Adverse events associated with molnupiravir: a real-world disproportionality analysis in food and drug administration adverse event reporting system

Construction and validation of a cell based reporter assay for identifying inhibitors of SARS coronavirus 2 RNA dependent RNA polymerase activity

Targeting RNA-dependent RNA polymerase (RdRp), a highly conserved enzyme essential for SARS coronavirus 2 (SARS-CoV-2) replication and transcription, represents a promising antiviral strategy due to its lower mutation rate than structural proteins such as Spike. This study introduces a cell-based assay system for screening potential SARS-CoV-2 RdRp inhibitors, contributing to ongoing efforts to identify effective antiviral agents. The assay utilizes a reporter vector containing the 3' untranslated region (UTR), luciferase reporter gene, and 5' UTR gene, sequentially arranged in reverse under the control of the cytomegalovirus promoter in the pcDNA3.1 vector. Co-transfection with SARS-CoV-2 RdRp resulted an increase in luminescence-based quantification of RdRp activity, achieving a Z-factor of 0.605, indicative of high reproducibility and reliability for high-throughput screening. Established RdRp inhibitors, including remdesivir, molnupiravir, tenofovir, and sofosbuvir, significantly reduced reporter activity, with remdesivir exhibiting the strongest inhibition. A newly identified RdRp inhibitor was further validated through primer extension polymerase and NMPylation assays, along with virus-based experiments, confirming its inhibitory mechanism. These results highlight the utility of this screening system in identifying effective RdRp-targeting antivirals, reinforcing the strategic importance of RdRp inhibition in combating SARS-CoV-2 and emerging variants.

Cost-Effectiveness Analysis of Molnupiravir Versus Best Supportive Care for the Treatment of Outpatient COVID-19 in High-Risk Older Adults in Japan

OBJECTIVES

This analysis aimed to evaluate the cost effectiveness of molnupiravir versus best supportive care for the treatment of older adult patients (aged ≥ 65 years) in Japan with mild to moderate COVID-19 who are at risk of disease progression leading to hospitalization, predominantly using input data derived from the Omicron era of the SARS-CoV2 pandemic.

METHODS

A decision-analytic model was developed, comprising a decision-tree model for the acute COVID-19 phase (30 days), followed by a lifetime Markov model. Inputs used to parametrize the model were derived from a database study conducted in Japan and a published systematic literature review of real-world studies, and from ad-hoc literature searches and other research (for disease progression, cost, and utility estimates). This analysis modelled death averted due to COVID-19 hospitalization as an indirect effect of molnupiravir (through preventing hospitalization). Costs were expressed in 2022 Japanese yen (¥; JPY), from the perspective of payers (the base case) or society (in a scenario analysis). Costs and QALYs were discounted at 2% per year. Cost effectiveness of molnupiravir versus best supportive care was primarily compared to a willingness-to-pay (WTP) threshold of ¥5,000,000 per quality-adjusted life year (QALY) gained.

RESULTS

Treatment with molnupiravir is associated with a QALY gain of 0.018 and an incremental cost of ¥81,472 over best supportive care and is cost effective (with an incremental cost-effectiveness ratio [ICER] of ¥4,638,477) versus best supportive care based on the predefined WTP threshold of ¥5,000,000 per QALY gained. Molnupiravir leads to a reduction in the proportion of patients who die due to COVID-19 hospitalization (0.09% with molnupiravir vs 0.29% with best supportive care). Molnupiravir is also associated with lower costs associated with COVID-19 hospitalizations compared with best supportive care (¥22,527 vs ¥27,472). In a deterministic sensitivity analysis, the top five most sensitive parameters were baseline hospitalization rate, mortality benefit of molnupiravir, mortality rate in general ward, discount rate, and mortality rate in intensive care unit. In a probabilistic sensitivity analysis, at the predefined WTP threshold of ¥5,000,000 per QALY gained, molnupiravir had an 80% probability of being cost effective versus best supportive care.

CONCLUSIONS

Molnupiravir is a cost-effective treatment option for the treatment of older adult outpatients (age ≥ 65 years) with symptomatic COVID-19 in Japan, relative to best supportive care.

Genetic Predictors of Paxlovid Treatment Response: The Role of IFNAR2, OAS1, OAS3, and ACE2 in COVID-19 Clinical Course

Background: This study investigated the role of genetic polymorphisms in IFNAR2, OAS1, OAS3, and ACE2 as predictors of Paxlovid treatment response, specifically examining their influence on the clinical course and laboratory parameters of COVID-19 patients. Methods: We analyzed the impact of polymorphisms in genes associated with the interferon pathway (IFNAR2 rs2236757), antiviral response (OAS1 rs10774671, OAS3 rs10735079), and viral entry (ACE2 rs2074192) in individuals treated with Paxlovid. Results: Our findings suggest that genetic variations in these genes may modulate the immune response and coagulation pathways in the context of Paxlovid treatment during COVID-19 infection. Specifically, the IFNAR2 rs2236757 G allele was associated with alterations in inflammatory and coagulation markers, while polymorphisms in OAS1 and OAS3 influenced coagulation parameters. Furthermore, specific genotypes were linked to changes in clinical parameters such as oxygen saturation, leukocyte count, and liver function markers in Paxlovid-treated patients. Conclusions: These results highlight the potential of considering genetic factors in understanding individual responses to COVID-19 treatment with Paxlovid and informing future personalized approaches.

Selected Acute Safety Events Following the Use of Nirmatrelvir/Ritonavir or Molnupiravir for COVID-19: A Nationwide Cohort Study in South Korea

There had been concerns about the acute complications during or shortly after coronavirus disease 2019 (COVID-19) treatment with nirmatrelvir/ritonavir (NMVr) and molnupiravir (MOL). This study aimed to compare the risks of selected acute safety events in patients treated with or without NMVr or MOL using the COVID-19 oral treatment safety assessment data, constructed through the linkage of nationwide databases: National COVID-19 registry, Real-time Prescription Surveillance, and National Health Insurance data. We identified all adults diagnosed with COVID-19 between January and November 2022, and then constructed two cohorts by matching up to four patients without antiviral treatment records to NMVr or MOL users using propensity score matching. Outcomes of interest were incident-selected cardiac (i.e., atrial fibrillation, other arrhythmia, bradycardia), neurological (i.e., seizure, neuropathy, encephalomyelitis), and miscellaneous (i.e., acute pancreatitis, acute liver injury, dysgeusia) events. A total of 739,935 NMVr users were matched with 2,951,690 comparators and 150,431 MOL users with 759,521 comparators. NMVr users were at lower risk for developing selected cardiac events (hazard ratio 0.74 [95% CI 0.65-0.87] for atrial fibrillation, 0.81 [0.65-0.99] for other arrhythmia, and 0.82 [0.70-0.96] for bradycardia) and dysgeusia (0.58 [0.45-0.74]). For MOL users, the risk was lower for atrial fibrillation (0.72 [0.53-0.96]) and dysgeusia (0.34 [0.18-0.65]). Overall, there were no increased risks of acute complications during and shortly after treatment with oral COVID-19 antivirals. Rather, the findings underscore their effectiveness in attenuating the risk of potential acute sequelae of COVID-19.

Mass spectrometry-based metabolomics reveals metabolism of molnupiravir may lead to metabolic disorders and hepatotoxicity

Molnupiravir (MO) is a pyrimidine nucleoside anti-SARS-CoV-2 drug. MO treatment could cause mild liver injury. However, the underlying mechanism of MO-induced liver injury and the metabolic pathway of MO in vivo are unclear. In this study, metabolomics analysis and molecular biology methods were used to explore these issues. Through metabolomics analysis, it was found that the homeostasis of pyrimidine, purine, lysophosphatidylcholine (LPC), and amino acids in mice was destroyed after MO treatment. A total of 80 changed metabolites were detected. Among these changed metabolites, 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 was related to the elevation of alkaline phosphatase (ALP), interleukin-6 (IL6), and nuclear factor kappa-B (NF-κB). The levels of 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 in plasma were positively correlated with their levels in the liver, suggesting that these metabolites were associated with MO-induced liver injury. MO treatment could increase NHC and cytidine levels, activate cytidine deaminase (CDA), and increase LPC levels. CDA and LPC could increase the mRNA expression level of toll-like receptor (TLR). The current study indicated that the elevation of hepatic TLR may be an important reason for MO leading to the liver injury.

Adverse drug events associated with linezolid administration: a real-world pharmacovigilance study from 2004 to 2023 using the FAERS database

Introduction: Linezolid is an oxazolidinone antibiotic that is active against drug-resistant Gram-positive bacteria and multidrug-resistant Mycobacterium tuberculosis. Real-world studies on the safety of linezolid in large populations are lacking. This study aimed to determine the adverse events associated with linezolid in real-world settings by analyzing data from the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Methods: We retrospectively extracted reports on adverse drug events (ADEs) from the FAERS database from the first quarter of 2004 to that of 2023. By using disproportionality analysis including reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), along with the multi-item gamma Poisson shrinker (MGPS), we evaluated whether there was a significant association between linezolid and ADE. The time to onset of ADE was further analyzed in the general population and within each age, weight, reporting population, and weight subgroups. Results: A total of 11,176 reports of linezolid as the "primary suspected" drug and 263 significant adverse events of linezolid were identified, including some common adverse events such as thrombocytopenia (n = 1,139, ROR 21.98), anaemia (n = 704, ROR 7.39), and unexpected signals that were not listed on the drug label such as rhabdomyolysis (n = 90, ROR 4.33), and electrocardiogram QT prolonged (n = 73, ROR 4.07). Linezolid-induced adverse reactions involved 27 System Organ Class (SOC). Gender differences existed in ADE signals related to linezolid. The median onset time of all ADEs was 6 days, and most ADEs (n = 3,778) occurred within the first month of linezolid use but some may continue to occur even after a year of treatment (n = 46). Conclusion: This study reports the time to onset of adverse effects in detail at the levels of SOC and specific preferred term (PT). The results of our study provide valuable insights for optimizing the use of linezolid and reducing potential side effects, expected to facilitate the safe use of linezolid in clinical settings.