A clinical trial of intravenous peramivir compared with oral oseltamivir for the treatment of seasonal influenza in hospitalized adults

Antivirals for treatment of severe influenza: a systematic review and network meta-analysis of randomised controlled trials

BACKGROUND

The optimal antiviral drug for treatment of severe influenza remains unclear. To support updated WHO influenza clinical guidelines, this systematic review and network meta-analysis evaluated antivirals for treatment of patients with severe influenza.

METHODS

We systematically searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, Global Health, Epistemonikos, and ClinicalTrials.gov for randomised controlled trials published up to Sept 20, 2023, that enrolled hospitalised patients with suspected or laboratory-confirmed influenza and compared direct-acting influenza antivirals against placebo, standard care, or another antiviral. Pairs of coauthors independently extracted data on study characteristics, patient characteristics, antiviral characteristics, and outcomes, with discrepancies resolved by discussion or by a third coauthor. Key outcomes of interest were time to alleviation of symptoms, duration of hospitalisation, admission to intensive care unit, progression to invasive mechanical ventilation, duration of mechanical ventilation, mortality, hospital discharge destination, emergence of antiviral resistance, adverse events, adverse events related to treatments, and serious adverse events. We conducted frequentist network meta-analyses to summarise the evidence and evaluated the certainty of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. This study is registered with PROSPERO, CRD42023456650.

FINDINGS

Of 11 878 records identified by our search, eight trials with 1424 participants (mean age 36-60 years for trials that reported mean or median age; 43-78% male patients) were included in this systematic review, of which six were included in the network meta-analysis. The effects of oseltamivir, peramivir, or zanamivir on mortality compared with placebo or standard care without placebo for seasonal and zoonotic influenza were of very low certainty. Compared with placebo or standard care, we found low certainty evidence that duration of hospitalisation for seasonal influenza was reduced with oseltamivir (mean difference -1·63 days, 95% CI -2·81 to -0·45) and peramivir (-1·73 days, -3·33 to -0·13). Compared with standard care, there was little or no difference in time to alleviation of symptoms with oseltamivir (0·34 days, -0·86 to 1·54; low certainty evidence) or peramivir (-0·05 days, -0·69 to 0·59; low certainty evidence). There were no differences in adverse events or serious adverse events with oseltamivir, peramivir, and zanamivir (very low certainty evidence). Uncertainty remains about the effects of antivirals on other outcomes for patients with severe influenza. Due to the small number of eligible trials, we could not test for publication bias.

INTERPRETATION

In hospitalised patients with severe influenza, oseltamivir and peramivir might reduce duration of hospitalisation compared with standard care or placebo, although the certainty of evidence is low. The effects of all antivirals on mortality and other important patient outcomes are very uncertain due to scarce data from randomised controlled trials.

FUNDING

World Health Organization.

Comparative effectiveness of oseltamivir versus peramivir for hospitalized children (aged 0-5 years) with influenza infection

OBJECTIVES

The effectiveness of oseltamivir versus peramivir in children infected with influenza remains unclear. This study aimed to evaluate their effectiveness in young children (aged 0-5 years) infected with severe influenza A virus (IAV) or influenza B virus (IBV).

METHODS

We analyzed a cohort of 1662 young children with either IAV (N = 1095) or IBV (N = 567) who received oseltamivir or peramivir treatment from January 1, 2018 to March 31, 2022. Propensity score matching methods were applied to match children who were oseltamivir-treated versus peramivir-treated.

RESULTS

Children who were IAV-infected and IBV-infected shared similar features, such as influenza-associated symptoms and comorbidities at baseline. Among children infected with IAV with bacterial coinfection, the recovery rate was significantly greater in children treated with oseltamivir than in children treated with peramivir (15.6% vs 4.4%, P = 0.01). The median duration of hospitalization was also shorter in children treated with oseltamivir. Among children infected with IAV without bacterial coinfection, the recovery rate was greater in children treated with oseltamivir than in children treated with peramivir (21.1% vs 3.7%, P = 0.002). However, oseltamivir and peramivir offered similar recovery rates and duration of hospitalization (P >0.05 for both) among children infected with IBV.

CONCLUSION

Oseltamivir and peramivir exhibit similar effectiveness in young children with severe influenza B, whereas oseltamivir demonstrated improved recovery and shorter hospitalization in the treatment of severe influenza A in hospitalized children.

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.

Antiviral Treatments for Influenza

Influenza is an acute respiratory illness caused by the influenza A, B, and C viruses. It can occur in local outbreaks or seasonal epidemics, with possibility to spread worldwide in a pandemic when a novel strain with significant antigenic differences emerges. During the past years, several new drugs have become available, with different accessibility related to specific countries' approval. We have conducted a review of literature, analyzing the most recent data on efficacy and safety of drugs currently available to treat influenza, with a particular attention toward special populations. Efficacy and safety profile of neuraminidase inhibitors (oseltamivir, zanamivir, laninamivir, peramivir) and recently approved cap-dependent endonuclease inhibitor baloxavir marboxil are reported in literature, but still little information is available about special populations such as critically ill patients and patients with a history of chronic respiratory disease. Moreover, the emergence of strains with reduced or no susceptibility to current drugs is a matter of concern, suggesting the need of constant monitoring of viral variants.

Comparative effectiveness of neuraminidase inhibitors in patients with influenza: A systematic review and network meta-analysis

The aim of this study was to use a network meta-analysis (NWA) to evaluate the relative efficacy and safety of various neuraminidase inhibitors (NAIs) in reducing the duration of influenza symptoms, and thereby, informing the selection of suitable therapeutic regimens for patients with influenza. We conducted a systematic review of randomized controlled trials comparing the clinical effects of four NAIs administered to patients with influenza and placebo. Relevant studies were found in the PubMed and Cochrane databases. Unpublished studies were collected from the ClinicalTrials.gov registry and through hand searching. We carried out NWA to compare the different regimens with each other and across subgroups of age and medical status (high-risk patients). A total of 58 two-arm studies were identified. Five regimens were efficacious in reducing the time to alleviation of influenza symptoms in all populations; this efficacy was comparable. No significant improvements were seen in combination therapy groups. The mean difference in the time to alleviation of symptoms ranged from 12.78 to 19.51 h. According to the summarized mean difference and surface under the cumulative ranking curve (SUCRA), peramivir (SUCRA = 82.6%), zanamivir (SUCRA = 64%), and oseltamivir (SUCRA = 55.1%) were the three top-ranking drugs for treating influenza. Zanamivir and peramivir were the preferred pharmacologic intervention among all investigated interventions based on the calculated "value preference of SUCRA." This study is a network meta-analysis to explore the therapeutic effects of NAIs in patients with influenza. Peramivir might be the best choice for reducing the time to alleviation of symptoms.

Respiratory Viruses in Solid Organ Transplant Recipients

Solid organ transplantation is often lifesaving, but does carry an increased risk of infection. Respiratory viral infections are one of the most prevalent infections, and are a cause of significant morbidity and mortality, especially among lung transplant recipients. There is also data to suggest an association with acute rejection and chronic lung allograft dysfunction in lung transplant recipients. Respiratory viral infections can appear at any time post-transplant and are usually acquired in the community. All respiratory viral infections share similar clinical manifestations and are all currently diagnosed using nucleic acid testing. Influenza has good treatment options and prevention strategies, although these are hampered by resistance to neuraminidase inhibitors and lower vaccine immunogenicity in the transplant population. Other respiratory viruses, unfortunately, have limited treatments and preventive methods. This review summarizes the epidemiology, clinical manifestations, therapies and preventive measures for clinically significant RNA and DNA respiratory viruses, with the exception of SARS-CoV-2. This area is fast evolving and hopefully the coming decades will bring us new antivirals, immunologic treatments and vaccines.

Comparison of Antiviral Agents for Seasonal Influenza Outcomes in Healthy Adults and Children: A Systematic Review and Network Meta-analysis

IMPORTANCE

Antiviral treatment of influenza is recommended for patients with influenza-like illness during periods of community cocirculation of influenza viruses and SARS-CoV-2; however, questions remain about which treatment is associated with the best outcomes and fewest adverse events.

OBJECTIVE

To compare the efficacy and safety of neuraminidase inhibitors and the endonuclease inhibitor for the treatment of seasonal influenza among healthy adults and children.

DATA SOURCES

Medline, Embase, and the Cochrane Register of Clinical Trials were searched from inception to January 2020 (the last search was updated in October 2020).

STUDY SELECTION

Included studies were randomized clinical trials conducted among patients of all ages with influenza treated with neuraminidase inhibitors (ie, oseltamivir, peramivir, zanamivir, or laninamivir) or an endonuclease inhibitor (ie, baloxavir) compared with other active agents or placebo.

DATA EXTRACTION AND SYNTHESIS

Two investigators identified studies and independently abstracted data. Frequentist network meta-analyses were performed; relative ranking of agents was conducted using P-score probabilities. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations criteria. Data were analyzed in October 2020.

MAIN OUTCOMES AND MEASURES

The time to alleviation of influenza symptoms (TTAS), complications of influenza, and adverse events (total adverse events, nausea, and vomiting).

RESULTS

A total of 26 trials were identified that investigated antiviral drugs at high or low doses; these trials included 11 897 participants, among whom 6294 (52.9%) were men and the mean (SD) age was 32.5 (16.9) years. Of all treatments comparing with placebo in efficacy outcomes, high-quality evidence indicated that zanamivir was associated with the shortest TTAS (hazard ratio, 0.67; 95% CI, 0.58-0.77), while baloxavir was associated with the lowest risk of influenza-related complications (risk ratio [RR], 0.51; 95% CI, 0.32-0.80) based on moderate-quality evidence. In safety outcomes, baloxavir was associated with the lowest risk of total adverse events (RR, 0.84; 95% CI, 0.74-0.96) compared with placebo based on moderate-quality evidence. There was no strong evidence of associations with risk of nausea or vomiting among all comparisons, except for 75 mg oseltamivir, which was associated with greater occurrence of nausea (RR, 1.82; 95% CI, 1.38-2.41) and vomiting (RR, 1.88; 95% CI, 1.47-2.41).

CONCLUSIONS AND RELEVANCE

In this systematic review and network meta-analysis, all 4 antiviral agents assessed were associated with shortening TTAS; zanamivir was associated with the shortest TTAS, and baloxavir was associated with reduced rate of influenza-related complications.

Comparing intravenous peramivir with oral oseltamivir for patients with influenza: a meta-analysis of randomized controlled trials

BACKGROUND

The study was to compare the efficacy between IV peramivir and oral oseltamivir treatments in patients with influenza.

METHODS

The PubMed, EMBASE, Scopus, ClinicalTrials.gov, and Cochrane Library databases were searched for studies published before January 2020.

RESULTS

The meta-analysis was conducted to calculate the pooled effect size by using a random-effects model. Seven randomized controlled trials (RCTs) including 1,138 patients were reviewed. The incidence of total complications revealed no significant difference between 600 mg IV peramivir (P600) and 75 mg oral oseltamivir (O75) treatments (2.8% vs. 4.1%; risk ratio [RR] = 0.70; 95% confidence interval [CI]: 0.36-1.38). The incidence of pneumonia was not significantly different between the P600 and O75 treatment groups (2.2% vs. 2.7%; RR = 0.74; 95% CI: 0.37-1.51). Regarding the time to the alleviation of symptoms, no difference was found in P600 and O75 treatment (MD = -3.00; 95% CI: -11.07 to 5.06). The rate of fever clearance in 24 h and the time to fever resolution were not statistically different between the IV peramivir and oral oseltamivir treatments (at different dosages) groups.

CONCLUSIONS

The treatment of influenza with IV peramivir or oral oseltamivir had similar clinical efficacy.

Influenza management with new therapies

PURPOSE OF REVIEW

Influenza represents a significant treatment burden to critical care services. A variety of treatment strategies exist, with more and more therapeutic avenues opening up as research progresses. We examined both pharmacological and supportive treatment strategies currently available to see how they might be applied in an ICU setting.

RECENT FINDINGS

Supportive care in Influenza centres around optimizing respiratory failure, particularly through well established and recognized ventilatory strategies. Noninvasive ventilation and high-flow nasal oxygen may have a limited role in selected patients under carefully monitored circumstances. Drug therapy exerts only a modest clinical effect and has been poorly studied in the critically ill, though there is some evidence to support the use of neuraminidase inhibitors (NAI) - particularly oseltamivir - as early as possible in this cohort. Newer agents have failed to demonstrate superiority over NAIs but may be useful options if the patient fails to respond or should resistant influenza strains emerge. Steroid therapy, in the absence of another indication, must be recommended against given the repeated trend towards increased mortality in this group.

SUMMARY

Influenza management is an evolving field of significant interest to any critical care provider. Currently, good respiratory supportive care and early enteral oseltamivir are the best supported treatment strategies. Further study in the intensive care setting will be needed before the use of novel agents can be recommended.

Respiratory viruses

Respiratory viruses are commonly detected in both healthy and immunocompromised children. In most healthy children, respiratory viruses are associated with self-limited upper respiratory tract infections and are not accompanied by significant morbidity. In immunocompromised hosts, including hematopoietic cell transplant recipients, solid organ transplant recipients, and oncology patients, respiratory viruses can be associated with significant clinical manifestations, including prolonged viral shedding, lower respiratory tract disease, the need for supplemental oxygen, late airflow obstruction, and even death. This chapter reviews the major respiratory viruses, including respiratory syncytial virus, human metapneumovirus, influenza, parainfluenza viruses, human rhinoviruses, and human coronaviruses. Other viruses can manifest as pulmonary infection; however, these viruses are discussed elsewhere (see Chapter 17 for discussion of cytomegalovirus and Chapter 22 for discussion of adenoviruses).

Efficacy of baloxavir marboxil on household transmission of influenza infection

Background

Baloxavir marboxil (baloxavir) is a new anti-influenza virus agent that is comparable to oseltamivir phosphate (oseltamivir). Since the efficacy of baloxavir in preventing household transmission of influenza is not well established, we compared the secondary household influenza virus transmission rates between patients on baloxavir vs oseltamivir.

Methods

Between October 2018 and March 2019, we enrolled index patients (diagnosed with influenza and treated with baloxavir or oseltamivir) and household members. The secondary attack rate of household members was compared between index patients treated with baloxavir vs oseltamivir. Risk factors of household transmission were determined using multivariate logistic analyses.

Results

In total, 169 index patients with influenza type A were enrolled. The median age was 27.0 (interquartile range; 11–57) years. The number of index patients treated with baloxavir and oseltamivir was 49 and 120, respectively. The secondary attack rate was 9.0% (95% confidence interval [CI]: 4.6–15.6) in the baloxavir group and 13.5% (95% CI: 9.8–17.9) in the oseltamivir group. In the multivariate analysis, independent risk factors were 0–6 years of age (odds ratio [OR] 2.78, 95% CI: 1.33–5.82, p < 0.01) and not being on baloxavir treatment. (OR: 0.63, 95% CI: 0.30–1.32, p = 0.22).

Conclusion

The household secondary attack rate of influenza was comparable in patients treated with baloxavir vs oseltamivir. Therefore, baloxavir can be used as an alternative therapy to oseltamivir in reducing household transmission of influenza.

Trial registration

Patients in this study were retrospectively registered. https://www.tosei.or.jp/clinical/pdf/2_influenza.pdf.

Effect of peramivir on respiratory symptom improvement in patients with influenza virus infection and pre-existing chronic respiratory disease: Findings of a randomized, open-label study

Background

The efficacy of neuraminidase inhibitors on improvement of respiratory symptoms triggered by influenza in patients with pre‐existing chronic respiratory diseases is unknown.

Methods

This 2‐week, randomized, open‐label study evaluated intravenous peramivir 600 mg on two consecutive days (peramivir‐repeat), peramivir 300 mg single dose (peramivir‐single), and oral oseltamivir 75 mg twice daily for 5 days in patients with confirmed influenza and chronic respiratory diseases. Patients recorded symptom scores daily. The primary endpoint of cumulative area of time vs symptoms (CATVS) was expressed as an index value of area under the curve vs time of the total score of cough, sore throat, and nasal congestion from baseline to 2 weeks.

Results

Of 214 randomized patients, 209 (56% female, 77% aged <65 years, 94% outpatients, 91% bronchial asthma, 62% influenza A) received ≥1 dose of study drug. Mean (standard deviation) CATVS was similar for peramivir‐repeat (782.78 [487.17]) vs peramivir‐single (717.35 [347.55]; P = .4371), and for peramivir‐repeat vs oseltamivir (856.34 [404.99]; P = 1.00). However, CATVS was significantly shorter for peramivir‐single vs oseltamivir, with an estimated treatment difference (TD) of −145.07 (95% confidence interval: −284.57, −5.56; P = .0416). In subgroup analyses, CATVS was significantly shorter for peramivir‐single vs oseltamivir among patients with influenza A (TD: −206.31 [−383.86, −28.76]; P = .0231), bronchial asthma (TD: −156.57 [−300.22, −12.92]; P = .0328), baseline respiratory severity score <5 (TD: −265.32 [−470.42, −60.21]; P = .0120), and age <65 (TD: −184.30 [−345.08, −23.52]; P = .0249).

Conclusions

In patients with chronic respiratory diseases, peramivir‐single was not significantly different from peramivir‐repeat and was more effective than oseltamivir at alleviating respiratory symptoms.

Alternative Regimens of Neuraminidase Inhibitors for Therapy of Hospitalized Adults with Influenza: A Systematic Review of Randomized Controlled Trials

INTRODUCTION

Influenza in hospitalized intensive care unit (ICU) patients with respiratory failure is associated with 25% mortality, despite timely oseltamivir treatment. A systematic review of randomized controlled trials (RCTs) was conducted to evaluate the efficacy and safety of alternative neuraminidase inhibitor (NAI) regimens compared to standard of care in patients hospitalized for H1N1, H3N2, or B influenza.

METHODS

The Cochrane collaboration searching methods were followed in Cochrane Library, PubMed, and Web of Science databases (2009-2019). Eligibility criteria were RCTs comparing different regimens of NAIs in hospitalized patients (at least 1 year old) for clinically diagnosed influenza (H1N1, H3N2, or B). Pre-defined endpoints were time to clinical resolution (TTCR), overall mortality, hospital discharge, viral clearance, drug-related adverse events (AEs), and serious adverse events.

RESULTS

Seven trials (1579 patients) were included. Two trials compared two regimens of oral oseltamivir therapy, and one trial compared two regimens of intravenous zanamivir therapy vs oral oseltamivir therapy. Four trials focused on intravenous peramivir therapy: two trials compared two different regimens and two trials compared two different regimens vs oral oseltamivir therapy. Overall, the different regimens were well tolerated, with no significant differences in AEs; nonetheless non-significant differences were reported among different regimens regarding TTCR, mortality, and viral clearance.

CONCLUSION

Higher compared to standard doses of NAIs or systemic peramivir therapy compared to oral oseltamivir therapy did not demonstrate benefit.

Clinical Effectiveness of Intravenous Peramivir versus Oseltamivir for the Treatment of Influenza in Hospitalized Patients

Purpose

To compare the clinical efficacy between peramivir and oseltamivir in hospitalized patients with influenza.

Patients and Methods

Retrospective cohort study examined data from 542 adult patients with laboratory-confirmed seasonal influenza hospitalized in five teaching hospitals and one secondary hospital between August 2017 and May 2018. The main outcome was the defervescence rate within 3 days from the first administration of peramivir or oseltamivir. The secondary outcomes were mortality and duration of hospitalization/intensive care unit (ICU) stay.

Results

Of the 542 enrolled patients, 251 were administered the standard dose of peramivir (300 mg, single dose), 42 were administered peramivir at doses exceeding 300 mg, and 249 were administered oseltamivir (75 mg, twice daily for 5 days). There were more ICU and pneumonia cases and older patients in the peramivir group, especially the high-dose group. The Charlson comorbidity index (CCI) scores were similar among the three groups. There were no significant differences in defervescence rates within 3 days between the three groups. The mortality and duration of hospital and ICU stays also did not differ significantly. The factors associated with 30-day mortality were ICU admission, high CCI score, and pneumonia.

Conclusion

Treatment of influenza with either peramivir or oseltamivir in hospitalized adults resulted in generally similar clinical outcomes. Peramivir treatment showed good clinical response in influenza patients with pneumonia or admitted to the ICU.

A Meta-Analysis Comparing the Efficacy and Safety of Peramivir with Other Neuraminidase Inhibitors for Influenza Treatment

Background and Objectives: This meta-analysis compared the efficacy and safety of peramivir compared to other neuraminidase inhibitors (NAIs). Materials and Methods: Data from PubMed, Embase, and Cochrane databases and ClinicalTrials.gov were searched until January 2019. Randomized controlled trials (RCTs) and observational studies (OSs) comparing peramivir with other NAIs for treating influenza were included. The Grading of Recommendations, Assessments, Development, and Evaluations (GRADE) system was used to judge the overall certainty of evidence; the result was moderate. The primary outcome was time to alleviation of symptoms. Twelve articles involving 2681 patients were included in this meta-analysis. We used a random-effect model to pool the effect size, which is expressed as the difference in means (MD), risk ratio (RR), and 95% confidence interval (CI). Results: Overall, peramivir was superior to other NAIs (MD = −11.214 hours, 95% CI: −19.119 to −3.310). The incidence of adverse events (RR = 1.023, 95% CI: 0.717 to 1.460) and serious adverse events (RR = 1.068, 95% CI: 0.702 to 1.625) in the peramivir group was similar to those in the oseltamivir group. In addition, peramivir had higher efficacy than each NAI alone. Conclusion: In conclusion, the efficacy of peramivir might be higher than that of other NAIs, and this agent is tolerated as well as other NAIs.

Influenza virus-related critical illness: prevention, diagnosis, treatment

Annual seasonal influenza epidemics of variable severity result in significant morbidity and mortality in the United States (U.S.) and worldwide. In temperate climate countries, including the U.S., influenza activity peaks during the winter months. Annual influenza vaccination is recommended for all persons in the U.S. aged 6 months and older, and among those at increased risk for influenza-related complications in other parts of the world (e.g. young children, elderly). Observational studies have reported effectiveness of influenza vaccination to reduce the risks of severe disease requiring hospitalization, intensive care unit admission, and death. A diagnosis of influenza should be considered in critically ill patients admitted with complications such as exacerbation of underlying chronic comorbidities, community-acquired pneumonia, and respiratory failure during influenza season. Molecular tests are recommended for influenza testing of respiratory specimens in hospitalized patients. Antigen detection assays are not recommended in critically ill patients because of lower sensitivity; negative results of these tests should not be used to make clinical decisions, and respiratory specimens should be tested for influenza by molecular assays. Because critically ill patients with lower respiratory tract disease may have cleared influenza virus in the upper respiratory tract, but have prolonged influenza viral replication in the lower respiratory tract, an endotracheal aspirate (preferentially) or bronchoalveolar lavage fluid specimen (if collected for other diagnostic purposes) should be tested by molecular assay for detection of influenza viruses.Observational studies have reported that antiviral treatment of critically ill adult influenza patients with a neuraminidase inhibitor is associated with survival benefit. Since earlier initiation of antiviral treatment is associated with the greatest clinical benefit, standard-dose oseltamivir (75 mg twice daily in adults) for enteric administration is recommended as soon as possible as it is well absorbed in critically ill patients. Based upon observational data that suggest harms, adjunctive corticosteroid treatment is currently not recommended for children or adults hospitalized with influenza, including critically ill patients, unless clinically indicated for another reason, such as treatment of asthma or COPD exacerbation, or septic shock. A number of pharmaceutical agents are in development for treatment of severe influenza.

Influenza virus-related critical illness: prevention, diagnosis, treatment

Annual seasonal influenza epidemics of variable severity result in significant morbidity and mortality in the United States (U.S.) and worldwide. In temperate climate countries, including the U.S., influenza activity peaks during the winter months. Annual influenza vaccination is recommended for all persons in the U.S. aged 6 months and older, and among those at increased risk for influenza-related complications in other parts of the world (e.g. young children, elderly). Observational studies have reported effectiveness of influenza vaccination to reduce the risks of severe disease requiring hospitalization, intensive care unit admission, and death. A diagnosis of influenza should be considered in critically ill patients admitted with complications such as exacerbation of underlying chronic comorbidities, community-acquired pneumonia, and respiratory failure during influenza season. Molecular tests are recommended for influenza testing of respiratory specimens in hospitalized patients. Antigen detection assays are not recommended in critically ill patients because of lower sensitivity; negative results of these tests should not be used to make clinical decisions, and respiratory specimens should be tested for influenza by molecular assays. Because critically ill patients with lower respiratory tract disease may have cleared influenza virus in the upper respiratory tract, but have prolonged influenza viral replication in the lower respiratory tract, an endotracheal aspirate (preferentially) or bronchoalveolar lavage fluid specimen (if collected for other diagnostic purposes) should be tested by molecular assay for detection of influenza viruses.Observational studies have reported that antiviral treatment of critically ill adult influenza patients with a neuraminidase inhibitor is associated with survival benefit. Since earlier initiation of antiviral treatment is associated with the greatest clinical benefit, standard-dose oseltamivir (75 mg twice daily in adults) for enteric administration is recommended as soon as possible as it is well absorbed in critically ill patients. Based upon observational data that suggest harms, adjunctive corticosteroid treatment is currently not recommended for children or adults hospitalized with influenza, including critically ill patients, unless clinically indicated for another reason, such as treatment of asthma or COPD exacerbation, or septic shock. A number of pharmaceutical agents are in development for treatment of severe influenza.

The effect of neuraminidase inhibitors on household transmission in Japanese patients with influenza A and B infection: A prospective, observational study

Background

The relative ability of neuraminidase inhibitors (NAIs) to reduce household influenza transmission when given to index patients is not established.

Objectives

To compare daily secondary infection rates (SIR) of influenza A (A/H1pdm and A/H3) and B in households of index patients treated with oseltamivir, zanamivir, laninamivir, or peramivir.

Patients/Methods

This Japanese, single‐center, prospective, observational study (UMIN‐CTR: UMIN000024650) enrolled index patients with confirmed influenza who were treated with an NAI during 6 influenza seasons (2010‐2016). Secondary infection patients were household members diagnosed with the same influenza subtype 1‐7 days after onset in the index patient. Daily SIR was calculated using a modified Reed‐Frost model. The rate of household members with secondary infection and proportion of households with any secondary infection were also calculated.

Results

Index patients with influenza A (n = 1146) or B (n = 661) were enrolled (~3400 total index and secondary patients). Daily SIR for all virus subtypes was highest when oseltamivir was used (eg, unadjusted estimate: type A, 1.47% vs 0.71%‐1.13%; type B, 1.30% vs 0.59%‐0.88%). Pairwise comparisons revealed significant differences in daily SIR between NAIs for influenza type A, type B, and subtype A/H3; for example, for type A, SIR was significantly higher with oseltamivir than with peramivir or zanamivir. The rate of household members with secondary infection and proportion of households with any secondary infection also varied between NAIs.

Conclusions

Neuraminidase inhibitors differed in their ability to reduce household influenza transmission; transmission was highest with oseltamivir. Physicians may consider effects on household transmission when deciding which NAI to prescribe.

Safety and Effectiveness of Peramivir in Korean Adult Influenza Patients: Prospective Observational Study Based on Post-Marketing Surveillance Data

BACKGROUND

The safety and clinical effectiveness data of peramivir in the real clinical field are limited. A prospective observational study was conducted based on the post-marketing surveillance data to evaluate the post-marketing safety and effectiveness of peramivir in Korean adults with seasonal influenza.

METHODS

Among adults aged 20 years or older who were diagnosed with influenza A or B, patients who started peramivir within 48 hours from the initial symptoms of influenza were enrolled. All adverse events (AEs) that occurred within 7 days after administration of peramivir were checked. For the evaluation of effectiveness, changes in the severity of influenza symptoms and daily living performance were examined before and 7 days after the administration of peramivir. The date on which influenza related symptoms disappeared was checked.

RESULTS

A total of 3,024 patients were enrolled for safety evaluation and 2,939 patients were for effectiveness evaluation. In the safety evaluation, 42 AEs were observed in 35 (1.16%) patients. The most common AE was fever. AEs were mostly rated as mild in severity. Serious AEs were observed in 10 patients and two of them died. However, both deaths were considered to be less relevant to peramivir. In the effectiveness evaluation, the severity of influenza symptoms decreased by 10.68 ± 4.01 points and daily living performance was improved 5.59 ± 2.16 points. Influenza related symptoms disappeared on average 3.02 ± 2.39 days after peramivir administration.

CONCLUSION

Peramivir showed a tolerable safety profile and acceptable effectiveness in Korean adult patients with seasonal influenza.

Post-transplant Viral Respiratory Infections in the Older Patient: Epidemiology, Diagnosis, and Management

Organ and stem cell transplantation has been one of the greatest advances in modern medicine, and is the primary treatment modality for many end-stage diseases. As our population ages, so do the transplant recipients, and with that comes many new challenges. Respiratory viruses have been a large contributor to the mortality and morbidity of solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. Respiratory viruses are generally a long-term complication of transplantation and primarily acquired in the community. With the emergence of molecular methods, newer respiratory viruses are being detected. Respiratory viruses appear to cause severe disease in the older transplant population. Influenza vaccine remains the mainstay of prevention in transplant recipients, although immunogenicity of current vaccines is suboptimal. Limited therapies are available for other respiratory viruses. The next decade will likely bring newer antivirals and vaccines to the forefront. Our goal is to provide the most up to date knowledge of respiratory viral infections in our aging transplant population.

Immune responses after live attenuated influenza vaccination

Since 2003 (US) and 2012 (Europe) the live attenuated influenza vaccine (LAIV) has been used as an alternative to the traditional inactivated influenza vaccines (IIV). The immune responses elicted by LAIV mimic natural infection and have been found to provide broader clinical protection in children compared to the IIVs. However, our knowledge of the detailed immunological mechanisims induced by LAIV remain to be fully elucidated, and despite 14 years on the global market, there exists no correlate of protection. Recently, matters are further complicated by differing efficacy data from the US and Europe which are not understood. Better understanding of the immune responses after LAIV may aid in achieving the ultimate goal of a future "universal influenza vaccine". In this review we aim to cover the current understanding of the immune responses induced after LAIV.

Emergence of Oseltamivir-Resistant H7N9 Influenza Viruses in Immunosuppressed Cynomolgus Macaques

Antiviral compounds (eg, the neuraminidase inhibitor oseltamivir) are invaluable for the treatment of individuals infected with influenza A viruses of the H7N9 subtype (A[H7N9]), which have infected and killed hundreds of persons. However, oseltamivir treatment often leads to the emergence of resistant viruses in immunocompromised individuals. To better understand the emergence and properties of oseltamivir-resistant A(H7N9) viruses in immunosuppressed individuals, we infected immunosuppressed cynomolgus macaques with an A(H7N9) virus and treated them with oseltamivir. Disease severity and mortality were higher in immunosuppressed than in immunocompetent animals. Oseltamivir treatment at 2 different doses reduced A(H7N9) viral titers in infected animals, but even high-dose oseltamivir did not block viral replication sufficiently to suppress the emergence of resistant variants. Some resistant variants were not appreciably attenuated in cultured cells, but an oseltamivir-resistant A(H7N9) virus did not transmit among ferrets. These findings are useful for the control of A(H7N9) virus infections in clinical settings.

Comparison of Efficacy of Intravenous Peramivir and Oral Oseltamivir for the Treatment of Influenza: Systematic Review and Meta-Analysis

PURPOSE

Peramivir is the first intravenously administered neuramidase inhibitor for immediate delivery of an effective single-dose treatment in patients with influenza. However, limited data are available on intravenous (IV) peramivir treatment compared to oral oseltamivir for these patients.

MATERIALS AND METHODS

With a systematic review and meta-analysis, we compared the efficacy of IV peramivir with oral oseltamivir for treatment of patients with seasonal influenza. MEDLINE, EMBASE, and Cochrane Central Register were searched for relevant clinical trials.

RESULTS

A total of seven trials [two randomized controlled trials (RCTs) and five non-randomized observational trials] involving 1676 patients were finally analyzed. The total number of peramivir- and oseltamivir-treated patients was 956 and 720, respectively. Overall, the time to alleviation of fever was lower in the peramivir-treated group compared with the oseltamivir-treated group [mean difference (MD), -7.17 hours; 95% confidence interval (CI) -11.00 to -3.34]. Especially, pooled analysis of observational studies (n=4) and studies of outpatients (n=4) demonstrated the superiority of the peramivir-treated group (MD, -7.83 hours; 95% CI -11.81 to -3.84 and MD, -7.71 hours; 95% CI -11.61 to -3.80, respectively). Mortality, length of hospital stay, change in virus titer 48 hours after admission, and the incidence of adverse events in these patients were not significantly different between the two groups.

CONCLUSION

IV peramivir therapy might reduce the time to alleviation of fever in comparison with oral oseltamivir therapy in patients with influenza; however, we could not draw clear conclusions from a meta-analysis because of the few RCTs available and methodological limitations.

Safety and efficacy of anti-influenza drugs, intravenous peramivir against influenza virus infection in elderly patients with underlying disease

We retrospectively analyzed data of 38 elderly patients, each with an underlying disease, to evaluate peramivir safety and efficacy. Six patients (15.8%) experienced adverse events, all tolerated. Median time from administration until the return to normal temperatures was 31.5 h (95% CI: 22.4-40.6). Results confirm intravenous peramivir's usefulness.

Analysis of an ordinal endpoint for use in evaluating treatments for severe influenza requiring hospitalization

Background/Aims A single best endpoint for evaluating treatments of severe influenza requiring hospitalization has not been identified. A novel six-category ordinal endpoint of patient status is being used in a randomized controlled trial (FLU-Intravenous Immunoglobulin - FLU-IVIG) of intravenous immunoglobulin. We systematically examine four factors regarding the use of this ordinal endpoint that may affect power from fitting a proportional odds model: (1) deviations from the proportional odds assumption which result in the same overall treatment effect as specified in the FLU-IVIG protocol and which result in a diminished overall treatment effect, (2) deviations from the distribution of the placebo group assumed in the FLU-IVIG design, (3) the effect of patient misclassification among the six categories, and (4) the number of categories of the ordinal endpoint. We also consider interactions between the treatment effect (i.e. factor 1) and each other factor. Methods We conducted a Monte Carlo simulation study to assess the effect of each factor. To study factor 1, we developed an algorithm for deriving distributions of the ordinal endpoint in the two treatment groups that deviated from proportional odds while maintaining the same overall treatment effect. For factor 2, we considered placebo group distributions which were more or less skewed than the one specified in the FLU-IVIG protocol by adding or subtracting a constant from the cumulative log odds. To assess factor 3, we added misclassification between adjacent pairs of categories that depend on subjective patient/clinician assessments. For factor 4, we collapsed some categories into single categories. Results Deviations from proportional odds reduced power at most from 80% to 77% given the same overall treatment effect as specified in the FLU-IVIG protocol. Misclassification and collapsing categories can reduce power by over 40 and 10 percentage points, respectively, when they affect categories with many patients and a discernible treatment effect. But collapsing categories that contain no treatment effect can raise power by over 20 percentage points. Differences in the distribution of the placebo group can raise power by over 20 percentage points or reduce power by over 40 percentage points depending on how patients are shifted to portions of the ordinal endpoint with a large treatment effect. Conclusion Provided that the overall treatment effect is maintained, deviations from proportional odds marginally reduce power. However, deviations from proportional odds can modify the effect of misclassification, the number of categories, and the distribution of the placebo group on power. In general, adjacent pairs of categories with many patients should be kept separate to help ensure that power is maintained at the pre-specified level.

Antiviral Treatments

Most viral respiratory tract infections are caused by classic respiratory viruses, including influenza, respiratory syncytial virus, human metapneumovirus, parainfluenza, rhinovirus, and adenovirus, whereas other viruses, such as herpes simplex, cytomegalovirus, and measles virus, can opportunistically affect the respiratory tract. The M2 inhibitors, amantadine and rimantadine, were historically effective for the prevention and treatment of influenza A but all circulating strains are currently resistant to these drugs. Neuraminidase inhibitors are the sole approved class of antivirals to treat influenza. Ribavirin, especially when combined with intravenous antibody, reduces morbidity and mortality among immunosuppressed patients.

In Vitro Evaluation of Absorption Characteristics of Peramivir for Oral Delivery

BACKGROUND AND OBJECTIVE

Peramivir is a novel antiviral agent approved for the treatment of severe influenza. However, the development of oral formulation of peramivir has been severely hurdled by poor bioavailability (human, ≤3%). The present work aims to evaluate oral permeability characteristics of peramivir.

METHODS

In vitro gastrointestinal stability, metabolic stability in human intestinal S9 fraction and Caco-2 permeability were performed. The liquid chromatography with tandem mass spectrometric (LC-MS/MS) was used to quantify peramivir in buffer and biological sample. Using GastroPlus™ software, intestinal effective permeability coefficient (P _eff) of peramivir was estimated.

RESULTS

Our results indicated that peramivir maintained stability in pH 5.5 and 7.4 buffers, fasted state simulated gastric fluid and fasted state simulated intestinal fluid, and human intestinal S9 fractions. The apparent permeability coefficient (P _app) values of peramivir (10 μM) were 3.29 ± 0.73 × 10^-7 cm/s in a Caco-2 cell model. In vivo intestinal effective permeability coefficient (P _eff) was estimated to be 0.06 × 10^-4 cm/s. Furthermore, co-incubating with cyclosporine, mitoxantrone, rifampicin, or paroxetine, the apical (AP) to basolateral (BL) flux of peramivir decreased (p < 0.05). The efflux and influx of peramivir was not significantly affected with co-incubation with verapamil, MK-571, or diclofenac (p > 0.05).

CONCLUSIONS

These results revealed that carrier-mediated transports, including OATP1B (organic anion transport 1B) and OCT1 (organic cation transport 1), might be involved in the absorption of peramivir. In conclusion, our results provide insight into the poor oral bioavailability of peramivir. Peramivir can be classified as a BCS-III (high solubility/low permeability) and BDDCS-III high solubility/poor metabolism) drug. The oral bioavailability of peramivir primarily depends on its permeability across cell membranes. Both of passive and active transports are involved in the permeability of peramivir.

Peramivir injection in the treatment of acute influenza: a review of the literature

Influenza virus infection is a major cause of morbidity and mortality in children and adults globally. Seasonal epidemics are common due to the rapid virus evolution, whereas the frequent emergence of antigenic variants can result in pandemics and sporadic/endemic avian influenza virus infections. Although annual vaccination is the mainstay for influenza prevention and control, the use of antiviral agents must be considered for treatment and prophylaxis against influenza. Currently available antiviral drugs include neuraminidase inhibitors (NAIs), adamantanes, and a novel polymerase inhibitor (favipiravir). Peramivir is a recently US Food and Drug Administration-approved NAI for the treatment of acute uncomplicated influenza in adults. The chemical structure of peramivir allows it to bind to the influenza neuraminidase with much higher affinity than oseltamivir. Peramivir is effective against a variety of influenza A and B subtypes and has a lower half-maximal inhibitory concentration compared to other NAIs in in vitro studies. Peramivir can be administered intravenously, a route that is favorable for hospitalized, critically ill patients with influenza. The long half-life of peramivir allows for once-daily dosing. The drug is eliminated primarily by the kidneys, warranting dose adjustments in patients with renal dysfunction. Studies have assessed the clinical efficacy of peramivir for treatment of pandemic influenza A (H1N1). Although anecdotal evidence supports the use of peramivir in pediatric patients, pregnant women, and hospitalized patients with severe influenza receiving continuous renal replacement therapy and extracorporeal membrane oxygenation, well-designed, controlled clinical trials should be conducted in order to assess its clinical efficacy in these patient populations.

Virological response to peramivir treatment in adults hospitalised for influenza-associated lower respiratory tract infections

An open-label trial on intravenous peramivir was conducted among adult patients hospitalised for influenza-associated lower respiratory tract complications (LRTCs). Virus culture and quantitative reverse transcription PCR (qRT-PCR) were performed serially until Day 10. Peramivir treatment was associated with viral RNA decline as well as culture and RNA negativity, which occurred at rates comparable with those of oseltamivir: by Day 5, viral load decline -2.5 log10 copies/mL [βinteraction -0.071, standard error (SE) 0.121, 95% confidence interval (CI) -0.309 to 0.167]; culture-negative, 94% (vs. 95%); and RNA-negative, 44% (vs. 36%). Extended treatment of >5 days was required in 69% of cases because of slow clinical resolution and viral clearance in LRTCs. Peramivir was well tolerated. These data are useful for future trial design in this unique population.

Peramivir: A Novel Intravenous Neuraminidase Inhibitor for Treatment of Acute Influenza Infections

Peramivir is a novel cyclopentane neuraminidase inhibitor of influenza virus. It was approved by the Food and Drug Administration in December 2014 for treatment of acute uncomplicated influenza in patients 18 years and older. For several months prior to approval, the drug was made clinically available under Emergency Use authorization during the 2009 H1N1 influenza pandemic. Peramivir is highly effective against human influenza A and B isolates as well as emerging influenza virus strains with pandemic potential. Clinical trials demonstrated that the drug is well-tolerated in adult and pediatric populations. Adverse events are generally mild to moderate and similar in frequency to patients receiving placebo. Common side effects include gastrointestinal disorders and decreased neutrophil counts but are self-limiting. Peramivir is administered as a single-dose via the intravenous route providing a valuable therapeutic alternative for critically ill patients or those unable to tolerate other administration routes. Successful clinical trials and post-marketing data in pediatric populations in Japan support the safety and efficacy of peramivir in this population where administration of other antivirals might not be feasible.

How I treat respiratory viral infections in the setting of intensive chemotherapy or hematopoietic cell transplantation

The widespread use of multiplex molecular diagnostics has led to a significant increase in the detection of respiratory viruses in patients undergoing cytotoxic chemotherapy and hematopoietic cell transplantation (HCT). Respiratory viruses initially infect the upper respiratory tract and then progress to lower respiratory tract disease in a subset of patients. Lower respiratory tract disease can manifest itself as airflow obstruction or viral pneumonia, which can be fatal. Infection in HCT candidates may require delay of transplantation. The risk of progression differs between viruses and immunosuppressive regimens. Risk factors for progression and severity scores have been described, which may allow targeting treatment to high-risk patients. Ribavirin is the only antiviral treatment option for noninfluenza respiratory viruses; however, high-quality data demonstrating its efficacy and relative advantages of the aerosolized versus oral form are lacking. There are significant unmet needs, including data defining the virologic characteristics and clinical significance of human rhinoviruses, human coronaviruses, human metapneumovirus, and human bocavirus, as well as the need for new treatment and preventative options.

Clinical Implications of Antiviral Resistance in Influenza

Influenza is a major cause of severe respiratory infections leading to excessive hospitalizations and deaths globally; annual epidemics, pandemics, and sporadic/endemic avian virus infections occur as a result of rapid, continuous evolution of influenza viruses. Emergence of antiviral resistance is of great clinical and public health concern. Currently available antiviral treatments include four neuraminidase inhibitors (oseltamivir, zanamivir, peramivir, laninamivir), M2-inibitors (amantadine, rimantadine), and a polymerase inhibitor (favipiravir). In this review, we focus on resistance issues related to the use of neuraminidase inhibitors (NAIs). Data on primary resistance, as well as secondary resistance related to NAI exposure will be presented. Their clinical implications, detection, and novel therapeutic options undergoing clinical trials are discussed.

Peramivir: evidence to support the use of the first approved intravenous therapy for influenza

Peramivir, an intravenous neuraminidase inhibitor, was first available in clinical practice during the 2009 A/H1N1 pandemic under an Emergency Use Authorization by the US FDA. As the lone intravenous neuraminidase inhibitor available and with a novel structure compared with the available neuraminidase inhibitors, it was offered as an alternative to patients not responding to existing therapy or without enteric access. Since the expiration of the Emergency Use Authorization, peramivir has undergone multiple clinical trials for the treatment of both uncomplicated influenza infection in the ambulatory setting and complicated influenza infection in the hospitalized setting. With the recent FDA approval of single-dose therapy for uncomplicated influenza infection, we will review the preclinical and clinical data, to date, on peramivir.

Emerging novel and antimicrobial-resistant respiratory tract infections: new drug development and therapeutic options

The emergence and spread of antimicrobial-resistant bacterial, viral, and fungal pathogens for which diminishing treatment options are available is of major global concern. New viral respiratory tract infections with epidemic potential, such as severe acute respiratory syndrome, swine-origin influenza A H1N1, and Middle East respiratory syndrome coronavirus infection, require development of new antiviral agents. The substantial rise in the global numbers of patients with respiratory tract infections caused by pan-antibiotic-resistant Gram-positive and Gram-negative bacteria, multidrug-resistant Mycobacterium tuberculosis, and multiazole-resistant fungi has focused attention on investments into development of new drugs and treatment regimens. Successful treatment outcomes for patients with respiratory tract infections across all health-care settings will necessitate rapid, precise diagnosis and more effective and pathogen-specific therapies. This Series paper describes the development and use of new antimicrobial agents and immune-based and host-directed therapies for a range of conventional and emerging viral, bacterial, and fungal causes of respiratory tract infections.

Safety and efficacy of peramivir for influenza treatment

Objective

This report presents a review of the efficacy and safety of peramivir, a neuraminidase inhibitor that was granted Emergency Use Authorization by the US Food and Drug Administration (FDA) from October 23, 2009 to June 23, 2010 during the 2009 H1N1 pandemic.

Methods

Literature was accessed via PubMed (January 2000–April 2014) using several search terms: peramivir; BCX-1812; RWJ 270201; H1N1, influenza; antivirals; and neuraminidase inhibitors. The peramivir manufacturers, Shionogi and Co Ltd and BioCryst Pharmaceuticals, were contacted to obtain unpublished data and information presented at recent scientific meetings. Information was obtained from the Centers for Disease Control and Prevention (CDC) and from US FDA websites. English-language and Japanese-language reports in the literature were reviewed and selected based on relevance, along with information from the CDC, US FDA, and the drug manufacturers.

Results

We obtained eleven clinical trial reports of intravenous peramivir, two of which described comparisons with oseltamivir. Seven of nine other recently reported published studies was a dose–response study. Clinical reports of critically ill patients and pediatric patients infected with pandemic H1N1 described that early treatment significantly decreased mortality. Peramivir administered at 300 mg once daily in adult patients with influenza significantly reduces the time to alleviation of symptoms or fever compared to placebo. It is likely to be as effective as other neuraminidase inhibitors.

Conclusion

Although peramivir shows efficacy for the treatment of seasonal and pH1N1 influenza, it has not received US FDA approval. Peramivir is used safely and efficiently in hospitalized adult and pediatric patients with suspected or laboratory-confirmed influenza. Peramivir might be a beneficial alternative antiviral treatment for many patients, including those unable to receive inhaled or oral neuraminidase inhibitors, or those requiring nonintravenous drug delivery.

Oseltamivir Dosing in Critically Ill Patients With Severe Influenza

OBJECTIVE

To evaluate the literature for published reports regarding the efficacy of standard versus higher dosing of oseltamivir in critically ill patients with severe influenza.

DATA SOURCES

An English-language literature search was conducted using MEDLINE (1966-February 2014) using the terms oseltamivir and influenza limited to humans and adults older than 19 years. Additional articles were identified through a manual search of the references obtained from the MEDLINE search.

STUDY SELECTION AND DATA EXTRACTION

Articles were manually screened for inclusion related to pharmacokinetic or clinical studies comparing varying doses of oseltamivir, particularly in the critically ill patient population. Studies investigating the pharmacokinetics of oseltamivir in continuous renal replacement therapy (CRRT) and extracorporeal membrane oxygenation (ECMO) were also included.

DATA SYNTHESIS

During the 2009 H1N1 influenza pandemic, the World Health Organization suggested 150 mg twice daily as a consideration in critically ill patients with severe influenza. The basis for the recommendation can be traced back to animal studies investigating the H5N1 virus. Three different studies in humans investigating higher doses in severe influenza have found no differences in clinical outcomes between standard and higher dosing. Pharmacokinetic studies suggest adequate absorption in critically ill patients. Although no dosage adjustment appears to be needed for ECMO patients, reduction may berequired for CRRT..

CONCLUSIONS

. Although additional data are needed for a definitive conclusion, the small body of literature available in humans does not support routine use of high-dose oseltamivir in critically ill patients.

Vaccination for seasonal influenza in patients with cancer: recommendations of the Italian Society of Medical Oncology (AIOM)

Background

Influenza virus causes annual epidemics in the winter–spring season with significant morbidity in the general population and important mortality in high-risk groups, including cancer patients. Opinions on the suitability of patients with malignancies not undergoing active treatment and in different phases of antineoplastic therapy, to receive influenza vaccination, vary considerably among oncologists, sometimes even within one center.

Methods

We reviewed available data, including recommendations by national health authorities, on impact of influenza in patients with cancer and their capacity to mount protective immunological responses to vaccination, thus allowing, on behalf of Italian Association of Medical Oncology, to make suitable recommendations for the prevention and treatment of seasonal influenza.

Results and discussion

Patients with cancer often have disease- or treatment-related immunosuppression, and as a consequence, they may have a suboptimal serologic response to influenza vaccination. The protective effect of the different preparations of influenza vaccines in patients with cancer has not been widely investigated, especially in adult patients harboring solid tumors. The optimal timing for administration of influenza vaccines in patients receiving chemotherapy is also not clearly defined. However, since vaccination is the most effective method, along with antiviral drugs in selected patients, for preventing influenza infection, it has to be recommended for cancer patients. Implementing vaccination of close contacts of oncology patients would be an additional tool for enhancing protection in fragile patient populations.

The effect of intravenous peramivir, compared with oral oseltamivir, on the outcome of post-influenza pneumococcal pneumonia in mice

BACKGROUND

Pneumococcal pneumonia often occurs secondary to influenza infection and accounts for a large proportion of the morbidity and mortality associated with seasonal and pandemic influenza outbreaks. Peramivir is a novel, intravenous neuraminidase inhibitor that exhibits potent antiviral activity against influenza A and B viruses. We investigated the efficacy of peramivir for modulating the severity of secondary pneumococcal pneumonia.

METHODS

CBA/JNCrlj mice, infected with influenza virus and superinfected with Streptococcus pneumoniae, were treated with either intravenous peramivir (single or multiple doses of 60 mg/kg/day) or oral oseltamivir at doses of 10 or 40 mg/kg/day in divided doses. The survival rate, viable bacterial count and virus titre in the lungs, as well as cytokine/chemokine concentration and histopathological findings were compared between both groups.

RESULTS

The median duration of survival of coinfected mice was significantly prolonged by treatment with multiple doses of peramivir, relative to mice treated with oseltamivir at either dose. Viable bacterial counts and virus titres in the lungs were significantly reduced by intravenous peramivir treatment compared with no treatment or oral oseltamivir treatment. The production of inflammatory cytokines/chemokines was also significantly suppressed by multiple dosing of peramivir compared with oseltamivir. Increased survival appeared to be mediated by decreased inflammation, manifested as lower levels of inflammatory cells and proinflammatory cytokines in the lungs and less severe histopathological findings. The lungs of mice treated with multiple doses of peramivir showed mild inflammatory changes compared to oseltamivir.

CONCLUSIONS

This study demonstrated that a multiple-dose regimen of intravenous peramivir was more efficacious than a single peramivir dose or multiple doses of oseltamivir for improving outcomes in pneumococcal pneumonia following influenza virus infection in mice.

Effect of double dose oseltamivir on clinical and virological outcomes in children and adults admitted to hospital with severe influenza: double blind randomised controlled trial

OBJECTIVE

To investigate the validity of recommendations in treatment guidelines to use higher than approved doses of oseltamivir in patients with severe influenza.

DESIGN

Double blind randomised trial.

SETTING

Thirteen hospitals in Indonesia, Singapore, Thailand, and Vietnam.

PARTICIPANTS

Patients aged ≥ 1 year admitted to hospital with confirmed severe influenza.

INTERVENTIONS

Oral oseltamivir at double dose (150 mg twice a day/paediatric equivalent) versus standard dose (75 mg twice a day/paediatric equivalent).

MAIN OUTCOME MEASURE

Viral status according to reverse transcriptase polymerase chain reaction (RT-PCR) for influenza RNA in nasal and throat swabs on day five.

RESULTS

Of 326 patients (including 246 (75.5%) children aged <15), 165 and 161 were randomised to double or standard dose oseltamivir, respectively. Of these, 260 (79.8%) were infected with influenza virus A (133 (40.8%) with A/H3N2, 72 (22.1%) with A/H1N1-pdm09, 38 (11.7%) with seasonal A/H1N1, 17 (5.2%) with A/H5N1) and 53 (16.2%) with influenza virus B. A further 3.9% (13) were false positive by rapid antigen test (negative by RT-PCR and no rise in convalescent haemagglutination inhibition titers). Similar proportions of patients were negative for RT-PCR on day five of treatment: 115/159 (72.3%, 95% confidence interval 64.9% to 78.7%) double dose recipients versus 105/154 (68.2%, 60.5% to 75.0%) standard dose recipients; difference 4.2% (-5.9 to 14.2); P=0.42. No differences were found in clearance of virus in subgroup analyses by virus type/subtype, age, and duration of illness before randomisation. Mortality was similar: 12/165 (7.3%, 4.2% to 12.3%) in double dose recipients versus 9/161 (5.6%, 3.0% to 10.3%) in standard dose recipients. No differences were found between double and standard dose arms in median days on supplemental oxygen (3 (interquartile range 2-5) v 3.5 (2-7)), in intensive care (4.5 (3-6) v 5 (2-11), and on mechanical ventilation (2.5 (1-16) v 8 (1-16)), respectively. No important differences in tolerability were found.

CONCLUSIONS

There were no virological or clinical advantages with double dose oseltamivir compared with standard dose in patients with severe influenza admitted to hospital.

REGISTRATION

Clinical Trials NCT00298233.