Occurrence and environmental fate of anti-influenza drugs in a subcatchment of the Yodo River Basin, Japan.

Understanding the current situation and risk of environmental contamination by anti-influenza drugs in aquatic environments is key to prevent the unexpected emergence and spread of drug-resistant viruses. However, few reports have been focused on newer drugs that have recently been introduced in clinical settings. In this study, the behaviour of the prodrug baloxavir marboxil (BALM)-the active ingredient of Xofluza, an increasingly popular anti-influenza drug-and its pharmacologically active metabolite baloxavir (BAL) in the aquatic environment was evaluated. Additionally, their presence in urban rivers and a wastewater treatment plant (WWTP) in the Yodo River basin was investigated and compared with those of the major anti-influenza drugs used to date (favipiravir (FAV), peramivir (PER), laninamivir (LAN), and its active metabolite, laninamivir octanoate (LANO), oseltamivir (OSE), and its active metabolite, oseltamivir carboxylate (OSEC), and zanamivir (ZAN)) to comprehensively assess their environmental fate in the aquatic environment. The results clearly showed that BALM, FAV, and BAL were rapidly degraded through photolysis (2-h, 0.6-h, and 0.4-h half-lives, respectively), followed by LAN, which was gradually biodegraded (7-h half-life). In addition, BALM and BAL decreased by up to 47 % after 4 days and 34 % after 2 days of biodegradation in river water. However, the remaining conventional drugs, except for LANO (<1 % after 10 days), were persistent, being transported from the upstream to downstream sites. The LogKd values for the rates of sorption of BALM (0.5-1.6) and BAL (1.8-3.1) on river sediment were higher than those of conventional drugs (-0.5 to 1.7). Notably, all anti-influenza drugs were effectively removed by ozonation (>90-99.9 % removal) after biological treatment at a WWTP. Thus, these findings suggest the importance of introducing ozonation to reduce pollution loads in rivers and the environmental risks associated with drug-resistant viruses in aquatic environments, thereby promoting safe river environments.

Antivirals for monkeypox virus: Proposing an effective machine/deep learning framework.

Monkeypox (MPXV) is one of the infectious viruses which caused morbidity and mortality problems in these years. Despite its danger to public health, there is no approved drug to stand and handle MPXV. On the other hand, drug repurposing is a promising screening method for the low-cost introduction of approved drugs for emerging diseases and viruses which utilizes computational methods. Therefore, drug repurposing is a promising approach to suggesting approved drugs for the MPXV. This paper proposes a computational framework for MPXV antiviral prediction. To do this, we have generated a new virus-antiviral dataset. Moreover, we applied several machine learning and one deep learning method for virus-antiviral prediction. The suggested drugs by the learning methods have been investigated using docking studies. The target protein structure is modeled using homology modeling and, then, refined and validated. To the best of our knowledge, this work is the first work to study deep learning methods for the prediction of MPXV antivirals. The screening results confirm that Tilorone, Valacyclovir, Ribavirin, Favipiravir, and Baloxavir marboxil are effective drugs for MPXV treatment.

Synergistic activity of an RNA polymerase PA-PB1 interaction inhibitor with oseltamivir against human and avian influenza viruses in cell culture and in ovo.

In search of novel therapeutic options to treat influenza virus (IV) infections, we previously identified a series of inhibitors that act by disrupting the interactions between the PA and PB1 subunits of the viral RNA polymerase. These compounds showed broad-spectrum antiviral activity against human influenza A and B viruses and a high barrier to the induction of drug resistance in vitro. In this short communication, we investigated the effects of combinations of the PA-PB1 interaction inhibitor 54 with oseltamivir carboxylate (OSC), zanamivir (ZA), favipiravir (FPV), and baloxavir marboxil (BXM) on the inhibition of influenza A and B virus replication in vitro. We observed a synergistic effect of the 54/OSC and 54/ZA combinations and an antagonistic effect when 54 was combined with either FPV or BXM. Moreover, we demonstrated the efficacy of 54 against highly pathogenic avian influenza viruses (HPAIVs) both in cell culture and in the embryonated chicken eggs model. Finally, we observed that 54 enhances OSC protective effect against HPAIV replication in the embryonated eggs model. Our findings represent an advance in the development of alternative therapeutic strategies against both human and avian IV infections.

Comparison of the Effectiveness of Baloxavir and Oseltamivir in Outpatients With Influenza B.

This retrospective cohort study analyzed data from a Japanese health insurance database to assess the effectiveness of baloxavir (n = 4822) for preventing severe events compared with oseltamivir (n = 10,523) in patients with influenza B. The primary endpoint was hospitalization incidence (Days 2-14). The secondary endpoints included intravenous antibacterial drug use, pneumonia hospitalization, heart failure hospitalization, inhalational oxygen requirement, and use of other anti-influenza drugs. The hospitalization incidence was significantly lower with baloxavir (0.15% vs. 0.37%; risk ratio: 2.48, 95% confidence interval: 1.13-5.43). Pneumonia and additional anti-influenza therapy were also less frequent with baloxavir, thus supporting its use. Trial Registration: UMIN Clinical Trials Registry Study ID: UMIN000051382.

Evaluating the Public Health and Health Economic Impacts of Baloxavir Marboxil and Oseltamivir for Influenza Pandemic Control in China: A Cost-Effectiveness Analysis Using a Linked Dynamic Transmission-Economic Evaluation Model.

BACKGROUND: Pandemic influenza poses a recurring threat to public health. Antiviral drugs are vital in combating influenza pandemics. Baloxavir marboxil (BXM) is a novel agent that provides clinical and public health benefits in influenza treatment. METHODS: We constructed a linked dynamic transmission-economic evaluation model combining a modified susceptible-exposed-infected-recovered (SEIR) model and a decision tree model to evaluate the cost-effectiveness of adding BXM to oseltamivir in China's influenza pandemic scenario. The cost-effectiveness was evaluated for the general population from the Chinese healthcare system perspective, although the users of BXM and oseltamivir were influenza-infected persons. The SEIR model simulated the transmission dynamics, dividing the population into four compartments: susceptible, exposed, infected, and recovered, while the decision tree model assessed disease severity and costs. We utilized data from clinical trials and observational studies in the literature to parameterize the models. Costs were based on 2021 CN¥ and not discounted due to a short time-frame of one year in the model. One-way, two-way, and probabilistic sensitivity analyses were also conducted. RESULTS: The integrated model demonstrated that adding BXM to treatment choices reduced the cumulative incidence of infection from 49.49% to 43.26% and increased quality-adjusted life years (QALYs) by 0.00021 per person compared with oseltamivir alone in the base-case scenario. The intervention also amounted to a positive net monetary benefit of CN¥77.85 per person at the willingness to pay of CN¥80,976 per QALY. Sensitivity analysis confirmed the robustness of these findings, with consistent results across varied key parameters and assumptions. CONCLUSIONS: Adding BXM to treatment choices instead of only treating with oseltamivir for influenza pandemic control in China appears to be cost-effective compared with oseltamivir alone. The dual-agent strategy not only enhances population health outcomes and conserves resources, but also mitigates influenza transmission and alleviates healthcare burden.

Detection of influenza A(H3N2) viruses with polymerase acidic subunit substitutions after and prior to baloxavir marboxil treatment during the 2022-2023 influenza season in Japan.

Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n = 234), with a minor circulation of A(H1N1)pdm09 (n = 10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23 K/G, or I38 M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6-100 %), a polymorphism and a mixture of PA/E23 K/G, and I38 M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 h and a median symptom duration of 93.7 h, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza.

Genotypic and phenotypic susceptibility of emerging avian influenza A viruses to neuraminidase and cap-dependent endonuclease inhibitors.

Avian influenza outbreaks, including ones caused by highly pathogenic A(H5N1) clade 2.3.4.4b viruses, have devastated animal populations and remain a threat to humans. Risk elements assessed for emerging influenza viruses include their susceptibility to approved antivirals. Here, we screened >20,000 neuraminidase (NA) or polymerase acidic (PA) protein sequences of potentially pandemic A(H5Nx), A(H7Nx), and A(H9N2) viruses that circulated globally in 2010-2023. The frequencies of NA or PA substitutions associated with reduced inhibition (RI) or highly reduced inhibition (HRI) by NA inhibitors (NAIs) (oseltamivir, zanamivir) or a cap-dependent endonuclease inhibitor (baloxavir) were low: 0.60% (137/22,713) and 0.62% (126/20,347), respectively. All tested subtypes were susceptible to NAIs and baloxavir at sub-nanomolar concentrations. A(H9N2) viruses were the most susceptible to oseltamivir, with IC50s 3- to 4-fold lower than for other subtypes (median IC50: 0.18 nM; n = 22). NA-I222M conferred RI of A(H5N1) viruses by oseltamivir (with a 26-fold IC50 increase), but NA-S246N did not reduce inhibition. PA-E23G, PA-K34R, PA-I38M/T, and the previously unreported PA-A36T caused RI by baloxavir in all subtypes tested. Avian A(H9N2) viruses endemic in Egyptian poultry predominantly acquired PA-I38V, which causes only a <3-fold decrease in the baloxavir EC50 and fails to meet the RI criteria. PA-E199A/D in A(H7Nx) and A(H9N2) viruses caused a 2- to 4-fold decrease in EC50 (close to the borderline for RI) and should be closely monitored. Our data indicate antiviral susceptibility is high among avian influenza A viruses with pandemic potential and present novel markers of resistance to existing antiviral interventions.

High throughput profiling identified PA-L106R amino acid substitution in A(H1N1)pdm09 influenza virus that confers reduced susceptibility to baloxavir in vitro.

Baloxavir acid (BXA) is a pan-influenza antiviral that targets the cap-dependent endonuclease of the polymerase acidic (PA) protein required for viral mRNA synthesis. To gain a comprehensive understanding on the molecular changes associated with reduced susceptibility to BXA and their fitness profile, we performed a deep mutational scanning at the PA endonuclease domain of an A (H1N1)pdm09 virus. The recombinant virus libraries were serially passaged in vitro under increasing concentrations of BXA followed by next-generation sequencing to monitor PA amino acid substitutions with increased detection frequencies. Enriched PA amino acid changes were each introduced into a recombinant A (H1N1)pdm09 virus to validate their effect on BXA susceptibility and viral replication fitness in vitro. The I38 T/M substitutions known to confer reduced susceptibility to BXA were invariably detected from recombinant virus libraries within 5 serial passages. In addition, we identified a novel L106R substitution that emerged in the third passage and conferred greater than 10-fold reduced susceptibility to BXA. PA-L106 is highly conserved among seasonal influenza A and B viruses. Compared to the wild-type virus, the L106R substitution resulted in reduced polymerase activity and a minor reduction of the peak viral load, suggesting the amino acid change may result in moderate fitness loss. Our results support the use of deep mutational scanning as a practical tool to elucidate genotype-phenotype relationships, including mapping amino acid substitutions with reduced susceptibility to antivirals.

Simultaneous quantification of baloxavir marboxil and its active metabolite in human plasma using UHPLC-MS/MS: Application to a human pharmacokinetic study with different anticoagulants.

Baloxavir marboxil (BXM) is a cap-dependent nucleic acid endonuclease inhibitor, which exerts its antiviral effects after being metabolized to its active form baloxavir acid (BXA). Ethylenediamine tetra-acetic acid (EDTA) and heparin are the two most used anticoagulants in clinical blood sample collection to estimate drug levels in plasma. However, compared to heparin plasma, there is a lack of clinical pharmacokinetic data of BXA using EDTA anticoagulant tubes for blood collection. In the present study, an efficient, rapid, and sensitive ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous quantification of BXM and its active metabolite BXA in human plasma with its isotopic baloxavir-d5 (BXA-d5) as internal standard (IS). Plasma samples (50 µL) were undergone using acetonitrile containing 0.1 % formic acid a precipitant. Chromatographic separation was achieved by a Waters XBridge®C8 (2.1 mm × 50 mm, 2.5 µm) column. The gradient mobile phase was 0.1 % formic acid in water (A, pH 2.8) and 0.1 % formic acid in acetonitrile (B) and delivered at a flow rate of 0.6 mL/min for 4.5 min. BXM and BXA were monitored using a positive electrospray triple quadrupole mass spectrometer (TRIPLE QUAD™ 6500+) via multiple reaction monitoring mode. The mass-to-charge ratios (m/z) were 572.2→247.0, 484.2→247.0 and 489.2→252.0 for BXM, BXA, and BXA-d5 (IS). Calibration curves exhibited excellent linearity in the range of 0.1-10 ng/mL for BXM (r2 > 0.996), and 0.3-300 ng/mL for BXA (r2 > 0.998). Within-run and between-run precisions in coefficients of variations were less than 11.62 % for BXM and less than 7.47 % for BXA, and accuracies in relative error were determined to be within -7.78 % to 5.70 % for BXM and -6.67 % to 8.56 % for BXA. Extraction recovery efficiency was 92.76 % for BXM, 95.32 % for BXA, and 99.26 % for BXA-d5, respectively. The matrix effect of BXM and BXA was in line with the requirements, where the relative deviation of the accuracy was less than 6.67 % and the precision was less than 6.69 %. The validated efficient and simple UHPLC-MS/MS method was successfully used in the pharmacokinetic study of BXM and BXA in healthy human volunteers with K2EDTA and heparin tubes for blood collection. EDTA might compete with BXA for chelating metal ions and thereby decrease the plasma ratio in whole blood, leading to approximately 50 % lower measurement of pharmacokinetic parameters as compared with those obtained from heparin plasma anticoagulant tubes.

Stereoselective Synthesis of Baloxavir Marboxil Using Diastereoselective Cyclization and Photoredox Decarboxylation of l-Serine.

Baloxavir marboxil (1; BXM) is a potent drug used for treating influenza infections. The current synthetic route to BXM (1) is based on optical resolution; however, this method results in the loss of nearly 50% of the material. This study aimed to describe an efficient and simpler method for the synthesis of BXM. We achieved a stereoselective synthesis of BXM (1). The tricyclic triazinanone core possessing a chiral center was prepared via diastereoselective cyclization utilizing the readily available amino acid l-serine. The carboxyl moiety derived from l-serine was removed via photoredox decarboxylation under mild conditions to furnish the chiral tricyclic triazinanone core ((R)-14). The synthetic route demonstrated herein provides an efficient and atomically economical method for preparing this potent anti-influenza agent.

Zanamivir and baloxavir combination to cure persistent influenza and coronavirus infections after hematopoietic stem cell transplant.

OBJECTIVES: Immunocompromised patients may experience prolonged shedding of influenza virus potentially leading to severe infections. Alternatives to monotherapy with neuraminidase inhibitors should be evaluated to entirely suppress viral replication and prevent drug-resistant mutations. METHODS: We investigated the clinical and virological evolution in a case of persistent influenza A and human coronavirus OC43 (HCoV-OC43) coinfection in a hematopoietic stem cell transplant recipient after different therapeutic strategies. RESULTS: Successive oseltamivir and zanamivir monotherapies failed to control both infections, with positive results persisting for over 110 days each. This led to the emergence of highly resistant oseltamivir strains due to neuraminidase mutations (E119V and R292K) followed by a deletion (del245-248), while maintaining sensitivity to zanamivir. The intra-host viral diversity data showed that the treatments impacted viral diversity of influenza virus, but not of HCoV-OC43. Considering the patient's underlying condition and the impact of prolonged viral shedding on pulmonary function, eradicating the influenza virus was necessary. A 10-day regimen combining zanamivir and baloxavir-marboxil effectively controlled influenza virus replication and was associated with the clearance of HCoV-OC43, finally resulting in comprehensive respiratory recovery. CONCLUSION: These observations underscore the importance of further investigating combination treatments as the primary approach to achieve influenza eradication in immunocompromised patients.

A cost-effectiveness analysis of reduced viral transmission with baloxavir marboxil versus oseltamivir or no treatment for seasonal and pandemic influenza management in the United Kingdom.

BACKGROUND: Baloxavir marboxil is an oral, single-dose, cap-dependent endonuclease inhibitor that reduces the duration of influenza symptoms and rapidly stops viral shedding. We developed a susceptible, exposed, infected, recovered (SEIR) model to inform a cost-effectiveness model (CEM) of baloxavir versus oseltamivir or no antiviral treatment in the UK. RESEARCH DESIGN AND METHODS: The SEIR model estimated the attack rates among otherwise healthy and high-risk individuals in seasonal and pandemic settings. The CEM assumed that a proportion of infected patients would receive antiviral treatment. Results were reported at the population level (per 10,000 at risk of infection). RESULTS: The SEIR model estimated greater reductions in infections with baloxavir. In a seasonal setting, baloxavir provided incremental cost-effectiveness ratios (ICERs) of £1884 per quality-adjusted life-year (QALY) gained versus oseltamivir and a dominant cost-effectiveness position versus no antiviral treatment in the total population; ICERs of £2574/QALY versus oseltamivir and £128/QALY versus no antiviral treatment were seen in the high-risk population. Baloxavir was also cost-effective versus oseltamivir or no antiviral treatment and reduced population-level health system occupancy concerns during a pandemic. CONCLUSION: Baloxavir treatment resulted in the fewest influenza cases and was cost-effective versus oseltamivir or no antiviral treatment from a UK National Health Service perspective.

Baloxavir marboxil ('baloxavir') is a prescription medicine for people who become ill with influenza (or 'the flu') that can reduce how long flu symptoms last and the likelihood of complications from the flu that may require going to the hospital. Baloxavir can also reduce the amount and duration of virus shed by infected individuals thus potentially slow or stop the flu from spreading to healthy people. We studied differences in reducing predicted flu infections between baloxavir and another flu treatment, known as oseltamivir, or no flu treatment at all. Treatment with baloxavir resulted in fewer flu infections in the UK population than oseltamivir or no treatment. We then studied how these differences might affect costs between baloxavir and oseltamivir or no treatment at a population level in the UK. Overall, in the majority of scenarios explored in the model, baloxavir was cost-effective as an antiviral treatment for people with the flu in the UK.

Duration of fever in children infected with influenza A(H1N1)pdm09, A(H3N2) or B virus and treated with baloxavir marboxil, oseltamivir, laninamivir, or zanamivir in Japan during the 2012-2013 and 2019-2020 influenza seasons.

We compared the duration of fever in children infected with A(H1N1)pdm09, A(H3N2), or influenza B viruses following treatment with baloxavir marboxil (baloxavir) or neuraminidase inhibitors (NAIs) (oseltamivir, zanamivir, or laninamivir). This observational study was conducted at 10 outpatient clinics across 9 prefectures in Japan during the 2012-2013 and 2019-2020 influenza seasons. Patients with influenza rapid antigen test positive were treated with one of four anti-influenza drugs. The type/subtype of influenza viruses were identified from MDCK or MDCK SIAT1 cell-grown samples using two-step real-time PCR. Daily self-reported body temperature after treatment were used to evaluate the duration of fever by treatment group and various underlying factors. Among 1742 patients <19 years old analyzed, 452 (26.0%) were A(H1N1)pdm09, 827 (48.0%) A(H3N2), and 463 (26.0%) influenza B virus infections. Among fours treatment groups, baloxavir showed a shorter median duration of fever compared to oseltamivir in univariate analysis for A(H1N1)pdm09 virus infections (baloxavir, 22.0 h versus oseltamivir, 26.7 h, P < 0.05; laninamivir, 25.5 h, and zanamivir, 25.0 h). However, this difference was not significant in multivariable analyses. For A(H3N2) virus infections, there were no statistically significant differences observed (20.3, 21.0, 22.0, and 19.0 h) uni- and multivariable analyses. For influenza B, baloxavir shortened the fever duration by approximately 15 h than NAIs (20.3, 35.0, 34.3, and 34.1 h), as supported by uni- and multivariable analyses. Baloxavir seems to have comparable clinical effectiveness with NAIs on influenza A but can be more effective for treating pediatric influenza B virus infections than NAIs.

FOUR-WEEK ORAL ADMINISTRATION OF BALOXAVIR MARBOXIL AS AN ANTI-INFLUENZA VIRUS DRUG SHOWS NO TOXICITY IN CHICKENS.

High pathogenicity avian influenza is an acute zoonotic disease with high mortality in birds caused by a high pathogenicity avian influenza virus (HPAIV). Recently, HPAIV has rapidly spread worldwide and has killed many wild birds, including endangered species. Baloxavir marboxil (BXM), an anti-influenza agent used for humans, was reported to reduce mortality and virus secretion from HPAIV-infected chickens (Gallus domesticus, order Galliformes) at a dosage of ≥2.5 mg/kg when administered simultaneously with viral challenge. Application of this treatment to endangered birds requires further information on potential avian-specific toxicity caused by repeated exposure to BXM over the long term. To obtain information of potential avian-specific toxicity, a 4-wk oral repeated-dose study of BXM was conducted in chickens (n = 6 or 7 per group), which are commonly used as laboratory avian species. The study was conducted in reference to the human pharmaceutical guidelines for nonclinical repeated-dose drug toxicity studies to evaluate systemic toxicity and exposure. No adverse changes were observed in any organs examined, and dose proportional increases in systemic exposure to active pharmaceutical ingredients were noted from 12.5 to 62.5 mg/kg per day. BXM showed no toxicity to chickens at doses of up to 62.5 mg/kg per day, at which systemic exposure was approximately 71 times higher than systemic exposure at 2.5 mg/kg, the reported efficacious dosage amount, in HPAIV-infected chickens. These results also suggest that BXM could be considered safe for treating HPAIV-infected endangered birds due to its high safety margin compared with the efficacy dose. The data in this study could contribute to the preservation of endangered birds by using BXM as a means of protecting biodiversity.

Monitoring Influenza C and D Viruses in Patients With Respiratory Diseases in Japan, January 2018 to March 2023.

BACKGROUND: Influenza viruses can cause zoonotic infections that pose public health risks. Surveillance of influenza A and B viruses is conducted globally; however, information on influenza C and D viruses is limited. Longitudinal monitoring of influenza C virus in humans has been conducted in several countries, but there has been no long-term monitoring of influenza D virus in humans. The public health risks associated with the influenza D virus therefore remain unknown. METHODS: We established a duplex real-time RT-PCR to detect influenza C and D viruses and analyzed respiratory specimens collected from 2144 patients in Japan with respiratory diseases between January 2018 and March 2023. We isolated viruses and conducted hemagglutination inhibition tests to examine antigenicity and focus reduction assays to determine susceptibility to the cap-dependent endonuclease inhibitor baloxavir marboxil. RESULTS: We detected three influenza C viruses belonging to the C/Kanagawa- or C/Sao Paulo-lineages, which recently circulated globally. None of the specimens was positive for the influenza D virus. The C/Yokohama/1/2022 strain, isolated from the specimen with the highest viral RNA load and belonging to the C/Kanagawa-lineage, showed similar antigenicity to the reference C/Kanagawa-lineage strain and was susceptible to baloxavir. CONCLUSIONS: Our duplex real-time RT-PCR is useful for the simultaneous detection of influenza C and D viruses from the same specimen. Adding the influenza D virus to the monitoring of the influenza C virus would help in assessing the public health risks posed by this virus.

Safety analysis of Oseltamivir and Baloxavir Marboxil after market approval: a pharmacovigilance study based on the FDA adverse event reporting system.

BACKGROUND AND OBJECTIVES: Amidst limited influenza treatment options, evaluating the safety of Oseltamivir and Baloxavir Marboxil is crucial, particularly given their comparable efficacy. This study investigates post-market safety profiles, exploring adverse events (AEs) and their drug associations to provide essential clinical references. METHODS: A meticulous analysis of FDA Adverse Event Reporting System (FAERS) data spanning the first quarter of 2004 to the fourth quarter of 2022 was conducted. Using data mining techniques like reporting odds ratio (ROR), proportional reporting ratio, Bayesian Confidence Propagation Neural Network, and Multiple Gamma Poisson Shrinkage, AEs related to Oseltamivir and Baloxavir Marboxil were examined. Venn analysis compared and selected specific AEs associated with each drug. RESULTS: Incorporating 15,104 Oseltamivir cases and 1,594 Baloxavir Marboxil cases, Wain analysis unveiled 21 common AEs across neurological, psychiatric, gastrointestinal, dermatological, respiratory, and infectious domains. Oseltamivir exhibited 221 significantly specific AEs, including appendicolith [ROR (95% CI), 459.53 (340.88 ∼ 619.47)], acne infantile [ROR (95% CI, 368.65 (118.89 ∼ 1143.09)], acute macular neuroretinopathy [ROR (95% CI), 294.92 (97.88 ∼ 888.64)], proctitis [ROR (95% CI), 245.74 (101.47 ∼ 595.31)], and Purpura senile [ROR (95% CI), 154.02 (81.96 ∼ 289.43)]. designated adverse events (DMEs) associated with Oseltamivir included fulminant hepatitis [ROR (95% CI), 12.12 (8.30-17.72), n=27], ventricular fibrillation [ROR (95% CI), 7.68 (6.01-9.83), n=64], toxic epidermal necrolysis [ROR (95% CI), 7.21 (5.74-9.05), n=75]. Baloxavir Marboxil exhibited 34 specific AEs, including Melaena [ROR (95% CI), 21.34 (14.15-32.18), n = 23], cystitis haemorrhagic [ROR (95% CI), 20.22 (7.57-54.00), n = 4], ileus paralytic [ROR (95% CI), 18.57 (5.98-57.71), n = 3], and haemorrhagic diathesis [ROR (95% CI), 16.86 (5.43-52.40)), n = 3]. DMEs associated with Baloxavir Marboxil included rhabdomyolysis [ROR (95% CI), 15.50 (10.53 ∼ 22.80), n = 26]. CONCLUSION: Monitoring fulminant hepatitis during Oseltamivir treatment, especially in patients with liver-related diseases, is crucial. Oseltamivir's potential to induce abnormal behavior, especially in adolescents, necessitates special attention. Baloxavir Marboxil, with lower hepatic toxicity, emerges as a potential alternative for patients with liver diseases. During Baloxavir Marboxil treatment, focused attention on the occurrence of rhabdomyolysis is advised, necessitating timely monitoring of relevant indicators for those with clinical manifestations. The comprehensive data aims to provide valuable insights for clinicians and healthcare practitioners, facilitating an understanding of the safety profiles of these influenza treatments in real-world scenarios.

Comparative Effectiveness of Baloxavir Marboxil and Oseltamivir Treatment in Reducing Household Transmission of Influenza: A Post Hoc Analysis of the BLOCKSTONE Trial.

BACKGROUND: The transmission of influenza virus in households, especially by children, is a major route of infection. Prior studies suggest that timely antiviral treatment of ill cases may reduce infection in household contacts. The aim of the study was to compare the effects of oseltamivir (OTV) and baloxavir marboxil (BXM) treatment of index cases on the secondary attack rate (SAR) of influenza within household. METHODS: A post hoc analysis was done in BLOCKSTONE trial-a placebo-controlled, double-blinded post-exposure prophylaxis of BXM. Data were derived from the laboratory-confirmed index cases' household contacts who received placebo in the trial and also from household members who did not participate in the trial but completed illness questionnaires. To assess the SAR of household members, multivariate analyses adjusted for factors including age, vaccination status, and household size were performed and compared between contacts of index cases treated with BXM or OTV. RESULTS: In total, 185 index cases (116 treated with BXM and 69 treated with OTV) and 410 household contacts (201 from trial, 209 by questionnaire) were included. The Poisson regression modeling showed that the SAR in household contacts of index cases treated with BXM and OTV was 10.8% and 18.5%, respectively; the adjusted relative reduction in SAR was 41.8% (95% confidence interval: 1.0%-65.7%, p = 0.0456) greater with BXM than OTV. Similar reductions were found in contacts from the trial and those included by questionnaire. CONCLUSION: BXM treatment of index cases appeared to result in a greater reduction in secondary household transmission than OTV treatment.

Discovery of baloxavir sodium as a novel anti-CCHFV inhibitor: Biological evaluation of in vitro and in vivo.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic bunyavirus with a fatality rate of up to 40%. Currently, there are no licensed antiviral drugs for the treatment of CCHF; thus, the World Health Organization (WHO) listed the disease as a priority. A unique viral transcription initiation mechanism called "cap-snatching" is shared by influenza viruses and bunyaviruses. Thus, we tested whether baloxavir (an FDA-approved anti-influenza drug that targets the "cap-snatching" mechanism) could inhibit CCHFV infection. In cell culture, baloxavir acid effectively inhibited CCHFV infection and targeted CCHFV RNA transcription/replication. However, it has weak oral bioavailability. Baloxavir marboxil (the oral prodrug of baloxavir) failed to protect mice against a lethal dose challenge of CCHFV. To solve this problem, baloxavir sodium was synthesized owing to its enhanced aqueous solubility and pharmacokinetic properties. It consistently and significantly improved survival rates and decreased tissue viral loads. This study identified baloxavir sodium as a novel scaffold structure and mechanism of anti-CCHF compound, providing a promising new strategy for clinical treatment of CCHF after further optimization.

Biophysical and structural study of La Crosse virus endonuclease inhibition for the development of new antiviral options.

The large Bunyavirales order includes several families of viruses with a segmented ambisense (-) RNA genome and a cytoplasmic life cycle that starts by synthesizing viral mRNA. The initiation of transcription, which is common to all members, relies on an endonuclease activity that is responsible for cap-snatching. In La Crosse virus, an orthobunyavirus, it has previously been shown that the cap-snatching endonuclease resides in the N-terminal domain of the L protein. Orthobunyaviruses are transmitted by arthropods and cause diseases in cattle. However, California encephalitis virus, La Crosse virus and Jamestown Canyon virus are North American species that can cause encephalitis in humans. No vaccines or antiviral drugs are available. In this study, three known Influenza virus endonuclease inhibitors (DPBA, L-742,001 and baloxavir) were repurposed on the La Crosse virus endonuclease. Their inhibition was evaluated by fluorescence resonance energy transfer and their mode of binding was then assessed by differential scanning fluorimetry and microscale thermophoresis. Finally, two crystallographic structures were obtained in complex with L-742,001 and baloxavir, providing access to the structural determinants of inhibition and offering key information for the further development of Bunyavirales endonuclease inhibitors.

Interaction and antiviral treatment of coinfection between SARS-CoV-2 and influenza in vitro.

BACKGROUND: The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has lasted for three years. Coinfection with seasonal influenza may occur resulting in more severe diseases. The interaction between these two viruses for infection and the effect of antiviral treatment remains unclear. METHODS: A SARS-CoV-2 and influenza H1N1 coinfection model on Calu-3 cell line was established, upon which the simultaneous and sequential coinfection was evaluated by comparing the viral load. The efficacy of molnupiravir and baloxavir against individual virus and coinfection were also studied. RESULTS: The replication of SARS-CoV-2 was significantly interfered when the influenza virus was infected simultaneously or in advance (p < 0.05). On the contrary, the replication of the influenza virus was not affected by the SARS-CoV-2. Molnupiravir monotherapy had significant inhibitory effect on SARS-CoV-2 when the concentration reached to 6.25 µM but did not show any significant anti-influenza activity. Baloxavir was effective against influenza within the dosage range and showed significant effect of anti-SARS-CoV-2 at 16 µM. In the treatment of coinfection, molnupiravir had significant effect for SARS-CoV-2 from 6.25 µM to 100 µM and inhibited H1N1 at 100 µM (p < 0.05). The tested dosage range of baloxavir can inhibit H1N1 significantly (p < 0.05), while at the highest concentration of baloxavir did not further inhibit SARS-CoV-2, and the replication of SARS-CoV-2 significantly increased in lower concentrations. Combination treatment can effectively inhibit influenza H1N1 and SARS-CoV-2 replication during coinfection. Compared with molnupiravir or baloxavir monotherapy, combination therapy was more effective in less dosage to inhibit the replication of both viruses. CONCLUSIONS: In coinfection, the replication of SARS-CoV-2 would be interfered by influenza H1N1. Compared with molnupiravir or baloxavir monotherapy, treatment with a combination of molnupiravir and baloxavir should be considered for early treatment in patients with SARS-CoV-2 and influenza coinfection.