Lopinavir

An in-depth analysis of COVID-19 treatment: Present situation and prospects

Coronavirus disease 2019 (COVID-19) the most contagious infection caused by the unique type of coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), produced a global pandemic that wreaked havoc on the health-care system, resulting in high morbidity and mortality. Several methods were implemented to tackle the virus, including the repurposing of existing medications and the development of vaccinations. The purpose of this article is to provide a complete summary of the current state and future possibilities for COVID-19 therapies. We describe the many treatment classes, such as antivirals, immunomodulators, and monoclonal antibodies, that have been repurposed or developed to treat COVID-19. We also looked at the clinical evidence for these treatments, including findings from observational studies and randomized-controlled clinical trials, and highlighted the problems and limitations of the available evidence. Furthermore, we reviewed existing clinical trials and prospective COVID-19 therapeutic options, such as novel medication candidates and combination therapies. Finally, we discussed the long-term consequences of COVID-19 and the importance of ongoing research into the development of viable treatments. This review will help physicians, researchers, and policymakers to understand the prevention and mitigation of COVID-19.

The Chinese herb Styrax triggers pharmacokinetic herb-drug interactions via inhibiting intestinal CYP3A

Human cytochrome P450 3A4 (hCYP3A4) is a predominant enzyme to trigger clinically relevant drug/herb-drug interactions (DDIs or HDIs). Although a number of herbal medicines have been found with strong anti-hCYP3A4 effects in vitro, the in vivo modulatory effects of herbal medicines on hCYP3A4 and their potential risks to trigger HDIs are rarely investigated. Herein, we demonstrate a case study to efficiently find the herbal medicine(s) with potent hCYP3A4 inhibition in vitro and to accurately assess the potential HDIs risk in vivo. Following screening over 100 herbal medicines, the Chinese herb Styrax was found with the most potent hCYP3A4 inhibition in HLMs. In vitro assays demonstrated that Styrax could potently inhibit mammalian CYP3A in liver and intestinal microsomes from both humans and rats. In vivo pharmacokinetic assays showed that Styrax (i.g., 100 mg/kg) significantly elevated the plasma exposure of two CYP3A-substrate drugs (midazolam and felodipine) when midazolam or felodipine was administered orally. By contrast, the plasma exposure of either midazolam or felodipine was hardly affected by Styrax (i.g.) when the victim drug was administered intravenously. Further investigations demonstrated that seven pentacyclic triterpenoid acids (PTAs) in Styrax were key substances responsible for CYP3A inhibition, while these PTAs could be exposed to intestinal tract at relatively high exposure levels but their exposure levels in rat plasma and liver were extremely low. These findings well explained why Styrax (i.g.) could elevate the plasma exposure of victim drugs only when these agents were orally administrated. Collectively, our findings demonstrate that Styrax can modulate the pharmacokinetic behavior of CYP3A-substrate drugs via inhibiting intestinal CYP3A, which is very helpful for the clinical pharmacologists to better assess the HDIs triggered by Styrax or Styrax-related herbal products.

The efficacy and adverse effects of favipiravir on patients with COVID-19: A systematic review and meta-analysis of published clinical trials and observational studies

OBJECTIVES

This study aimed to evaluate the efficacy and adverse events of favipiravir in patients with COVID-19.

METHODS

Our protocol was registered on PROSPERO (CRD42020206305). Fourteen databases were searched until February 8th, 2021. An update search for new RCTs was done on March 2nd, 2022. Meta-analysis was done for randomized controlled trials (RCTs) and non-RCTs.

RESULTS

Overall, 157 studies (24 RCTs, 1 non-RCT, 21 observational studies, 2 case series, and 106 case reports) were included. On hospitalized patients, in comparison to standard of care, favipiravir showed a higher rate of viral clearance at day 5 (RR = 1.60, p = 0.02), defervescence at day 3-4 (RR = 1.99, p <0.01), chest radiological improvement (RR = 1.33, p <0.01), hospital discharge at day 10-11 (RR = 1.19, p <0.01), and shorter clinical improvement time (MD = -1.18, p = 0.05). Regarding adverse events, favipiravir groups had higher rates of hyperuricemia (RR = 9.42, p <0.01), increased alanine aminotransferase (RR = 1.35, p <0.01) but lower rates of nausea (RR = 0.42, p <0.01) and vomiting (R R= 0.19, p=0.02). There were no differences regarding mortality (RR=1.19, p=0.32), and increased aspartate aminotransferase (RR = 1.11, p = 0.25). On nonhospitalized patients, no significant differences were reported.

CONCLUSIONS

Adding favipiravir to the standard of care provides better outcomes for hospitalized patients with COVID-19. Pregnant, lactating women, and patients with a history of hyperuricemia should avoid using favipiravir.

In-line treatments and clinical initiatives to fight against COVID-19 outbreak

In December 2019, when the whole world is waiting for Christmas and New Year, the physicians of Wuhan, China, are astounded by clusters of patients suffering from pneumonia from unknown causes. The pathogen isolated from the respiratory epithelium of the patients is similar to previously known coronaviruses with some distinct features. The disease was initially called nCoV-2019 or SARS-nCoV-2 and later termed as COVID-19 by WHO. The infection is rapidly propagating from the day of emergence, spread throughout the globe and now became a pandemic which challenged the competencies of developed nations in terms of health care management. As per WHO report, 216 countries are affected with SARS-CoV-19 by August 5, 2020 with 18, 142, 718 confirmed cases and 691,013 deaths reports. Such huge mortality and morbidity rates are truly threatening and calls for some aggressive and effective measures to slow down the disease transmission. The scientists are constantly engaged in finding a potential solution to diagnose and treat the pandemic. Various FDA approved drugs with the previous history of antiviral potency are repurposed for COVID-19 treatment. Different drugs and vaccines are under clinical trials and some rapid and effective diagnostic tools are also under development. In this review, we have highlighted the current epidemiology through infographics, disease transmission and progression, clinical features and diagnosis and possible therapeutic approaches for COVID-19. The article mainly focused on the development and possible application of various FDA approved drugs, including chloroquine, remdesivir, favipiravir, nefamostate mesylate, penciclovir, nitazoxanide, ribavirin etc., vaccines under development and various registered clinical trials exploring different therapeutic measures for the treatment of COVID-19. This information will definitely help the researchers to understand the in-line scientific progress by various clinical agencies and regulatory bodies against COVID-19.

Therapeutic options in coronavirus treatment

This chapter details the various therapeutic options available for the treatment of the novel coronavirus, SARS-CoV-2, that has brought the world to a standstill. As at 3.53 CEST, June 28, 2020, WHO reported 9,843,073 confirmed cases of COVID-19, with a death toll of 495,760. The rate of the spread of this disease is alarming posing serious threat to the world healthcare system. Clinical investigations and research are on the way for the development of vaccines or antiviral drugs. Despite this effort, no medication has been found to be very effective for its treatment. In this chapter, emphasis was laid on the need for repurposing of antiviral drugs to combat COVID-19 along with other alternatives such as convalescent plasma therapy and exploitation of drugs from medicinal plants and other natural resources.

Viral Proteases as Targets for Coronavirus Disease 2019 Drug Development

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to be a global threat since its emergence. Although several COVID-19 vaccines have become available, the prospective timeframe for achieving effective levels of vaccination across global populations remains uncertain. Moreover, the emergence of SARS-CoV-2 variants presents continuing potential challenges for future vaccination planning. Therefore, development of effective antiviral therapies continues to be an urgent unmet need for COVID-19. Successful antiviral regimens for the treatment of human immunodeficiency virus and hepatitis C virus infections have established viral proteases as validated targets for antiviral drug development. In this context, we review protease targets in drug development, currently available antiviral protease inhibitors, and therapeutic development efforts on SARS-CoV-2 main protease and papain-like protease. SIGNIFICANCE STATEMENT: Coronavirus disease 2019 (COVID-19) continues to be a global threat since its emergence. The development of effective antiviral therapeutics for COVID-19 remains an urgent and long-term need. Because viral proteases are validated drug targets, specific severe acute respiratory syndrome coronavirus 2 protease inhibitors are critical therapeutics to be developed for treatment of COVID-19.

Synthetic and Semi-synthetic Drugs as a Promising Therapeutic Option for the Treatment of COVID-19

The novel coronavirus disease-19 (COVID-19) is a global pandemic that emerged from Wuhan, China, and has spread all around the world, affecting 216 countries or territories with 21,732,472 people infected and 770,866 deaths globally (as per WHO COVID-19 updates of August 18, 2020). Continuous efforts are being made to repurpose the existing drugs and develop vaccines for combating this infection. Despite, to date, no certified antiviral treatment or vaccine exists. Although, few candidates have displayed their efficacy in in vitro studies and are being repurposed for COVID- 19 treatment. This article summarizes synthetic and semi-synthetic compounds displaying potent activity in clinical uses or studies on COVID-19 and also focuses on the mode of action of drugs being repositioned against COVID-19.

Lopinavir/Ritonavir: A Review of Analytical Methodologies for the Drug Substances, Pharmaceutical Formulations and Biological Matrices

Lopinavir/ritonavir is a potent coformulation of protease inhibitors used against HIV infection. Lopinavir is the main responsible for viral load suppression, whereas ritonavir is a pharmacokinetic enhancer. Both of them have recently gained relevance as candidate drugs against severe coronavirus disease (COVID-19). However, significant beneficial effects were not observed in randomized clinical trials. This review summarizes the main physical-chemical, pharmacodynamic, and pharmacokinetic properties of ritonavir and lopinavir, along with the analytical methodologies applied for biological matrices, pharmaceutical formulations, and stability studies. The work also aimed to provide a comprehensive impurity profile for the combined formulation. Several analytical methods in four different pharmacopeias and 37 articles in literature were evaluated and summarized. Chromatographic methods for these drugs frequently use C8 or C18 stationary phases with acetonitrile and phosphate buffer (with ultraviolet detection) or acetate buffer (with tandem mass spectrometry detection) as the mobile phase. Official compendia methods show disadvantages as extended total run time and complex mobile phases. HPLC tandem-mass spectrometry provided high sensitivity in methodologies applied for human plasma and serum samples, supporting the therapeutic drug monitoring in HIV patients. Ritonavir and lopinavir major degradation products arise in alkaline and acidic environments, respectively. Other non-chromatographic methods were also summarized. Establishing the impurity profile for the combined formulation is challenging due to a large number of impurities reported. Easier and faster analytical methods for impurity assessment are still needed.

The Emergence of Novel Coronavirus Disease, Global Treatment Update and its Containment Strategies in Overpopulated Countries: A Review

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The ongoing pandemic of the novel coronavirus SARS-CoV-2 (COVID-19) has created a major challenge for the public health worldwide. The reported cases indicate that the outbreak is more widespread than initially assumed. Around 18 million people have been infected with 689,000 reported deaths (August 2020; the number is increasing daily); with a high mutation rate, this virus poses an even more serious threat worldwide. The actual source of COVID-19 is still unclear; even if the initial reports link it to the Chinese seafood wet market in Wuhan, other animals such as birds, snakes, and many small mammals including bats are also linked with this novel coronavirus. The structure of the COVID-19 shows distinctive proteins among which spike proteins have a pivotal role in host cell attachment and virus-cell membrane fusion in order to facilitate virus infection. Currently, no specific antiviral treatment or vaccine is available. Various drug candidates, including SARS-CoV and MERS-CoV protease inhibitors, neuraminidase inhibitors, RNA synthesis inhibitors, ACE2 inhibitors and lungs supportive therapy, are under trials. Cell-based therapy also appeared with remarkable treatment possibilities. In this article, we endeavored to succinctly cover the current and available treatment options, including pharmaceuticals, cell-based therapy, and traditional medicine. We also focused on the extent of damages by this novel coronavirus in India, Pakistan, and Bangladesh; the strategies adopted and the research activities initiated so far by these densely populated countries (neighboring China) are explained in this review.

Potential therapeutic agents to COVID-19: An update review on antiviral therapy, immunotherapy, and cell therapy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, in December 2020 and coronavirus disease 19 (COVID-19) was later announced as pandemic by the World Health Organization (WHO). Since then, several studies have been conducted on the prevention and treatment of COVID-19 by potential vaccines and drugs. Although, the governments and global population have been attracted by some vaccine production projects, the presence of SARS-CoV-2-specific antiviral drugs would be an urge necessity in parallel with the efficient preventive vaccines. Various nonspecific drugs produced previously against other bacterial, viral, and parasite infections were recently evaluated for treating patients with COVID-19. In addition to therapeutic properties of these anti-COVID-19 compounds, some adverse effects were observed in different human organs as well. Not only several attentions were paid to antiviral therapy and treatment of COVID-19, but also nanomedicine, immunotherapy, and cell therapy were conducted against this viral infection. In this review study, we planned to introduce the present and potential future treatment strategies against COVID-19 and define the advantages and disadvantages of each treatment strategy.

Discovery of human coronaviruses pan-papain-like protease inhibitors using computational approaches

The papain-like protease (PLpro) is vital for the replication of coronaviruses (CoVs), as well as for escaping innate-immune responses of the host. Hence, it has emerged as an attractive antiviral drug-target. In this study, computational approaches were employed, mainly the structure-based virtual screening coupled with all-atom molecular dynamics (MD) simulations to computationally identify specific inhibitors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PLpro, which can be further developed as potential pan-PLpro based broad-spectrum antiviral drugs. The sequence, structure, and functional conserveness of most deadly human CoVs PLpro were explored, and it was revealed that functionally important catalytic triad residues are well conserved among SARS-CoV, SARS-CoV-2, and middle east respiratory syndrome coronavirus (MERS-CoV). The subsequent screening of a focused protease inhibitors database composed of ∼7,000 compounds resulted in the identification of three candidate compounds, ADM_13083841, LMG_15521745, and SYN_15517940. These three compounds established conserved interactions which were further explored through MD simulations, free energy calculations, and residual energy contribution estimated by MM-PB(GB)SA method. All these compounds showed stable conformation and interacted well with the active residues of SARS-CoV-2 PLpro, and showed consistent interaction profile with SARS-CoV PLpro and MERS-CoV PLpro as well. Conclusively, the reported SARS-CoV-2 PLpro specific compounds could serve as seeds for developing potent pan-PLpro based broad-spectrum antiviral drugs against deadly human coronaviruses. Moreover, the presented information related to binding site residual energy contribution could lead to further optimization of these compounds.

Pharmacological treatments of COVID-19

The viral infection due to the new coronavirus or coronavirus disease 2019 (COVID-19), which was reported for the first time in December 2019, was named by the World Health Organization (WHO) as Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV2), because of the very similar genome and also its related symptoms to SARS-CoV1. The ongoing COVID-19 pandemic with significant mortality, morbidity, and socioeconomic impact is considered by the WHO as a global public health emergency. Since there is no specific treatment available for SARS-CoV2 infection, and or COVID-19, several clinical and sub-clinical studies are currently undertaken to find a gold-standard therapeutic regimen with high efficacy and low side effect. Based on the published scientific evidence published to date, we summarized herein the effects of different potential therapies and up-to-date clinical trials. The review is intended to help readers aware of potentially effective COVID-19 treatment and provide useful references for future studies.

Existing antiviral options against SARS-CoV-2 replication in COVID-19 patients

COVID-19 caused by SARS-CoV-2, is an international concern. This infection requires urgent efforts to develop new antiviral compounds. To date, no specific drug in controlling this disease has been identified. Developing the new treatment is usually time consuming, therefore using the repurposing broad-spectrum antiviral drugs could be an effective strategy to respond immediately. In this review, a number of broad-spectrum antivirals with potential efficacy to inhibit the virus replication via targeting the virus spike protein (S protein), RNA-dependent RNA polymerase (RdRp), 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro) that are critical in the pathogenesis and life cycle of coronavirus, have been evaluated as possible treatment options against SARS-CoV-2 in COVID-19 patients.

Targeting Proteases for Treating COVID-19

The unprecedented pandemic of coronavirus disease 2019 (COVID-19) demands effective treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The infection of SARS-CoV-2 critically depends on diverse viral or host proteases, which mediate viral entry, viral protein maturation, as well as the pathogenesis of the viral infection. Endogenous and exogenous agents targeting for proteases have been proved to be effective toward a variety of viral infections ranging from HIV to influenza virus, suggesting protease inhibitors as a promising antiviral treatment for COVID-19. In this Review, we discuss how host and viral proteases participated in the pathogenesis of COVID-19 as well as the prospects and ongoing clinical trials of protease inhibitors as treatments.

Coronavirus Disease 2019: A Brief Review of the Clinical Manifestations and Pathogenesis to the Novel Management Approaches and Treatments

The recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19) in China, which spread to the rest of the world, led the World Health Organization to classify it as a global pandemic. COVID-19 belongs to the Bettacoronavirus genus of the Coronaviridae family, and it mainly spreads through the respiratory tract. Studies have now confirmed a human-to-human transmission as the primary pathway of spread. COVID-19 patients with a history of diseases such as respiratory system diseases, immune deficiency, diabetes, cardiovascular disease, and cancer are prone to adverse events (admission to the intensive care unit requiring invasive ventilation or even death). The current focus has been on the development of novel therapeutics, including antivirals, monoclonal antibodies, and vaccines. However, although there is undoubtedly an urgent need to identify effective treatment options against infection with COVID-19, it is equally important to clarify management protocols for the other significant diseases from which these patients may suffer, including cancer. This review summarizes the current evidence regarding the epidemiology, pathogenesis, and management of patients with COVID-19. It also aims to provide the reader with insights into COVID-19 in pregnant patients and those with cancer, outlining necessary precautions relevant to cancer patients. Finally, we provide the available evidence on the latest potent antiviral drugs and vaccines of COVID-19 and the ongoing drug trials.

Novel β-Coronavirus (SARS-CoV-2): Current and future aspects of pharmacological treatments

The novel coronavirus outbreak has reported to be rapidly spreading across the countries and becomes a foremost community health alarm. At present, no vaccine or specific drug is on hand for the treatment of this infectious disease. This review investigates the drugs, which are being evaluated and found to be effective against nCOVID-19 infection. A thorough literature search was performedon the recently published research papers in between January 2020 to May 2020, through various databases like "Science Direct", "Google Scholar", "PubMed","Medline", "Web of Science", and "World Health Organization (WHO)". We reviewed and documented the information related with the current and future aspects for the management and cure of COVID-19. As of 21st July 2020 a total of 14,562,550 confirmed cases of coronavirus and 607,781 deaths have been reported world-wide. The main clinical feature of COVID-19 ranges from asymptomatic disease to mild lower respiratory tract illness to severe pneumonia, acute lung injury, acute respiratory distress syndrome (ARDS), multiple organ dysfunction, and death. The drugs at present used in COVID-19 patients and ongoing clinical trials focusing on drug repurposing of various therapeutic classes of drug e.g. antiviral, anti-inflammatory and/or immunomodulatory drugs along with adjuvant/supportive care. Many drugs on clinical trials shows effective results on preliminary scale and now used currently in patients. Adjuvant/supportive care therapy are used in patients to get the best results in order to minimize the short and long-term complications. However, further studies and clinical trials are needed on large scale of population to reach any firm conclusion in terms of its efficacy and safety.

Derivatization and combination therapy of current COVID-19 therapeutic agents: a review of mechanistic pathways, adverse effects, and binding sites

Current treatment of patients with coronavirus 2019 (COVID-19) involves repurposed drugs that inhibit viral infection by either binding to their respective targets or via modulating cellular signal transduction. However, there is still a great deal of efficacy enhancement through combination therapy and derivatization. Combination therapy should involve agents with significant activity and different mechanisms of action. The structural map of the interaction between a drug and its target protein will help guide drug discovery for devising safe and effective ways to treat COVID-19. Herein, we report numerous synthetic designs based on enhanced affinity to the viral carbohydrate-rich protein spikes and protein-binding sites of COVID-19.

Advances in the possible treatment of COVID-19: A review

The emergence of the global pandemic caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has put a challenge to identify or derive the therapeutics for its prevention and treatment. Despite the unprecedented advances in the modern medicinal system, currently, there are no proven effective therapies. However, rapid research on SARS-CoV-2 epidemiology help unveiling some new targets for potential drug therapies. Many drugs have been screened, and even their clinical trials are going on at an exceptional pace. Amongst these RNA-dependent RNA polymerase inhibitors (favipiravir and remdesivir) and steroids especially dexamethasone showed promising effects. The biological agents like tocilizumab, interferons, and convalescent plasma prove to be beneficial in viral clearance. Moreover, many immunomodulatory and viral S protein targeting vaccines have their ongoing clinical trials. The establishment of various in vitro and in vivo models for preclinical studies can additionally help the current research. The volume and the pace of the clinical trials launched to evaluate the safety and efficacy of various agents against coronavirus disease 2019 (COVID-19) reflect the need for high-quality evidence for various therapies to be practiced by clinicians. This study aims to sum up all the current advances in the global medicinal system against the COVID-19.

Clopidogrel drug interactions: a review of the evidence and clinical implications

INTRODUCTION

Patients with cardiovascular disease are commonly affected by a number of comorbidities leading to a high prevalence of polypharmacy. Polypharmacy increases the probability of drug-drug interactions (DDIs). Amongst these, DDIs involving clopidogrel, the most commonly utilized platelet P2Y₁₂ inhibitor, is a topic of potential clinical concern.

AREAS COVERED

This article reviews DDIs between clopidogrel and drugs which are widely used in clinical practice. In particular, drugs shown to interfere with the pharmacodynamic and pharmacokinetic effects of clopidogrel and the clinical implications of these findings are reviewed. These drugs include inhibitors of gastric acid secretion, statins, calcium channel blockers, antidiabetic agents, and antimicrobial agents. For the references, we searched PubMed, EMBASE, or the Cochrane Library.

EXPERT OPINION

Clopidogrel-drug interactions are common. Most of these DDIs are limited to laboratory findings showing an impact on clopidogrel-induced antiplatelet effects. While variability in clopidogrel-induced antiplatelet effects is known to affect clinical outcomes, with high platelet reactivity being associated with thrombotic complications among patients undergoing coronary stenting, most studies assessing the clinical implications of clopidogrel-drug interactions have not shown to significantly affect outcomes. However, awareness of these DDIs remains important for optimizing the selection of concomitant therapies.

Lopinavir-ritonavir for COVID-19: A living systematic review

Objective

Provide a timely, rigorous, and continuously updated summary of the evidence on the role of lopinavir/ritonavir in the treatment of patients with COVID-19.

Methods

We conducted searches in the special L·OVE (Living OVerview of Evidence) platform for COVID-19, a system that performs regular searches in PubMed, Embase, CENTRAL, and other 33 sources. We searched for randomized trials and non-randomized studies evaluating the effect of lopinavir/ritonavir versus placebo or no treatment in patients with COVID-19. Two reviewers independently evaluated potentially eligible studies, according to predefined selection criteria, and extracted data using a predesigned standardized form. We performed meta-analyses using random-effect models and assessed overall certainty in evidence using the GRADE approach. A living, web-based version of this review will be openly available during the COVID-19 pandemic.

Results

Our search strategy yielded 862 references. Finally, we identified 12 studies, including two randomized trials, evaluating lopinavir/ritonavir, in addition to standard care versus standard care alone in 250 adult inpatients with COVID-19. The evidence from randomized trials shows lopinavir/ritonavir may reduce mortality (relative risk: 0.77; 95% confidence interval: 0.45 to 1.3; low certainty evidence), but the anticipated magnitude of the absolute reduction in mortality, varies across different risk groups. Lopinavir/ritonavir also had a slight reduction in the risk of requiring invasive mechanical ventilation, developing respiratory failure, or acute respiratory distress syndrome. However, it did not lead to any difference in the duration of hospitalization and may lead to an increase in the number of total adverse effects. The overall certainty of the evidence was low or very low.

Conclusions

For severe and critical patients with COVID-19, lopinavir/ritonavir might play a role in improving outcomes, but the available evidence is still limited. A substantial number of ongoing studies should provide valuable evidence to inform researchers and decision-makers soon.

Possible therapeutic agents for COVID-19: a comprehensive review

INTRODUCTION

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has emerged in China. There are no available vaccines or antiviral drugs for COVID-19 patients. Herein, we represented possible therapeutic agents that may stand as a potential therapy against COVID-19.

AREAS COVERED

We searched PubMed, Google Scholar, and clinicaltrials.gov for relevant papers. We showed some agents with potentially favorable efficacy, acceptable safety as well as good pharmacokinetic profiles. Several therapies are under assessment to evaluate their efficacy and safety for COVID-19. However, some drugs were withdrawn due to their side effects after demonstrating some clinical efficacy. Indeed, the most effective therapies could be organ function support, convalescent plasma, anticoagulants, and immune as well as antiviral therapies, especially anti-influenza drugs due to the similarities between respiratory viruses regarding viral entry, uncoating, and replication. We encourage giving more attention to favipiravir, remdesivir, and measles vaccine.

EXPERT OPINION

A combination, at least dual or even triple therapy, of the aforementioned efficacious and safe therapies is greatly recommended for COVID-19. Further, patients should have a routine assessment for their coagulation and bleeding profiles as well as their inflammatory and cytokine concentrations.

Medical Management of COVID-19: Evidence and Experience

Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and this infectious disease is termed COVID-19 in short. On a global scale, as of June 1, 2020, the World Health Organization (WHO) published statistics of 6,057,853 infected patients and 371,166 deaths worldwide. Despite reported observational data about the experimental use of certain drugs, there is no conclusively proven curative therapy for COVID-19 as of now; however, remdesivir received emergency use authorization (EUA) by the Food and Drug Administration (FDA) recently for use in patients hospitalized with COVID-19. There are several ongoing clinical trials related to the pharmacological choices of therapy for COVID-19 patients; however, drug trials related to observational studies so far have yielded mixed results and therefore have created a sense of confusion among healthcare professionals (HCPs). In this review article, we seek to collate and provide a summary of treatment strategies for COVID-19 patients with a variable degree of illness and discuss pharmacologic and other therapies intended to be used either as experimental medicine/therapy or as part of supportive care in complicated cases of COVID-19.

Pharmacologic Treatment of Transplant Recipients Infected With SARS-CoV-2: Considerations Regarding Therapeutic Drug Monitoring and Drug-Drug Interactions

COVID-19 is a novel infectious disease caused by the severe acute respiratory distress (SARS)-coronavirus-2 (SARS-CoV-2). Several therapeutic options are currently emerging but none with universal consensus or proven efficacy. Solid organ transplant recipients are perceived to be at increased risk of severe COVID-19 because of their immunosuppressed conditions due to chronic use of immunosuppressive drugs (ISDs). It is therefore likely that solid organ transplant recipients will be treated with these experimental antivirals.

A global treatments for coronaviruses including COVID-19

In late December 2019 in Wuhan, China, several patients with viral pneumonia were identified as 2019 novel coronavirus (2019‐nCoV). So far, there are no specific treatments for patients with coronavirus disease‐19 (COVID‐19), and the treatments available today are based on previous experience with similar viruses such as severe acute respiratory syndrome‐related coronavirus (SARS‐CoV), Middle East respiratory syndrome coronavirus (MERS‐CoV), and Influenza virus. In this article, we have tried to reach a therapeutic window of drugs available to patients with COVID‐19. Cathepsin L is required for entry of the 2019‐nCoV virus into the cell as target teicoplanin inhibits virus replication. Angiotensin‐converting‐enzyme 2 (ACE2) in soluble form as a recombinant protein can prevent the spread of coronavirus by restricting binding and entry. In patients with COVID‐19, hydroxychloroquine decreases the inflammatory response and cytokine storm, but overdose causes toxicity and mortality. Neuraminidase inhibitors such as oseltamivir, peramivir, and zanamivir are invalid for 2019‐nCoV and are not recommended for treatment but protease inhibitors such as lopinavir/ritonavir (LPV/r) inhibit the progression of MERS‐CoV disease and can be useful for patients of COVID‐19 and, in combination with Arbidol, has a direct antiviral effect on early replication of SARS‐CoV. Ribavirin reduces hemoglobin concentrations in respiratory patients, and remdesivir improves respiratory symptoms. Use of ribavirin in combination with LPV/r in patients with SARS‐CoV reduces acute respiratory distress syndrome and mortality, which has a significant protective effect with the addition of corticosteroids. Favipiravir increases clinical recovery and reduces respiratory problems and has a stronger antiviral effect than LPV/r. currently, appropriate treatment for patients with COVID‐19 is an ACE2 inhibitor and a clinical problem reducing agent such as favipiravir in addition to hydroxychloroquine and corticosteroids.

A systematic review of lopinavir therapy for SARS coronavirus and MERS coronavirus-A possible reference for coronavirus disease-19 treatment option

In the past few decades, coronaviruses have risen as a global threat to public health. Currently, the outbreak of coronavirus disease‐19 (COVID‐19) from Wuhan caused a worldwide panic. There are no specific antiviral therapies for COVID‐19. However, there are agents that were used during the severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) epidemics. We could learn from SARS and MERS. Lopinavir (LPV) is an effective agent that inhibits the protease activity of coronavirus. In this review, we discuss the literature on the efficacy of LPV in vitro and in vivo, especially in patients with SARS and MERS, so that we might clarify the potential for the use of LPV in patients with COVID‐19.

LPV is an effective agent inhibiting coronavirus in vitro and animal studies.

The treatment of LPV improved outcomes of SARS and MERS patients.

LPV may be a potential treatment option for COVID‐19.

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.

Differences in genetic variants in lopinavir disposition among HIV-infected Bantu Africans

INTRODUCTION

Variability in lopinavir (LPV) plasma concentration among patients could be due to genetic polymorphisms. This study set to evaluate significance of variants in CYP3A4/5, SLCO1B1 and ABCC2 on LPV plasma concentration among African HIV-positive patients.

MATERIALS & METHODS

Eighty-six HIV-positive participants on ritonavir (LPV/r) were genetically characterized and LPV plasma concentration determined.

RESULTS & DISCUSSION

LPV plasma concentrations differed >188-fold (range 0.0206-38.6 µg/ml). Both CYP3A4*22 and SLCO1B1 rs4149056G (c.521C) were not observed in this cohort. CYP3A4*1B, CYP3A5*3, CYP3A5*6 and ABCC2 c.1249G>A which have been associated with LPV plasma concentration, showed no significant association.

CONCLUSION

These findings highlight the need to include African groups in genomics research to identify variants of pharmacogenomics significance.

Evaluation of pharmacokinetic interactions between long-acting HIV-1 fusion inhibitor albuvirtide and lopinavir/ritonavir, in HIV-infected subjects, combined with clinical study and simulation results

1. A clinical study to assess the interactions between albuvirtide (320 mg) and lopinavir/ritonavir (400/100 mg) was conducted in 10 HIV-1-infected subjects. Because albuvirtide requires a long period to achieve steady state, and extended monotherapy may lead to early resistance, it is unethical to take albuvirtide alone to achieve steady state. Therefore, a population pharmacokinetic model was developed to predict steady-state concentration-time curve of solely administered albuvirtide. 2. When albuvirtide and lopinavir/ritonavir were co-administered, the plasma concentration of albuvirtide when the infusion ended (C_end) increased by about 34%, but the geometric mean ratios and 90% confidence intervals (90% CIs) of AUC_(0-t) [1.09 (0.96-1.24)] and C_trough [1.00 (0.83-1.20)] were within the range of 0.8-1.25. For lopinavir, the ratios (90% CIs) of AUC_(0-t), C_max and C_trough were 0.63 (0.49-0.82), 0.67 (0.53-0.86) and 0.65 (0.46-0.91); for ritonavir, those ratios (90% CIs) were 0.62 (0.42-0.91), 0.61 (0.38-0.99) and 0.72 (0.40-1.26), respectively. 3. Co-administration of albuvirtide with lopinavir/ritonavir has little effect on albuvirtide exposure, but it decreases the plasma exposures of lopinavir/ritonavir. However, the drug-drug interactions may not reduce the effectiveness of this co-therapy, the trough concentration of lopinavir may be sufficient and this combination could achieve similar clinical efficacy with marketed drugs. So, a phase 3 clinical trial without dose adjustment is underway to validate their effectiveness and safety.

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.

Are lopinavir and efavirenz serum concentrations in HIV-infected children in the therapeutic range in clinical practice?

BACKGROUND

In antiretroviral treatment the role of therapeutic drug monitoring via measurement of serum levels remains unclear, especially in children.

AIM

To quantify exposure to LPV and EFV in children receiving therapy in a routine clinical setting in order to identify risk factors associated with inadequate drug exposure.

METHOD

A prospective study was conducted in a routine clinical setting in Tygerberg Children's Hospital, South Africa. A total of 53 random serum levels were analyzed. Serum concentrations were determined by an established high-performance liquid chromatography method.

RESULTS

Of 53 HIV-infected children treated with lopinavir (n = 29, median age 1·83 y) or efavirenz (n = 24, median age 9·3 years), 12 showed serum levels outside the therapeutic range (efavirenz) or below Cmin (lopinavir). Low bodyweight, rifampicin co-treatment, and significant comorbidity were potential risk factors for inadequate drug exposure.

CONCLUSION

These findings, together with previous studies, indicate that therapeutic drug monitoring can improve the management of antiretroviral therapy in children at risk.

Overview of antiviral and anti-inflammatory treatment for severe acute respiratory syndrome

In 2003, an outbreak of a novel respiratory virus exploded from mainland China into an international issue, catching the world by surprise. The ensuing challenges to hospital and public health workers rose to a level never before seen in healthcare, in part due to the unknown nature of the disease, the fear of the human-to-human transmission and the significant media involvement. A new coronavirus was identified as the causative agent and named the severe acute respiratory syndrome-associated virus. A number of antiviral and anti-inflammatory treatment strategies were explored during the epidemic, with varying success. Following the epidemic, in vitro antiviral analyses of numerous compounds have been conducted. This review summarizes treatment agents assessed during and after the 2003 severe acute respiratory syndrome outbreak, with the aim of guiding future decision makers should the virus return.

Pediatric response to second-line antiretroviral therapy in South Africa

BACKGROUND

With improved access to pediatric antiretroviral therapy (ART) in resource-limited settings, more children could experience first-line ART treatment failure.

METHODS

We performed a retrospective cohort analysis using electronic medical records from HIV-infected children who initiated ART at McCord Hospital's Sinikithemba Clinic in KwaZulu-Natal, South Africa, from August 2003 to December 2010. We analyzed all records from children who began second-line ART due to first-line treatment failure. We used logistic regression to compare viral outcomes in Protease Inhibitor (PI)-based versus Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI)-based second-line ART, controlling for time on first-line ART, sex, and whether HIV genotyping guided the regimen change.

RESULTS

Of the 880 children who initiated ART during this time period, 80 (9.1%) switched to second-line ART due to therapeutic failure of first-line ART after a median of 95 weeks (IQR 65-147 weeks). Eight (10%) of the failures received NNRTI-based second-line ART, all of whom failed a PI-based first-line regimen. Seventy (87.5%) received PI-based second-line ART, all of whom failed a NNRTI-based first-line regimen. Two children (2.5%) received non-standard dual therapy as second-line ART. Six months after switching ART regimens, the viral suppression rate was significantly higher in the PI group (82%) than in the NNRTI group (29%; p=0.003). Forty-one children (51%) were tested for genotypic resistance prior to switching to second-line ART. There was no significant difference in six month viral suppression (p=0.38) between children with and without genotype testing.

CONCLUSION

NNRTI-based second-line ART carries a high risk of virologic failure compared to PI-based second-line ART.

Association of lopinavir concentrations with plasma lipid or glucose concentrations in HIV-infected South Africans: a cross sectional study

Background

Dyslipidaemia and dysglycaemia have been associated with exposure to ritonavir-boosted protease inhibitors. Lopinavir/ritonavir, the most commonly used protease inhibitor in resource-limited settings, often causes dyslipidaemia. There are contradictory data regarding the association between lopinavir concentrations and changes in lipids.

Aim

To investigate associations between plasma lopinavir concentrations and lipid and glucose concentrations in HIV-infected South African adults.

Methods

Participants stable on lopinavir-based antiretroviral therapy were enrolled into a cross-sectional study. After an overnight fast, total cholesterol, triglycerides, and lopinavir concentrations were measured and an oral glucose tolerance test was performed. Regression analyses were used to determine associations between plasma lopinavir concentrations and fasting and 2 hour plasma glucose, fasting cholesterol, and triglycerides concentrations.

Results

There were 84 participants (72 women) with a median age of 36 years. The median blood pressure, body mass index and waist: hip ratio were 108/72 mmHg, 26 kg/m² and 0.89 respectively. The median CD4 count was 478 cells/mm³. Median duration on lopinavir was 18.5 months. The median (interquartile range) lopinavir concentration was 8.0 (5.2 to 12.8) μg/mL. Regression analyses showed no significant association between lopinavir pre-dose concentrations and fasting cholesterol (β-coefficient −0.04 (95% CI −0.07 to 0.00)), triglycerides (β-coefficient −0.01 (95% CI −0.04 to 0.02)), fasting glucose (β-coefficient −0.01 (95% CI −0.04 to 0.02)), or 2-hour glucose concentrations (β-coefficient −0.02 (95% CI −0.09 to 0.06)). Lopinavir concentrations above the median were not associated with presence of dyslipidaemia or dysglycaemia.

Conclusions

There was no association between lopinavir plasma concentrations and plasma lipid and glucose concentrations.

A drug discovery platform: a simplified immunoassay for analyzing HIV protease activity

Although numerous methods for the determination of HIV protease (HIV-PR) activity have been described, new high-throughput assays are required for clinical and pharmaceutical applications due to the occurrence of resistant strains. In this study, a simple enzymatic immunoassay to identify HIV-PR activity was developed based on a Ni(2+)-immobilized His(6)-Matrix-Capsid substrate (H(6)MA-CA) is cleaved by HIV protease-His(6) (HIV-PRH(6)) which removes the CA domain and exposes the free C terminus of MA. Following this cleavage, two monoclonal antibodies specific for either the free C-terminal MA or CA epitope are used to quantify the proteolytic activity using a standard ELISA-based system. Specificity for detection of the HIV-PRH(6) activity was confirmed with addition of protease inhibitor (PI), lopinavir. In addition, the assay was able to detect an HIV-PR variant activity indicating that this assay is capable of assessing viral mutation affect HIV-PR activity. The efficacy of commercially available PIs and their 50% inhibitory concentration (IC(50)) were determined. This assay provides a high-throughput method for both validating the efficiency of new drugs in vitro and facilitating the discovery of new PIs. In addition, it could serve as a method for examining the influence of various mutations in HIV-PRs isolated from drug-resistant strains.

Characterization of gut-associated cathepsin D hemoglobinase from tick Ixodes ricinus (IrCD1)

To identify the gut-associated tick aspartic hemoglobinase, this work focuses on the functional diversity of multiple Ixodes ricinus cathepsin D forms (IrCDs). Out of three encoding genes representing Ixodes scapularis genome paralogs, IrCD1 is the most distinct enzyme with a shortened propeptide region and a unique pattern of predicted post-translational modifications. IrCD1 gene transcription is induced by tick feeding and is restricted to the gut tissue. The hemoglobinolytic role of IrCD1 was further supported by immunolocalization of IrCD1 in the vesicles of tick gut cells. Properties of recombinantly expressed rIrCD1 are consistent with the endo-lysosomal environment because the zymogen is autoactivated and remains optimally active in acidic conditions. Hemoglobin cleavage pattern of rIrCD1 is identical to that produced by the native enzyme. The preference for hydrophobic residues at the P1 and P1' position was confirmed by screening a novel synthetic tetradecapeptidyl substrate library. Outside the S1-S1' regions, rIrCD1 tolerates most amino acids but displays a preference for tyrosine at P3 and alanine at P2'. Further analysis of the cleavage site location within the peptide substrate indicated that IrCD1 is a true endopeptidase. The role in hemoglobinolysis was verified with RNAi knockdown of IrCD1 that decreased gut extract cathepsin D activity by >90%. IrCD1 was newly characterized as a unique hemoglobinolytic cathepsin D contributing to the complex intestinal proteolytic network of mainly cysteine peptidases in ticks.

CYP3A4-mediated lopinavir bioactivation and its inhibition by ritonavir

The combination of lopinavir (LPV) and ritonavir (RTV) is one of the preferred regimens for the treatment of HIV infection with confirmed efficacy and relatively low toxicity. LPV alone suffers the poor bioavailability due to its rapid and extensive metabolism. RTV boosts the plasma concentration of LPV by suppressing its metabolism and thus increasing LPV efficacy. In the current study, we found that RTV also inhibits LPV bioactivation. LPV bioactivation was investigated in human liver microsomes and cDNA-expressed human cytochromes P450. Twelve GSH-trapped reactive metabolites of LPV were identified by using a metabolomic approach. Semicarbazide-trapped reactive metabolites of LPV were also detected. RTV effectively suppressed all pathways of LPV bioactivation via CYP3A4 inhibition. Our data together with previous reports suggest that LPV plus RTV is an ideal combination because RTV not only boosts LPV plasma concentration, but it decreases LPV bioactivation.

Peptidase inhibitors in the MEROPS database

The MEROPS website (http://merops.sanger.ac.uk) includes information on peptidase inhibitors as well as on peptidases and their substrates. Displays have been put in place to link peptidases and inhibitors together. The classification of protein peptidase inhibitors is continually being revised, and currently inhibitors are grouped into 67 families based on comparisons of protein sequences. These families can be further grouped into 38 clans based on comparisons of tertiary structure. Small molecule inhibitors are important reagents for peptidase characterization and, with the increasing importance of peptidases as drug targets, they are also important to the pharmaceutical industry. Small molecule inhibitors are now included in MEROPS and over 160 summaries have been written.

Population analysis of the pregnancy-related modifications in lopinavir pharmacokinetics and their possible consequences for dose adjustment

OBJECTIVES

To investigate the possible necessity of an increase in lopinavir dose during pregnancy in order to achieve the concentrations previously defined as predictive of virological efficacy.

PATIENTS AND METHODS

Lopinavir pharmacokinetics were investigated by a population approach performed on 145 HIV-infected women, including 74 pregnant women. The final model was used to determine the probability of achievement of the target trough concentrations by Monte Carlo simulations.

RESULTS

The typical population estimates (inter-individual variability %) of apparent clearance (CL/F) and volume of distribution were 4.38 L/h (24%) and 58.4 L (59%), respectively. Pregnancy associated with a gestational age >15 weeks and delivery were found to increase lopinavir CL/F by 39% and 58%, respectively. With the standard 400 mg twice-a-day regimen, the probability of reaching the 1 mg/L target trough concentration for protease inhibitor (PI)-naive patients was 99% and 96% for non-pregnant and pregnant women, respectively. An important decrease in the probability of achieving the 5.7 mg/L target trough concentration for salvage therapy was observed for non-pregnant women (55%), this decrease being even greater for pregnant women (21%). Raising the lopinavir dose to 600 mg twice daily increased these probabilities to 87% and 53% for non-pregnant and pregnant women, respectively.

CONCLUSIONS

Modification of the lopinavir dose is unlikely to be required for PI-naive pregnant women; however, in pregnant women who have previously received a PI, therapeutic drug monitoring and/or empirical increasing of the dose should be considered.

Both P-gp and MRP2 mediate transport of Lopinavir, a protease inhibitor

Polarized epithelial non-human (canine) cell lines stably transfected with human or murine complementary DNA (cDNA) encoding for various efflux transporters (P-gp/MDR1, MRP1, MRP2, and Bcrp1) were used to study transepithelial transport of Lopinavir (LVR) and compare results with the MDCKII-wild type cells. These transmembrane proteins cause multidrug resistance by decreasing the total intracellular accumulation of drugs. Lopinavir efflux was directional and was completely inhibited by MK-571, a selective MRP family inhibitor in the MDCKII-MRP2 cell line. Similarly, LVR efflux was also inhibited by P-gp inhibitors P-gp-4008 and GF120918 in the MDCKII-MDR1 cell line. The efflux ratios of LVR in the absence of any efflux inhibitors in the MDCK-wild type, MDCKII-MDR1, MDCKII-MRP1 and MDCKII-MRP2 cell monolayers were 1.32, 4.91, 1.26 and 2.89 respectively. The MDCKII-MDR1 and MDCKII-MRP2 cells have significantly increased LVR efflux ratio relative to the parental cells due to the apically directed transport by MDR1 and MRP2 respectively. The efflux ratios in MRP2 and MDR1 transfected cell lines were close to unity in the presence of MK-571 and P-gp-4008, respectively, indicating that LVR efflux by MRP2 and P-gp was completely inhibited by their selective inhibitors. MDCKII-MRP1 cells did not exhibit a significant reduction in the LVR efflux relative to the parental cells, indicating that LVR is not a good substrate for MRP1. Transport studies across MDCKII-Bcrp1 cells indicated that LVR is not transported by Bcrp1 and is not a substrate for this efflux protein. In conclusion, this study presents direct evidence that LVR is effluxed by both P-gp and MRP2 which may contribute to its poor oral bioavailability and limited penetration into the CNS.

Population analysis of weight-, age-, and sex-related differences in the pharmacokinetics of lopinavir in children from birth to 18 years

The pharmacokinetics of lopinavir were investigated by the use of a population approach performed with the nonlinear mixed effect modeling program NONMEM and 157 children ranging in age from 3 days to 18 years. The pharmacokinetics of lopinavir were well described by a one-compartment model in which the absorption and the elimination rate constants were equal. Typical population estimates of the apparent volume of distribution (V/F) and plasma clearance (CL/F) were 24.6 liters and 2.58 liters/h, respectively. The lopinavir V/F and CL/F were both related to body weight (BW), with an important increase in weight-normalized CL/F for the lowest BW. Combined treatment with lopinavir and nevirapine was found to increase the CL/F. The lopinavir CL/F was also age and sex related, as a 39% increase was observed after the age of 12 years for boys compared to the CL/F for girls. The consequences of these pharmacokinetic discrepancies and the necessity to modify the currently recommended dosage regimen should be further investigated.

Population pharmacokinetics of lopinavir in combination with ritonavir in HIV-1-infected patients

AIMS

To develop a population pharmacokinetic model for lopinavir in combination with ritonavir, in which the interaction between both drugs was characterized, and in which relationships between patient characteristics and pharmacokinetics were identified.

METHODS

The pharmacokinetics of lopinavir in combination with ritonavir were described using NONMEM (version V, level 1.1). First, ritonavir data were fitted to a previously developed model to obtain individual Bayesian estimates of pharmacokinetic parameters. Hereafter, an integrated model for the description of the pharmacokinetics of lopinavir with ritonavir was designed.

RESULTS

From 122 outpatients 748 lopinavir and 748 ritonavir plasma concentrations were available for analysis. The interaction between the drugs was described by a time-independent inverse relationship between the exposure to ritonavir over a dosing-interval and the apparent clearance (CL/F) of lopinavir. The model parameters volume of distribution and absorption rate constant were 61.6 l (95% prediction interval (PI) 22.4, 83.7) and 0.564 h(-1) (95% PI 0.208, 0.947), respectively. The model yielded a theoretical value for the CL/F of lopinavir without ritonavir of 14.8 l h(-1) (95%PI 12.1, 20.1), which translates to a value of 5.73 l h(-1) in the presence of ritonavir. The only factor with significant effect on the pharmacokinetics was concurrent use of non-nucleoside reverse transcriptase inhibitors (NNRTI), which increased the CL/F of lopinavir by 39% (P < 0.001).

CONCLUSIONS

We have developed a model that has defined a time-independent inverse relationship between the exposure to ritonavir and the CL/F of lopinavir, and provided an adequate description of the pharmacokinetic parameters for the latter. Concomitant use of the NNRTIs efavirenz and nevirapine increased the CL/F of lopinavir.

Effects of highly active antiretroviral therapy with nelfinavir in vertically HIV-1 infected children: 3 years of follow-up. Long-term response to nelfinavir in children

BACKGROUND

Antiretroviral treatment (ART) in children has special features and consequently, results obtained from clinical trials with antiretroviral drugs in adults may not be representative of children. Nelfinavir (NFV) is an HIV-1 Protease Inhibitor (PI) which has become as one of the first choices of PI for ART in children. We studied during a 3-year follow-up period the effects of highly active antiretroviral therapy with nelfinavir in vertically HIV-1 infected children.

METHODS

Forty-two vertically HIV-infected children on HAART with NFV were involved in a multicentre prospective study. The children were monitored at least every 3 months with physical examinations, and blood sample collection to measure viral load (VL) and CD4+ cell count. We performed a logistic regression analysis to determinate the odds ratio of baseline characteristics on therapeutic failure.

RESULTS

Very important increase in CD4+ was observed and VL decreased quickly and it remained low during the follow-up study. Children with CD4+ <25% at baseline achieved CD4+ >25% at 9 months of follow-up. HIV-infected children who achieved undetectable viral load (uVL) were less than 40% in each visit during follow-up. Nevertheless, HIV-infected children with VL >5000 copies/ml were less than 50% during the follow-up study. Only baseline VL was an important factor to predict VL control during follow-up. Virological failure at defined end-point was confirmed in 30/42 patients. Along the whole of follow-up, 16/42 children stopped HAART with NFV. Baseline characteristics were not associated with therapeutic change.

CONCLUSION

NFV is a safe drug with a good profile and able to achieve an adequate response in children.

Discovery of imidazolidine-2,4-dione-linked HIV protease inhibitors with activity against lopinavir-resistant mutant HIV

A new series of HIV protease inhibitors has been designed and synthesized based on the combination of the (R)-(hydroxyethylamino)sulfonamide isostere and the cyclic urea component of lopinavir. The series was optimized by replacing the 6-membered cyclic urea linker with an imidazolidine-2,4-dione which readily underwent N-alkylation to incorporate various methylene-linked heterocycle groups that bind favorably in site 3 of HIV protease. Significant improvements compared to lopinavir were seen in cell culture activity versus wild-type virus (pNL4-3) and the lopinavir-resistant mutant virus A17 (generated by in vitro serial passage of HIV-1 (pNL4-3) in MT-4 cells). Select imidazolidine-2,4-dione containing PIs were also more effective at inhibiting highly resistant patient isolates Pt1 and Pt2 than lopinavir. Pharmacokinetic data collected for compounds in this series varied considerably when coadministered orally in the rat with an equal amount of ritonavir (5 mg/kg each). The AUC values ranged from 0.144 to 12.33 microg h/mL.