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

Cardiovascular Drug Interactions with Nirmatrelvir/Ritonavir for COVID-19: Considerations for Daily Practice

Cardiovascular disease is associated with progression to severe COVID-19 and patients with the condition are among those in whom early antiviral therapy should be warranted. The combination of nirmatrelvir/ritonavir (Paxlovid®) has been approved for clinical use by the Food and Drug Administration and European Medicines Agency. Because patients with cardiovascular disease are often on polypharmacy, physicians need to be aware of potential drug-drug interactions (DDIs) when treating COVID-19 with nirmatrelvir/ritonavir. Guidance is given for avoiding DDIs, emphasising that preventing and managing potential DDIs with nirmatrelvir/ritonavir requires thorough assessment and knowledge. The present review summarises the clinical pharmacology of nirmatrelvir/ritonavir and provides details on potential DDIs with a focus on daily practice in patients with cardiovascular disease. Particular attention is needed for drugs that are predominantly metabolised by cytochrome P450 3A4, are substrates of P-glycoprotein and have a narrow therapeutic index. Proper management of potential DDIs must balance the benefit of nirmatrelvir/ ritonavir to prevent severe disease with the risk of serious adverse events.

Physiologically Based Pharmacokinetic Modeling to Investigate the Disease-Drug-Drug Interactions between Voriconazole and Nirmatrelvir/Ritonavir in COVID-19 Patients with CYP2C19 Phenotypes

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis superinfection with cytokine storm is associated with increased mortality. This study aimed to establish a physiologically-based pharmacokinetic (PK) model to investigate the disease-drug-drug interactions between voriconazole and nirmatrelvir/ritonavir in patients with COVID-19 with elevated interleukin-6 (IL-6) levels carrying various CYP2C19 phenotypes. The model was constructed and validated using PK data on voriconazole, ritonavir, and IL-6, and was subsequently verified against clinical data from 78 patients with COVID-19. As a result, the model predicted voriconazole, ritonavir, and IL-6 PK parameters and drug-drug interaction-related fold changes in healthy subjects and patients with COVID-19 with acceptable prediction error, demonstrating its predictive capability. Simulations indicated ritonavir could increase voriconazole exposure to CYP2C19 intermediate and poor metabolizers rather than decrease it, in contrast to what is indicated in the drug package insert. However, the predicted ritonavir exposures were comparable across subjects. In patients with COVID-19, both ritonavir and IL-6 increased voriconazole trough concentrations, which may lead to CYP2C19 phenotype-dependent overexposure. In conclusion, COVID-19-induced IL-6 elevation and ritonavir increased voriconazole exposure, and the magnitude of interactions was influenced by CYP2C19 phenotype. Thus, caution is warranted when prescribing voriconazole concomitantly with Paxlovid in patients with COVID-19.

Abnormally Elevated Blood Tacrolimus Level Following the Concomitant Use of Nirmatrelvir/Ritonavir With Extended-Release Tacrolimus in a Post-lung Transplant Patient: A Case Report and a Literature Review

Although nirmatrelvir/ritonavir (NMV/r) reportedly increases blood levels of tacrolimus (TAC) due to CYP3A4 inhibition and other factors, reports on the use of NMV/r in combination with tacrolimus hydrate extended-release capsules (TAC-ER) in lung transplant patients are limited. Herein, we present a case with post-lung transplantation of elevated blood trough levels of TAC after concomitant use of NMV/r. A woman in her 60s had undergone lung transplantation. She had coronavirus disease 2019 (COVID-19) and was co-administered NMV/r and TAC-ER, with the trough level controlled at approximately 4 μg/mL. Upon the co-administration of NMV/r and TAC-ER, the patient developed diarrhea and vomiting and was hospitalized. TAC-ER was discontinued on day 6, and TAC level was measured on day 8 and had risen above 100 ng/mL. This level gradually decreased to 17.8 ng/mL on day 11 and 2.4 ng/mL on day 15; therefore, TAC-ER was resumed at 2.5 mg/day. On day 18, the TAC level was 5.2 ng/mL, which was within the target range, and the patient was discharged on day 19. This is the first report of a post-lung transplant patient co-administered TAC-ER with NMV/r, who showed abnormally high blood TAC levels above the detection limit. In patients using TAC-ER after lung transplantation, it may be useful to confirm that the TAC blood level is below the effective therapeutic range before resuming TAC-ER safely.

A comprehensive examination of ACE2 receptor and prediction of spike glycoprotein and ACE2 interaction based on in silico analysis of ACE2 receptor

The ACE2 receptor plays a vital role not only in the SARS-CoV-induced epidemic but also in various other diseases, including cardiovascular diseases and ARDS. While studies have explored the interactions between ACE2 and SARS-CoV proteins, comprehensive research utilizing bioinformatic tools on the ACE2 protein has been lacking. The one aim of present study was to extensively analyze the regions of the ACE2 protein. After utilizing all bioinformatics tools especially G104 and L108 regions on ACE2 were come forward. The results of our analysis revealed that possible mutations or deletions in the G104 and L108 regions play a critical role in both the biological functioning and the determination of the chemical-physical properties of ACE2. Additionally, these regions were found to be more susceptible to mutations or deletions compared to other regions of the ACE2 protein. Notably, the randomly selected peptide, LQQNGSSVLS (100-109), which includes G104 and L108, exhibited a crucial role in binding the RBD of the spike protein, as supported by docking scores. Furthermore, both MDs and iMODs results provided evidence that G104 and L108 influence the dynamics of ACE2-spike complexes. This study is expected to offer a new perspective on the ACE2-SARS-CoV interaction and other research areas where ACE2 plays a significant role, such as biotechnology (protein engineering, enzyme optimization), medicine (RAS, pulmonary and cardiac diseases), and basic research (structural motifs, stabilizing protein folds, or facilitating important inter molecular contacts, protein's proper structure and function).Communicated by Ramaswamy H. Sarma.

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.

A global phase II randomized trial comparing oral taxane ModraDoc006/r to intravenous docetaxel in metastatic castration resistant prostate cancer

STUDY AIM

ModraDoc006, an oral formulation of docetaxel, is co-administered with the cytochrome P450-3A4 and P-glycoprotein inhibitor, ritonavir (r): ModraDoc006/r. The preliminary efficacy and safety of oral ModraDoc006/r was evaluated in a global randomized phase II trial and compared to the current standard chemotherapy regimen of intravenous (i.v.) docetaxel and prednisone.

METHODS

103 mCRPC patients, chemotherapy-naïve with/without abiraterone and/or enzalutamide pretreated, with adequate organ function and evaluable disease per RECIST v1.1 and PCWG3 guidelines were randomized 1:1 into two cohorts. In Cohort 1, 49 patients received docetaxel 75 mg/m2 i.v. every 3 weeks (Q3W). In Cohort 2, 52 patients received ModraDoc006/r; 21 patients with a starting dose of ModraDoc006 30 mg with ritonavir 200 mg in the morning and ModraDoc006 20 mg with ritonavir 100 mg in the evening (30-20/200-100 mg) bi-daily-once-weekly (BIDW) on Days 1, 8, and 15 of a 21-day cycle. To alleviate tolerability, the starting dose was amended to ModraDoc006/r 20-20/200-100 mg in another 31 patients. All patients received prednisone 10 mg daily. Primary endpoint was rPFS.

RESULTS

There was no significant difference in rPFS between the 2 arms (p = 0.1465). Median rPFS was 9.5 months and 11.1 months (95% CI) for ModraDoc006/r and i.v. docetaxel, respectively. Partial response was noted in 44.1% and 38.7% measurable disease patients, and 50% decline of PSA was seen in 23 (50%) and 26 (56.5%) evaluable cases treated with ModraDoc006/r and i.v. docetaxel, respectively. The safety profile of ModraDoc006/r 20-20/200-100 mg dose was significantly better than i.v. docetaxel, with mild (mostly Grade 1) gastrointestinal toxicities, no hematologic adverse events, and neuropathy and alopecia incidence of 11.5% and 25%, respectively.

CONCLUSIONS

ModraDoc006/r potentially represents a widely applicable, convenient, effective, and better tolerated oral taxane therapy option for mCRPC. Further investigation of ModraDoc006/r in a large randomized trial is warranted.

Pharmacist's role in the management of drug-drug interactions caused by nirmatrelvir/ritonavir in COVID-19 oncohematology patients

OBJECTIVE

New drugs developed for SARS-CoV-2 infection, such as nirmatrelvir/ritonavir (NMV/r), represent a potential for oncohematology patients, but also pose a challenge in managing the potential clinically relevant drug-drug interactions (pDDIs) that may arise. The aim of this study is to assess the frequency, severity, and pharmacist detection of pDDIs.

METHODS

This prospective, observational, study spanned 8 months, involving 42 oncohematology patients prescribed NMV/r in a tertiary-level hospital. A Board Certified oncology pharmacist assessed pDDIs using three databases and made recommendations to prescribing physicians. Linear and logistic regression analyses were employed to explore the relationship between prescribed drugs and pDDIs.

RESULTS

Clinically relevant pDDIs were detected in 76.2% of patients, with 18.1% of all medications involved in drug-drug interactions (DDIs). The most common drugs implicated were atorvastatin and imatinib. Micromedex® identified 63.3% of interactions as major severity, while Lexicomp® and University of Liverpool classifications were less restrictive. Pharmacists prevented most DDIs from reaching patients through different interventions, including treatment monitoring (44.2%), discontinuation (36.5%), and dose reduction (17.3%).

CONCLUSION

This study highlights the high prevalence of clinically significant pDDIs in oncohematology patients receiving NMV/r for COVID-19. Pharmacists, as integral members of the healthcare team, played a crucial role in detecting, categorizing, and mitigating these interactions. The results underscore the need for comprehensive studies to evaluate the impact of pharmacist-led interventions in optimizing drug therapy and enhancing patient safety in this vulnerable population.

Exploration of P1 and P4 modifications of nirmatrelvir: Design, synthesis, biological evaluation, and X-ray structural studies of SARS-CoV-2 Mpro inhibitors

We report the synthesis, biological evaluation, and X-ray structural studies of a series of SARS-CoV-2 Mpro inhibitors based upon the X-ray crystal structure of nirmatrelvir, an FDA approved drug that targets the main protease of SARS-CoV-2. The studies involved examination of various P4 moieties, P1 five- and six-membered lactam rings to improve potency. In particular, the six-membered P1 lactam ring analogs exhibited high SARS-CoV-2 Mpro inhibitory activity. Several compounds effectively blocked SARS-CoV-2 replication in VeroE6 cells. One of these compounds maintained good antiviral activity against variants of concern including Delta and Omicron variants. A high-resolution X-ray crystal structure of an inhibitor bound to SARS-CoV-2 Mpro was determined to gain insight into the ligand-binding properties in the Mpro active site.

The effects of nirmatrelvir/ritonavir on tacrolimus levels in lung transplant recipients: A single-center study

BACKGROUND

Lung transplant recipients (LTRs) have a higher risk of hospitalization and mortality due to COVID-19 compared with the immunocompetent population. The use of nirmatrelvir/ritonavir (NR), an effective oral treatment for COVID-19, is quite challenging due to its potent drug-drug interactions with immunosuppressants and azole antifungals. As there are few clinical reports of the use of NR in LTRs, we measured tacrolimus levels in patients receiving NR in our hospital to improve safety when prescribing NR.

METHODS

In total, 48 adult LTRs who received NR between November 19, 2022, and January 19, 2023, at China-Japan Friendship Hospital were retrospectively included and followed for 20 days after initiating NR. Tacrolimus was held at least 12 h before initiating NR and re-administered based on the trough levels after completing NR treatment. All concomitant medications, drug concentrations, laboratory results, and genotypes were recorded and analyzed.

RESULTS

Most patients showed stable tacrolimus trough levels despite high individual variability. Four patients exhibited supratherapeutic trough levels of tacrolimus (more than 15 ng/mL). Two patients who received 0.5 mg of tacrolimus during NR treatment had trough levels below 3.0 ng/mL. In addition, we found that in 13 patients, the trough levels were 130% of baseline after cessation of tacrolimus, and logistic regression revealed that increased trough level was significantly associated with age more than 60 years.

CONCLUSIONS

NR can be safely used in LTRs with close monitoring of tacrolimus levels and appropriate dose adjustments. However, more attention should be paid to elderly patients, as NR may more severely affect their drug metabolism. Due to the limited sample size, further studies are needed to guide the optimal use of tacrolimus following treatment with NR and explore the risk factors significantly affecting the interactions between NR and tacrolimus.

Clinical course and management of COVID-19 in the era of widespread population immunity

The clinical implications of COVID-19 have changed since SARS-CoV-2 first emerged in humans. The current high levels of population immunity, due to prior infection and/or vaccination, have been associated with a vastly decreased overall risk of severe disease. Some people, particularly those with immunocompromising conditions, remain at risk for severe outcomes. Through the course of the pandemic, variants with somewhat different symptom profiles from the original SARS-CoV-2 virus have emerged. The management of COVID-19 has also changed since 2020, with the increasing availability of evidence-based treatments in two main classes: antivirals and immunomodulators. Selecting the appropriate treatment(s) for patients with COVID-19 requires a deep understanding of the evidence and an awareness of the limitations of applying data that have been largely based on immune-naive populations to patients today who most likely have vaccine-derived and/or infection-derived immunity. In this Review, we provide a summary of the clinical manifestations and approaches to caring for adult patients with COVID-19 in the era of vaccine availability and the dominance of the Omicron subvariants, with a focus on the management of COVID-19 in different patient groups, including immunocompromised, pregnant, vaccinated and unvaccinated 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.

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.

SARS-CoV-2 papain-like protease (PLpro) inhibitory and antiviral activity of small molecule derivatives for drug leads

We report here the synthesis and biological evaluation of a series of small molecule SARS-CoV-2 PLpro inhibitors. We compared the activity of selected compounds in both SARS-CoV-1 and SARS-CoV-2 PLpro inhibitory and antiviral assays. We have synthesized and evaluated several new structural variants of previous leads against SARS-CoV-2 PLpro. The replacement of the carboxamide functionality with sulfonamide derivatives resulted in PLpro inhibitors with potent PLpro inhibitory and antiviral activity in VeroE6 cells similar to GRL0617. To obtain molecular insight, we created an optimized model of a potent sulfonamide derivative in the SARS-CoV-2 PLpro active site.

Oral Molnupiravir and Nirmatrelvir/Ritonavir for the Treatment of COVID-19: A Literature Review with a Focus on Real-World Evidence

Vaccines remain the cornerstone of medical prevention and are highly effective in reducing the risk of severe disease and death due to coronavirus disease 2019 (COVID-19). In the context of expanding the therapeutic armamentarium against COVID-19, molnupiravir (Lagevrio) and ritonavir-boosted nirmatrelvir (Paxlovid) were developed, constituting the first effective oral treatments against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this narrative review, we retrospectively inquired into the clinical trials and real-world studies investigating the efficacy of these agents. Overall, clinical trials and real-world studies have demonstrated the efficacy of both agents in reducing hospitalization and death rates in COVID-19 patients. As per current recommendations, their use is suggested in patients with mild to moderate symptoms who are at high risk of developing severe disease. Nevertheless, limited data exist regarding their efficacy in specific subpopulations, such as immunocompromised patients, those with severe kidney disease, pregnant women, and children.

Molnupiravir for the treatment of non-severe COVID-19: a systematic review and meta-analysis of 14 randomized trials with 34 570 patients

BACKGROUND

Molnupiravir has been considered a promising candidate for COVID-19. Its efficacy and safety in non-severe COVID-19 patients and the differences between patients with different risk factors need further evaluation.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials that allocated adult patients with non-severe COVID-19 to molnupiravir or a control. We used random-effects models, and conducted subgroup analyses and meta-regression for COVID-19 patients with high-risk factors. The GRADE approach was used to rate the certainty of evidence.

RESULTS

Fourteen trials with 34 570 patients were included. Moderate- to low-certainty evidence showed that molnupiravir was associated with a reduction in the risk of hospitalization (relative risk [RR] = 0.63, 95% CI: 0.47-0.85), risk of mechanical ventilation (RR = 0.37, 95% CI: 0.19-0.72) and time to symptom resolution (mean differences [MD] = -2.91 days, 95% CI: -3.66 to -2.16). However, no significant differences were found in adverse events, all-cause mortality, rate of and time to viral clearance, or duration of hospitalization. For the rate of viral clearance, subgroup effects were found between trials with low and high risk of bias (P = 0.001) and between trials with male or female majority (P < 0.001). For admission to hospital, subgroup effects were also found between trials with ≥50% and <50% of the participants being female (P = 0.04). Meta-regression showed a significant association between higher trial mean age and elevated risk of hospitalization (P = 0.011), and female majority and elevated risk of hospitalization (P = 0.011).

CONCLUSIONS

Molnupiravir was found to be effective in non-severe COVID-19, but the efficacy varied with age and sex.

Nirmatrelvir plus ritonavir remains effective in vaccinated patients at risk of progression with COVID-19: A systematic review and meta-analysis

Background

The efficacy of nirmatrelvir plus ritonavir (NMV-r) for vaccinated COVID-19 patients at high risk of progression is not adequately recognised. To address this gap, we conducted a systematic review and meta-analysis of current literature.

Methods

We searched PubMed, Web of Science, Embase, Cochrane Library, and medRxiv for articles published up to 8 January 2023 on NMV-r in outpatients. At least two researchers screened articles, extracted data, and assessed the quality of selected studies. We evaluated the results via risk ratios (RRs) with 95% confidence intervals (CIs) and tested for heterogeneity using I² statistics.

Results

We included seven observational cohort studies comprising 224 238 vaccinated patients. According to our meta-analysis, NMV-r reduced 47% incidence of all-cause death or hospitalisation within 30 days for vaccinated patients (RR = 0.53; 95% CI = 0.40-0.70; I² = 81%). After excluding the most influential result by sensitivity analysis, NMV-r still reduced risk of all-cause death or hospitalisation by 38% (RR = 0.62; 95% CI = 0.56-0.69; I² = 0%). In our secondary outcome, NMV-r also showed its benefits in reducing all-cause death in vaccinated patients (RR = 0.40; 95% CI = 0.19-0.85; I² = 23%).

Conclusions

We found positive evidence for the use of NMV-r for vaccinated patients at high-risk of progression with mild to moderate COVID-19. However, large-scale RCTs are needed to confirm these findings.

Registration

PROSPERO CRD42023391349.

Synthesis of optically active SARS-CoV-2 Mpro inhibitor drug nirmatrelvir (Paxlovid): an approved treatment of COVID-19

Nirmatrelvir (Paxlovid) is an FDA approved drug that targets SARS-COV-2 3CLprotease. We report an optically active synthesis of nirmatrelvir that avoids a critical epimerization step. Our initial coupling of gem-dimethyl bicyclo[3.1.0]proline methyl ester with tert-leucine-trifluoroacetamide using standard coupling reagents, EDC and HOBt, provided the corresponding dipeptide derivative in excellent yield, however, a significant epimerization was observed at the tert-leucine bearing chiral center. To circumvent this epimerization problem, we developed a ZnCl2-mediated direct N-trifluroacetylation of Boc-derivatives for the synthesis of nirmatrelvir. This protocol has been utilized for N-acyl bond formation with other anhydrides without epimerization. The present synthetic route can be useful for the synthesis of structural variants of nirmatrelvir without significant epimerization.

Mpro-targeted anti-SARS-CoV-2 inhibitor-based drugs

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 is a global health emergency. The main protease is an important drug target in coronaviruses. It plays an important role in the processing of viral RNA-translated polyproteins and is highly conserved in the amino acid sequence and three-dimensional structure, making it a good drug target for which several small molecule inhibitors are available. This paper describes the various anti-severe acute respiratory syndrome coronavirus 2 inhibitor drugs targeting Mpro discovered since the severe acute respiratory syndrome coronavirus 2 outbreak at the end of 2019, with all these compounds inhibiting severe acute respiratory syndrome coronavirus 2 Mpro activity in vitro. This provides a reference for the development of severe acute respiratory syndrome coronavirus 2 Mpro-targeted inhibitors and the design of therapeutic approaches to address newly emerged severe acute respiratory syndrome coronavirus 2 mutant strains with immune evasion capabilities.

A case report of a prolonged decrease in tacrolimus clearance due to co-administration of nirmatrelvir/ritonavir in a lung transplant recipient receiving itraconazole prophylaxis

BACKGROUND

Drug-drug interaction management is complex. Nirmatrelvir/ritonavir is a potent cytochrome P450 (CYP) 3A inhibitor and influences pharmacokinetics of co-administered drugs. Although there are several reports about drug-drug interactions of nirmatrelvir/ritonavir, an influence of a concomitant use of nirmatrelvir/ritonavir and another potent CYP3A inhibitor on tacrolimus remains unclear. Here, we experienced a lung transplant patient with the novel coronavirus disease 2019 (COVID-19). In this patient, nirmatrelvir/ritonavir was administered, and the inhibitory effect of itraconazole on CYP3A was prolonged.

CASE PRESENTATION

We present a case in forties who had undergone lung transplantation. He was administered itraconazole and tacrolimus 1.0 mg/d, with a trough value of 8-12 ng/mL. The patient contracted the COVID-19, and a nirmatrelvir/ritonavir treatment was initiated. During the antiviral treatment, tacrolimus administration was discontinued for 5 d. Tacrolimus was resumed at 1.0 mg/d after completion of the nirmatrelvir/ritonavir treatment, but the trough value after 7 d was high at 31.6 ng/mL. Subsequently, the patient was placed on another 36-h tacrolimus discontinuation, but the trough value decreased to only 16.0 ng/mL.

CONCLUSIONS

Co-administration of ritonavir caused a prolonged decrease in tacrolimus clearance through its inhibitory effects on CYP3A in a patient taking itraconazole. Management of drug-drug interaction by pharmacists can be important for patients with multiple medications.

Radu E, Matei L, Maria Ruta S, Bleotu C. SARS-CoV-2 Variant Surveillance in Genomic Medicine Era

In the genomic medicine era, the emergence of SARS-CoV-2 was immediately followed by viral genome sequencing and world-wide sequences sharing. Almost in real-time, based on these sequences, resources were developed and applied around the world, such as molecular diagnostic tests, informed public health decisions, and vaccines. Molecular SARS-CoV-2 variant surveillance was a normal approach in this context yet, considering that the viral genome modification occurs commonly in viral replication process, the challenge is to identify the modifications that significantly affect virulence, transmissibility, reduced effectiveness of vaccines and therapeutics or failure of diagnostic tests. However, assessing the importance of the emergence of new mutations and linking them to epidemiological trend, is still a laborious process and faster phenotypic evaluation approaches, in conjunction with genomic data, are required in order to release timely and efficient control measures.

MecDDI: Clarified Drug-Drug Interaction Mechanism Facilitating Rational Drug Use and Potential Drug-Drug Interaction Prediction

Drug-drug interactions (DDIs) are a major concern in clinical practice and have been recognized as one of the key threats to public health. To address such a critical threat, many studies have been conducted to clarify the mechanism underlying each DDI, based on which alternative therapeutic strategies are successfully proposed. Moreover, artificial intelligence-based models for predicting DDIs, especially multilabel classification models, are highly dependent on a reliable DDI data set with clear mechanistic information. These successes highlight the imminent necessity to have a platform providing mechanistic clarifications for a large number of existing DDIs. However, no such platform is available yet. In this study, a platform entitled "MecDDI" was therefore introduced to systematically clarify the mechanisms underlying the existing DDIs. This platform is unique in (a) clarifying the mechanisms underlying over 1,78,000 DDIs by explicit descriptions and graphic illustrations and (b) providing a systematic classification for all collected DDIs based on the clarified mechanisms. Due to the long-lasting threats of DDIs to public health, MecDDI could offer medical scientists a clear clarification of DDI mechanisms, support healthcare professionals to identify alternative therapeutics, and prepare data for algorithm scientists to predict new DDIs. MecDDI is now expected as an indispensable complement to the available pharmaceutical platforms and is freely accessible at: https://idrblab.org/mecddi/.

Association between spironolactone use and COVID-19 outcomes in population-scale claims data: a retrospective cohort study

Background

Spironolactone has been proposed as a potential modulator of SARS-CoV-2 cellular entry. We aimed to measure the effect of spironolactone use on the risk of adverse outcomes following COVID-19 hospitalization.

Methods

We performed a retrospective cohort study of COVID-19 outcomes for patients with or without exposure to spironolactone, using population-scale claims data from the Komodo Healthcare Map. We identified all patients with a hospital admission for COVID-19 in the study window, defining treatment status based on spironolactone prescription orders. The primary outcomes were progression to respiratory ventilation or mortality during the hospitalization. Odds ratios (OR) were estimated following either 1:1 propensity score matching (PSM) or multivariable regression. Subgroup analysis was performed based on age, gender, body mass index (BMI), and dominant SARS-CoV-2 variant.

Findings

Among 898,303 eligible patients with a COVID-19-related hospitalization, 16,324 patients (1.8%) had a spironolactone prescription prior to hospitalization. 59,937 patients (6.7%) met the ventilation endpoint, and 26,515 patients (3.0%) met the mortality endpoint. Spironolactone use was associated with a significant reduction in odds of both ventilation (OR 0.82; 95% CI: 0.75-0.88; p < 0.001) and mortality (OR 0.88; 95% CI: 0.78-0.99; p = 0.033) in the PSM analysis, supported by the regression analysis. Spironolactone use was associated with significantly reduced odds of ventilation for all age groups, men, women, and non-obese patients, with the greatest protective effects in younger patients, men, and non-obese patients.

Interpretation

Spironolactone use was associated with a protective effect against ventilation and mortality following COVID-19 infection, amounting to up to 64% of the protective effect of vaccination against ventilation and consistent with an androgen-dependent mechanism. The findings warrant initiation of large-scale randomized controlled trials to establish a potential therapeutic role for spironolactone in COVID-19 patients.

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.

Viral proteases as therapeutic targets

Some medically important viruses-including retroviruses, flaviviruses, coronaviruses, and herpesviruses-code for a protease, which is indispensable for viral maturation and pathogenesis. Viral protease inhibitors have become an important class of antiviral drugs. Development of the first-in-class viral protease inhibitor saquinavir, which targets HIV protease, started a new era in the treatment of chronic viral diseases. Combining several drugs that target different steps of the viral life cycle enables use of lower doses of individual drugs (and thereby reduction of potential side effects, which frequently occur during long term therapy) and reduces drug-resistance development. Currently, several HIV and HCV protease inhibitors are routinely used in clinical practice. In addition, a drug including an inhibitor of SARS-CoV-2 main protease, nirmatrelvir (co-administered with a pharmacokinetic booster ritonavir as Paxlovid®), was recently authorized for emergency use. This review summarizes the basic features of the proteases of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and SARS-CoV-2 and discusses the properties of their inhibitors in clinical use, as well as development of compounds in the pipeline.

COVID-19 and antiepileptic drugs: an approach to guide practices when nirmatrelvir/ritonavir is co-prescribed

Management and dose adjustment are a major concern for clinicians in the absence of specific clinical outcome data for patients on antiepileptic drugs (AEDs), in the event of short-term (5 days) nirmatrelvir/ritonavir co-exposure. Therefore, in this report, we identified drugs that require dose adjustment because of drug-drug interactions (DDIs) between nirmatrelvir/ritonavir and AEDs. We hereby used four databases (Micromedex Drug Interaction, Liverpool Drug Interaction Group for COVID-19 Therapies, Medscape Drug Interaction Checker, and Lexicomp Drug Interactions) and DDI-Predictor.In the light of applying the DDI-Predictor, for carbamazepine, clobazam, oxcarbazepine, eslicarbazepine, phenytoin, phenobarbital, pentobarbital, rufinamide, and valproate as CYP3A4 inducers, we recommend that a dose adjustment of short-term nirmatrelvir/ritonavir as a substrate (victim) drug would be more appropriate instead of these AEDs to avoid impending DDI-related threats in patients with epilepsy.

Randomized Trial of Metformin, Ivermectin, and Fluvoxamine for Covid-19

BACKGROUND

Early treatment to prevent severe coronavirus disease 2019 (Covid-19) is an important component of the comprehensive response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic.

METHODS

In this phase 3, double-blind, randomized, placebo-controlled trial, we used a 2-by-3 factorial design to test the effectiveness of three repurposed drugs - metformin, ivermectin, and fluvoxamine - in preventing serious SARS-CoV-2 infection in nonhospitalized adults who had been enrolled within 3 days after a confirmed diagnosis of infection and less than 7 days after the onset of symptoms. The patients were between the ages of 30 and 85 years, and all had either overweight or obesity. The primary composite end point was hypoxemia (≤93% oxygen saturation on home oximetry), emergency department visit, hospitalization, or death. All analyses used controls who had undergone concurrent randomization and were adjusted for SARS-CoV-2 vaccination and receipt of other trial medications.

RESULTS

A total of 1431 patients underwent randomization; of these patients, 1323 were included in the primary analysis. The median age of the patients was 46 years; 56% were female (6% of whom were pregnant), and 52% had been vaccinated. The adjusted odds ratio for a primary event was 0.84 (95% confidence interval [CI], 0.66 to 1.09; P = 0.19) with metformin, 1.05 (95% CI, 0.76 to 1.45; P = 0.78) with ivermectin, and 0.94 (95% CI, 0.66 to 1.36; P = 0.75) with fluvoxamine. In prespecified secondary analyses, the adjusted odds ratio for emergency department visit, hospitalization, or death was 0.58 (95% CI, 0.35 to 0.94) with metformin, 1.39 (95% CI, 0.72 to 2.69) with ivermectin, and 1.17 (95% CI, 0.57 to 2.40) with fluvoxamine. The adjusted odds ratio for hospitalization or death was 0.47 (95% CI, 0.20 to 1.11) with metformin, 0.73 (95% CI, 0.19 to 2.77) with ivermectin, and 1.11 (95% CI, 0.33 to 3.76) with fluvoxamine.

CONCLUSIONS

None of the three medications that were evaluated prevented the occurrence of hypoxemia, an emergency department visit, hospitalization, or death associated with Covid-19. (Funded by the Parsemus Foundation and others; COVID-OUT ClinicalTrials.gov number, NCT04510194.).

Efficacy of Licensed Monoclonal Antibodies and Antiviral Agents against the SARS-CoV-2 Omicron Sublineages BA.1 and BA.2

Newly emerging SARS-CoV-2 variants may escape monoclonal antibodies (mAbs) and antiviral drugs. By using live virus assays, we assessed the ex vivo inhibition of the B.1 wild-type (WT), delta and omicron BA.1 and BA.2 lineages by post-infusion sera from 40 individuals treated with bamlanivimab/etesevimab (BAM/ETE), casirivimab/imdevimab (CAS/IMD), and sotrovimab (SOT) as well as the activity of remdesivir, nirmatrelvir and molnupiravir. mAbs and drug activity were defined as the serum dilution (ID50) and drug concentration (IC50), respectively, showing 50% protection of virus-induced cytopathic effect. All pre-infusion sera were negative for SARS-CoV-2 neutralizing activity. BAM/ETE, CAS/IMD, and SOT showed activity against the WT (ID50 6295 (4355-8075) for BAM/ETE; 18,214 (16,248-21,365) for CAS/IMD; and 456 (265-592) for SOT) and the delta (14,780 (ID50 10,905-21,020) for BAM/ETE; 63,937 (47,211-79,971) for CAS/IMD; and 1103 (843-1334) for SOT). Notably, only SOT was active against BA.1 (ID50 200 (37-233)), whereas BA.2 was neutralized by CAS/IMD (ID50 174 (134-209) ID50) and SOT (ID50 20 (9-31) ID50), but not by BAM/ETE. No significant inter-variant IC50 differences were observed for molnupiravir (1.5 ± 0.1/1.5 ± 0.7/1.0 ± 0.5/0.8 ± 0.01 μM for WT/delta/BA.1/BA.2, respectively), nirmatrelvir (0.05 ± 0.02/0.06 ± 0.01/0.04 ± 0.02/0.04 ± 0.01 μM) or remdesivir (0.08 ± 0.04/0.11 ± 0.08/0.05 ± 0.04/0.08 ± 0.01 μM). Continued evolution of SARS-CoV-2 requires updating the mAbs arsenal, although antivirals have so far remained unaffected.

First-generation Oral Antivirals Against SARS-CoV-2

Background

Objectives

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Content

Implications