Prescribing Nirmatrelvir/Ritonavir for COVID-19 in Advanced CKD

The effectiveness of nirmatrelvir/ritonavir regimen in hospitalized renal transplant patients with prolonged COVID-19 infection: a multicenter clinical experience

OBJECTIVES

Effectiveness of nirmatrelvir/ritonavir (NR) in kidney transplant recipients (KTRs) infected COVID-19 for more than 5 days has not been evaluated.

METHODS

In this multicenter retrospective study, 85 KTRs with COVID-19 were enrolled, including 50 moderate, 21 severe, and 14 critical patients.

RESULTS

The median time from onset to starting NR treatment was 14 (IQR, 11-19) days. Before NR treatment, 96.5% patients reduced use of antimetabolites. They also stopped using calcineurin inhibitors (CNI) 12-24 hours before NR treatment, with CNI concentrations well-controlled during NR treatment. The use of intravenous corticosteroids increased with COVID-19 severity. The median time to reach viral negative conversion was 5 (IQR, 4-8) days for all patients. For moderate and severe COVID-19 patients, they had a low rate of ICU admission (1.4%), exacerbation requiring upgraded oxygen therapy (5.6%), and dialysis (2.8%); no intubation and mechanical ventilation, and no deaths were observed. Patients with critical COVID-19 had a low mortality rate (7.1%).

CONCLUSIONS

A regimen including NR for clearing SARS-CoV-2 along with reducing immunosuppressants and using intravenous corticosteroids is associated with lower rates of exacerbation and mortality in KTRs who have moderate to critical SARS-CoV-2 infection and the virus still present after 5 days.

Target Attainment and Population Pharmacokinetics of Nirmatrelvir/Ritonavir in Critically Ill Adult Patients

Background

The population pharmacokinetics of nirmatrelvir/ritonavir (NIR/RIT) has not yet been described for critically ill adult patient.

Purpose

This was a prospective observational population pharmacokinetic study of nirmatrelvir/ritonavir (NIR/RIT) in critically ill adult patients and identify optimal dosing regimens.

Patients and Methods

The prescription of NIR/RIT is determined by the attending physician and ranges from 150mg/100mg to 300mg/100mg twice a day. Two to three serial blood samples were collected for each patient after the second doses. We developed and validated PK model for plasma NIR and plasma RIT. Monte Carlo dosing simulations were performed to assess target attainment.

Results

We analyzed 89 plasma samples from 31 adult patients. The data were best described by a one-compartment model. Among the covariates tested on pharmacokinetic parameters, creatinine clearance (CrCL) and area under curve (AUC) of RIT had a significant effect on apparent clearance (CL/F) of NIR. Mean (SD) parameters estimates for the absorption rate constant (Ka), apparent distribution (V/F) and CL/F were 0.42 (0.10) h-1. 36.5 (8.5) L, 3.6 (0.26) L/h, respectively. Dosing simulations showed that the target in vitro 90% effective concentration (EC90) was more likely to be achieved twice a day than once a day at the same daily dose of NIR. High CrCL, low AUC of RIT were associated with a reduced likelihood of NIR reaching the target EC90.

Conclusion

Based on our dosing simulations, the initial dosage of NIR/RIT was 300mg/100mg twice a day in critically ill patients with CrCL>45 mL/min; When CrCL in critically ill patients is between 15 and 45 mL/min, NIR/RIT is 150mg/100mg twice a day. The maintenance dose is adjusted according to CrCL and AUC of RIT, with the dosages varying between 75mg/100mg and 300mg/100mg.

Population pharmacokinetics of nirmatrelvir in Chinese patients with COVID-19: Therapeutic drug monitoring and dosing regimen selection in clinical practice

OBJECTIVES

To establish a population pharmacokinetics (PopPK) model of nirmatrelvir in Chinese COVID-19 patients and provide reference for refining the dosing strategy of nirmatrelvir in patients confirmed to be infected with SARS-CoV-2.

METHODS

A total of 80 blood samples were obtained from 35 mild to moderate COVID-19 patients who were orally administered nirmatrelvir/ritonavir tablets. The PopPK model of nirmatrelvir was developed using a nonlinear mixed effects modelling approach. The stability and prediction of the final model were assessed through a combination of goodness-of-fit and bootstrap method. The exposure of nirmatrelvir across various clinical scenarios was simulated using Monte Carlo simulations.

RESULTS

The pharmacokinetics of nirmatrelvir was well characterised by a one-compartment model with first-order absorption, and with creatinine clearance (Ccr) as the significant covariate. Typical population parameter estimates of apparent clearance and distribution volume for a patient with a Ccr of 95.5 mL·min-1were 3.45 L·h-1 and 48.71 L, respectively. The bootstrap and visual predictive check procedures demonstrated satisfactory predictive performance and robustness of the final model.

CONCLUSION

The final model was capable of offering an early prediction of drug concentration ranges for different nirmatrelvir dosing regimens and optimise the dose regimen of nirmatrelvir in individuals with confirmed SARS-CoV-2 infection.

Efficacy and Safety of Nirmatrelvir/Ritonavir in Severe Hospitalized Patients with COVID-19 and in Patients at High Risk for Progression to Critical Illness: A Real-World Study

Background: Nirmatrelvir/Ritonavir is an orally administered anti-SARS-Cov-2 drug used in mild-to-moderate COVID-19 patients. Our retrospective cohort study aims to evaluate the efficacy and safety of Nirmatrelvir/Ritonavir in severe hospitalized patients with Omicron infection, as well as in patients at high risk for progression to critical illness in real-world settings. Methods: A total of 350 patients received Nirmatrelvir/Ritonavir while 350 matched controls did not. Patients with confirmed COVID-19 were administered Nirmatrelvir 300 mg and Ritonavir 100 mg orally twice a day for 5 days, with the medication initiated on the first day after admission. The primary endpoint of the study was a composite outcome of hospitalization or death from any cause within 28 days. Secondary endpoints included the occurrence of adverse events and the evaluation of serum levels of IL-6 and viral load. Results: We documented the mortality risk from any cause within 28 days, viral load, serum IL-6 levels, and adverse events. Nirmatrelvir/Ritonavir reduced the 28-day risk of all-cause mortality by 86% (P = .011, hazard ratio (HR) = 0.14, 95% confidence interval (CI) = 0.03, 0.64). At baseline, the serum level of IL-6 was significantly higher in the antiviral treatment group compared to the control group (P < .001), but no significant difference (P = .990) was found between the two groups at discharge. In CKD patients undergoing hemodialysis, no significant worsening of renal function was observed in the Nirmatrelvir/Ritonavir treatment group compared to the control group. Conclusion: Nirmatrelvir/Ritonavir may reduce the 28-day risk of all-cause mortality in critically ill patients with COVID-19 and in patients at high risk for critical disease progression.

Pharmacokinetics of nirmatrelvir/ritonavir and the drug-drug interaction with calcineurin inhibitor in renal transplant recipients

OBJECTIVES

To describe the pharmacokinetic (PK) characteristics of nirmatrelvir/ritonavir in renal transplant recipients and explore the potential factors that related to the PK variance of nirmatrelvir/ritonavir and its interaction with calcineurin inhibitor (CNI).

METHODS

Renal transplant recipients treated with CNI and nirmatrelvir/ritonavir were prospectively enrolled. Steady-state plasma concentrations of nirmatrelvir/ritonavir were determined by high-performance liquid chromatography-tandem mass spectrometry, and the PK parameters were calculated using non-compartmental analysis. Spearman correlation analysis was used for exploring influencing factors.

RESULTS

A total of eight recipients were enrolled; for nirmatrelvir and ritonavir, AUC/dose was 0.24179 ± 0.14495 and 0.06196 ± 0.03767 μg·h·mL-1·mg-1. Red blood cell (RBC), hematocrit (Ht), hemoglobins (Hb), and creatinine clearance (Ccr) were negatively correlated with AUC/dose of nirmatrelvir, while Ccr, CYP3A5 genotype, and CYP3A4 genotype were related to the AUC/dose of ritonavir. Ccr was negatively correlated with the C0/dose of tacrolimus (TAC) after termination of nirmatrelvir/ritonavir (rs =  -0.943, p = 0.008).

CONCLUSIONS

The PK characteristics of nirmatrelvir/ritonavir vary greatly among renal transplant recipients. Factors including Ccr and CYP3A5 genotype were related to the in vivo exposure of nirmatrelvir/ritonavir. During the whole process before and after nirmatrelvir/ritonavir therapy, it is recommended to adjust the CNI basing on renal function to avoid CNI toxicity exposure.

COVID-19 therapeutics

SUMMARYSince the emergence of COVID-19 in 2020, an unprecedented range of therapeutic options has been studied and deployed. Healthcare providers have multiple treatment approaches to choose from, but efficacy of those approaches often remains controversial or compromised by viral evolution. Uncertainties still persist regarding the best therapies for high-risk patients, and the drug pipeline is suffering fatigue and shortage of funding. In this article, we review the antiviral activity, mechanism of action, pharmacokinetics, and safety of COVID-19 antiviral therapies. Additionally, we summarize the evidence from randomized controlled trials on efficacy and safety of the various COVID-19 antivirals and discuss unmet needs which should be addressed.

Comparison of safety and efficacy between Nirmatrelvir-ritonavir and molnupiravir in the treatment of COVID-19 infection in patients with advanced kidney disease: a retrospective observational study

Background

Nirmatrelvir-ritonavir is used in patients with coronavirus disease 2019 (COVID-19) with normal or mild renal impairment (eGFR ≥30 ml/min per 1.73 m2). There is limited data regarding its use in advanced kidney disease (eGFR <30 ml/min per 1.73 m2). We performed a retrospective territory-wide observational study evaluating the safety and efficacy of nirmatrelvir-ritonavir when compared with molnupiravir in the treatment of patients with COVID-19 with advanced kidney disease.

Methods

We adopted target trial emulation using data from a territory-wide electronic health record database on eligible patients aged ≥18 years with advanced kidney disease (history of eGFR <30 ml/min per 1.73 m2) who were infected with COVID-19 and were prescribed with either molnupiravir or nirmatrelvir-ritonavir within five days of infection during the period from 16 March 2022 to 31 December 2022. A sequence trial approach and 1:4 propensity score matching was applied based on the baseline covariates including age, sex, number of COVID-19 vaccine doses received, Charlson comorbidity index (CCI), hospitalisation, eGFR, renal replacement therapy, comorbidities (cancer, respiratory disease, myocardial infarction, ischaemic stroke, diabetes, hypertension), and drug use (renin-angiotensin-system agents, beta blockers, calcium channel blockers, diuretics, nitrates, lipid lowering agents, insulins, oral antidiabetic drugs, antiplatelets, immuno-suppressants, corticosteroids, proton pump inhibitors, histamine H2 receptor antagonists, monoclonal antibody infusion) within past 90 days. Individuals were followed up from the index date until the earliest outcome occurrence, death, 90 days from index date or the end of data availability. Stratified Cox proportional hazards regression adjusted with baseline covariates was used to compare the risk of outcomes between nirmatrelvir-ritonavir recipients and molnupiravir recipients which include (i) all-cause mortality, (ii) intensive care unit (ICU) admission, (iii) ventilatory support, (iv) hospitalisation, (v) hepatic impairment, (vi) ischaemic stroke, and (vii) myocardial infarction. Subgroup analyses included age (<70; ≥70 years); sex, Charlson comorbidity index (≤5; >5), and number of COVID-19 vaccine doses received (0-1; ≥2 doses).

Findings

A total of 4886 patients were included (nirmatrelvir-ritonavir: 1462; molnupiravir: 3424). There were 347 events of all-cause mortality (nirmatrelvir-ritonavir: 74, 5.06%; molnupiravir: 273, 7.97%), 10 events of ICU admission (nirmatrelvir-ritonavir: 4, 0.27%; molnupiravir: 6, 0.18%), 48 events of ventilatory support (nirmatrelvir-ritonavir: 13, 0.89%; molnupiravir: 35, 1.02%), 836 events of hospitalisation (nirmatrelvir-ritonavir: 218, 23.98%; molnupiravir: 618, 28.14%), 1 event of hepatic impairment (nirmatrelvir-ritonavir: 0, 0%; molnupiravir: 1, 0.03%), 8 events of ischaemic stroke (nirmatrelvir-ritonavir: 3, 0.22%; molnupiravir: 5, 0.16%) and 9 events of myocardial infarction (nirmatrelvir-ritonavir: 2, 0.15%; molnupiravir: 7, 0.22%). Nirmatrelvir-ritonavir users had lower rates of all-cause mortality (absolute risk reduction (ARR) at 90 days 2.91%, 95% CI: 1.47-4.36%) and hospitalisation (ARR at 90 days 4.16%, 95% CI: 0.81-7.51%) as compared with molnupiravir users. Similar rates of ICU admission (ARR at 90 days -0.09%, 95% CI: -0.4 to 0.2%), ventilatory support (ARR at 90 days 0.13%, 95% CI: -0.45 to 0.72%), hepatic impairment (ARR at 90 days 0.03%, 95% CI: -0.03 to 0.09%), ischaemic stroke (ARR at 90 days -0.06%, 95% CI: -0.35 to 0.22%), and myocardial infarction (ARR at 90 days 0.07%, 95% CI: -0.19 to 0.33%) were found between nirmatrelvir-ritonavir and molnupiravir users. Consistent results were observed in relative risk adjusted with baseline characteristics. Nirmatrelvir-ritonavir was associated with significantly reduced risk of all-cause mortality (HR: 0.624, 95% CI: 0.455-0.857) and hospitalisation (HR: 0.782, 95% CI: 0.64-0.954).

Interpretation

Patients with COVID-19 with advanced kidney disease receiving nirmatrelvir-ritonavir had a lower rate of all-cause mortality and hospital admission when compared with molnupiravir. Other adverse clinical outcomes were similar in both treatment groups.

Funding

Health and Medical Research Fund (COVID1903010), Health Bureau, The Government of the Hong Kong Special Administrative Region, China.

Safety, efficacy, and pharmacokinetics of nirmatrelvir and ritonavir in patients with severe COVID-19 and renal impairment: A case report

Nirmatrelvir/ritonavir (N/r) has received emergency use authorization for mild-to-moderate COVID-19 treatment in adult and pediatric patients (aged and weighing at least 12 years and 40 kg, respectively) presenting positive direct SARS-CoV-2 viral testing results and a high risk of disease progression to severe COVID-19. However, information remains limited concerning the corresponding drug safety, efficacy, and pharmacokinetics in patients with severe renal impairment. In this study, we present the case of a 91-year-old Chinese man who, despite exhibiting recurrent positive SARS-CoV-2 results and progression to severe COVID-19, was treated with N/r. Due to severe renal impairment and concurrent administration of continuous renal replacement therapy (continuous venovenous hemofiltration) during medication, we aimed to determine the serum N/r drug concentration in the patient. Our analysis revealed Cmax values of 12.42 and 2.001 μg/mL for nirmatrelvir and ritonavir, respectively. Despite the particularly high serum N/r concentration in this patient, the clinical and laboratory test analyses confirmed that the treatment was safe and effective. Nevertheless, N/r should be used with caution and at lower doses in patients with severe renal impairment to avoid potential high N/r concentration-related adverse reactions and events.

Clinical effectiveness of oral antiviral agents for treating non-hospitalized COVID-19 patients with chronic kidney disease

OBJECTIVES

This study examined the effectiveness of nirmatrelvir plus ritonavir (NMV-r) and molnupiravir (MOV) in treating COVID-19 among chronic kidney disease (CKD) patients.

METHODS

This retrospective cohort study, using the TriNetX research network, identified stage 3-5 CKD and end-stage kidney disease (ESKD) patients with non-hospitalized COVID-19 between 1 January 2022, and 31 May 2023. Propensity score matching (PSM) was used to compare patients on NMV-r or MOV (antiviral group) against those not receiving these treatments (control group). The primary composite outcome was the cumulative hazard ratio (HR) for all-cause hospitalization or death within the 30-day follow-up.

RESULTS

After PSM, two balanced cohorts of 6,275 patients each were established. The antiviral group exhibited a lower incidence of all-cause hospitalization or mortality (5.93% vs. 9.53%; HR: 0.626; 95% CI: 0.550-0.713) than controls. Additionally, antiviral recipients were associated with a lower risk of all-cause hospitalization (HR: 0.679; 95% CI: 0.594-0.777) and mortality (HR: 0.338; 95% CI: 0.227-0.504). The beneficial effects of antiviral agents were consistent across sex, age, vaccination status, antiviral type, and CKD stage.

CONCLUSION

Oral antiviral agents could be associated with lower rates of all-cause hospitalization or death among non-hospitalized COVID-19 patients with CKD.

Management of nirmatrelvir/ritonavir and tacrolimus interaction in kidney transplant recipients infected by COVID-19: a three-case series

OBJECTIVES

Nirmatrelvir/ritonavir may cause a clinically relevant drug-drug interaction (DDI) with immunosuppressive drugs, such as tacrolimus, which may condition the use of this antiviral in transplant patients. We aimed to describe the management of this interaction.

METHODS

Descriptive study in which renal transplant patients in treatment with nirmatrelvir/ritonavir and tacrolimus were included. They suspended tacrolimus the day before starting the antiviral treatment, and the decision to restart it was made based on their tacrolimus blood levels. Main variables studied to measure this DDI were tacrolimus blood concentration, dose adjustment and serum creatinine.

RESULTS

Three patients were included. During the study, tacrolimus levels elevation did not have repercussion in the serum creatinine, that remained stable in all patients. No patient required hospitalisation or showed signs of rejection.

CONCLUSIONS

Our experience provides further evidence that this interaction should not be a contraindication to treatment with nirmatrelvir/ritonavir, and can be managed with close monitoring of tacrolimus levels.

Simultaneous quantification of nirmatrelvir/ritonavir in human serum by LC-HRMS

In December 2021, the U.S. Food and Drug Administration (FDA) granted emergency authorization for Paxlovid® as an antiviral treatment for COVID-19. Paxlovid® is composed of two tablets, nirmatrelvir and ritonavir. Dose adjustment is necessary in cases of renal insufficiency. The aim of present study is to establish a LC-HRMS method for simultaneous determination of nirmatrelvir/ritonavir in human serum for therapeutic drug monitoring. Internal standard saquinavir was added in 25 μL human serum samples, and then the samples were precipitated with methanol. The analytes were separated by gradient elution on a C18 column, using a mobile phase of 0.1 % formic acid-water and methanol, at a flow rate of 0.4 mL/min. The injection volume was 2 μL, and the analysis time was 5 min. The determination of the analytes was performed by electrospray ionization in positive mode by full mass monitoring. The detected ions of nirmatrelvir, ritonavir and saquinavir were m/z 500.24792, 721.32004 and 671.39155, respectively. The linear concentration range for nirmatrelvir was 78.13-20000 ng mL-1, for ritonavir was 15.63-4000 ng mL-1 (r2＞0.9900). The accuracy ranged from 87.45 %∼104.63 %, and the intra-day and inter-day precision RSD was <15 %. The recovery of nirmatrelvir ranged from 98.72 %∼109.83 %, and that of ritonavir was 95.41∼112.36 %. The matrix effect of nirmatrelvir was 88.31∼97.73 %, and that of ritonavir was 85.17∼103.05 %. This method was used to measure the trough concentrations of nirmatrelvir/ritonavir in 17 patients. The trough concentration of nirmatrelvir was 1331.7-8352.5 ng/mL, and that of ritonavir was 53.4-1325.5 ng mL-1, with large individual differences. The method is simple, sensitive, specific, and reproducible, and can be used for monitoring the blood concentration and pharmacokinetic study of nirmatrelvir/ritonavir in COVID-19 patients.

High concentrations of nirmatrelvir/ritonavir in critically ill patients receiving continuous renal replacement therapy

OBJECTIVES

Nirmatrelvir/ritonavir is a highly efficacious agent against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although dose adjustment is recommended in patients with renal impairment according to the package insert for Paxlovid (Pfizer), there is no dose recommendation for patients with severe renal impairment who require continuous renal replacement therapy (CRRT).

METHODS

To characterise the features of nirmatrelvir/ritonavir in critically ill Chinese patients undergoing CRRT, therapeutic drug monitoring of nirmatrelvir/ritonavir was performed by high-performance liquid chromatography tandem mass spectrometry assay in eight patients.

RESULTS

Nirmatrelvir trough concentrations ranged from 3325.34 ng/mL to 15 625.46 ng/mL. Concentrations were up to 7-fold higher compared with patients with normal renal function and 2-fold higher compared with patients with end-stage renal disease undergoing haemodialysis.

CONCLUSIONS

These results suggest that a dose reduction should be implemented in the treatment of patients with CRRT.

Homogeneous liquid-liquid microextraction coupled with HPLC/DAD for determination of nirmatrelvir and ritonavir as COVID-19 combination therapy in human plasma

The study reports the development of a high-performance liquid chromatography/diode array detection method to measure the levels of nirmatrelvir and ritonavir in human plasma. These two antiviral medications are used for the treatment of COVID-19 and are marketed as Paxlovid®. The method employed sugaring-out induced homogeneous liquid-liquid microextraction to improve sensitivity. Optimization of the method was performed using the one variable at a time approach by adjusting several factors such as type of sugar, extractant, amount of sugar, volume of extractant, and pH of the aqueous sample to achieve the highest efficiency. The developed method was validated according to the Food and Drug Administration guidelines and demonstrated good linearity, accuracy, and precision. The range of linearity was from 1000 to 20,000 ng/mL for nirmatrelvir and 200 to 20,000 ng/mL for ritonavir with correlation coefficient values of 0.998 and 0.996, respectively. Selectivity studies revealed that no others peaks appeared in the retention times of the studied drugs. The stability of nirmatrelvir and ritonavir were also investigated through short term and three cycles of freeze-thaw, and both drugs were found stable. This analytical method could be useful for monitoring drug concentrations in patients undergoing treatment with these medications for COVID-19. In this work, for the first time, SULLME was used for the sensitive determination of nirmatrelvir and ritonavir in biological fluids. The developed method was able to determine both drugs in therapeutic levels with no need to sophisticated techniques like LC-MS. In addition to that, SULLME is considered a simple and green sample preparation in comparison with conventional sample preparation methods.

Safety Profile and Clinical and Virological Outcomes of Nirmatrelvir-Ritonavir Treatment in Patients With Advanced Chronic Kidney Disease and Coronavirus Disease 2019

BACKGROUND

Nirmatrelvir-ritonavir is currently not recommended in patients with an estimated glomerular filtration rate (eGFR) <30 mL/minute/1.73 m2.

METHODS

To determine the safety profile and clinical and virological outcomes of nirmatrelvir-ritonavir use at a modified dosage in adults with chronic kidney disease (CKD), a prospective, single-arm, interventional trial recruited patients with eGFR <30 mL/minute/1.73 m2 and on dialysis. Primary outcomes included safety profile, adverse/serious adverse events, and events leading to drug discontinuation. Disease symptoms, virological outcomes by serial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral polymerase chain reaction (PCR) tests, rapid antigen tests, and virological and symptomatic rebound were also recorded.

RESULTS

Fifty-nine (69.4%) of the 85 participants had stage 5 CKD and were on dialysis. Eighty (94.1%) completed the full treatment course; 9.4% and 5.9% had adverse and serious adverse events, and these were comparable between those with eGFR < or >30 mL/minute/1.73 m2. The viral load significantly decreased on days 5, 15, and 30 (P < .001 for all), and the reduction was consistent in the subgroup with eGFR <30 mL/minute/1.73 m2. Ten patients had virological rebound, which was transient and asymptomatic.

CONCLUSIONS

Among patients with CKD, a modified dose of nirmatrelvir-ritonavir is a well-tolerated therapy in mild COVID-19 as it can effectively suppress the SARS-CoV-2 viral load with a favorable safety profile. Virological and symptomatic rebound, although transient with low infectivity, may occur after treatment. Nirmatrelvir-ritonavir should be considered for use in patients with CKD, including stage 5 CKD on dialysis. Clinical Trials Registration. Clinical Trials.gov; identifier: NCT05624840.

Nirmatrelvir/ritonavir use in patients with COVID-19 on hemodialysis: a case series

Patients undergoing hemodialysis (HD) are particularly vulnerable to coronavirus disease 2019 (COVID-19) and are at increased risk of developing severe infection. However, given the exclusion of such patients from clinical trials, there are limited data regarding the effectiveness of the antiviral drug nirmatrelvir/ritonavir (N/R) in patients on HD. We prescribed N/R to 4 patients on HD with COVID-19 after obtaining informed consent. Their clinical symptoms were improved at approximately 3 days after N/R administration. The viral load was reduced after approximately 10 days. The main adverse effects were nausea and vomiting. Rational dosage adjustment obtained good tolerance but did not influence the efficacy. These results suggest that N/R may be a promising agent for patients on HD with COVID-19.

Elevated Tacrolimus Blood Concentration Due to the Interaction with Nirmatrelvir/Ritonavir During COVID-19 Treatment: A Case Report

BACKGROUND

Nirmatrelvir/ritonavir, a newly authorized drug for the treatment of COVID-19, is a strong CYP3A4 inhibitor that can interact with many drugs, such as tacrolimus, reducing its metabolism. The reported case is a renal transplant patient who experienced a strong increase in tacrolimus blood concentration (up to 112ng/mL, more than ten times above the target range) when treated with both drugs at the same time, which caused a neurologic condition that required hospital admission for its control and treatment. The resolution of the symptoms was rapid, but the elevation of tacrolimus concentration remained for several days, even after discontinuing both drugs. This case shows the importance of developing a protocol for managing this interaction to guarantee the efficacy and safety of treatment with nirmatrelvir/ritonavir in transplant patients.

Higher sensitive selective spectrofluorometric determination of ritonavir in the presence of nirmatrelvir: application to new FDA approved co-packaged COVID-19 pharmaceutical dosage and spiked human plasma

BACKGROUND

Ritonavir was recently combined with nirmatrelvir in a new approved co-packaged medication form for the treatment of COVID-19. Quantitative analysis based on fluorescence spectroscopy measurement was extensively used for sensitive determination of compounds exhibited unique fluorescence features.

OBJECTIVE

The main objective of this work was to develop higher sensitive cost effective spectrofluorometric method for selective determination of ritonavir in the presence of nirmatrelvir in pure form, pharmaceutical tablet as well as in spiked human plasma.

METHODS

Ritonavir was found to exhibit unique native emission fluorescence at 404 nm when excited at 326 nm. On the other hand, nirmatrelvir had no emission bands when excited at 326 nm. This feature allowed selective determination of ritonavir without any interference from nirmatrelvir. The variables affecting fluorescence intensity of ritonavir were optimized in terms of sensitivity parameters and principles of green analytical chemistry. Ethanol was used a green solvent which provided efficient fluorescence intensity of the cited drug.

RESULTS

The method was validated in accordance with the ICH Q2 (R1) standards in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision and specificity. The described method was successfully applied for ritonavir assay over the concentration range of 2.0-20.0 ng/mL.

CONCLUSION

Ritonavir determination in the spiked human plasma was successfully done with satisfactory accepted results.

Paxlovid as a potential treatment for long COVID

INTRODUCTION

On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United States National Institutes of Health opened enrollment for RECOVER-Vital, a randomized study to evaluate new treatment options for long Coronavirus (long COVID).

AREAS COVERED

The RECOVER Initiative is a $1.15 billion research platform intended to describe, categorize, treat, and prevent long-term symptoms following infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‑CoV‑2), the virus that causes Coronavirus (COVID-19). More than 200 symptoms have been associated with long COVID, potentially affecting nearly all body systems, and current estimates suggest that between 7 million and 23 million Americans have developed long COVID. However, there are no approved treatments for this condition.

EXPERT OPINION

The first prospective, randomized study of the RECOVER research initiative, RECOVER-Vital, will evaluate the SARS-CoV-2 antiviral nirmatrelvir/ritonavir (Paxlovid) as a potential treatment for long COVID. This manuscript explores what is known about Paxlovid to treat and prevent long COVID and examines the rationale for addressing this condition with an antiviral agent.

Update of the recommendations on the management of the SARS-CoV-2 coronavirus pandemic (COVID-19) in kidney transplant patients

SARS-CoV-2 infection (COVID-19) has had a significant impact on transplant activity in our country. Mortality and the risk of complications associated with COVID-19 in kidney transplant recipients (KT) were expected to be higher due to their immunosuppressed condition and the frequent associated comorbidities. Since the beginning of the pandemic in March 2020 we have rapidly improved our knowledge about the epidemiology, clinical features and management of COVID-19 post-transplant, resulting in a better prognosis for our patients. KT units have been able to adapt their programs to this new reality, normalizing both donation and transplantation activity in our country. This manuscript presents a proposal to update the general recommendations for the prevention and treatment of infection in this highly vulnerable population such as KT.

Nirmatrelvir/Ritonavir for hemodialysis patients with COVID-19

Background: Hemodialysis patients have a high risk of severe/critical COVID-19 and related high mortality, but nirmatrelvir/ritonavir is not recommended for hemodialysis patients with COVID-19 infection because of lack of evidence of safety. Objectives: Our study aims to evaluate the minimum plasma concentration (Cmin) of nirmatrelvir and its safety of different doses of nirmatrelvir/ritonavir in hemodialysis patients with mild COVID-19. Method: This was a prospective, two step, nonrandomized, open-label study. Participants were treated with nirmatrelvir 150 mg or 300 mg once a day (another 75 mg or 150 mg supplied after hemodialysis) and ritonavir 100 mg twice daily for 5 days, respectively. The primary outcome was the safety of nirmatrelvir/ritonavir, including the Cmin of nirmatrelvir and the number of adverse events (AE). The secondary outcome was the time of viral elimination in hemodialysis patients. Results: Adverse events were happened in 3 and 7 participants in the step 1 and step 2 group, respectively (p = 0.025). Among them, 2 and 6 participants were identified as drug-related adverse events (p = 0.054). No SAE or liver function damage happened. The Cmin of nirmatrelvir in step 1 and step 2 group were 5,294.65 ± 2,370.59 ng/mL and 7,675.67 ± 2,745.22 ng/mL (p = 0.125). The Cmin of the control group was 2,274.10 ± 1,347.25 ng/mL (p = 0.001 compared to step 2 and p = 0.059 compared to step 1). Compared to hemodialysis patients without nirmatrelvir/ritonavir, there were no statistical differences in overall viral elimination time (p = 0.232). Conclusion: In our study, two doses of nirmatrelvir/ritonavir appeared to be excessive for hemodialysis patients. Although all of the patients tolerated 5-day administration, nearly half of the patients experienced drug-related adverse events. In addition, the medication group did not show a significant advantage in the time of viral elimination.

Simultaneous green TLC determination of nirmatrelvir and ritonavir in the pharmaceutical dosage form and spiked human plasma

Quantitative analysis of pharmaceutical compounds up to Nano gram levels is highly recommended to introduce feasible and sensitive tool for determination of the compounds in the pharmaceutical and biological samples. Nirmatrelvir plus ritonavir was recently approved in the US, the UK and Europe as a new co-packaged dosage form for the treatment of COVID-19. The objective of this work was to develop a more sensitive TLC method based on using β-cyclodextrin as a chiral selector additive in the mobile phase for simultaneous determination of nirmatrelvir and ritonavir in pure form, pharmaceutical formulation and spiked human plasma. The analysis procedures were developed using TLC aluminum silica gel plates and methanol-water- 2% urea solution of β-cyclodextrin (40:10:.5, by volume) as a mobile phase with UV detection at 215 nm. The developed method was successfully applied over a linearity range of 10-50 ng/band for both nirmatrelvir and ritonavir. The method was validated for limits of detection and quantitation, accuracy, precision, specificity, system suitability, and robustness. Furthermore, the eco-friendliness of the proposed method was assessed using the analytical eco-scale and the green analytical procedure index. The described method exhibited compliance with green analytical chemistry principles based on common green metric values.

Sotrovimab in SARS-COV-2 chronic hemodialysis patients in the Omicron era. Is intradialytic administration feasible? Report of 4 cases

Chronic hemodialysis patients are at high risk of morbidity and mortality in case of SARS-CoV-2 infection and they may need to be treated with monoclonal antibodies, either because they have not been vaccinated, or because they have a low anti spike antibody titer. Administration of Sotrovimab has recently been proposed for hemodialysis patients, but data are on the results lacking. We report on four cases of chronic dialysis patients who received Sotrovimab during intermittent dialysis sessions. In our series, no adverse reactions were recorded; intradialytic administration resulted safe and allowed an adequate observation time without prolonging hospital stay in chronic hemodialysis outpatients.

Early Experience with Modified Dose Nirmatrelvir/Ritonavir in Dialysis Patients with Coronavirus Disease 2019

BACKGROUND

Nirmatrelvir/ritonavir was approved for use in high-risk outpatients with coronavirus disease 2019 (COVID-19). However, patients with severe CKD were excluded from the phase 3 trial, and the drug is not recommended for those with GFR <30 ml/min per 1.73 m 2 . On the basis of available pharmacological data, we developed a modified low-dose regimen of nirmatrelvir/ritonavir 300/100 mg on day 1, followed by 150/100 mg daily from day 2 to 5. In this study, we report our experience with this modified dose regimen in dialysis patients in the Canadian province of Ontario.

METHODS

We included dialysis patients who developed COVID-19 and were treated with the modified dose nirmatrelvir/ritonavir regimen during a 60-day period between April 1 and May 31, 2022. Details of nirmatrelvir/ritonavir use and outcomes were captured manually, and demographic data were obtained from a provincial database. Data are presented with descriptive statistics. The principal outcomes we describe are 30-day hospitalization, 30-day mortality, and required medication changes with the modified dose regimen.

RESULTS

A total of 134 dialysis patients with COVID-19 received nirmatrelvir/ritonavir during the period of study. Fifty-six percent were men, and the mean age was 64 years. Most common symptoms were cough and/or sore throat (60%). Medication interactions were common with calcium channel blockers, statins being the most frequent. Most patients (128, 96%) were able to complete the course of nirmatrelvir/ritonavir, and none of the patients who received nirmatrelvir/ritonavir died of COVID-19 in the 30 days of follow-up.

CONCLUSIONS

A modified dose of nirmatrelvir/ritonavir use was found to be safe and well tolerated, with no serious adverse events being observed in a small sample of maintenance dialysis patients.

COVID-19 in Elderly Patients Receiving Haemodialysis: A Current Review

There is an increased incidence of elderly adults diagnosed with kidney failure as our global aging population continues to expand. Hence, the number of elderly adults indicated for kidney replacement therapy is also increasing simultaneously. Haemodialysis initiation is more commonly observed in comparison to kidney transplantation and peritoneal dialysis for the elderly. The onset of the coronavirus 2019 (COVID-19) pandemic brought new paradigms and insights for the care of this patient population. Elderly patients receiving haemodialysis have been identified as high-risk groups for poor COVID-19 outcomes. Age, immunosenescence, impaired response to COVID-19 vaccination, increased exposure to sources of COVID-19 infection and thrombotic risks during dialysis are key factors which demonstrated significant associations with COVID-19 incidence, severity and mortality for this patient group. Recent findings suggest that preventative measures such as regular screening and, if needed, isolation in COVID-19-positive cases, alongside the fulfillment of COVID-19 vaccination programs is an integral strategy to reduce the number of COVID-19 cases and consequential complications from COVID-19, particularly for high-risk groups such as elderly haemodialysis patients. The COVID-19 pandemic brought about the rapid development and repurposing of a number of medications to treat patients in the viral and inflammatory stages of their disease. However, elderly haemodialysis patients were grossly unrepresented in many of these trials. We review the evidence for contemporary treatments for COVID-19 in this population to provide clinicians with an up-to-date guide. We hope our article increases awareness on the associations and impact of COVID-19 for the elderly haemodialysis population, and encourage research efforts to address knowledge gaps in this topical area.

Serial viral load analysis by DDPCR to evaluate FNC efficacy and safety in the treatment of mild cases of COVID-19

Introduction

The SARS-CoV-2 outbreak has threatened the human population globally as the numbers of reinfection cases even after large-scale vaccination. Trials have been carried out to find drugs effective in fighting the disease, as COVID-19 is being considered a treatable disease only after we have antivirals. A clinical candidate originally developed for HIV treatment, AZVUDINE (FNC), is a promising drug in the treatment of COVID-19.

Methods

To predict the clinical outcome of COVID-19, we examined the course of viral load, every 48 h, by RT-PCR, and disease severity using an antiviral drug, FNC, with 281 participants. A randomized clinical trial was performed to evaluate the efficacy of FNC added to standard treatment, compared with placebo group added to standard treatment, for patients with mild COVID-19. RT-qPCR and ddPCR were applied to estimate the viral load in samples from patients. Also, the clinical improvement was evaluated as well as the liver and kidney function.

Results and discussion

Notably, the FNC treatment in the mild COVID-19 patients may shorten the time of the nucleic acid negative conversion (NANC) versus placebo group. In addition, the FNC was effective in reducing the viral load of these participants. The present clinical trial results showed that the FNC accelerate the elimination of the virus in and could reduce treatment time of mild patients and save a lot of medical resources, making it a strong candidate for the outpatient and home treatment of COVID-19.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT05033145, identifier NCT05033145.

How to use COVID-19 antiviral drugs in patients with chronic kidney disease

Antiviral drugs such as Remdesivir (Veklury), Nirmatrelvir with Ritonavir (Paxlovid), Azvudine, and Molnupiravir (Lagevrio) can reduce the risk for severe and fatal Coronavirus Disease (COVID)-19. Although chronic kidney disease is a highly prevalent risk factor for severe and fatal COVID-19, most clinical trials with these drugs excluded patients with impaired kidney function. Advanced CKD is associated with a state of secondary immunodeficiency (SIDKD), which increases the susceptibility to severe COVID-19, COVID-19 complications, and the risk of hospitalization and mortality among COVID-19 patients. The risk to develop COVID-19 related acute kidney injury is higher in patients with precedent CKD. Selecting appropriate therapies for COVID-19 patients with impaired kidney function is a challenge for healthcare professionals. Here, we discuss the pharmacokinetics and pharmacodynamics of COVID-19-related antiviral drugs with a focus on their potential use and dosing in COVID-19 patients with different stages of CKD. Additionally, we describe the adverse effects and precautions to be taken into account when using these antivirals in COVID-19 patients with CKD. Lastly, we also discuss about the use of monoclonal antibodies in COVID-19 patients with kidney disease and related complications.

Nirmatrelvir and COVID-19: development, pharmacokinetics, clinical efficacy, resistance, relapse, and pharmacoeconomics

Nirmatrelvir/ritonavir (N/R) is one of the most effective antiviral drugs against SARS-CoV-2. The preclinical development, pharmacodynamics and pharmacokinetics of N/R are reviewed herein. Randomized clinical trials have been conducted exclusively with pre-Omicron variants of concern, but in vitro studies show that efficacy against all Omicron sublineages is preserved, as confirmed by post-marketing observational studies. Nevertheless, investigations of large viral genome repositories have shown that mutation in the main protease causing resistance to N/R are increasingly frequent. In addition, virological and clinical rebounds after N/R discontinuation have been reported in immunocompetent patients. This finding is of concern when translated to immunocompromised patients, in whom N/R efficacy has not been formally investigated in clinical trials. Economical sustainability and perspectives for this therapeutic arena are discussed.

Simultaneous quantification of nirmatrelvir and ritonavir by LC-MS/MS in patients treated for COVID-19

Nirmatrelvir is an antiviral agent active against SARS-CoV-2, the virus causing the pandemic disease COVID-19. It is administrated in combination with the protease inhibitor ritonavir, which acts in case of COVID-19 mainly as enzyme blocking agent preventing the premature metabolic elimination of nirmatrelvir. The combination of the two drugs in separate tablets is marketed under the brand name Paxlovid® and shows good effectivity in preventing the progression of COVID-19 to severe disease state. In this work, we described a LC-MS/MS method for the simultaneous quantification of nirmatrelvir and ritonavir in human plasma of patients treated for COVID-19 with Paxlovid®. After addition of D₆-ritonavir as internal standard, plasma proteins were precipitated by the addition of methanol. The analytes were separated by gradient elution on a C18-column and were detected by tandem mass spectrometry. Calibration functions were linear in the ranges of 10 – 10000 ng/mL for nirmatrelvir and 2 – 2000 ng/mL for ritonavir. Inter-day and intra-day precision and accuracy was better than 15 % in the quality control samples and better than 20 % at the LLOQ. The method was successfully applied on samples of hospitalized patients treated for COVID-19 and proved to be capable in supporting therapeutic drug monitoring (TDM).

[Update of the recommendations on the management of the SARS-CoV-2 coronavirus pandemic (COVID-19) in kidney transplant patients.]

SARS-CoV-2 infection (COVID-19) has had a significant impact on transplant activity in our country. Mortality and the risk of complications associated with COVID-19 in kidney transplant recipients (KT) were expected to be higher due to their immunosuppressed condition and the frequent associated comorbidities. Since the beginning of the pandemic in March 2020 we have rapidly improved our knowledge about the epidemiology, clinical features and management of COVID-19 post-transplant, resulting in a better prognosis for our patients. KT units have been able to adapt their programs to this new reality, normalizing both donation and transplantation activity in our country.This manuscript presents a proposal to update the general recommendations for the prevention and treatment of infection in this highly vulnerable population such as KT.

Pharmacokinetics of Nirmatrelvir and Ritonavir in COVID-19 Patients with End-Stage Renal Disease on Intermittent Hemodialysis

Nirmatrelvir/ritonavir is an effective antiviral therapy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Use is not recommended in patients with end-stage renal disease (ESDR) due to a lack of data. We investigated the pharmacokinetics of nirmatrelvir/ritonavir (150 mg/100 mg twice a day) in four patients with ESRD undergoing hemodialysis. Nirmatrelvir peak concentrations ranged from 4,563 to 7,898 ng/mL and declined after hemodialysis. Concentrations were up to 4-fold higher but still within the range known from patients without ESRD, without accumulation of nirmatrelvir after the end of treatment.

The Pharmacist's Role in Managing COVID-19 in Chronic Kidney Disease Patients: A Review of Existing Strategies and Future Implications

The global burden of the COVID-19 pandemic has not only disrupted healthcare delivery but has also compromised patients’ access to healthcare on account of the scarcity of medications and trained healthcare professionals. COVID-19 has been particularly challenging for patient subpopulations constituting immunocompromised individuals, geriatric patients, and those afflicted by chronic ailments. Reports indicate that diminished kidney function in chronic kidney disease (CKD) renders patients highly susceptible to complications during COVID-19 treatment. Pharmacists, being medication experts, have a significant role in making treatment decisions during COVID-19 infection. This article describes pharmacists’ interventions for monitoring and managing COVID-19 in patients with CKD. Given the massive increase in off-label use of medications to treat COVID-19, pharmacists can contribute substantially towards dosing decisions, reporting adverse medication events, and managing drug–drug interactions in COVID-19 patients suffering from CKD. In addition to traditional methods of delivering their services, the pharmacist should also adopt innovative tele-health systems to optimize patient care and ensure that patients receive safe and effective therapy during the pandemic.