Analysis of Clinical Drug-Drug Interaction Data To Predict Magnitudes of Uncharacterized Interactions between Antiretroviral Drugs and Comedications

Mitigating COVID-19 Mortality and Morbidity in China's Aging Population: A Focus on Available Medications and Future Developments

The COVID-19 pandemic, often referred to as the geropandemic, has put immense pressure on global healthcare systems worldwide, leading to a rush in the development and approval of medications for the treatment of the viral infection. Clinical trials on efficacy and safety had a limited spectrum on inclusion and endpoints because of the urgent need for fast results. The chronologically and biologically aged population is especially at risk for severe or lethal disease, as well as treatment-associated toxicity. In China, the growing elderly population segment has been a focus in public health measurements of COVID-19, guiding towards herd immunity with a mild variant, thus minimizing overall deaths and morbidity. While the COVID-19 pandemic has now been reclassified and the virus weakened, there is a clear need for novel therapies to protect the elderly. This paper reviews the current safety and efficacy of available COVID-19 medications in China, with a specific focus on 3CL protease inhibitors and the aging population. The current COVID wave in China has demonstrated a significant impact on the elderly and the need for new drugs that are effective at low doses and can be used alone, without harmful side effects, generation of viral resistance, and drug-drug interactions. The rush to develop and approve COVID-19 medications has brought up important questions about the balance between speed and caution, resulting in a pipeline of novel therapies now moving through clinical trials, including third-generation 3CL protease inhibitors. A majority of those therapeutics are being developed in China.

Antiviral Treatment in Older Chinese Patient with SARS-CoV-2 and Influenza A Virus Co-Infection: A Case Series

Coronavirus disease 2019 (COVID-19) emergence in late 2019, and wide spread quickly in the world. In China, the COVID-19 epidemic situation entered a low level now. With the arrival of flu season, the number of patients with respiratory symptoms is increasing. We reported three cases of patients who co-infected with SARS-CoV-2 and influenza A virus (IAV), and they were all treated with nirmatrelvir-ritonavir (NMV/r) and baloxavir marboxil. Due to the overlapping clinical features between the two diseases, it is important to identified them and gave the antiviral therapy timely.

Recommendations for the Management of Drug-Drug Interactions Between the COVID-19 Antiviral Nirmatrelvir/Ritonavir (Paxlovid) and Comedications

The coronavirus disease 2019 (COVID-19) antiviral nirmatrelvir/ritonavir (Paxlovid) has been granted authorization or approval in several countries for the treatment of patients with mild to moderate COVID-19 at high risk of progression to severe disease and with no requirement for supplemental oxygen. Nirmatrelvir/ritonavir will be primarily administered outside the hospital setting as a 5-day course oral treatment. The ritonavir component boosts plasma concentrations of nirmatrelvir through the potent and rapid inhibition of the key drug-metabolizing enzyme cytochrome P450 (CYP) 3A4. Thus nirmatrelvir/ritonavir, even given as a short treatment course, has a high potential to cause harm from drug-drug interactions (DDIs) with other drugs metabolized through this pathway. Options for mitigating risk from DDIs with nirmatrelvir/ritonavir are limited due to the clinical illness, the short window for intervention, and the related difficulty of implementing clinical monitoring or dosage adjustment of the comedication. Pragmatic options are largely confined to preemptive or symptom-driven pausing of the comedication or managing any additional risk through counseling. This review summarizes the effects of ritonavir on drug disposition (i.e., metabolizing enzymes and transporters) and discusses factors determining the likelihood of having a clinically significant DDI. Furthermore, it provides a comprehensive list of comedications likely to be used in COVID-19 patients which are categorized according to their potential DDI risk with nirmatrelvir/ritonavir. It also discusses recommendations for the management of DDIs which balance the risk of harm from DDIs with a short course of ritonavir, against unnecessary denial of nirmatrelvir/ritonavir treatment.

Prescribing Nirmatrelvir-Ritonavir: How to Recognize and Manage Drug-Drug Interactions

Nirmatrelvir–ritonavir (NMV/r) is now being used to treat high-risk patients with mild to moderate COVID-19. This article provides advice to clinicians regarding recognition of medications likely to interact with NMV/r and suggests approaches to managing such drug–drug interactions. An algorithm is provided to assist in decision making.

Real-life management of drug-drug interactions between antiretrovirals and statins

BACKGROUND

PIs cause drug-drug interactions (DDIs) with most statins due to inhibition of drug-metabolizing enzymes and/or the hepatic uptake transporter OATP1B1, which may alter the pharmacodynamic (PD) effect of statins.

OBJECTIVES

To assess the management of DDIs between antiretrovirals (ARVs) and statins in people living with HIV (PLWH) considering statin plasma concentrations, compliance with dosing recommendations and achievement of lipid targets.

METHODS

PLWH of the Swiss HIV Cohort Study were eligible if they received a statin concomitantly with ARVs. HDL, total cholesterol (TC) and statin plasma concentration were measured during follow-up visits. Individual non-HDL and TC target values were set using the Framingham score and the 2018 European AIDS Clinical Society recommendations.

RESULTS

Data were analysed for rosuvastatin (n = 99), atorvastatin (n = 92), pravastatin (n = 46) and pitavastatin (n = 21). Rosuvastatin and atorvastatin underdosing frequently led to suboptimal PD response. Insufficient lipid control was observed with PIs despite high atorvastatin concentrations, likely explained by inhibition of OATP1B1 resulting in less statin uptake in the liver. Target lipid values were more often achieved with unboosted integrase inhibitors due to both their favourable DDI profiles and neutral effect on lipids. Insufficient lipid control was common with pravastatin and pitavastatin regardless of co-administered ARVs and despite using maximal recommended statin doses. The latter suggests lower efficacy compared with rosuvastatin or atorvastatin.

CONCLUSIONS

Suboptimal management of DDIs with statin underdosing was observed in 29% of prescriptions. Integrase inhibitor-based regimens and/or treatment with rosuvastatin or atorvastatin should be favoured in patients with refractory dyslipidaemia.

Physiologically Based Pharmacokinetic Modelling to Identify Pharmacokinetic Parameters Driving Drug Exposure Changes in the Elderly

BACKGROUND

Medication use is highly prevalent with advanced age, but clinical studies are rarely conducted in the elderly, leading to limited knowledge regarding age-related pharmacokinetic changes.

OBJECTIVE

The objective of this study was to investigate which pharmacokinetic parameters determine drug exposure changes in the elderly by conducting virtual clinical trials for ten drugs (midazolam, metoprolol, lisinopril, amlodipine, rivaroxaban, repaglinide, atorvastatin, rosuvastatin, clarithromycin and rifampicin) using our physiologically based pharmacokinetic (PBPK) framework.

METHODS

PBPK models for all ten drugs were developed in young adults (20-50 years) following the best practice approach, before predicting pharmacokinetics in the elderly (≥ 65 years) without any modification of drug parameters. A descriptive relationship between age and each investigated pharmacokinetic parameter (peak concentration [C_max], time to C_max [t_max], area under the curve [AUC], clearance, volume of distribution, elimination-half-life) was derived using the final PBPK models, and verified with independent clinically observed data from 52 drugs.

RESULTS

The age-related changes in drug exposure were successfully simulated for all ten drugs. Pharmacokinetic parameters were predicted within 1.25-fold (70%), 1.5-fold (86%) and 2-fold (100%) of clinical data. AUC increased progressively by 0.9% per year throughout adulthood from the age of 20 years, which was explained by decreased clearance, while C_max, t_max and volume of distribution were not affected by human aging. Additional clinical data of 52 drugs were contained within the estimated variability of the established age-dependent correlations for each pharmacokinetic parameter.

CONCLUSION

The progressive decrease in hepatic and renal blood flow, as well as glomerular filtration, rate led to a reduced clearance driving exposure changes in the healthy elderly, independent of the drug.

Potential drug-drug interactions of antiretrovirals and antimicrobials detected by three databases

Standard treatment for HIV infection involves a combination of antiretrovirals. Additionally, opportunistic infections in HIV infected patients require further antimicrobial medications that might cause drug-drug interactions (DDIs). The objective of this study was to to compare the recognition of DDIs between antiretrovirals and antimicrobials by three proprietary databases and evaluate their concordance. 114 items of antiretrovirals and antimicrobials from the National List of Essential Medicines of Thailand 2018 were used in the study. However, 21 items were not recognised by Micromedex, Drugs.com, and Liverpool HIV interactions. Only 93 items were available for the detection of potential DDIs by the three databases. Potential DDIs detected from the three databases included 292 pairs. Liverpool showed the highest number of DDIs with 285 pairs compared with 259 pairs by drugs.com and 133 pairs by Micromedex. Regarding the severity classifications, Liverpool reported 10% Contraindicated; Micromedex reported 14% contraindicated and 59% major; Drugs.com reported 21% major. The Fleiss’ kappa agreements were fair to poor among the three databases, higher agreement was observed for DDIs classified as severe. This study highlights the need to harmonize the evaluation and interpretation of DDI risk in order to produce standardized information to support prescribers.

Physiologically-Based Pharmacokinetic Modeling to Support the Clinical Management of Drug-Drug Interactions With Bictegravir

Bictegravir is equally metabolized by cytochrome P450 (CYP)3A and uridine diphosphate‐glucuronosyltransferase (UGT)1A1. Drug–drug interaction (DDI) studies were only conducted for strong inhibitors and inducers, leading to some uncertainty whether moderate perpetrators or multiple drug associations can be safely coadministered with bictegravir. We used physiologically‐based pharmacokinetic (PBPK) modeling to simulate DDI magnitudes of various scenarios to guide the clinical DDI management of bictegravir. Clinically observed DDI data for bictegravir coadministered with voriconazole, darunavir/cobicistat, atazanavir/cobicistat, and rifampicin were predicted within the 95% confidence interval of the PBPK model simulations. The area under the curve (AUC) ratio of the DDI divided by the control scenario was always predicted within 1.25‐fold of the clinically observed data, demonstrating the predictive capability of the used modeling approach. After the successful verification, various DDI scenarios with drug pairs and multiple concomitant drugs were simulated to analyze their effect on bictegravir exposure. Generally, our simulation results suggest that bictegravir should not be coadministered with strong CYP3A and UGT1A1 inhibitors and inducers (e.g., atazanavir, nilotinib, and rifampicin), but based on the present modeling results, bictegravir could be administered with moderate dual perpetrators (e.g., efavirenz). Importantly, the inducing effect of rifampicin on bictegravir was predicted to be reversed with the concomitant administration of a strong inhibitor such as ritonavir, resulting in a DDI magnitude within the efficacy and safety margin for bictegravir (0.5–2.4‐fold). In conclusion, the PBPK modeling strategy can effectively be used to guide the clinical management of DDIs for novel drugs with limited clinical experience, such as bictegravir.

Population pharmacokinetic modelling to quantify the magnitude of drug-drug interactions between amlodipine and antiretroviral drugs

PURPOSE

Drug-drug interactions (DDIs) with antiretroviral drugs (ARVs) represent an important issue in elderly people living with HIV (PLWH). Amlodipine is a commonly prescribed antihypertensive drug metabolized by CYP3A4, thus predisposed to a risk of DDIs. Guidance on the management of DDIs is mostly based on theoretical considerations derived from coadministration with other CYP3A4 inhibitors. This study aimed at characterizing the magnitude of DDIs between amlodipine and ARV drugs in order to establish dosing recommendations.

METHODS

A population pharmacokinetic analysis was developed using non-linear mixed effect modelling (NONMEM) and included 163 amlodipine concentrations from 55 PLWH. Various structural and error models were compared to characterize optimally the concentration-time profile of amlodipine. Demographic and clinical characteristics as well as comedications were tested as potential influential covariates. Model-based simulations were performed to compare amlodipine exposure (i.e. area under the curve, AUC) between coadministered ARV drugs.

RESULTS

Amlodipine concentration-time profile was best described using a one-compartment model with first-order absorption and a lag-time. Amlodipine apparent clearance was influenced by both CYP3A4 inhibitors and efavirenz (CYP3A4 inducer). Model-based simulations revealed that amlodipine AUC increased by 96% when coadministered with CYP3A4 inhibitors, while efavirenz decreased drug exposure by 59%.

CONCLUSION

Coadministered ARV drugs significantly impact amlodipine disposition in PLWH. Clinicians should adjust amlodipine dosage accordingly, by halving the dosage in PLWH receiving ARV with inhibitory properties (mainly ritonavir-boosted darunavir), whereas they should double amlodipine doses when coadministering it with efavirenz, under appropriate monitoring of clinical response and tolerance.

Clinical Data Combined With Modeling and Simulation Indicate Unchanged Drug-Drug Interaction Magnitudes in the Elderly

Age-related comorbidities and consequently polypharmacy are highly prevalent in the elderly, resulting in an increased risk for drug-drug interactions (DDIs). The effect of aging on DDI magnitudes is mostly uncertain, leading to missing guidance regarding the clinical DDI management in the elderly. Clinical data obtained in aging people living with HIV ≥ 55 years, who participated in the Swiss HIV Cohort Study, demonstrated unchanged DDI magnitudes with advanced aging for four studied DDI scenarios. These data plus published data for midazolam in the presence of clarithromycin and rifampicin in elderly individuals assessed the predictive potential of the used physiologically-based pharmacokinetic (PBPK) model to simulate DDIs in the elderly. All clinically observed data were generally predicted within the 95% confidence interval of the PBPK simulations. The verified model predicted subsequently the magnitude of 50 DDIs across adulthood (20-99 years) with 42 scenarios being only verified in adults aged 20-50 years in the absence of clinically observed data in the elderly. DDI magnitudes were not impacted by aging regardless of the involved drugs, DDI mechanism, mediators of DDIs, or the sex of the investigated individuals. The prediction of unchanged DDI magnitudes with advanced aging were proofed by 17 published, independent DDIs that were investigated in young and elderly subjects. In conclusion, this study demonstrated by combining clinically observed data with modeling and simulation that aging does not impact DDI magnitudes and thus, clinical management of DDIs can a priori be similar in aging men and women in the absence of severe comorbidities.

Use of comedications and potential drug-drug interactions in people living with HIV in China

BACKGROUND

Because people living with HIV (PLWH) are ageing, they will inevitably develop non-communicable diseases (NCDs) and the number of non-HIV medications will increase. Drug-drug interactions(DDIs) will become an ever-increasing issue. However, little is known about this important issue in Chinese PLWH. This study aimed to investigate the prevalence and risk factors of DDIs among PLWH in China.

METHODS

Chinese PLWH aged ≥18 years were enrolled prospectively from October 2018 to April 2019 and after informed consent was obtained, they were ask to fill out a questionnaire about comorbidity and co-medications. Potential DDIs were identified using the University of Liverpool HIV Drug Interaction Checker.

RESULTS

A total of 1804 questionnaires were included. Antiretroviral drugs (ARVs) that most frequently were prescribed were lamivudine (96.18%), efavirenz(64.64%) and tenofovir(60.62%). 16.96% of the participations reported current co-infection with HIV and14.69% reported NCDs. 263(14.57%) participations reported they had used co-medications in the past six months while 186(10.31%) reported they were taking co-medications. Age≥50 years (p < 0.001), living in developed areas(p < 0.001) and lower CD4 cell count(p = 0.045) were independently associated with the use of co-medications. Potential DDIs were identified in 54 (19.15%) persons using co-medications. Age≥50 [OR = 2.272(1.241-4.158)], PLWH with NCDs[OR = 2.889(1.509-5.532)] and usage of protease inhibitors[OR = 2.538(1.250-5.156)] were independently associated with the potential DDIs.

CONCLUSION

The prevalence of the use of co-medications and potential DDIs among Chinese PLWH are low. Older age, NCDs and use of PIs were risk factors for the potential of developing DDIs. With the aging of PLWH, co-medications and DDIs in China warrants more attention.

The challenge of HIV treatment in an era of polypharmacy

INTRODUCTION

The availability of potent antiretroviral therapy has transformed HIV infection into a chronic disease such that people living with HIV (PLWH) have a near normal life expectancy. However, there are continuing challenges in managing HIV infection, particularly in older patients, who often experience age-related comorbidities resulting in complex polypharmacy and an increased risk for drug-drug interactions. Furthermore, age-related physiological changes may affect the pharmacokinetics and pharmacodynamics of both antiretrovirals and comedications thereby predisposing elderly to adverse drug reactions. This review provides an overview of the therapeutic challenges when treating elderly PLWH (i.e. >65 years). Particular emphasis is placed on drug-drug interactions and other common prescribing issues (i.e. inappropriate drug use, prescribing cascade, drug-disease interaction) encountered in elderly PLWH.

DISCUSSION

Prescribing issues are common in elderly PLWH due to the presence of age-related comorbidities, organ dysfunction and physiological changes leading to a higher risk for drug-drug interactions, drugs dosage errors and inappropriate drug use.

CONCLUSIONS

The high prevalence of prescribing issues in elderly PLWH highlights the need for ongoing education on prescribing principles and the optimal management of individual patients. The knowledge of adverse health outcomes associated with polypharmacy and inappropriate prescribing should ensure that there are interventions to prevent harm including medication reconciliation, medication review and medication prioritization according to the risks/benefits for each patient.

Prescribing issues in elderly individuals living with HIV

Introduction: Combined antiretroviral therapy has transformed HIV infection into a chronic disease thus people living with HIV (PLWH) live longer. As a result, the management of HIV infection is becoming more challenging as elderly experience age-related comorbidities leading to complex polypharmacy and a higher risk for drug-drug or drug-disease interactions. Furthermore, age-related physiological changes affect pharmacokinetics and pharmacodynamics thereby predisposing elderly PLWH to incorrect dosing or inappropriate prescribing and consequently to adverse drug reactions and the subsequent risk of starting a prescribing cascade. Areas covered: This review discusses the demographics of the aging HIV population, physiological changes and their impact on drug response as well as comorbidities. Particular emphasis is placed on common prescribing issues in elderly PLWH including drug-drug interactions with antiretroviral drugs. A PubMed search was used to compile relevant publications until February 2019. Expert opinion: Prescribing issues are highly prevalent in elderly PLWH thus highlighting the need for education on geriatric prescribing principles. Adverse health outcomes potentially associated with polypharmacy and inappropriate prescribing should promote interventions to prevent harm including medication reconciliation, medication review, and medication prioritization according to the risks/benefits for a given patient. A multidisciplinary team approach is recommended for the care of elderly PLWH.

Managing Pharmacotherapy in People Living With HIV and Concomitant Malignancy

Objective: To describe data with selected malignancies in people living with HIV (PLWH) and HIV in individuals affected by both conditions and to summarize drug-drug interactions (DDIs) with clinical recommendations for point-of-care review of combination therapies. Data Sources: Literature searches were performed (2005 to December 2018) in MEDLINE and EMBASE to identify studies of malignancies in PLWH in the modern era. Study Selection and Data Extraction: Article bibliographies and drug interaction databases were reviewed. Search terms included HIV, antiretroviral therapy, antineoplastic agents, malignancies, and drug interactions. Data Synthesis: In the pre-antiretroviral therapy (ART) era, malignancies in PLWH were AIDS-defining illnesses, and life expectancy was shorter. Nowadays, PLWH are living longer and developing malignancies, including lung, anal, and prostate cancers. Concurrently, the oncology landscape has evolved, with novel oral targeted agents and immunotherapies becoming routine elements of care. The increased need for and complexity with antineoplastics in PLWH has led to recommendations for multidisciplinary care of this unique population. Evaluation of DDIs requires review of metabolic pathways, absorption mechanisms, and various drug transporters associated with antineoplastics and ART. Relevance to Patient Care and Clinical Practice: This review summarizes available data of non-AIDS-defining malignancies, principles of HIV care in the patient with malignancy, and guidance for assessing DDIs between antineoplastics and ART. Summary DDI tables provide point-of-care recommendations. Conclusions: The availability of ART has transformed AIDS into a chronic medical condition, and PLWH are experiencing age-related malignancies. Pharmacists play an important role in the management of this patient population.