Pharmacokinetic drug evaluation of ritonavir (versus cobicistat) as adjunctive therapy in the treatment of HIV

Harnessing nanotechnology in HIV therapy: Exploring molecular pathogenesis and treatment strategies with special reference to chemotherapy and immunotherapy

Human immunodeficiency virus (HIV) continues to be a global threat, contributing substantially to social and economic burdens worldwide. Synthetic ARV drugs are classified into six different classes viz NRTIs, NNRTIs, PIs, IIs, INSTIs, and FIs. Highly active anti-retroviral therapy (HAART) which is a combination of two or more ARV drugs from different classes is gaining immense popularity in the HIV therapy regimen due to its better therapeutic outcome. However, despite its successful endeavor in significant viral suppression, synthetic drugs are associated with numerous adverse effects. To mitigate this issue, scientists are exploring ARV agents derived from various natural sources like plants, and marine organisms that can exhibit potent anti-HIV activity with minimal side effects. Nevertheless, both synthetically and naturally derived ARV agents have failed to exhibit eradication of HIV from latent reservoirs. Henceforth, researchers are shifting their attention towards formulating a drug-encapsulated nano-delivery system to ensure a significant amount of drug delivery into these reservoirs. Additionally, the discovery of a novel HIV vaccine that can induce robust immune responses against multiple HIV strains and facilitate complete removal of the virus before the establishment of a latent reservoir is the need of an hour. Briefly, we discussed various synthetic and natural chemotherapeutic agents along with their specificity and limitations, different drug-delivery devices for ART, immunotherapy, vaccines, and lastly, challenges and strategies associated with vaccine development.

Artificial intelligence to predict inhibitors of drug-metabolizing enzymes and transporters for safer drug design

INTRODUCTION

Drug-metabolizing enzymes (DMEs) and transporters (DTs) play integral roles in drug metabolism and drug-drug interactions (DDIs) which directly impact drug efficacy and safety. It is well-established that inhibition of DMEs and DTs often leads to adverse drug reactions (ADRs) and therapeutic failure. As such, early prediction of such inhibitors is vital in drug development. In this context, the limitations of the traditional in vitro assays and QSAR models methods have been addressed by harnessing artificial intelligence (AI) techniques.

AREAS COVERED

This narrative review presents the insights gained from the application of AI for predicting DME and DT inhibitors over the past decade. Several case studies demonstrate successful AI applications in enzyme-transporter interaction prediction, and the authors discuss workflows for integrating these predictions into drug design and regulatory frameworks.

EXPERT OPINION

The application of AI in predicting DME and DT inhibitors has demonstrated significant potential toward enhancing drug safety and effectiveness. However, critical challenges involve the data quality, biases, and model transparency. The availability of diverse, high-quality datasets alongside the integration of pharmacokinetic and genomic data are essential. Lastly, the collaboration among computational scientists, pharmacologists, and regulatory bodies is pyramidal in tailoring AI tools for personalized medicine and safer drug development.

Long-term durability of dolutegravir plus darunavir/cobicistat dual regimen in highly antiretroviral-experienced people with HIV (DoDaco study)

BACKGROUND

A dolutegravir plus darunavir/cobicistat regimen has been used as a simplified option in heavily treatment-experienced people with HIV (PWH). We report on long-term results of this regimen as assessed by treatment discontinuation (TD) for any reason.

METHODS

This was a retrospective, observational, multicentre study. PWH started on dolutegravir plus darunavir/cobicistat from 1 December 2015 to 31 December 2022 were included. The primary endpoint was the rate of TD for any reason. Survival analysis with the Kaplan-Meier estimator was used to assess the probability of TD over time. Multiple Cox regression was used to estimate the probability of TD at 1 year following regimen initiation.

RESULTS

Three hundred and twenty-seven subjects were included. At baseline, 63.6% of individuals had HIV RNA of <50 copies/mL. Primary resistance-associated mutations for NRTIs, NNRTIs, PIs and integrase inhibitors were documented in 88.0%, 70.0%, 24.5% and 6.6%, respectively. Median follow-up was 4 years (IQR 3.3-6.9). Probability of TD was 8.3%, 13.0%, 18.0%, 22.0%, 25.0%, 30.0% and 35.0% after 1, 2, 3, 4, 5, 6 and 7 years of treatment, respectively. TD occurred in 83 subjects, largely due to death (n = 20), simplification (n = 13), toxicity (n = 11), intolerance (n = 9), drug interactions (n = 10) and virological failure (n = 7). At Cox regression analysis, factors associated with a higher probability of TD over time were baseline HIV RNA of >50 copies/mL (HR = 2.14, 95% CI 1.20-3.81; P = 0.01) and the presence of PI or integrase strand transfer inhibitor resistance mutations (HR = 5.48, 95% CI 2.42-12.4; P < 0.001).

CONCLUSIONS

Dolutegravir plus darunavir/cobicistat is a durable combination in heavily treatment-experienced PWH. Those who were viraemic at the time of switch were more likely to discontinue, although most reasons for TD were other than virological failure.

Management of polypharmacy and potential drug-drug interactions in people with HIV and cancer: insights from a 4-year multidisciplinary clinic experience

BACKGROUND

People with HIV and cancer (PWHC) are often treated with different combinations of antiretroviral and oncology drugs, frequently associated with other co-medications; this significantly increases the risk of potential drug-drug interactions (DDIs).

RESEARCH DESIGN AND METHODS

A prospective observational study has been carried out from May 2020 to May 2024 to describe the management of therapies in PWHC in an outpatient clinic.

RESULTS

140 PWHC treated with 42 different antiretroviral and 59 oncology regimens were enrolled, resulting in the identification of 410 DDIs. Of these, 8% were scored as red-flag DDIs). Among antiretroviral medications, 77% of red-flag DDIs involved ritonavir or cobicistat. Paclitaxel was the oncology drug most frequently associated with red-flag-DDIs (77%). Proton pump inhibitors (PPIs) were involved in 19% of red-flag and 32 of orange-flag DDIs. The most frequent recommendations included performing an electrocardiogram (38%), conducting therapeutic drug monitoring (31%), discontinuing PPIs (29%) and/or adjusting the timing of drug intake (28%).

CONCLUSIONS

A high prevalence of polypharmacy and clinically relevant DDIs was observed in our cohort of PWHC. A multidisciplinary team could play a pivotal role in optimizing pharmacological therapies in this clinical setting, for example, by reducing the use of PPIs and booster-based antiretroviral regimens.

The Case of Dolutegravir Plus Darunavir Antiretroviral Regimens: Is It Always Useful to Double the Drug Doses?

BACKGROUND

Antiretroviral drug combinations affect dolutegravir trough concentrations. Here, the authors focused on dolutegravir plus booster darunavir antiretroviral regimens to investigate the effect of the booster and/or timing of drug administration on dolutegravir and darunavir plasma trough concentrations.

METHODS

This retrospective observational study included consecutive people with HIV (PWH) receiving dolutegravir plus booster darunavir antiretroviral regimens for at least 3 months, with at least one assessment of dolutegravir and darunavir plasma trough concentrations.

RESULTS

A total of 200 drug therapeutic drug monitoring results from 116 PWH were included. Dolutegravir and darunavir trough concentrations ranged, respectively, from 70 to 3648 mcg/L and from 102 to 11,876 mcg/L. The antiretroviral drug combination associated with the highest dolutegravir trough concentration was dolutegravir plus darunavir/cobicistat, both once daily (1410 ± 788 mcg/L), whereas dolutegravir once daily plus darunavir/ritonavir twice daily had the lowest trough concentrations (686 ± 481 mcg/L). Doubling the dose of dolutegravir did not significantly increase drug trough concentrations compared with that of once-daily regimens. Instead, the highest darunavir trough concentrations were with ritonavir (2850 ± 1456 mcg/L, P < 0.05 versus cobicistat-based regimens). Doubling the drug dose resulted in a significant increase in the darunavir trough concentration (4445 ± 2926 mcg/L, P < 0.05).

CONCLUSIONS

Dolutegravir trough concentrations were significantly reduced in PWH receiving darunavir/ritonavir twice daily. This evidence should be carefully considered in clinical conditions requiring higher dolutegravir exposure, such as in the presence of drug-drug interactions with drugs known to reduce dolutegravir bioavailability or in highly experienced PWH.

Physiologically Based Pharmacokinetic Modeling to Assess Ritonavir-Digoxin Interactions and Recommendations for Co-Administration Regimens

BACKGROUND

Digoxin is a commonly used cardiac glycoside drug in clinical practice, primarily transported by P-glycoprotein (P-gp) and susceptible to the influence of P-gp inhibitors/inducers. Concurrent administration of ritonavir and digoxin may significantly increase the plasma concentration of digoxin. Due to the narrow therapeutic window of digoxin, combined use may lead to severe toxic effects.

PURPOSE

Utilize a Physiology-Based Pharmacokinetic (PBPK) model to simulate and predict the impact of the interaction between ritonavir and digoxin on the pharmacokinetics (PK) of digoxin, and provide recommendations for the combined medication regimen.

METHODS

Using PK-Sim®, develop individual PBPK models for ritonavir and digoxin. Simulate the exposure in a drug-drug interaction (DDI) scenario by implementing ritonavir's inhibition of P-glycoprotein (P-gp) on digoxin. Evaluate the performance of the models by comparing the predicted and observed plasma concentration-time curves and predicted versus observed PK parameter values. Finally, adjust the dosing regimen for the combined therapy based on the changes in exposure.

RESULTS

According to the model simulations, the steady-state exposure of digoxin increased by 86.5% and 90.2% for oral administration, and 80.2% and 90.2% for intravenous administration, respectively, when 0.25 mg or 0.5 mg of digoxin was administered concurrently with ritonavir. By reducing the dose of digoxin by 45% or doubling the oral administration interval, similar steady-state concentrations can be achieved compared to when the drugs are not co-administered.

CONCLUSIONS

In clinical practice, the influence of drug interactions on the plasma concentration changes of digoxin within the body should be considered to ensure the safety and effectiveness of treatment.

Ritonavir: 25 Years' Experience of Concomitant Medication Management. A Narrative Review

Ritonavir is a potent inhibitor of the cytochrome P450 3A4 enzyme and is commonly used as a pharmacokinetic (PK) enhancer in antiviral therapies because it increases bioavailability of concomitantly administered antivirals. Decades of experience with ritonavir-enhanced HIV therapies and, more recently, COVID-19 therapies demonstrate that boosting doses of ritonavir are well tolerated, with an established safety profile. The mechanisms of PK enhancement by ritonavir result in the potential for drug-drug interactions (DDIs) with several classes of drugs, thus making co-medication management an important consideration with enhanced antiviral therapies. However, rates of DDIs with contraindicated medications are low, suggesting these risks are manageable by infectious disease specialists who have experience with the use of PK enhancers. In this review, we provide an overview of ritonavir's mechanisms of action and describe approaches and resources available to mitigate adverse events and manage concomitant medication in both chronic and short-term settings.

Physiologically based pharmacokinetic modeling of ritonavir-oxycodone drug interactions and its implication for dosing strategy

The concomitant administration of ritonavir and oxycodone may significantly increase the plasma concentrations of oxycodone. This study was aimed to simulate DDI between ritonavir and oxycodone, a widely used opioid, and to formulate dosing protocols for oxycodone by using physiologically based pharmacokinetic (PBPK) modeling. We developed a ritonavir PBPK model incorporating induction and competitive and time-dependent inhibition of CYP3A4 and competitive inhibition of CYP2D6. The ritonavir model was evaluated with observed clinical pharmacokinetic data and validated for its CYP3A4 inhibition potency. We then used the model to simulate drug interactions between oxycodone and ritonavir under various dosing scenarios. The developed model captured the pharmacokinetic characteristics of ritonavir from clinical studies. The model also accurately predicts exposure changes of midazolam, triazolam, and oxycodone in the presence of ritonavir. According to model simulations, the steady-state maximum, minimum and average concentrations of oxycodone increased by up to 166% after co-administration with ritonavir, and the total exposure increased by approximately 120%. To achieve similar steady-state concentrations, halving the dose with an unchanged dosing interval or doubling the dosing interval with an unaltered single dose should be practical for oxycodone, whether formulated in uncoated or controlled-release tablets during long-term co-medication with ritonavir. The results revealed exposure-related risks of oxycodone-ritonavir interactions that have not been studied clinically and emphasized PBPK as a workable method to direct judicious dosage.

Polypharmacy and Aging in People Living with HIV: 6 Years of Experience in a Multidisciplinary Outpatient Clinic

BACKGROUND

Despite the availability of potent antiretroviral drugs, the management of human immunodeficiency virus (HIV) infection still presents some important challenges, especially in older patients who often experience age-related comorbidities and complex polypharmacy.

OBJECTIVE

To describe the results of our 6 year experience with the outpatient clinic [Gestione Ambulatoriale Politerapie (GAP)] for the management of polypharmacy in people living with HIV (PLWH).

METHODS

Demographic characteristics, antiretroviral regimens, and number and type of comedications were collected in all PLWH included in the database of GAP from September 2016 to September 2022. Therapies were stratified based on the number of anti-HIV drugs (dual versus triple regimens) and on the presence of pharmacokinetic boosters (ritonavir or cobicistat).

RESULTS

A total of 556 PLWH were included in the GAP database. Overall, the enrolled patients were administered 4.2 ± 2.7 drugs (range 1-17) in addition to antiretroviral therapies. The number of comedications greatly increased with age (3.0 ± 2.2 versus 4.1 ± 2.5 versus 6.3 ± 3.2 in PLWH aged < 50 versus 50-64 versus > 65 years; p < 0.001 for all comparisons). PLWH on dual antiretroviral therapies were significantly older (58 ± 9 versus 54 ± 11 years; p < 0.001) and were concomitantly treated with more drugs (5.1 ± 3.2 versus 3.8 ± 2.5; p < 0.001) compared with those on triple therapies. A significant reduction of boosted antiretroviral regimens (53% versus 23%; p < 0.001) and in the number of comedications (4.0 ± 2.9 versus 3.1 ± 2.2 drugs; p < 0.001) was observed in the subgroup of patients (n = 198) with two GAP visits.

CONCLUSIONS

The high prevalence of polypharmacy in PLWH, especially among older adults, place these patients at high risk for clinically relevant drug-drug interactions (DDIs). A multidisciplinary approach involving physicians and clinical pharmacologists could help to optimize medication regimens associated with reduced risk.

Potential herb‒drug interactions between anti-COVID-19 drugs and traditional Chinese medicine

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide. Effective treatments against COVID-19 remain urgently in need although vaccination significantly reduces the incidence, hospitalization, and mortality. At present, antiviral drugs including Nirmatrelvir/Ritonavir (PaxlovidTM), Remdesivir, and Molnupiravir have been authorized to treat COVID-19 and become more globally available. On the other hand, traditional Chinese medicine (TCM) has been used for the treatment of epidemic diseases for a long history. Currently, various TCM formulae against COVID-19 such as Qingfei Paidu decoction, Xuanfei Baidu granule, Huashi Baidu granule, Jinhua Qinggan granule, Lianhua Qingwen capsule, and Xuebijing injection have been widely used in clinical practice in China, which may cause potential herb-drug interactions (HDIs) in patients under treatment with antiviral drugs and affect the efficacy and safety of medicines. However, information on potential HDIs between the above anti-COVID-19 drugs and TCM formulae is lacking, and thus this work seeks to summarize and highlight potential HDIs between antiviral drugs and TCM formulae against COVID-19, and especially pharmacokinetic HDIs mediated by metabolizing enzymes and/or transporters. These well-characterized HDIs could provide useful information on clinical concomitant medicine use to maximize clinical outcomes and minimize adverse and toxic effects.

The inhibitory and inducing effects of ritonavir on hepatic and intestinal CYP3A and other drug-handling proteins

Ritonavir, originally developed as HIV protease inhibitor, is widely used as a booster in several HIV pharmacotherapy regimens and more recently in Covid-19 treatment (e.g., Paxlovid). Its boosting capacity is due to the highly potent irreversible inhibition of the cytochrome P450 (CYP) 3 A enzyme, thereby enhancing the plasma exposure to coadministered drugs metabolized by CYP3A. Typically used booster doses of ritonavir are 100-200 mg once or twice daily. This review aims to address several aspects of this booster drug, including the possibility to use lower ritonavir doses, 20 mg for instance, resulting in partial CYP3A inactivation in patients. If complete CYP3A inhibition is not needed, lower ritonavir doses could be used, thereby reducing unwanted side effects. In this context, there are contradictory reports on the actual recovery time of CYP3A activity after ritonavir discontinuation, but probably this will take at least one day. In addition to ritonavir's CYP3A inhibitory effect, it can also induce and/or inhibit other CYP enzymes and drug transporters, albeit to a lesser extent. Although ritonavir thus exhibits gene induction capacities, with respect to CYP3A activity the inhibition capacity clearly predominates. Another potent CYP3A inhibitor, the ritonavir analog cobicistat, has been reported to lack the ability to induce enzyme and transporter genes. This might result in a more favorable drug-drug interaction profile compared to ritonavir, although the actual benefit appears to be limited. Indeed, ritonavir is still the clinically most used pharmacokinetic enhancer, indicating that its side effects are well manageable, even in chronic administration regimens.

Therapeutic Drug Monitoring and Dosage Adjustments of Immunosuppressive Drugs When Combined With Nirmatrelvir/Ritonavir in Patients With COVID-19

ABSTRACT

Nirmatrelvir/ritonavir (Paxlovid) consists of a peptidomimetic inhibitor (nirmatrelvir) of the SARS-CoV-2 main protease and a pharmacokinetic enhancer (ritonavir). It is approved for the treatment of mild-to-moderate COVID-19. This combination of nirmatrelvir and ritonavir can mediate significant and complex drug-drug interactions (DDIs), primarily due to the ritonavir component. Indeed, ritonavir inhibits the metabolism of nirmatrelvir through cytochrome P450 3A (CYP3A) leading to higher plasma concentrations and a longer half-life of nirmatrelvir. Coadministration of nirmatrelvir/ritonavir with immunosuppressive drugs (ISDs) is particularly challenging given the major involvement of CYP3A in the metabolism of most of these drugs and their narrow therapeutic ranges. Exposure of ISDs will be drastically increased through the potent ritonavir-mediated inhibition of CYP3A, resulting in an increased risk of adverse drug reactions. Although a decrease in the dosage of ISDs can prevent toxicity, an inappropriate dosage regimen may also result in insufficient exposure and a risk of rejection. Here, we provide some general recommendations for therapeutic drug monitoring of ISDs and dosing recommendations when coadministered with nirmatrelvir/ritonavir. Particularly, tacrolimus should be discontinued, or patients should be given a microdose on day 1, whereas cyclosporine dosage should be reduced to 20% of the initial dosage during the antiviral treatment. Dosages of mammalian target of rapamycin inhibitors (m-TORis) should also be adjusted while dosages of mycophenolic acid and corticosteroids are expected to be less impacted.

A Combination of Novel HIV-1 Protease Inhibitor and Cytochrome P450 (CYP) Enzyme Inhibitor to Explore the Future Prospective of Antiviral Agents: Evotaz

Viruses belong to the class of micro-organisms that are well known for causing infections in the human body. Antiviral medications are given out to prevent the spread of disease-causing viruses. When the viruses are actively reproducing, these agents have their greatest impact. It is particularly challenging to develop virus-specific medications since viruses share the majority of the metabolic functions of the host cell. In the continuous search for better antiviral agents, the United States Food and Drug Administration (USFDA) approved a new drug named Evotaz on January 29, 2015 for the treatment of human immunodeficiency virus (HIV). Evotaz is a combined once-daily fixed drug, containing Atazanavir, an HIV protease inhibitor, and cobicistat, an inhibitor of the human liver cytochrome P450 (CYP) enzyme. The medication is created such that it can kill viruses by concurrently inhibiting protease and CYP enzymes. The medicine is still being studied for a number of criteria, but its usefulness in children under the age of 12 is currently unknown. The preclinical and clinical characteristics of Evotaz, as well as its safety and efficacy profiles and a comparison of the novel drug with antiviral medications presently available in the market, are the main topics of this review paper.

Assessment of A new Strategy to Prevent Prescribing Errors Involving COVID-19 Patients in Community Pharmacies

Background: Because COVID-19 patients are vulnerable to prescribing errors (PEs) and adverse drug events, designing and implementing a new approach to prevent prescribing errors (PEs) involving COVID-19 patients has become a priority in pharmacotherapy research. Objectives: To investigate whether using WhatsApp to deliver prescribing error (PE)-related clinical scenarios to community pharmacists could enhance their ability to detect PEs and conduct successful pharmaceutical interventions (PIs). Methods: In this study, 110 community pharmacies were recruited from different regions across Jordan and equally allocated to 2 groups. Over the course of 4 weeks, WhatsApp was used to send PEs-related clinical case scenarios to the active group. The second group was controlled with no clinical scenarios. After completion of the 4-week phase, pharmacists from both groups were asked to document PEs in COVID-19 patients and their interventions using a data-collection form. Results: The incidence of PEs in COVID-19 patients documented in the active group (18.54%) was higher than that reported in the control group (3.09%) (P = .001). Of the 6598 and 968 PIs conducted by participants working in the active and control group pharmacies, 6013 (91.13%) and 651 (67.25%) were accepted, respectively. The proportions of wrong drug (contraindication), wrong drug (unnecessary drug prescribed/no proof of its benefits), and omission of a drug between the active and control groups were 15.30% versus 7.21% (P = .001), 11.85% versus 6.29% (P = .03), and 17.78% versus 10.50% (0.01), respectively. Additionally, the proportions of lethal, serious, and significant errors were 0.74% versus 0.35% (P = .04), 10.52% versus 2.57% (0.002), and 47.88% versus 9.57% (0.001), respectively. Addition of drug therapy interventions (AOR = 0.62; 95% CI, 0.21-0.84) and errors with significant clinical seriousness (AOR = 0.32; 95% CI, 0.16-0.64). Conclusions PEs involving COVID-19 patients in community settings are common and clinically significant. The intervention assessed in this study could be promising for designing a feasible and time-efficient interventional tool to encourage pharmacists' involvement in identifying and correcting PEs in light of COVID-19.

Management of drug-drug interactions with nirmatrelvir/ritonavir in patients treated for Covid-19: Guidelines from the French Society of Pharmacology and Therapeutics (SFPT)

Objectives

Nirmatrelvir in association with ritonavir (PAXLOVID™, Pfizer) is an antiviral agent targeting the 3-chymotrypsin–like cysteine protease enzyme (3C-like protease or Mpro) which is a key enzyme of the viral cycle of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This combination with a well-known pharmacokinetic enhancer leads to a high risk for drug-drug interactions in a polymedicated elected population for treatment. The aim of this work was to provide recommendations on behalf of the national French society of pharmacology (French Society of Pharmacology and Therapeutics; SFPT), by suggesting optimal and pragmatic therapeutic strategies if nirmatrelvir/ritonavir is to be given together with drugs commonly used, in order to ensure secured physicians’ prescription.

Methods

Six clinical pharmacologists search the scientific literature to provide a first draft of recommendations. Thereafter, twelve other clinical pharmacologists verified the recommendations and proposed modifications. The final draft was then validated by all 18 participants.

Results

Five distinct recommendations were issued: i) contra-indications, ii) “PAXLOVID™ not recommended with the comedication”, iii) “PAXLOVID™ possible whether the comedication is discontinued”, iv) “PAXLOVID™ possible only after an expert advice” and v) “PAXLOVID™ possible without modification of the associated treatment”. The final document comprises recommendations for 171 drugs/therapeutic classes aiming to secure prescription. In complex situations, clinicians are advised to contact their pharmacology department to obtain specific recommendations on the management of drug-drug interactions with nirmatrelvir/ritonavir.

Conclusion

These recommendations intend to be a help for clinicians willing to prescribe nirmatrelvir/ritonavir and to prevent drug-drug interactions leading to adverse drug reactions or loss of efficacy. They constitute a guideline for primary care situations. Of course, some complex situations may require expert advices and here, again, clinical pharmacologists are at the forefront in providing therapeutic advice.

Drug repurposing for identification of potential spike inhibitors for SARS-CoV-2 using molecular docking and molecular dynamics simulations

For the last two years, the COVID-19 pandemic has continued to bring consternation on most of the world. According to recent WHO estimates, there have been more than 5.6 million deaths worldwide. The virus continues to evolve all over the world, thus requiring both vigilance and the necessity to find and develop a variety of therapeutic treatments, including the identification of specific antiviral drugs. Multiple studies have confirmed that SARS-CoV-2 utilizes its membrane-bound spike protein to recognize human angiotensin-converting enzyme 2 (ACE2). Thus, preventing spike-ACE2 interactions is a potentially viable strategy for COVID-19 treatment as it would block the virus from binding and entering into a host cell. This work aims to identify potential drugs using an in silico approach. Molecular docking was carried out on both approved drugs and substances previously tested in vivo. This step was followed by a more detailed analysis of selected ligands by molecular dynamics simulations to identify the best molecules that thwart the ability of the virus to interact with the ACE2 receptor. Because the SARS-CoV-2 virus evolves rapidly due to a plethora of immunocompromised hosts, the compounds were tested against five different known lineages. As a result, we could identify substances that work well on individual lineages and those showing broader efficacy. The most promising candidates among the currently used drugs were zafirlukast and simeprevir with an average binding affinity of -22 kcal/mol for spike proteins originating from various lineages. The first compound is a leukotriene receptor antagonist that is used to treat asthma, while the latter is a protease inhibitor used for hepatitis C treatment. From among the in vivo tested substances that concurrently exhibit promising free energy of binding and ADME parameters (indicating a possible oral administration) we selected the compound BDBM50136234. In conclusion, these molecules are worth exploring further by in vitro and in vivo studies against SARS-CoV-2.

The role of pharmacogenetics in Efficacy and safety of protease inhibitor based therapy in human immunodeficiency virus type (HIV) infection

Antiretroviral therapy has markedly reduced morbidity and mortality for persons living with human immunodeficiency virus (HIV). HIV can now be classified as a chronic disease; until a cure is found, patients are likely to require life-long therapy. However, despite these undoubted advances, there are many issues that need to be resolved, including the problems associated with long-term efficacy and toxicity. Moreover, pharmacotherapy of patients infected with HIV is challenging because a great number of comorbidities increase polypharmacy and the risk for drug-drug interactions. There is considerable interindividual variability in patient outcomes in terms of drug disposition, drug efficacy and adverse events. The basis of these differences is multifactorial, but host genetics are believed to play a significant part. HIV-infected population consists of ethnically diverse individuals on complex and potentially toxic antiretroviral regimens on a long-term basis. These individuals would benefit greatly from predictive tests that identify the most durable regimens. Pharmacogenetics holds that promise. Thus, detailed understanding of the metabolism and transport of antiretrovirals and the influence of genetics on these pathways is important. To this end, this review provides an up-to-date overview of the metabolism of antiHIV therapeutics of the protease inhibitors Lopinavir and Ritonavir and the impact of genetic variation in drug metabolism and transport on the treatment of HIV.

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.

Drug-Drug Interactions and Prescription Appropriateness in Patients with COVID-19: A Retrospective Analysis from a Reference Hospital in Northern Italy

Background

Patients hospitalised with severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2; coronavirus 2019 disease (COVID-19)] infection are frequently older with co-morbidities and receiving polypharmacy, all of which are known risk factors for drug–drug interactions (DDIs). The pharmacological burden may be further aggravated by the addition of treatments for COVID-19.

Objective

The aim of this study was to assess the risk of potential DDIs upon admission and during hospitalisation in patients with COVID-19 treated at our hospital.

Methods

We retrospectively analysed 502 patients with COVID-19 (mean age 61 ± 16 years, range 15–99) treated at our hospital with a proven diagnosis of SARS-CoV-2 infection hospitalised between 21 February and 30 April 2020 and treated with at least two drugs.

Results

Overall, 68% of our patients with COVID-19 were exposed to at least one potential DDI, and 55% were exposed to at least one potentially severe DDI. The proportion of patients experiencing potentially severe DDIs increased from 22% upon admission to 80% during hospitalisation. Furosemide, amiodarone and quetiapine were the main drivers of potentially severe DDIs upon admission, and hydroxychloroquine and particularly lopinavir/ritonavir were the main drivers during hospitalisation. The majority of potentially severe DDIs carried an increased risk of cardiotoxicity. No potentially severe DDIs were identified in relation to tocilizumab and remdesivir.

Conclusions

Among hospitalised patients with COVID-19, concomitant treatment with lopinavir/ritonavir and hydroxychloroquine led to a dramatic increase in the number of potentially severe DDIs. Given the high risk of cardiotoxicity and the scant and conflicting data concerning their efficacy in treating SARS-CoV-2 infection, the use of lopinavir/ritonavir and hydroxychloroquine in patients with COVID-19 with polypharmacy needs to be carefully considered.

Inhibition and induction of CYP enzymes in humans: an update

The cytochrome P450 (CYP) enzyme family is the most important enzyme system catalyzing the phase 1 metabolism of pharmaceuticals and other xenobiotics such as herbal remedies and toxic compounds in the environment. The inhibition and induction of CYPs are major mechanisms causing pharmacokinetic drug–drug interactions. This review presents a comprehensive update on the inhibitors and inducers of the specific CYP enzymes in humans. The focus is on the more recent human in vitro and in vivo findings since the publication of our previous review on this topic in 2008. In addition to the general presentation of inhibitory drugs and inducers of human CYP enzymes by drugs, herbal remedies, and toxic compounds, an in-depth view on tyrosine-kinase inhibitors and antiretroviral HIV medications as victims and perpetrators of drug–drug interactions is provided as examples of the current trends in the field. Also, a concise overview of the mechanisms of CYP induction is presented to aid the understanding of the induction phenomena.

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.