Prescription factors influencing baloxavir prescription during the 2018/2019 and 2019/2020 seasons: a administrative database study in Japan.

BACKGROUND: We aimed to evaluate the factors associated with baloxavir prescription in Japanese hospitals using a health insurance claim-based database (MDV analyzer), during the 2018/2019 and 2019/2020 influenza seasons. The MDV analyzer contains anonymized claims data from approximately 420 Diagnosis Procedure Combination hospitals, and does not contain data from clinics. METHODS: Data were collected for influenza patients treated with anti-influenza drugs during the 2018/2019 and 2019/2020 influenza seasons. Multivariate analysis was used to identify factors associated with baloxavir prescription. RESULTS: During the study period, 322,063 influenza patients were included for analyses. In multivariate analysis, children, female sex, inpatient, hospital bed capacity, and private hospitals were negatively associated with baloxavir prescription. Compared to elderly patients, the adjusted odds ratio (OR) for baloxavir prescription was 0.612 (95% confidence interval (CI), 0.587-0.637) in children aged 6-11 years, and 0.119 (95% CI, 0.111-0.128) in children aged 0-5 years. Compared to small hospitals (bed capacity, 20-299), the adjusted OR for baloxavir prescription was 0.559 (95% CI, 0.540-0.578) in large hospitals (bed capacity, ≥ 500). CONCLUSION: Children, female sex, inpatient, hospital bed capacity, and private hospitals were negatively associated with baloxavir prescription.

Preparing for the Next Influenza Season: Monitoring the Emergence and Spread of Antiviral Resistance.

Purpose: The relaxation of pandemic restrictions in 2022 has led to a reemergence of respiratory virus circulation worldwide and anticipation of substantial influenza waves for the 2022/2023 Northern Hemisphere winter. Therefore, the antiviral susceptibility profiles of human influenza viruses circulating in Germany were characterized. Methods: Between October 2019 (week 40/2019) and March 2022 (week 12/2022), nasal swabs from untreated patients with acute respiratory symptoms were collected in the national German influenza surveillance system. A total of 598 influenza viruses were isolated and analyzed for susceptibility to oseltamivir, zanamivir and peramivir, using a neuraminidase (NA) inhibition assay. In addition, next-generation sequencing was applied to assess molecular markers of resistance to NA, cap-dependent endonuclease (PA) and M2 ion channel inhibitors (NAI, PAI, M2I) in 367 primary clinical samples. Furthermore, a genotyping assay based on RT-PCR and pyrosequencing to rapidly assess the molecular resistance marker PA-I38X in PA genes was designed and established. Results: While NAI resistance in the strict sense, defined by a ≥ 10-fold (influenza A) or ≥5-fold (influenza B) increase of NAI IC50, was not detected, a subtype A(H1N1)pdm09 isolate displayed 2.3- to 7.5-fold IC50 increase for all three NAI. This isolate carried the NA-S247N substitution, which is known to enhance NAI resistance induced by NA-H275Y. All sequenced influenza A viruses carried the M2-S31N substitution, which confers resistance to M2I. Of note, one A(H3N2) virus displayed the PA-I38M substitution, which is associated with reduced susceptibility to the PAI baloxavir marboxil. Pyrosequencing analysis confirmed these findings in the original clinical specimen and in cultured virus isolate, suggesting sufficient replicative fitness of this virus mutant. Conclusion: Over the last three influenza seasons, the vast majority of influenza viruses in this national-level sentinel were susceptible to NAIs and PAIs. These findings support the use of antivirals in the upcoming influenza season.

Influenza antivirals and their role in pandemic preparedness.

Effective antivirals provide crucial benefits during the early phase of an influenza pandemic, when vaccines are still being developed and manufactured. Currently, two classes of viral protein-targeting drugs, neuraminidase inhibitors and polymerase inhibitors, are approved for influenza treatment and post-exposure prophylaxis. Resistance to both classes has been documented, highlighting the need to develop novel antiviral options that may include both viral and host-targeted inhibitors. Such efforts will form the basis of management of seasonal influenza infections and of strategic planning for future influenza pandemics. This review focuses on the two classes of approved antivirals, their drawbacks, and ongoing work to characterize novel agents or combination therapy approaches to address these shortcomings. The importance of these topics in the ongoing process of influenza pandemic planning is also discussed.

Infectious diseases

What’s new in infectious diseases in 2020? This year has been marked by the COVID-19 pandemic, prompting a review of the current knowledge on SARS-CoV-2 and its management in this article. The results of the Swiss project «PIRATE» indicate non-inferiority between CRP-guided antibiotic durations or fixed 7-day durations and 14-day durations for Gram-negative bacteremia. A Mongolian study did not show any benefit of vitamin D substitution in protecting children from tuberculosis. Baloxavir, a new antiviral against the flu, has been approved by Swissmedic. Finally, new American recommendations for therapeutic monitoring of vancomycin and universal screening for hepatitis C virus have been published.

Influenza in the Age of COVID-19

Very little data are available on how the coronavirus disease 2019 (COVID-19) pandemic will affect influenza, and although new information is emerging daily, much remains to be learned. Infection-control measures undertaken as a result of the COVID-19 pandemic have significantly impacted the annual influenza season, with a substantial drop in positive influenza cases compared with previous years. Despite the lack of influenza circulation, data suggest that coinfection with influaenza and severe acute respiratory syndrome coronavirus 2 worsens disease severity and worsens prognosis. Although the spread of influenza decreased, misinformation has widely increased. Pharmacists have proven to be essential in the community, offering support not only in vaccine administration and point-of-care testing but also in combating misinformation through education.

Kinetic degradation study for the first licensed anti-influenza polymerase inhibitor, baloxavir marboxil, using high-performance liquid chromatography-mass spectrometry.

The first licensed polymerase inhibitor, baloxavir marboxil was recently approved for the treatment of influenza A and B viruses. Furthermore, there is growing interest in testing the antiviral activity of baloxavir marboxil against Coronavirus. Despite its critical clinical value, there is no information on the degradation products, pathways, or kinetics of baloxavir marboxil under various stress conditions. In this study, a new high-performance liquid chromatography-ultraviolet detection method for accurately quantifying baloxavir marboxil in the presence of its degradation products was developed. A study of degradation kinetics revealed that acidic, thermal neutral, and photolytic degradation reactions have zero-order kinetics, whereas basic and oxidative degradation reactions have first-order kinetics. The structural characterization of baloxavir marboxil degradation products was performed by coupling the optimized high-performance liquid chromatography method to the triple-quadrupole tandem mass spectrometer. The proposed approach was validated according to the International Council for Harmonisation Q2 (R1) requirements for accuracy, precision, robustness, specificity, and linearity. The validated new method was successfully used to analyze baloxavir marboxil as raw material and its pharmaceutical dosage form, Xofluza.

Baloxavir Marboxil Polymorphs: Investigating the Influence of Molecule Packing on the Dissolution Behavior

Baloxavir marboxil (BXM) is a new blockbuster FDA-approved anti-influenza virus agent. However, its poor solubility has limited its oral bioavailability. In this study, BXM was crystallized from several organic solvents, obtaining three polymorphs, and their dissolution behaviors were studied. Detailed crystallographic examination revealed that Form I is monoclinic, space group P21, with unit cell parameters a = 7.1159 (3) Å, b = 20.1967 (8) Å, c = 9.4878 (4) Å, β = 109.033 (1)°, V = 1289.02 (9) Å3, and Z = 2, and Form II is monoclinic, space group P21, with unit cell parameters a = 7.1002 (14) Å, b = 39.310 (7) Å, c = 9.7808 (18) Å, β = 110.966 (5)°, V = 2549.2 (8) Å3, and Z = 4. Form I has a rectangular three-dimensional energy frameworks net, while Form II has a two-dimensional net. On the other hand, Form II has a much larger percentage of its surface area of exposed hydrogen bond acceptors than Form I. These crystallographic features offered increased solubility and dissolution rate to Form II. The results of stability and solubility experiments suggest that Form II may be preferred in the solid form used for the industrial preparation of BXM medicinal products.

Antiviral Drugs in Influenza.

Flu is a serious health, medical, and economic problem, but no therapy is yet available that has satisfactory results and reduces the occurrence of these problems. Nearly 20 years after the registration of the previous therapy, baloxavir marboxil, a drug with a new mechanism of action, recently appeared on the market. This is a promising step in the fight against the influenza virus. This article presents the possibilities of using all available antiviral drugs specific for influenza A and B. We compare all currently recommended anti-influenza medications, considering their mechanisms of action, administration, indications, target groups, effectiveness, and safety profiles. We demonstrate that baloxavir marboxil presents a similar safety and efficacy profile to those of drugs already used in the treatment of influenza. Further research on combination therapy is highly recommended and may have promising results.

Overcome Double Trouble: Baloxavir Marboxil Suppresses Influenza Thereby Mitigating Secondary Invasive Pulmonary Aspergillosis.

Influenza-associated pulmonary aspergillosis (IAPA) is a global recognized superinfection in critically ill influenza patients. Baloxavir marboxil, a cap-dependent endonuclease inhibitor, is a newly approved anti-influenza therapeutic. Although the benefits as a treatment for influenza are clear, its efficacy against an influenza-A. fumigatus co-infection has yet to be determined. We investigated the therapeutic effect of baloxavir marboxil in a murine model for IAPA. Immunocompetent mice received intranasal instillation of influenza A followed by orotracheal inoculation with Aspergillus fumigatus 4 days later. Administration of baloxavir marboxil or sham was started at day 0, day 2 or day 4. Mice were monitored daily for overall health status, lung pathology with micro-computed tomography (µCT) and fungal burden with bioluminescence imaging (BLI). In vivo imaging was supplemented with virological, mycological and biochemical endpoint investigations. We observed an improved body weight, survival and viral clearance in baloxavir marboxil treated mice. µCT showed less pulmonary lesions and bronchial dilation after influenza and after Aspergillus co-infection in a treatment-dependent pattern. Furthermore, baloxavir marboxil was associated with effective inhibition of fungal invasion. Hence, our results provide evidence that baloxavir marboxil mitigates severe influenza thereby decreasing the susceptibility to a lethal invasive Aspergillus superinfection.

Baloxavir Marboxil: An Original New Drug against Influenza.

Baloxavir marboxil is a new drug developed in Japan by Shionogi to treat seasonal flu infection. This cap-dependent endonuclease inhibitor is a prodrug that releases the biologically active baloxavir acid. This new medicine has been marketed in Japan, the USA and Europe. It is well tolerated (more than 1% of the patients experienced diarrhea, bronchitis, nausea, nasopharyngitis, and headache), and both influenza A and B viruses are sensitive, although the B strain is more resistant due to variations in the amino acid residues in the binding site. The drug is now in post-marketing pharmacovigilance phase, and its interest will be especially re-evaluated in the future during the annual flu outbreaks. It has been also introduced in a recent clinical trial against COVID-19 with favipiravir.

Combination of baloxavir and oseltamivir for treatment of severe influenza infection in hematopoietic cell transplant recipients: a novel treatment strategy for a high-risk population.

Baloxavir, a cap-dependent endonuclease inhibitor, was recently approved for treatment of severe influenza infections. Combining baloxavir with oseltamivir has been proposed to increase the response rate. We report 2 hematopoietic cell transplant recipients with severe influenza infections who were treated with this combination and discuss possible reasons for their different responses.

Influenza polymerase inhibitor resistance: Assessment of the current state of the art - A report of the isirv Antiviral group.

It is more than 20 years since the neuraminidase inhibitors, oseltamivir and zanamivir were approved for the treatment and prevention of influenza. Guidelines for global surveillance and methods for evaluating resistance were established initially by the Neuraminidase Inhibitor Susceptibility Network (NISN), which merged 10 years ago with the International Society for influenza and other Respiratory Virus Diseases (isirv) to become the isirv-Antiviral Group (isirv-AVG). With the ongoing development of new influenza polymerase inhibitors and recent approval of baloxavir marboxil, the isirv-AVG held a closed meeting in August 2019 to discuss the impact of resistance to these inhibitors. Following this meeting and review of the current literature, this article is intended to summarize current knowledge regarding the clinical impact of resistance to polymerase inhibitors and approaches for surveillance and methods for laboratory evaluation of resistance, both in vitro and in animal models. We highlight limitations and gaps in current knowledge and suggest some strategies for addressing these gaps, including the need for additional clinical studies of influenza antiviral drug combinations. Lessons learned from influenza resistance monitoring may also be helpful for establishing future drug susceptibility surveillance and testing for SARS-CoV-2.

[Pharmacotherapy for acute respiratory infections caused by influenza viruses: current possibilities].

Routinely the influenza virus significantly contributes to the formation of the annual incidence of acute respiratory infections, with a peak in winter season. The high level of mutagenic potential of influenza viruses is a standard factor determining the complexity of the rational choice of pharmacotherapy. The upcoming epidemiological season 20202021 brings additional challenges for health care practitioners mediated by the widespread prevalence in the human population of a new infection caused by the SARS-CoV-2 virus affecting the respiratory system among many organs and systems. An adequate choice of pharmacotherapy tools should be based on high efficiency and safety of drugs, with a possible reduction in such negative factors as polypharmacy. This review includes comparative pharmacological characteristics of drugs with activity against RNA viruses, along with parameters of their clinical efficacy.

Inhibitory efficacy of RNA virus drugs against SARS-CoV-2 proteins: An extensive study.

Herein we have made a comprehensive analysis of inhibitory efficacy of 16 RNA virus drugs against RdRp, Mpro and PLpro proteins of SARS-CoV-2. Analysis of docked conformation revealed that Baloxavir marboxil (BMX) corresponds to the highest binding energy. Analysis of residue confirmed that BMX strongly interact with these three proteins involving H-bonding, ionic as well as hydrophobic interactions. Molecular dynamics simulation and analysis of parameters like RMSD, RMSF, binding energy confirmed noticeable conformational alternation with these proteins with makeable effect on RdRp. The potentially inhibitory action of BMX against these three proteins suggests the inhibition of overall transcription process of SARS-CoV-2. These observation along with the recently observed inhibitory action of BMX on influenza with clinically proven no side effects emphasizes to uncover the role of BMX by in-vitro and in-vivo analysis.

Clinical Outcomes and Plasma Concentrations of Baloxavir Marboxil and Favipiravir in COVID-19 Patients: An Exploratory Randomized, Controlled Trial.

BACKGROUND: Effective antiviral drugs for COVID-19 are still lacking. This study aims to evaluate the clinical outcomes and plasma concentrations of baloxavir acid and favipiravir in COVID-19 patients. METHODS: Favipiravir and baloxavir acid were evaluated for their antiviral activity against SARS-CoV-2 in vitro before the trial initiation. We conducted an exploratory trial with 3 arms involving hospitalized adult patients with COVID-19. Patients were randomized assigned in a 1:1:1 ratio into baloxavir marboxil group, favipiravir group, and control group. The primary outcome was the percentage of subjects with viral negative by Day 14 and the time from randomization to clinical improvement. Virus load reduction, blood drug concentration and clinical presentation were also observed. The trial was registered with Chinese Clinical Trial Registry (ChiCTR 2000029544). RESULTS: Baloxavir acid showed antiviral activity in vitro with the half-maximal effective concentration (EC50) of 5.48 µM comparable to arbidol and lopinavir, but favipiravir didn't demonstrate significant antiviral activity up to 100 µM. Thirty patients were enrolled. The percentage of patients who turned viral negative after 14-day treatment was 70%, 77%, and 100% in the baloxavir marboxil, favipiravir, and control group respectively, with the medians of time from randomization to clinical improvement was 14, 14 and 15 days, respectively. One reason for the lack of virological effect and clinical benefits may be due to insufficient concentrations of these drugs relative to their antiviral activities. One of the limitations of this study is the time from symptom onset to randomization, especially in the baloxavir marboxil and control groups, which is higher than the favipiravir group. CONCLUSIONS: Our findings could not prove a benefit of addition of either baloxavir marboxil or favipiravir under the trial dosages to the existing standard treatment.

Baloxavir for the treatment of Influenza in allogeneic hematopoietic stem cell transplant recipients previously treated with oseltamivir.

BACKGROUND: Seasonal influenza causes significant morbidity and mortality in allogeneic stem cell transplant (SCT) recipients. In this population, influenza virus can replicate for prolonged periods, despite neuraminidase inhibitor treatment, leading to resistance and treatment failure. Baloxavir targets the influenza polymerase and may be an effective treatment option in these patients. METHODS: We used baloxavir to treat five allogeneic SCT recipients that were still symptomatic and shedding influenza virus after completing one or more treatment courses of oseltamivir and characterized the viral isolates before and during treatment. RESULTS: Two patients were infected with influenza A/H1pdm09 carrying a neuraminidase variant (H275Y) linked to oseltamivir resistance. Both these two patients were successfully treated with baloxavir. Of the three patients infected with wild-type influenza virus, two cleared the virus after baloxavir treatment, while the third patient developed the polymerase I38T variant linked to baloxavir resistance. CONCLUSIONS: Our data suggest that baloxavir treatment can be effective in treating neuraminidase inhibitor-resistant influenza in profoundly immunocompromised patients. Randomized clinical trials are needed to define the role of baloxavir alone and combined with oseltamivir for the treatment of influenza in SCT recipients and other immunocompromised populations.