Baloxavir Research Articles

922. Cost-effectiveness of baloxavir marboxil versus oseltamivir or no treatment for the management of influenza in the United States

Abstract Background Influenza poses a significant burden that can be effectively mitigated with antivirals. Baloxavir marboxil is an oral, single dose first-in-class endonuclease inhibitor that improves influenza symptoms and rapidly reduces virus shedding, shortening the infectious period and potentially reducing viral transmission. This study used real-world data to inform a cost-effectiveness (CE) model of antiviral treatment with baloxavir vs oseltamivir or no treatment. Methods A decision tree CE model was developed for seasonal influenza between 2018 and 2020. Patients aged 12 and older could receive baloxavir, oseltamivir or no treatment (Figure 1). Outcomes included complications, recovery and death. Patient profile and characteristics, complications and costs were derived from the Merative™ MarketScan® Research Databases, including US commercial claims, Medicare and Medicaid Supplemental databases. Healthcare resource use included outpatient visits, hospitalizations and intensive care unit admissions. Clinical inputs, recovery rates and utilities were derived from the literature. The base case model used a lifetime time horizon with 3.0% discounting for costs and 2.7% for quality-adjusted life-years (QALYs), assuming no transmission reduction. A subgroup analysis was conducted for otherwise healthy (OwH) and high-risk groups; scenario analyses explored the impact of reduced viral transmission with baloxavir. Results In the base case analysis, baloxavir resulted in an incremental CE ratio (ICER) of $7788/QALY vs oseltamivir and $311/QALY vs no treatment; subgroup analyses showed even greater CE in the high-risk population (Table 1). Scenario analyses showed increasing net monetary benefit (NMB) with incremental reductions in viral transmission with baloxavir, where a 5% reduction in transmission yielded a NMB for baloxavir of $4153 vs oseltamivir and $13,098 vs no treatment (Figure 2). Conclusion This real-world evidence-driven model showed that baloxavir is cost-effective vs oseltamivir or no treatment from a US payer perspective. Transmission reductions with baloxavir can have a substantial health economic benefit, and baloxavir may play an important role in management of seasonal influenza and pandemic preparedness. Disclosures Svenn Hansen, n/a, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds Shih-Chen Cheng, M.S., P.h.D, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Andy Surinach, MPH, Genentech/Roche: employee of Genesis Research which receives funding from Genentech/Roche for consulting services Vince Yau, PhD, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Jennie H. Best, PhD, Genentech: Stocks/Bonds Hassan Zaraket, PhD, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds Hao Zhou, PhD, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Marie-Helene Blanchet Zumofen, PhD MBA, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds

Prospective observational study of baloxavir marboxil in adults and adolescents with uncomplicated influenza from China

IntroductionThere are limited data on the efficacy of baloxavir marboxil (baloxavir) versus oseltamivir in Chinese patients with influenza A.MethodsThis study is an observational real-world investigation encompassing 246 patients (baloxavir, n = 147; oseltamivir, n = 99) confirmed positive for influenza A. The choice between baloxavir and oseltamivir antiviral treatments was determined collaboratively by the clinician and the patient. A thorough comparative analysis was undertaken between the two groups, examining parameters such as the duration of fever and symptoms, viral load dynamics, lymphocyte changes, and enhancements in health-related quality of life (QoL).ResultsNo significant differences were observed in demographic data between the two groups. The duration of fever was significantly shorter in the baloxavir group (P < 0.001). However, the duration of symptoms was not significant different (P = 0.167). Multivariable Cox analysis showed the independent factors affecting duration of fever were baloxavir treatment (HR = 2.033, P < 0.001), fever on day 1 (HR = 0.741, P = 0.010) and CRP level (HR = 1.009, P = 0.039). Moreover, sex (HR= 0.660, P = 0.019) and monocyte count (HR = 1.355, P = 0.018) were independent factors affecting the duration of symptoms. No significant difference in change of health-related quality of life (P > 0.05), positive rate of viral antigen on day 3 (P = 0.477) between the two groups. Remarkably, a mutation was observed in one case on the third-day after baloxavir treatment compared with first-day, from cysteine to serine at position 384 of the PA subunit.ConclusionIn the clinical setting, baloxavir demonstrated comparable clinical benefits to oseltamivir, establishing its efficacy as an effective antiviral therapy for Chinese patients with influenza.

Prophylactic Treatment with Baloxavir Protects Mice from Lethal Infection with Influenza A and B Viruses.

Influenza remains a worldwide health concern. Antiviral drugs are considered as one of the useful options for its prevention as a complementary measure to vaccination. Baloxavir acid selectively inhibits the cap-dependent endonuclease of influenza viruses and exhibits marked viral titre reduction in patients. Here, we describe the prophylactic potency of baloxavir acid against lethal infection with influenza A and B viruses in mice. BALB/c mice were subcutaneously administered once with baloxavir acid suspension, or orally administered once daily for 10 days with oseltamivir phosphate solution at human relevant doses. Next, the mice were intranasally inoculated with A/PR/8/34 (H1N1) or B/Hong Kong/5/72 strain at 24 to 96 h after the initial dosing. Prophylactic treatment with the antiviral drugs significantly reduced the lung viral titres and prolonged survival time. In particular, baloxavir acid showed a greater suppressive effect on lung viral titres compared to oseltamivir phosphate. In this model, baloxavir acid maintained significant prophylactic effects against influenza A and B virus infections when the plasma concentration at the time of infection was at least 0.88 and 3.58 ng/mL, respectively. The significant prophylactic efficacy observed in our mouse model suggests the potential utility of baloxavir marboxil for prophylaxis against influenza in humans.

Rhodium‐Catalyzed Asymmetric Transfer Hydrogenation of Heterocyclic Diaryl Ketones: Facile Access to Key Intermediate of Baloxavir†

Comprehensive SummaryTransition metal‐catalyzed asymmetric transfer hydrogenation has been proven to be a powerful approach for the synthesis of chiral alcohols. Herein, a highly efficient and enantioselective transfer hydrogenation of dibenzoheptaheterocyclic ketones catalyzed by an arene‐tethered TsDPEN‐based Rh(III) catalyst has been successfully developed, and a variety of dibenzoheptaheterocyclic ketones were reduced by a 1/1 mixture of formic acid and DBU (1,8‐diazabicyclo[5.4.0]undec‐7‐ene) with high yields and enantioselectivities. With this method, the asymmetric reduction of 7,8‐difluorodibenzo[b,e]thiepin‐11(6H)‐one has been realized, providing the key intermediate of baloxavir marboxil with >99% yield and >99% ee at a substrate/catalyst molar ratio of 1000.

Comparison of clinical efficacy and safety of baloxavir marboxil versus oseltamivir as the treatment for influenza virus infections: A systematic review and meta-analysis

IntroductionBaloxavir marboxil (BXM), a newly developed cap-dependent endonuclease inhibitor, is widely used to treat influenza virus infections in inpatients and outpatients. A previous meta-analysis included only outpatients and patients suspected of having an influenza virus infection based on clinical symptoms. However, whether BXM or oseltamivir is safer and more effective for inpatients remains controversial. Therefore, we conducted a systematic review and meta-analysis validating the effectiveness and safety of BXM versus oseltamivir in inpatients with influenza virus. MethodsThe Scopus, EMBASE, PubMed, Ichushi, and CINAHL databases were systematically searched for articles published until January 2023. The outcomes were mortality, hospitalization period, incidence of BXM- or oseltamivir-related adverse events, illness duration, and changes of virus titers and viral RNA load in patients with influenza virus infections. ResultsTwo randomized controlled trials with 1624 outpatients and two retrospective studies with 874 inpatients were enrolled. No deaths occurred in outpatients treated with BXM or oseltamivir. Among inpatients, BXM reduced mortality (p = 0.06) and significantly shortened hospitalization period (p = 0.01) compared to oseltamivir. In outpatients, BXM had a significantly lower incidence of adverse events (p = 0.03), reductions in influenza virus titers (p < 0.001) and viral RNA loads (p < 0.001), and a tendency to be a shorter illness duration compared with that of oseltamivir (p = 0.27). ConclusionsOur meta-analysis showed that BXM was safer and more effective in patients than oseltamivir; thus, supporting the use of BXM for the initial treatment of patients with proven influenza virus infection.

Development and validation of an ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of baloxavir in rat plasma and its application to pharmacokinetic studies.

In this study, an ultra-performance liquid chromatography-tandem mass spectrometry method was established for the development and validation of baloxavir acid (BXA) concentrations and the active ingredients of the antiviral drug baloxavir marboxil (BXM). Further, the method was applied to study the pharmacokinetics of BXA. BXA was determined by the electrospray ionization multiple reaction monitoring positive ion mode, and the mass-to-charge ratios (m/z) of BXA and internal standard baloxavir-d4 were 484.2 → 247.2 and 488.1 → 247.2. An Oasis max online column (2.1 × 20 mm, 30 μm) was used with 1% formic acid in water (A) and 2% formic acid in acetonitrile (B) as mobile phases at a flow rate of 0.5 mL·min-1 for chromatographic separation. The linearity was good in the range of 3-200 ng·mL-1 (r = 0.9994), with 3.00 ng·mL-1 lower limit of quantification. The relative standard deviation of the inter-assay precision was less than or equal to 6.51%, and the accuracy was in the range of 91.28%-104.29%. This method is suitable for the determination of BXA and for performing pharmacokinetic studies in clinical research.

Early Fever Resolution in Early Childhood Influenza Treated with Baloxavir Marboxil: A Retrospective Study Compared to Those with Oseltamivir.

Background and Objectives: Baloxavir marboxil is a novel cap-dependent endonuclease inhibitor prescribed for influenza treatment. Unlike neuraminidase inhibitors like oseltamivir, which impair viral release from infected host cells, baloxavir blocks influenza virus proliferation by inhibiting viral mRNA transcription. This study aimed to compare the effectiveness of baloxavir and oseltamivir for the treatment of early childhood influenza. Materials and Methods: Of 1410 patients diagnosed with influenza between 2015 and 2018 at a Japanese primary care outpatient clinic, 1111 pediatric patients aged 0-6 years who were treated with baloxavir (n = 555) or oseltamivir (n = 556) were enrolled retrospectively. The following clinical factors were compared between patients treated with baloxavir and oseltamivir: age, sex, time from fever onset to drug administration (<24 h or 24-48 h), time from drug administration to fever reduction, influenza type (A or B), and influenza vaccination before disease onset. The duration of the fever, which was used as an index of clinical effectiveness, was compared using the log-rank test. Clinical factors associated with fever duration were determined using multivariate logistic regression analysis. Results: Median age (3.0 vs. 2.5 years), influenza type A (99% vs. 47%), median duration from drug administration to fever resolution (1 day vs. 2 days), and influenza vaccination (done, 41% vs. not done, 65%) were significantly different between the baloxavir and oseltamivir groups (p < 0.001). The number of patients with a fever duration of one day was 553 (99.6%) in the baloxavir group and 6 (1.1%) in the oseltamivir group (p < 0.001). Baloxavir use was only significantly associated with fever duration in the multivariate analysis (odds ratio 50,201, p < 0.001). Apparent adverse effects were not observed in the baloxavir-treated group. Conclusions: Baloxavir treatment resulted in a shorter fever duration than oseltamivir treatment in early childhood influenza.

Computational insights into pediatric adenovirus inhibitors: in silico strategies for drug repurposing

Human adenovirus (HADV) infection can pose a serious threat to children, leading to a variety of respiratory illnesses and other complications. Particularly, children with weak immune systems are vulnerable to severe adenovirus infections with high mortality. The main focus of this study is to propose new antiviral agents as lead HADV inhibitors for children. So, several antiviral agents used in children were subjected to finding new HADV inhibitors using important computational methods of molecular docking, molecular dynamics (MD) simulation, Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) binding free energy calculations, density functional theory (DFT), and pharmacokinetic analysis. Molecular docking of standard cidofovir along with other ligands, suggested that sofosbuvir has the highest binding energy (−10.8 kcal/mol), followed by baloxavir marboxil (−10.36 kcal/mol). Further, the analysis of molecular interactions using MD simulation (100 ns) and MM-PBSA indicated that baloxavir marboxil has formed the most stable protein–ligand complex with HADV, followed by sofosbuvir. The binding free energies of baloxavir marboxil and sofosbuvir were found to be −61.724 kJ/mol and −48.123 kJ/mol, respectively. The DFT and drug-likeness properties of these compounds were also investigated. Overall, two antiviral agents, such as baloxavir marboxil, and sofosbuvir are suggested as lead repurposed candidates against HADV. Communicated by Ramaswamy H. Sarma

The current state of research on influenza antiviral drug development: drugs in clinical trial and licensed drugs.

Influenza viruses (IVs) threaten global human health due to the high morbidity, infection, and mortality rates. Currently, the influenza drugs recommended by the FDA are oseltamivir, zanamivir, peramivir, and baloxavir marboxil. Notably, owing to the high variability of IVs, no drug exists that can effectively treat all types and subtypes of IVs. Moreover, the current trend of drug resistance is likely to continue as the viral genome is constantly mutating. Therefore, there is an urgent need to develop drugs related to the treatment of influenza to deal with the next pandemic. Here, we summarized the cutting-edge research in mechanism of action, inhibitory activity, and clinical efficacy of drugs that have been approved and drugs that are still in clinical trials for influenza treatment. We hope this review will provide up-to-date and comprehensive information on influenza antivirals and generate hypotheses for screens and development of new broad-spectrum influenza drugs in the near future.

Safety and Efficacy of Baloxavir Marboxil in Influenza-infected Children 5-11 Years of Age: A Post Hoc Analysis of a Phase 3 Study (miniSTONE-2).

miniSTONE-2 (NCT03629184) was a global, phase 3, randomized, controlled study that investigated the safety and efficacy of single-dose baloxavir marboxil in otherwise healthy children aged 1-<12 years and showed a positive risk-benefit profile. This post hoc analysis evaluated the safety and efficacy of baloxavir versus oseltamivir in children aged 5-11 years with influenza. Children received single-dose baloxavir or twice-daily oseltamivir for 5 days. Safety was the primary objective. Efficacy and virological outcomes included time to alleviation of symptoms, duration of fever and time to cessation of viral shedding by titer. Data were summarized descriptively. Ninety-four children aged 5-11 years were included (61 baloxavir and 33 oseltamivir). Baseline characteristics were similar between the groups. The incidence of adverse events was balanced and low in both treatment groups, with the most common being vomiting (baloxavir 5% vs. oseltamivir 18%), diarrhea (5% vs. 0%) and otitis media (0% vs. 5%). No serious adverse events or deaths occurred. Median (95% CI) time to alleviation of symptoms with baloxavir was 138.4 hours (116.7-163.4) versus 126.1 hours (95.9-165.7) for oseltamivir; duration of fever was comparable between groups [41.2 hours (23.5-51.4) vs. 51.3 hours (30.7-56.8), respectively]. Median time to cessation of viral shedding was shorter in the baloxavir group versus oseltamivir (1 vs. ≈3 days). Safety, efficacy and virological results in children aged 5-11 years were similar to those from the overall study population aged 1-<12 years. Single-dose baloxavir provides an additional treatment option for pediatric patients aged 5-11 years with influenza.

Impact of Baloxavir Resistance-Associated Substitutions on Influenza Virus Growth and Drug Susceptibility.

Baloxavir marboxil (baloxavir) is a recently FDA-approved influenza virus polymerase acidic (PA) endonuclease inhibitor. Several PA substitutions have been demonstrated to confer reduced susceptibility to baloxavir; however, their impacts on measurements of antiviral drug susceptibility and replication capacity when present as a fraction of the viral population have not been established. We generated recombinant A/California/04/09 (H1N1)-like viruses (IAV) with PA I38L, I38T, or E199D substitutions and B/Victoria/504/2000-like virus (IBV) with PA I38T. These substitutions reduced baloxavir susceptibility by 15.3-, 72.3-, 5.4-, and 54.5-fold, respectively, when tested in normal human bronchial epithelial (NHBE) cells. We then assessed the replication kinetics, polymerase activity, and baloxavir susceptibility of the wild-type:mutant (WT:MUT) virus mixtures in NHBE cells. The percentage of MUT relative to WT virus necessary to detect reduced baloxavir susceptibility in phenotypic assays ranged from 10% (IBV I38T) to 92% (IAV E199D). While I38T did not alter IAV replication kinetics or polymerase activity, IAV PA I38L and E199D MUTs and the IBV PA I38T MUT exhibited reduced replication levels and significantly altered polymerase activity. Differences in replication were detectable when the MUTs comprised ≥90%, ≥90%, or ≥75% of the population, respectively. Droplet digital PCR (ddPCR) and next-generation sequencing (NGS) analyses showed that WT viruses generally outcompeted the respective MUTs after multiple replication cycles and serial passaging in NHBE cells when initial mixtures contained ≥50% of the WT viruses; however, we also identified potential compensatory substitutions (IAV PA D394N and IBV PA E329G) that emerged and appeared to improve the replication capacity of baloxavir-resistant virus in cell culture. IMPORTANCE Baloxavir marboxil, an influenza virus polymerase acidic endonuclease inhibitor, represents a recently approved new class of influenza antivirals. Treatment-emergent resistance to baloxavir has been observed in clinical trials, and the potential spread of resistant variants could diminish baloxavir effectiveness. Here, we report the impact of the proportion of drug-resistant subpopulations on the ability to detect resistance in clinical isolates and the impact of substitutions on viral replication of mixtures containing both drug-sensitive and drug-resistant variants. We also show that ddPCR and NGS methods can be successfully used for detection of resistant subpopulations in clinical isolates and to quantify their relative abundance. Taken together, our data shed light on the potential impact of baloxavir-resistant I38T/L and E199D substitutions on baloxavir susceptibility and other biological properties of influenza virus and the ability to detect resistance in phenotypic and genotypic assays.

Synthesis and Cap-Dependent Endonuclease Inhibition of Baloxavir Derivatives

Baloxavir marboxil is a creative antiviral drug for influenza A and B viruses with a novel mechanism of action. In this study, three series comprising a total of 21 previously unreported target compounds were designed and synthesized. The drug-likeness of these compounds was evaluated by molecular docking, PAINS-Remover and SwissADME. The inhibitory effect and affinity of the compounds on the cap-dependent endonuclease activity of the influenza virus were evaluated. Compounds I-4, II-1~II-9 and compound III-8 showed similar inhibitory activity to baloxavir (7.45 μM) on the cap-dependent endonuclease. In particular, compounds I-4 (3.29 μM) and II-2 (1.46 μM) showed strong cap-dependent endonuclease inhibitory activity. The structure–activity relationship studies showed that the inhibitive effect of the compounds on endonuclease was enhanced when the dibenzothiepin rings were substituted by diphenylmethyl containing chiral-center electron-withdrawing groups, dibenzocycloheptane, dihydrodibenzo[b,e]oxepin, and five-member heterocycles containing aryl substitution.

PA-E18G substitution in influenza A virus confers resistance to ZX-7101, a cap-dependent endonuclease inhibitor

Cap-dependent endonuclease (CEN) in the polymerase acidic protein (PA) of influenza A virus (IAV) represents a promising drug target due to its critical role in viral gene transcription. The CEN inhibitor, baloxavir marboxil (BXM), was approved in Japan and the US in 2018 and several other countries subsequently. Along with the clinical use of BXM, the emergence and spread of IAV variants with reduced susceptibility to BXM have aroused serious concern. Herein, we comprehensively characterized the in vitro and in vivo antiviral activities of ZX-7101A, an analogue of BXM. The active form of prodrug ZX-7101 showed broad-spectrum antiviral potency against various IAV subtypes, including pH1N1, H3N2, H7N9 and H9N2, in MDCK cells, and the 50% effective concentration (EC50) was calculated to nanomole level and comparable to that of baloxavir acid (BXA), the active form of BXM. Furthermore, in vivo assays showed that administration of ZX-7101A conferred significant protection against lethal pH1N1 challenge in mice, with reduced viral RNA loads and alleviated pulmonary damage. Importantly, serial passaging of H1N1 virus in MDCK cells under selection pressure of ZX-7101 led to a resistant variant at the 15th passage. Reverse genetic and sequencing analysis demonstrated that a single E18G substitution in the PA subunit contributed to the reduced susceptibility to both ZX-7101 and BXA. Taken together, our results not only characterized a new CEN inhibitor of IAV but also identified a novel amino acid substitution responsible for CEN inhibitor resistance, which provides critical clues for future drug development and drug resistance surveillance.

Improved Synthetic Process of Baloxavir Marboxil Intermediate 3-Benzyloxy-4-oxo-4H-pyran-2-carboxylic Acid

The article presents a process research study of 3-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid (1), a crucial intermediate in the synthesis of baloxavir marboxil. The original four-step sequence exhibited various limitations, such as low yield (43%), the use of problematic solvents, a large excess of costly reagents, safety concerns, and impurity control difficulties. To address these challenges, process optimization was carried out to achieve the desired goals for large-scale industrial production. Optimization of the enamine 4b synthesis was performed, resulting in the development of an azeotropic removal method for the byproduct methanol. This improvement led to minimized ring-opening impurity 15 and a significant reduction in the consumption of the condensation reagent. Furthermore, a simplified one-pot two-step oxidation sequence was devised to streamline the process for the synthesis of compound 1. This optimization involved controlling the formation of hydrolytic impurity 16 and its downstream aldol condensation form 17. The optimized process was successfully demonstrated on a 600 g scale with a product purity of 99.9%, and the overall yield was substantially improved, rising from 43 to 66%.

EE127 Healthcare Resource Utilization Among Influenza Patients Treated with Baloxavir Marboxil Compared with Oseltamivir with Medicaid Insurance Coverage

To compare all-cause and respiratory-related healthcare resource utilization (HRU) among influenza patients treated with antiviral agents baloxavir marboxil (BALOX) or oseltamivir (OSELT).

Protein sequence features of H1N1 swine influenza A viruses detected on commercial swine farms in Serbia.

Swine influenza A viruses (swIAVs) are characterised by high mutation rates and zoonotic and pandemic potential. In order to draw conclusions about virulence in swine and pathogenicity to humans, we examined the existence of molecular markers and accessory proteins, cross-reactivity with vaccine strains, and resistance to antiviral drugs in five strains of H1N1 swIAVs. Amino acid (AA) sequences of five previously genetically characterised swIAVs were analysed in MEGA 7.0 software and the Influenza Research Database. Amino acid analysis revealed three virus strains with 590S/591R polymorphism and T271A substitution within basic polymerase 2 (PB2) AA chains, which cause enhanced virus replication in mammalian cells. The other two strains possessed D701N and R251K substitutions within PB2 and synthesised PB1-F2 protein, which are the factors of increased polymerase activity and virulence in swine. All strains synthesised PB1-N40, PA-N155, PA-N182, and PA-X proteins responsible for enhanced replication in mammalian cells and downregulation of the immune response of the host. Mutations detected within haemagglutinin antigenic sites imply the antigenic drift of the five analysed viruses in relation to the vaccine strains. All viruses show susceptibility to neuraminidase inhibitors and baloxavir marboxil, which is important in situations of incidental human infections. The detection of virulence markers and accessory proteins in the analysed viruses suggests their higher propensity for replication in mammalian cells, increased virulence, and potential for transmission to humans, and implies compromised efficacy of influenza vaccines.

The use of trifluoromethyl tubercidin as a novel treatment of influenza in an overwhelmed health care setting: a correspondence

The use of trifluoromethyl tubercidin as a novel treatment of influenza in an overwhelmed health care setting: a correspondence

Stability-Indicating Method Development and Validation for Quantitative Estimation of Assay and Organic Impurities of anti-viral drug Baloxavir-Marboxil in Drug Substance and Pharmaceutical Dosage Form using HPLC and LC-MS Methods.

Baloxavir-Marboxil (BXM) is a polymerase-acidic-endonuclease inhibitor used as an anti-viral drug. A simple, reliable, and robust liquid chromatographic method was developed and validated per ICH Q2(R1) for estimating the assay and impurities of BXM in drug substance and pharmaceutical formulations. The chromatographic separation was carried-out on C18 (100 x 4.6 mm, 5-μm) with binary solvent delivery system (A:0.1% trifluoroacetic-acid in water; B:0.1% trifluoroacetic-acid in acetonitrile) along with detection wavelength of 260 nm, column temperature of 57°C, flow of 1.2-mL/min and injection volume of 10-μL. All five known impurities and unknown impurities were separated well with resolution >1.7, and were estimated accurately without any interference. Recovered values and regression value were 99.5-101.2% and R2 >0.999, respectively. The recovery and linearity studies covered from 50-150% for assay, and quantitation limit (QL) - 120% for five BXM impurities. Stability-indicating property of the HPLC developed method was assessed from the forced degradation studies. The mass spectral data of unknown impurity formed under oxidation stress condition was discussed. The developed method was also successfully utilized for stability samples analysis of drug substance and tablets dosage form.

Ecofriendly stability-indicating UHPLC-PDA method for determination of the new influenza antiviral prodrug Baloxavir Marboxil; application to degradation kinetic studies and structure elucidation of the major degradation products using LC-MS

Implementation of green chemistry principles in analytical procedures is of great importance. Green analytical chemistry minimizes the dangerous impact on human beings and the environment that is the primary objective nowadays. In the proposed work, a well-developed, fully validated and ecofriendly stability indicating UHPLC coupled with photodiode array detector (PDA) method was established for the determination of Baloxavir Marboxil (BXM), a novel antiviral drug for the treatment of influenza A and B, in raw materials and pharmaceutical formulations. The method employed Inertsil ODS-3 C18 column to separate BXM from its forced degradation products using a mobile phase composed of 0.1% citric acid (pH 2.5 ± 0.05)-methanol (50:50, v/v), at a flow rate of 0.8 mL/min in an isocratic separation mode. BXM was monitored using diode array detector at 260.0 nm. BXM stability was inspected using various stress conditions as per ICH recommendations. The impact of acid, base hydrolysis, and oxidative stress conditions was greater on BXM in comparison to photo and thermal hydrolysis. The formed degradation products were injected into the mass spectrometer (MS) to elucidate their structures. The suggested pathways for degradation mechanisms were presented. Moreover, the proposed method was effectively utilized to study the degradation kinetics of acid, base and oxidative degradation of BXM. Additionally, four assessment tools were employed to evaluate the greenness of the developed method, namely; the National Environmental Method Index, the Analytical Eco-scale, Green Analytical Procedure tool, and the Analytical Greenness metric. Moreover, a comparative study of the method's greenness was conducted with the reported HPLC method and the results confirming that the suggested method is superior regarding the guidelines and principles of green chemistry. In addition to, having higher qualitative and quantitative scores in comparison to the reported method, and providing reliable and precise results of the method greenness.

Clinical and Virologic Impacts of Respiratory Viral Co-infections in Children With Influenza.

Advances in multiplex polymerase chain reaction (PCR) methods have enabled the simultaneous detection of multiple respiratory viruses. We aimed to estimate the clinical and virologic impacts of influenza and other respiratory virus co-infection in children. We enrolled 38 and 35 children diagnosed with influenza and treated with baloxavir marboxil (baloxavir) and oseltamivir, respectively. We performed quantitative reverse transcription-PCR to detect and measure the levels of noninfluenza viruses from 3 nasopharyngeal swab samples collected before and on days 3 and 5 after the initial antiviral dose. We assessed patients' clinical information using questionnaires. One or more respiratory viruses other than influenza virus were detected in 26 (35.6%) of 73 children before antiviral treatment. The influenza virus load and clinical characteristics on the day of influenza onset were similar between children with and without virus co-infections. Of the 26 and 32 children without the emergence of the reduced baloxavir and oseltamivir susceptible variants after treatment, 8 (30.8%) and 7 (21.9%) children were dually co-infected with human rhinovirus only, respectively. The level of human rhinovirus RNA on day 0 in these children was less than -3 log 10 that of influenza virus RNA, and the human rhinovirus co-infection had no impact on the disease course either clinically or virologically. When multiple respiratory viruses are detected in the same patient, it is necessary to assess clinical symptoms as well as the levels of detected viruses to determine which virus contributes to the development of illness.