIV drug resistance in Belgium between 2013 and 2019

Background

To assess the prevalence and evolution of transmitted drug resistance (TDR) in Belgium, a total of 3708 baseline human immunodeficiency virus (HIV)-1 polymerase sequences from patients diagnosed between 2013 and 2019 were analyzed.

Methods

Protease and reverse-transcriptase HIV-1 sequences were collected from the 7 national Aids Reference Laboratories. Subtype determination and drug resistance scoring were performed using the Stanford HIV Drug Resistance Database. Trends over time were assessed using linear regression, and the maximum likelihood approach was used for phylogenetic analysis.

Results

A total of 17.9% of the patients showed evidence of TDR resulting in at least low-level resistance to 1 drug (Stanford score  ≥15). If only the high-level mutations (Stanford score ≥60) were considered, TDR prevalence dropped to 6.3%. The majority of observed resistance mutations impacted the sensitivity for nonnucleoside reverse-transcriptase inhibitors (NNRTIs) (11.4%), followed by nucleoside reverse-transcriptase inhibitors (6.2%) and protease inhibitors (2.4%). Multiclass resistance was observed in 2.4%. Clustered onward transmission was evidenced for 257 of 635 patients (40.5%), spread over 25 phylogenetic clusters.

Conclusions

The TDR prevalence remained stable between 2013 and 2019 and is comparable to the prevalence in other Western European countries. The high frequency of NNRTI mutations requires special attention and follow-up. Phylogenetic analysis provided evidence for local clustered onward transmission of some frequently detected mutations.

Oral Nirmatrelvir/Ritonavir Therapy for COVID-19: The Dawn in the Dark?

Nirmatrelvir/ritonavir (Paxlovid™) is an effective and safe antiviral drug that inhibits the main protease (M^pro), 3CL protease, of SARS-CoV-2. A reduction in COVID-19-related hospitalization or death was observed in patients treated with nirmatrelvir/ritonavir within five days of symptom onset. Moreover, good oral availability enables the usage of nirmatrelvir/ritonavir, not only in hospitalized patients, but also among outpatients. Nirmatrelvir (PF-07321332) has been demonstrated to stop the spread of COVID-19 in animal models. Despite frequent mutations in the viral genomes of SARS-CoV-2, nirmatrelvir shows an effective antiviral effect against recent coronavirus mutants. Despite the promising antiviral effect of nirmatrelvir, there are several unresolved concerns. First, the final results of large-scale clinical trials for early therapy of mild cases of COVID-19 are not yet published. Second, the effectiveness of nirmatrelvir against upcoming variants in the coming years requires close monitoring. Considering the promising preliminary results of the EPIC-HR trial, nirmatrelvir/ritonavir in conjunction with vaccines and non-pharmacological interventions, may represent the dawn in the dark of the COVID-19 pandemic.

Probing the interaction of anti-HIV drug Darunavir with dsDNA and HSA using electrochemical and spectroscopic measurements

Investigation of electrochemical and spectroscopic characteristics of anti-human immunodeficiency virus (HIV) drug provides important information related to the efficacy of the drug in relation with its interaction with several important biomolecules. In the present investigation we have developed an electrochemical and spectroscopic method for the detection of anti-HIV drug Darunavir (DRV) using the carbon paste as the working electrode. The analytical method has generated the detection limit of 1.86 µM (S/N = 3). The electrochemical investigations have also been carried out for the exploration of the interaction of DRV with double stranded deoxyribose nucleic acid DNA (dsDNA) and human serum albumin (HSA). Electrochemical investigations were supported from the spectroscopic measurements in evaluating the interaction. The results obtained from voltammetric and spectroscopic experiments shows strong interaction between the drug and the macromolecules. It has been observed that DRV forms strong complexes with HSA and dsDNA with the formation constants of 2.7 × 10⁴ and 4.2 × 10⁴ M^-1 respectively. The formation constants are varied with the pH of the solution, which leads to the assertion of the mechanism of the interaction between DRV and dsDNA.

Phosphine-catalyzed Divergent Domino Processes between γ-Substituted Allenoates and Carbonyl-Activated Alkenes

Highly enantioselective and chemodivergent domino reactions between γ-substituted allenoates and activated alkenes have been developed. In the presence of NUSIOC-Phos, triketone enone substrates smoothly reacted with γ-substituted allenoates to form bicyclic furofurans in good yields with high stereoselectivities. Alternatively, the reaction between diester-activated enone substrates and γ-substituted allenoates formed chiral conjugated 1,3-dienes in good yields with excellent enantioselectivities. Notably, by employing substrates with subtle structural difference, under virtually identical reaction conditions, we were able to access two types of chiral products, which are of biological relevance and synthetic importance.

Highly enantioselective and chemodivergent domino reactions between γ-substituted allenoates and activated alkenes have been developed.

Reproductive and developmental safety of nirmatrelvir (PF-07321332), an oral SARS-CoV-2 Mpro inhibitor in animal models

Nirmatrelvir (PF-07321332; NMV) the antiviral component of PAXLOVID™ is a potent and selective inhibitor of the SARS-CoV-2 main protease (M^pro), which plays a critical role in viral replication. PAXLOVID, comprised of nirmatrelvir and ritonavir (used as a pharmacokinetic enhancer), is an oral therapy currently in development as a therapeutic option for those infected with SARS-CoV-2 to prevent progression to severe disease, hospitalization, and death. PAXLOVID has been shown to be efficacious against hospitalization and death in two Phase 2/3 clinical studies that evaluated non hospitalized patients both with and without high risk factors for progression to severe illness. Given that males and females of reproductive age are included in the intended patient population, we assessed the potential effects of NMV up to the limit dose of 1000 mg/kg/day in ICH guideline embryo-fetal development studies in rats and rabbits, and a fertility and early embryonic development study in rats. There were no effects on male and female fertility or early embryonic development in rats, and no severe manifestations of developmental toxicity in rats or rabbits. The lack of adverse findings reported here in nonclinical species is consistent with the intended therapeutic target of NMV (a virus specific protein not present in mammalian cells), the favorable off-target selectivity profile, and lack of genetic toxicity. The results of these nonclinical studies with NMV along with existing ritonavir safety information indicate that there are no clinically relevant risks associated with PAXLOVID administration during pregnancy and in males and females of reproductive age.

Black-White racial disparities in health care utilization and self-reported health among cancer survivors: The role of food insecurity

BACKGROUND

Non-Hispanic Blacks continue to have worse cancer outcomes than non-Hispanic Whites. Suboptimal health care utilization and poor self-reported health among non-Hispanic Blacks contribute to these disparities. The relationship between race, food security status (FSS), and health care utilization or self-reported health among cancer survivors is not clear. This study aims to fill this gap in the science.

METHODS

The 2011-2018 National Health Interview Survey data were used. Bivariate and multivariable logistic regression analyses were used to examine the relationship between race (non-Hispanic Whites or non-Hispanic Blacks), FSS (high, marginal, low, or very low), health care utilization, and self-reported health among cancer survivors. Analyzed health care utilization measures included cost-related medication underuse (CRMU), cost-related delayed care, cost-related forgone care, seeing/talking to a medical specialist, seeing/talking to a general doctor, and overnight hospital stay.

RESULTS

A higher proportion of Blacks reported very low food security in comparison with Whites (10.58% vs 4.24%; P ≤ .0001). Blacks were significantly less likely to report a medical specialist visit and more likely to report fair/poor health in the past 12 months even after adjustments for FSS. There was a dose-response relationship between FSS and CRMU, cost-related delayed care, cost-related forgone care, overnight hospital stay, and self-reported health status for both Whites and Blacks.

CONCLUSIONS

Significant disparities in health care utilization and self-reported health across race and FSS persist among cancer survivors. Interventions that target food insecurity have the potential to reduce suboptimal health care utilization and self-reported health among cancer survivors.

An oral SARS-CoV-2 Mpro inhibitor clinical candidate for the treatment of COVID-19

[Figure: see text].

Management of Antiretroviral Therapy with Boosted Protease Inhibitors-Darunavir/Ritonavir or Darunavir/Cobicistat

A major challenge in the management of antiretroviral therapy (ART) is to improve the patient's adherence, reducing the burden caused by the high number of drugs that compose the treatment regimens for human immunodeficiency virus positive (HIV+) patients. Selection of the most appropriate treatment regimen is responsible for therapeutic success and aims to reduce viremia, increase the immune system response capacity, and reduce the incidence rate and intensity of adverse reactions. In general, protease inhibitor (PI) is one of the pillars of regimens, and darunavir (DRV), in particular, is frequently recommended, along with low doses of enzyme inhibitors as cobicistat (COBI) or ritonavir (RTV), by the international guidelines. The potential of clinically significant drug interactions in patients taking COBI or RTV is high due to the potent inhibitory effect on cytochrome CYP 450, which attracts significant changes in the pharmacokinetics of PIs. Regardless of the patient or type of virus, the combined regimens of DRV/COBI or DRV/RTV are available to clinicians, proving their effectiveness, with a major impact on HIV mortality/morbidity. This study presents current information on the pharmacokinetics, pharmacology, drug interactions, and adverse reactions of DRV; it not only compares the bioavailability, pharmacokinetic parameters, immunological and virological responses, but also the efficacy, advantages, and therapeutic disadvantages of DRV/COBI or DRV/RTV combinations.

Identification of potential antivirals against SARS-CoV-2 using virtual screening method

SARS-CoV-2 has triggered a major epidemic among people around the world, and it is the newest in the sequence to become prevalent among other infectious diseases. The drug repurposing concept has been utilized effectively for numerous viral infections. Considering the situation and the urgency, the idea of drug repurposing for coronavirus infection (COVID-19) is also being studied. The molecular docking method was used for the screening of 29 antiviral drugs against primary protease proteins (MPP) of SARS-CoV-2, spike ecto-domain, spike receptor binding domain, Nsp9 RNA binding protein, and HR2 domain. Among these drugs, in terms of least binding energy, Indinavir, Sorivudine, Cidofovir, and Darunavir showed minimum docking scores with all the key proteins. For ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analysis, the ADMET properties of the top 4 drug candidates were retrieved through literature study. This analysis revealed that these drug candidates are well metabolized, distributed, and bioavailable, but have some undesirable effects. Furthermore, some approved structural analogues, such as Telbivudine, Tenofovir, Amprenavir, Fosamprenavir, etc., were predicted as similar drugs which may also be used for treating viral infections. We highly recommend these drug candidates as potential fighters against the deadly SARS-CoV-2 virus, and suggest in vivo trials for experimental validation of our findings.

Update on Antiviral Strategies Against COVID-19: Unmet Needs and Prospects

By December 2020, the COVID-19 pandemic had caused more than 74 million confirmed cases and 1.6 million related deaths around the world. However, only a few drugs have been approved in certain areas and for use in conditional patients, and the vaccine candidates were only recently approved or authorized for emergency use without being fully implemented worldwide, suggesting that we are yet to reach effective control of the current outbreak as its uninhibited transmission continues precariously. Over the past few months, several therapeutic candidates have been proven ineffective in large clinical trials, while some other agents exhibited promising preliminary results. Meanwhile, the investigation of SARS-CoV-2-specific antivirals is underway. Despite still being preclinical, these agents could be beneficial for the long-term control of COVID-19 and deserve more research focus. In this article, we update the current status of therapeutic candidates that have been examined for COVID-19 management, including the virus-targeting inhibitors and host-targeting agents, with their antiviral efficacy in vitro, in vivo, and in clinical studies. Finally, we highlight the current challenges and future prospect of developing potent therapeutic agents against COVID-19.

Biocatalytic routes to anti-viral agents and their synthetic intermediates

An assessment of biocatalytic strategies for the synthesis of anti-viral agents, offering guidelines for the development of sustainable production methods for a future COVID-19 remedy.

Potential Therapeutic Options for COVID-19: Current Status, Challenges, and Future Perspectives

The COVID-19 pandemic represents an unprecedented challenge for the researchers to offer safe, tolerable, and effective treatment strategies for its causative agent known as SARS-CoV-2. With the rapid evolution of the pandemic, even the off-label use of existing drugs has been restricted by limited availability. Several old antivirals, antimalarial, and biological drugs are being reconsidered as possible therapies. The effectiveness of the controversial treatment options for COVID-19 such as nonsteroidal antiinflammatory drugs, angiotensin 2 conversion enzyme inhibitors and selective angiotensin receptor blockers was also discussed. A systemic search in the PubMed, Science Direct, LitCovid, Chinese Clinical Trial Registry, and ClinicalTrials.gov data bases was conducted using the keywords "coronavirus drug therapy," passive immunotherapy for COVID-19', "convalescent plasma therapy," (CPT) "drugs for COVID-19 treatment," "SARS-CoV-2," "COVID-19," "2019-nCoV," "coronavirus immunology," "microbiology," "virology," and individual drug names. Systematic reviews, case presentations and very recent clinical guidelines were included. This narrative review summarizes the available information on possible therapies for COVID-19, providing recent data to health professionals.

Darunavir: A comprehensive profile

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

Current Computational Approaches for the Development of Anti-HIV Inhibitors: An Overview

BACKGROUND

Today, HIV-1 infection has become an extensive problem to public health and a greater challenge to all working researchers throughout the world. Since the beginning of HIV-1 virus, several antiviral therapeutic agents have been developed at various stages to combat HIV-1 infection. But, many of antiviral drugs are on the platform of drug resistance and toxicology issues, needs an urgent constructive investigation for the development of productive and protective therapeutics to make an improvement of individual life suffering with viral infection. As developing a novel agent is very costly, challenging and time taking route in the recent times.

METHODS

The review summarized about the modern approaches of computational aided drug discovery to developing a novel inhibitor within a short period of time and less cost.

RESULTS

The outcome suggests on the premise of reported information that the computational drug discovery is a powerful technology to design a defensive and fruitful therapeutic agents to combat HIV-1 infection and recover the lifespan of suffering one.

CONCLUSION

Based on survey of the reported information, we concluded that the current computational approaches is highly supportive in the progress of drug discovery and controlling the viral infection.

Pharmacokinetics and pharmacodynamics of cytochrome P450 inhibitors for HIV treatment

INTRODUCTION

Drugs used in HIV treatment; all protease inhibitors, some non-nucleoside reverse transcriptase inhibitors, and pharmacoenhancers ritonavir and cobicistat can inhibit cytochrome P450 (CYP) enzymes. CYP inhibition can cause clinically significant drug-drug interactions (DDI), leading to increased drug exposure and potential toxicity. Areas covered: A complete understanding of pharmacodynamics and CYP-mediated DDI is crucial to prevent adverse side effects and to achieve optimal efficacy. We summarized the pharmacodynamics of all the CYP inhibitors used for HIV treatment, followed by a discussion of drug interactions between these CYP inhibitors and other drugs, and a discussion on the effect of CYP polymorphisms. We also discussed the potential advancements in improving the pharmacodynamics of these CYP inhibitors by using nanotechnology strategy. Expert opinion: The drug-interactions in HIV patients receiving ARV drugs are complicated, especially when patients are on CYP inhibitors-based ART regimens. Therefore, evaluation of CYP-mediated drug interactions is necessary prior to prescribing ARV drugs to HIV subjects. To improve the treatment efficacy and minimize DDI, novel approaches such as nanotechnology may be the potential alternative approach. However, further studies with large cohort need to be conducted to provide strong evidence for the use of nano-formulated ARVs to effectively treat HIV patients.

Spontaneous single-crystal to single-crystal transition with self-healing cracks involving solvent exchange

A single crystal of darunavir dihydrate was obtained by SCSCT, accompanied by crystal breaking to self-healing.

Multi-spectroscopic and molecular docking studies on the interaction of darunavir, a HIV protease inhibitor with calf thymus DNA

Molecular interaction of darunavir (DRV), a HIV protease inhibitor with calf thymus deoxyribonucleic acid (ct-DNA) was studied in physiological buffer (pH7.4) by multi-spectroscopic approaches hand in hand with viscosity measurements and molecular docking technique. The UV absorption and fluorescence results together revealed the formation of a DRV-ct-DNA complex having binding affinities of the order of 10³M^-1, which was more in keeping with the groove binding. The results that DRV bound to ct-DNA via groove binding mode was further evidenced by KI quenching studies, viscosity measurements, competitive binding investigations with EB and Rhodamine B and CD spectral analysis. The effect of ionic strength indicated the negligible involvement of electrostatic interaction between DRV and ct-DNA. The thermodynamic parameters regarding the binding interaction of DRV with ct-DNA in terms of enthalpy change (ΔH⁰) and entropy change (ΔS⁰) were -63.19kJ mol^-1 and -141.92J mol^-1K^-1, indicating that hydrogen bonds and van der Waals forces played a predominant role in the binding process. Furthermore, molecular simulation studies suggested that DRV molecule was prone to bind in the A-T rich region of the minor groove of DNA.

Darunavir-Loaded Lipid Nanoparticles for Targeting to HIV Reservoirs

Darunavir has a low oral bioavailability (37%) due to its lipophilic nature, metabolism by cytochrome P450 enzymes and P-gp efflux. Lipid nanoparticles were prepared in order to overcome its low bioavailability and to increase the binding efficacy of delivery system to the lymphoid system. Darunavir-loaded lipid nanoparticles were prepared using high-pressure homogenization technique. Hydrogenated castor oil was used as lipid. Peptide, having affinity for CD4 receptors, was grafted onto the surface of nanoparticles. The nanoparticles were evaluated for various parameters. The nanoparticles showed size of less than 200 nm, zeta potential of - 35.45 mV, and a high drug entrapment efficiency (90%). 73.12% peptide was found conjugated to nanoparticles as studied using standard BSA calibration plot. Permeability of nanoparticles in Caco-2 cells was increased by 4-fold in comparison to plain drug suspension. Confocal microscopic study revealed that the nanoparticles showed higher uptake in HIV host cells (Molt-4 cells were taken as model containing CD4 receptors) as compared to non-CD4 receptor bearing Caco-2 cells. In vivo pharmacokinetic in rats showed 569% relative increase in bioavailability of darunavir as compared to plain drug suspension. The biodistribution study revealed that peptide-grafted nanoparticles showed higher uptake in various organs (also in HIV reservoir organs namely the spleen and brain) except the liver compared to non-peptide-grafted nanoparticles. The prepared nanoparticles resulted in increased binding with the HIV host cells and thus could be promising carrier in active targeting of the drugs to the HIV reservoir.

Ritonavir-Boosted Darunavir Plus Two Nucleoside Reverse Transcriptase Inhibitors versus Other Regimens for Initial Antiretroviral Therapy for People with HIV Infection: A Systematic Review

BACKGROUND

Darunavir is a second-generation protease-inhibitor used with ritonavir (DRV/r) and two nucleoside reverse-transcriptase inhibitors as an option in first-line antiretroviral treatment (ART).

METHODS

We systematically reviewed randomized controlled trials (RCTs) of DRV/r versus other regimens in patients initiating ART. We searched five bibliographic databases and other key resources. We had no language limitations. We assessed bias risk with the Cochrane tool and used GRADE to assess evidence quality. We report findings in terms of risk ratio (RR) with 95% confidence intervals (CI).

FINDINGS

Three RCTs met inclusion criteria. In plasma viral load suppression, DRV/r outperformed ritonavir-boosted lopinavir at 48 weeks (RR 1.13, 95% CI 1.03-1.25), 96 weeks (RR 1.11, 95% CI 1.02-1.21), and 192 weeks (RR 1.20, 95% CI 1.07-1.35). DRV/r was similar to dolutegravir at 48 weeks (RR 0.96, 95% CI 0.87-1.06) but less effective at 96 weeks (RR 0.84, 95% CI 0.75-0.93). At 96 weeks, DRV/r underperformed raltegravir (RR 0.94, 95% CI 0.88-0.99) but was similar to ritonavir-boosted atazanavir (RR 1.02, 95% CI 0.96-1.09). Overall bias risk was moderate. Evidence quality was also moderate.

INTERPRETATION

Initial ART regimens using DRV/r should be considered in future World Health Organization guidelines.

Interaction between Darunavir and Etravirine Is Partly Mediated by CYP3A5 Polymorphism

OBJECTIVES

To assess the impact of the loss-of-function CYP3A5*3 allele (rs776746, 6986A>G SNP) on darunavir (DRV) plasma concentrations.

METHODS

135 HIV-1 infected patients treated with DRV-based therapy were included in the study and plasma samples were obtained immediately before drug intake in order to determine DRV trough concentrations using an ultra performance liquid chromatography method (UPLC) with diode-array detection (DAD). Noteworthy is the fact that in 16 (11.9%) patients, etravirine (ETR) was combined with DRV. CYP3A5 genotypes were determined using real time PCR method (TaqMan® genotyping assay). The patients were then classified into CYP3A5 expressors (CYP3A5*1 allele carriers) and non-expressors (CYP3A5*3 homozygous). Subsequently, the association between DRV plasma trough concentration ([DRV]plasma) and CYP3A5 genotype-based expression status was analyzed.

RESULTS

45% of the patients were classified as CYP3A5 expressors. In the whole cohort, mean [DRV]plasma was not different between CYP3A5 expressors and non-expressors (1894ng/ml [CI95%: 1566-2290] versus 1737ng/ml [CI95%: 1468-2057], p = 0.43). However, in the subgroup of the 16 patients receiving DRV combined with ETR, a significantly lower [DRV]plasma was observed for CYP3A5 expressors when compared to non-expressors (1385ng/ml [CI95%:886.3-2165] versus 3141ng/ml [CI95%:2042-4831], p = 0.007).

CONCLUSIONS

Interaction between DRV and ETR is partly mediated by CYP3A5 polymorphism with lower DRV plasma trough concentrations in CYP3A5 expressors suggesting a specific ETR-driven CYP3A5 activation only in CYP3A5 expressors. Consequently, these patients might be more at risk of infra-therapeutic [DRV]plasma. This potentially important observation is a good illustration of a genotype-based drug interaction, which could also have considerable consequences if translated to other CYP3A5-metabolized drugs. Further investigations are thus needed to confirm this association and to explore its clinical impact, mainly in the African population among whom CYP3A5 expressors are more frequent, before recommending systematic CYP3A5 pre-emptive genotyping for DRV-ETR co-administration.

Investigational protease inhibitors as antiretroviral therapies

INTRODUCTION

Highly Active Antiretroviral Therapy (HAART) has tremendously improved the life expectancy of the HIV-infected population over the past three decades. Protease inhibitors have been one of the major classes of drugs in HAART regimens that are effective in treating HIV. However, the emergence of resistance and cross-resistance against protease inhibitors encourages researchers to develop new PIs with broad-spectrum activity, as well as novel means of enhancing the efficacy of existing PIs.

AREAS COVERED

In this article we discuss recent advances in HIV protease inhibitor (PI) development, focusing on both investigational and experimental agents. We also include a section on pharmacokinetic booster drugs for improved bioavailability of protease inhibitors. Further, we discuss novel drug delivery systems using a variety of nanocarriers for the delivery of PIs across the blood-brain barrier to treat the HIV in the brain.

EXPERT OPINION

We discuss our opinion on the promises and challenges on the development of novel investigational and experimental PIs that are less toxic and more effective in combating drug-resistance. Further, we discuss the future of novel nanocarriers that have been developed to deliver PIs to the brain cells. Although these are promising findings, many challenges need to be overcome prior to making them a viable option.

Effectiveness, durability, and safety of darunavir/ritonavir in HIV-1-infected patients in routine clinical practice in Italy: a postauthorization noninterventional study

Current antiretroviral (ARV) therapy for the treatment of human immunodeficiency virus (HIV-1)-infected patients provides long-term control of viral load (VL). Darunavir (DRV) is a nonpeptidomimetic protease inhibitor approved for use with a ritonavir booster (DRV/r). This study evaluated the effectiveness of DRV/r in combination with other ARV agents in routine clinical practice in Italy. In this descriptive observational study, data on utilization of DRV/r, under the conditions described in the marketing authorization, were collected from June 2009 to December 2012. Effectiveness (VL <50 copies/mL), tolerability, and durability in four patient groups (two DRV/r-experienced, one ARV-experienced DRV/r-naïve, and one ARV-naïve) were analyzed. Secondary objectives included immunological response, safety, and persistence/discontinuation rates. In total, 875 of 883 enrolled patients were included in the analysis: of these, 662 (75.7%) completed the follow-up until the end of 2012 and 213 (24.3%) withdrew from the study earlier. Initial DRV dose was 600 mg twice daily (67.1%) or 800 mg once daily (32.9%). Only 16 patients (1.8%) withdrew from the study due to virological failure. Virological response proportions were higher in patients virologically suppressed at study entry versus patients with baseline VL ≥50 copies/mL in each ARV-experienced group, while there was no consistent difference across study groups and baseline VL strata according to baseline CD4⁺ cell count. CD4⁺ cell count increased from study entry to last study visit in all the four groups. DRV/r was well tolerated, with few discontinuations due to study-emergent nonfatal adverse events (3.0% overall, including 2.1% drug-related) or deaths (3.0% overall, all non-drug-related); 35.3% of patients reported ≥1 adverse events. These observational data show that DRV/r was effective and well tolerated in the whole patient population described here. The DRV/r-containing regimen provided viral suppression in a high percentage of patients in all groups, with low rates of discontinuation due to virological failure.

Antiretroviral drug toxicity in relation to pharmacokinetics, metabolic profile and pharmacogenetics

INTRODUCTION

Besides therapeutic effectiveness, drug tolerability is a key issue for treatments that must be taken indefinitely. Given the high prevalence of toxicity in HIV therapy, the factors implicated in drug-induced morbidities should be identified in order to improve the safety, tolerability and adherence to the treatments. Current approaches have focused almost exclusively on parent drug concentrations; whereas recent evidence suggests that drug metabolites resulting from complex genetic and environmental influences can also contribute to treatment outcome. Pharmacogenetic variations have shown to play a relevant role in the variability observed in antiretroviral drug exposure, clinical response and sometimes toxicity. The integration of pharmacokinetic, pharmacogenetic and metabolic determinants will more probably address current therapeutic needs in patients.

AREAS COVERED

This review offers a concise description of three classes of antiretroviral drugs. The review looks at the metabolic profile of these drugs and gives a comprehensive summary of the existing literature on the influence of pharmacogenetics on their pharmacokinetics and metabolic pathways, and the associated drug or metabolite toxicity.

EXPERT OPINION

Due to the high prevalence of toxicity and the related risk of low adherence to the treatments, association of kinetic, genetic and metabolic markers predictive of therapeutic or toxicity outcomes could represent a more complete approach for optimizing antiretroviral therapy.

Antiviral Drugs

Viruses are major pathogenic agents causing a variety of serious diseases in humans, other animals, and plants.

Drugs that combat viral infections are called antiviral drugs. There are no effective antiviral drugs for many viral infections. However, there are several drugs for influenza, a couple of drugs for herpesviruses, and some new antiviral drugs for treatment of HIV and hepatitis C infections.

The arsenal of antivirals is complex. As of March 2014, it consists of approximately 50 drugs approved by the FDA, approximately half of which are directed against HIV. Antiviral drug creation strategies are focused on two different approaches: targeting the viruses themselves or targeting host cell factors.

Direct virus-targeting antiviral drugs include attachment inhibitors, entry inhibitors, uncoating inhibitors, protease inhibitors, polymerase inhibitors, nucleoside and nucleotide reverse transcriptase inhibitors, nonnucleoside reverse-transcriptase inhibitors, and integrase inhibitors.

Protease inhibitors (darunavir, atazanavir, and ritonavir), viral DNA polymerase inhibitors (acyclovir, valacyclovir, valganciclovir, and tenofovir), and an integrase inhibitor (raltegravir) are included in the list of Top 200 Drugs by sales for the 2010s.

Quantification of darunavir and etravirine in human peripheral blood mononuclear cells using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS), clinical application in a cohort of 110 HIV-1 infected patients and evidence of a potential drug-drug interaction

OBJECTIVES

To describe the validation of a sensitive high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method allowing the simultaneous quantification of darunavir (DRV) and etravirine (ETR) in peripheral blood mononuclear cells (PBMCs) and its application in a cohort of HIV-1 infected patients.

METHODS

Blood samples were obtained from 110 patients. PMBCs were isolated using density gradient centrifugation. Drug extraction from PBMCs was performed with a 60:40 methanol-water (MeOH-H2O) solution containing deuterated IS (DRV-d9 and ETR-d8). The chromatographic separation was performed on a RP18 XBridge™ column.

RESULTS

The geometric mean (GM) of cell associated concentration ([DRV]CC) and plasmatic concentration ([DRV]plasma) were 360.5ng/mL (CI95%:294.5-441.2) and 1733ng/mL (CI95%:1486-2021), respectively. A geometric mean intracellular (IC)/plasma ratio (GMR) of 0.21 (CI95%:0.18-0.24) was calculated. Adjusted for dose/body surface area and post-intake time, a statistically significant correlation was observed between [DRV]Plasma and the eGFR (p=0.002) and between [DRV]Plasma and the concomitant use of ETR (p=0.038). For the 10 patients receiving ETR in addition to DRV, the GM of [ETR]Plasma (available for 8 out of 10 patients) and [ETR]CC were 492.3ng/mL and 2951ng/mL respectively. The GMR of ETR was 7.6 (CI95%: 3.61-13.83).

CONCLUSIONS

A handy and sensitive high performance LC-MS/MS method allowing the simultaneous quantification of DRV and ETR in PBMCs has been described and successfully applied in the largest cohort of DRV-treated patients reported to date. ETR accumulates more efficiently in PBMCs compared to DRV. We have also highlighted a possible impact of ETR on DRV plasma concentrations requiring further investigations.

Regimens for Patients Coinfected with Human Immunodeficiency Virus

Hepatitis C virus (HCV) coinfection is prevalent in patients with human immunodeficiency virus (HIV) and has an accelerated disease course. Direct-acting antiviral (DAA) therapies that do not require interferon increase response rates to levels identical to those seen in HCV monoinfection. However, drug-drug interaction between antiretrovirals and HCV medication is the major consideration in deciding on the appropriate HCV therapeutic approach in patients with HIV. This article summarizes the currently available data with HCV DAAs in patients with HIV, and focuses on predicting and managing drug interaction to facilitate successful DAA-based HCV therapy in those with HIV.

Medication Adherence and Health Outcomes of People Living with HIV Who Are Food Insecure and Prescribed Antiretrovirals That Should Be Taken with Food

INTRODUCTION

Food insecurity is a well-established predictor of poor health outcomes. Antiretroviral therapies (ARTs) that should be taken with food to increase bioavailability may further challenge food insecure patients. This study examined factors associated with antiretroviral adherence and HIV viral suppression among people living with HIV who are food insecure and prescribed medications that require food.

METHODS

A community sample of 313 men and 105 women who experienced food insecurity in the previous month and were currently taking ART completed computerized interviews, urine screening for drug use, prospective biweekly unannounced pill count adherence assessments, and obtained their HIV viral load and CD4 cell counts from medical records.

RESULTS

Individuals taking ART regimens that should be taken with food were significantly more likely to be unemployed, were living longer with an HIV diagnosis, had lower CD4 cell counts, poorer HIV suppression, and endorsed more beliefs that taking medications was necessary for their health. Multivariable regression models controlling for potential confounding factors showed that receiving ART that requires food was significantly related to poorer ART adherence and unsuppressed HIV in this food insecure sample.

CONCLUSION

People living with HIV who are food insecure likely experience multiple facets of poverty that challenge their medication adherence, but food insecurity is the only such factor that is directly related to the pharmacokinetics of some antiretroviral medications. Achieving optimal treatment outcomes for HIV infection will require routine assessment of access to food when determining patient-tailored ART regimens.

Darunavir: a review of its use in the management of HIV-1 infection

The latest HIV-1 protease inhibitor (PI) darunavir (Prezista™) has a high genetic barrier to resistance development and is active against wild-type HIV and HIV strains no longer susceptible to some older PIs. Ritonavir-boosted darunavir, as a component of antiretroviral therapy (ART), is indicated for the treatment of HIV-1 infection in adult and paediatric patients (aged ≥3 years), with or without treatment experience (details vary depending on region of approval). Several open-label or partially-blinded trials have evaluated the efficacy of ritonavir-boosted darunavir ART regimens for up to 192 weeks in these settings. In treatment-naïve adults, once-daily boosted darunavir was no less effective in establishing virological suppression than once- or twice-daily boosted lopinavir, yet was more effective at maintaining suppression long term. Moreover, treatment-experienced adults with no darunavir resistance-associated mutations (RAMs) had no less effective viral load suppression with once-daily than with twice-daily boosted darunavir. In treatment-experienced adults, including some with multiple major PI RAMs, twice-daily boosted darunavir was more effective than twice-daily boosted lopinavir or boosted control PIs in reducing viral load, and provided virological benefit as part of a salvage regimen in those with few remaining treatment options. Boosted darunavir also reduced viral load when administered once-daily in treatment-naïve adolescents or twice-daily in treatment-experienced children and adolescents. Boosted darunavir is generally well tolerated, with gastrointestinal disturbances and lipid abnormalities among the most common tolerability issues. It has a lipid profile more favourable than that of boosted lopinavir in terms of total cholesterol and triglyceride changes and, when administered once daily, its lipid effects are generally similar to those of boosted atazanavir. Thus, boosted darunavir is a useful option for the ART regimens of adult and paediatric patients with HIV-1 infection.