Secondary substitutions in the hemagglutinin and neuraminidase genes associated with neuraminidase inhibitor resistance are rare in the Influenza Resistance Information Study (IRIS)

Ziresovir in Hospitalized Infants with Respiratory Syncytial Virus Infection

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of severe illness in infants, with no effective treatment. Results of a phase 2 trial suggested that ziresovir may have efficacy in the treatment of infants hospitalized with RSV infection.

METHODS

In a phase 3, multicenter, double-blind, randomized, placebo-controlled trial conducted in China, we enrolled participants 1 to 24 months of age who were hospitalized with RSV infection. Participants were randomly assigned, in a 2:1 ratio, to receive ziresovir (at a dose of 10 to 40 mg, according to body weight) or placebo, administered twice daily, for 5 days. The primary end point was the change from baseline to day 3 (defined as 48 hours after the first administration) in the Wang bronchiolitis clinical score (total scores range from 0 to 12, with higher scores indicating greater severity of signs and symptoms). The intention-to-treat population included all the participants with RSV-confirmed infection who received at least one dose of ziresovir or placebo; the safety population included all the participants who received at least one dose of ziresovir or placebo.

RESULTS

The intention-to-treat population included 244 participants, and the safety population included 302. The reduction from baseline in the Wang bronchiolitis clinical score at day 3 was significantly greater with ziresovir than with placebo (-3.4 points [95% confidence interval {CI}, -3.7 to -3.1] vs. -2.7 points [95% CI, -3.1 to -2.2]; difference, -0.8 points [95% CI, -1.3 to -0.3]; P = 0.002). The reduction in the RSV viral load at day 5 was greater in the ziresovir group than in the placebo group (-2.5 vs. -1.9 log10 copies per milliliter; difference, -0.6 log10 copies per milliliter [95% CI, -1.1 to -0.2]). Improvements were observed in prespecified subgroups, including in participants with a baseline bronchiolitis score of at least 8 and in those 6 months of age or younger. The incidence of adverse events related to the drug or placebo was 16% with ziresovir and 13% with placebo. The most common adverse events that were assessed by the investigator as being related to the drug or placebo were diarrhea (in 4% and 2% of the participants, respectively), an elevated liver-enzyme level (in 3% and 3%, respectively), and rash (in 2% and 1%). Resistance-associated mutations were identified in 15 participants (9%) in the ziresovir group.

CONCLUSIONS

Ziresovir treatment reduced signs and symptoms of bronchiolitis in infants and young children hospitalized with RSV infection. No safety concerns were identified. (Funded by Shanghai Ark Biopharmaceutical; AIRFLO ClinicalTrials.gov number, NCT04231968.).

Sangbaipi decoction exerted in vitro and in vivo anti-influenza effect through inhibiting viral proteins

HEADINGS ETHNOPHARMACOLOGICAL RELEVANCE

Sangbaipi Decoction (SBPD) is an effective treatment for lung diseases caused by phlegm-heat obstruction according to Jingyue Quanshu, and soothes panting by purging the lung meridian. It is composed of anti-pyretic herbs (e.g., Scutellaria baicalensis Georgi and Coptis chinensis Franch.) and antitussive herbs (e.g., Cortex Mori and Armeniacae Semen Amarum). Therefore, we hypothesized that SBPD has therapeutic effects on lung injury caused by influenza virus.

AIM OF THE STUDY

This study aimed to explore anti-influenza activity, active components, and mechanisms of SBPD.

MATERIALS AND METHODS

The anti-influenza activities of SBPD were determined in 48 h drug-treated MDCK cell model using CPE and plaque reduction assays, and 24 h drug-treated A549 cells using qRT-PCR. The in vivo efficacy of SBPD (1.0 g/kg/day and 0.5 g/kg/day) was evaluated in PR8 infected BALB/c mice. The chemical component was assessed through HPLC-Q-TOF MS/MS analysis. Network pharmacology was built via TCMSP, GeneCards, DisgeNet, OMIM, DrugBank databases, and Cytoscape software. Additionally, TOA, HI and NAI assays were employed to investigate impact on the virus replication cycle with different concentrations of SBPD (2.5 mg/mL, 1.25 mg/mL, or 0.625 mg/mL).

RESULTS

In MDCK infected with viruses A/PR/8/34, A/Hong Kong/1/68, or A/California/4/2009, the IC50 values of SBPD were 0.80 mg/mL, 1.20 mg/mL, and 1.25 mg/mL. In A549 cells, SBPD treatment reduced cytokine expression (e.g., TNF-α, IL-6, IL-1β) (p < 0.05). In PR8 infected BALB/c mice, SBPD improved the survival rate of infected mice, reduced lung index (p < 0.05), protected lung tissue from pathological damage, and regulated cytokine overexpression (p < 0.05). 29 components of SBPD were identified in SBPD treated mouse serum including some phytochemicals targeting influenza proteins. HI and NAI assays suggested the potential antiviral mechanism of SBPD through inhibition of HA and NA.

CONCLUSION

This study is the first to demonstrate the anti-influenza and the anti-inflammatory effects of SBPD in vitro and in vivo. Its major anti-influenza phytochemicals were explored and its inhibitory effects on HA and NA protein were proved. It provides more options for anti-influenza drug discovery.

Genomic Analysis of Influenza A and B Viruses Carrying Baloxavir Resistance-Associated Substitutions Serially Passaged in Human Epithelial Cells

Baloxavir marboxil (baloxavir) is an FDA-approved inhibitor of the influenza virus polymerase acidic (PA) protein. Here, we used next-generation sequencing to compare the genomic mutational profiles of IAV H1N1 and H3N2, and IBV wild type (WT) and mutants (MUT) viruses carrying baloxavir resistance-associated substitutions (H1N1-PA I38L, I38T, and E199D; H3N2-PA I38T; and IBV-PA I38T) during passaging in normal human bronchial epithelial (NHBE) cells. We determined the ratio of nonsynonymous to synonymous nucleotide mutations (dN/dS) and identified the location and type of amino acid (AA) substitutions that occurred at a frequency of ≥30%. We observed that IAV H1N1 WT and MUT viruses remained relatively stable during passaging. While the mutational profiles for IAV H1N1 I38L, I38T, and E199D, and IBV I38T MUTs were relatively similar after each passage compared to the respective WTs, the mutational profile of the IAV H3N2 I38T MUT was significantly different for most genes compared to H3N2 WT. Our work provides insight into how baloxavir resistance-associated substitutions may impact influenza virus evolution in natural settings. Further characterization of the potentially adaptive mutations identified in this study is needed.

Detection of H275Y oseltamivir resistance gene mutation among Influenza A(H1N1)pdm09 patients by allelic discrimination real-time RT-PCR

Influenza viruses can mutate genetically and cause a range of respiratory ailments. The H275Y mutation in the neuraminidase (NA) gene reduces the effectiveness of oseltamivir, a widely used drug for the treatment of Influenza A and B virus infection. The World Health Organization (WHO) recommends single-nucleotide polymorphism assays to detect this mutation. The present study aims to estimate the prevalence of H275Y mutation conferring oseltamivir resistance in Influenza A(H1N1)pdm09 virus among hospitalized patients from June 2014 to December 2021. Following the WHO protocol, allelic discrimination real-time RT-PCR was performed for 752 samples. Out of the 752 samples, 1 tested positive for Y275 gene mutation by allelic discrimination real-time RT-PCR. In samples of years 2020 and 2021, neither the H275 nor Y275 genotype was detected. Sequencing of the NA gene of all negative samples showed a mismatch between the NA sequence and the probes used in the allelic discrimination assay. Also, Y275 mutation was detected in only 1 sample from 2020. The prevalence of oseltamivir resistance was estimated as 0.27% among the Influenza A(H1N1)pdm09 patients during 2014-2021. The study highlights that the WHO-recommended probes for detecting H275Y mutation may not be useful to detect 2020 and 2021 circulating strains of Influenza A(H1N1)pdm09, emphasizing the need for continuous monitoring of mutations in the influenza virus.