Safety and efficacy of peramivir for influenza treatment

Retracted and republished from: "The current state of research on influenza antiviral drug development: drugs in clinical trial and licensed drugs"

Influenza viruses (IVs) threaten global human health due to the high morbidity, infection, and mortality rates. Currently, the influenza drugs recommended by the Food and Drug Administration are oseltamivir, zanamivir, peramivir, and baloxavir marboxil. These recommended antivirals are currently effective for major subtypes of IVs as the compounds target conserved domains in neuraminidase or polymerase acidic (PA) protein. However, this trend may gradually change due to the selection of antiviral drugs and the natural evolution of IVs. Therefore, there is an urgent need to develop drugs related to the treatment of influenza to deal with the next pandemic. Here, we summarized the cutting-edge research in mechanism of action, inhibitory activity, and clinical efficacy of drugs that have been approved and drugs that are still in clinical trials for influenza treatment. We hope this review will provide up-to-date and comprehensive information on influenza antivirals and generate hypotheses for screens and development of new broad-spectrum influenza drugs in the near future.

Antiviral options and therapeutics against influenza: history, latest developments and future prospects

Drugs and chemotherapeutics have helped to manage devastating impacts of infectious diseases since the concept of 'magic bullet'. The World Health Organization estimates about 650,000 deaths due to respiratory diseases linked to seasonal influenza each year. Pandemic influenza, on the other hand, is the most feared health disaster and probably would have greater and immediate impact on humanity than climate change. While countermeasures, biosecurity and vaccination remain the most effective preventive strategies against this highly infectious and communicable disease, antivirals are nonetheless essential to mitigate clinical manifestations following infection and to reduce devastating complications and mortality. Continuous emergence of the novel strains of rapidly evolving influenza viruses, some of which are intractable, require new approaches towards influenza chemotherapeutics including optimization of existing anti-infectives and search for novel therapies. Effective management of influenza infections depend on the safety and efficacy of selected anti-infective in-vitro studies and their clinical applications. The outcomes of therapies are also dependent on understanding diversity in patient groups, co-morbidities, co-infections and combination therapies. In this extensive review, we have discussed the challenges of influenza epidemics and pandemics and discoursed the options for anti-viral chemotherapies for effective management of influenza virus infections.

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

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

Treatment and prevention of influenza in geriatric patients

INTRODUCTION

Older adults are the most vulnerable population to the effects of influenza. These patients have age-related characteristics that make response to both infection and therapeutics different than younger patients.

AREAS COVERED

Influenza vaccination and antiviral therapy are the foundational approaches to preventing and treating influenza in geriatric patients. Older adults should receive one of the three enhanced vaccines before influenza season beings. There are five antivirals used in influenza. Geriatric patients have been under-enrolled in antiviral studies but have been included in small numbers. Oseltamivir has the most abundant evidence, including in the hospital and long-term care (LTC) facilities, and the strongest evidence for reducing mortality and complications. Peramivir offers the shortest time for symptom alleviation, while baloxavir is best tolerated.

EXPERT OPINION

Oseltamivir has the most versatility in preventing and treating influenza in geriatric patients. Parenteral peramivir and zanamivir are second-line alternatives for complicated influenza when oseltamivir cannot be used. Single-dose peramivir and baloxavir are attractive alternatives to oseltamivir in uncomplicated influenza but will not increase in utilization until more evidence is available regarding mortality and complications, particularly in hospitalized and LTC patients. More studies, including comparative trials, are required to elucidate the role in therapy for each therapeutic in the geriatric population.

In Silico Studies Reveal Peramivir and Zanamivir as an Optimal Drug Treatment Even If H7N9 Avian Type Influenza Virus Acquires Further Resistance

An epidemic of avian type H7N9 influenza virus, which took place in China in 2013, was enhanced by a naturally occurring R294K mutation resistant against Oseltamivir at the catalytic site of the neuraminidase. To cope with such drug-resistant neuraminidase mutations, we applied the molecular docking technique to evaluate the fitness of the available drugs such as Oseltamivir, Zanamivir, Peramivir, Laninamivir, L-Arginine and Benserazide hydrochloride concerning the N9 enzyme with single (R294K, R119K, R372K), double (R119_294K, R119_372K, R294_372K) and triple (R119_294_372K) mutations in the pocket. We found that the drugs Peramivir and Zanamivir score best amongst the studied compounds, demonstrating their high binding potential towards the pockets with the considered mutations. Despite the fact that mutations changed the shape of the pocket and reduced the binding strength for all drugs, Peramivir was the only drug that formed interactions with the key residues at positions 119, 294 and 372 in the pocket of the triple N9 mutant, while Zanamivir demonstrated the lowest RMSD value (0.7 Å) with respect to the reference structure.

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.

Neuraminidase inhibitors are effective and safe in reducing influenza complications: meta-analysis of randomized controlled trials

BACKGROUND

There is scarce evidence verifying the impact of neuraminidase inhibitors (NAIs) in reducing influenza complications. The aim was to evaluate the available evidence from randomized-controlled trials (RCT) regarding the efficacy and safety of NAIs in reducing influenza complications.

METHODS

A systematic search of the literature was performed in the Cochrane Library, PubMed and Web of Science databases (2006-2019). Eligibility criteria were RCT that enrolled patients of any age or clinical severity with seasonal influenza (H₁N₁, H₃N_2, or B) or influenza-like syndrome and receiving NAIs comparing to placebo therapy.

RESULTS

Eighteen RCTs (9004 patients) were included: nine focused on oral oseltamivir, six on inhaled zanamivir, and three on intravenous peramivir. Administration of NAIs therapy significantly decreased the time to clinical resolution (median difference: -17.7 hours; and total influenza-related complications (OR: 0.64, 95%CI: 0.51-0.82). In addition, NAIs significantly decreased acute otitis media complication (OR: 0.50, 95%CI: 0.31-0.82) and need for antibiotic treatment (OR: 0.64, 95%CI: 0.46-0.90); and showed a trend towards a reduced occurrence of pneumonia (OR: 0.44, 95%CI: 0.10-2.00), bronchitis (OR: 0.80, 95%CI: 0.43-1.48), sinusitis (OR: 0.73, 95%CI: 0.40-1.32), asthma exacerbations (OR: 0.57, 95%CI: 0.28-1.16), and hospitalizations (OR: 0.57, 95%CI: 0.24-1.38). The overall proportion of AEs tend to increase with NAIs treatment (OR: 1.16, 95%CI: 0.92-1.47). Use of NAIs was associated with a significant increase of nausea and vomiting (OR: 1.61, 95%CI: 1.04-2.50) and a decrease on diarrhea (OR: 0.81, 95%CI: 0.65-1.00).

CONCLUSIONS

NAIs are effective in reducing time to clinical resolution, total influenza-related complications, otitis media, and need of antibiotic administration. Reductions on mortality, pneumonia, asthma exacerbations or hospitalization rates only did demonstrate a trend benefit in favor of NAIs. The only significant AE is the increased occurrence of nausea and vomiting.

Pharmacokinetic behavior of peramivir in the plasma and lungs of rats after trans-nasal aerosol inhalation and intravenous injection

Peramivir, a neuraminidase inhibitor, was approved globally and is indicated for the treatment of uncomplicated influenza in adults and children. However, the only approved intravenous formulation of peramivir limits its clinical application due to the need for the specialized dosing techniques and increases the risk of contracting influenza virus infection among healthcare professionals when dosing within a short distance to the patient. The purpose of this study was to investigate the pharmacokinetic profile of peramivir in plasma and the lung of rats and to compare the profiles following administration through trans-nasal aerosol inhalation (0.0888, 0.1776, and 0.3552 mg/kg) and intravenous injection (30 mg/kg). The plasma concentration reached the C_max within 1.0 h (upon inhalation) and decreased at a t_1/2 of 6.71 and 10.9 h after inhalation and injection, respectively. The absolute bioavailability of peramivir after inhalation was 78.2 %. Overall, the pharmacokinetic exposure of peramivir in the lungs was higher than that in the plasma after aerosol inhalation. After inhalation, the C_max of peramivir in the lung was achieved within 1.0 h, and the elimination of the drug was slower than in the case of intravenous injection with t_1/2 values 1.81 h for injection and 5.72, 53.5, and 32.1 h for low, middle, and high doses administered through inhalation. The C_max and AUC_0-t values for peramivir in the lungs increased linearly with the increased inhalation dose. The results elucidate the pharmacokinetic process of peramivir after trans-nasal aerosol inhalation to rats and provide useful information for further rational application of this drug formulation.

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.

Peramivir for Influenza A and B Viral Infections: A Pharmacokinetic Case Series

Objective

To describe the peramivir (PRV) pharmacokinetics in critically ill children treated for influenza A or B viral infections.

Design

Retrospective electronic medical record review of prospectively collected data from critically ill children receiving peramivir for influenza A or B viral infections in the pediatric intensive care unit (PICU).

Setting

A 189‐bed, freestanding children's tertiary care teaching hospital in Philadelphia, PA.

Patients

Critically ill children admitted to the PICU who were infected with influenza between January 1, 2016 and March 31, 2018.

Interventions

None.

Results

Eleven patients, two females (18%) and nine males (82%), accounted for 24 peramivir samples for therapeutic drug management. The median age was 5 years (interquartile range 1.5–6.5 yrs) with a median weight of 16.4 kg (interquartile range 14–24 kg). Ten (91%) patients demonstrated a larger volume of distribution, 11 (100%) patients demonstrated an increase in clearance, and 11 (100%) patients demonstrated a shorter half‐life estimate as compared with the package insert and previous pediatric trial data for peramivir. Eight (73%) patients tested positive for a strain of influenza A and 3 (27%) patients tested positive for influenza B; 4 of 11 (36%) patients tested positive for multiple viruses. All patients had adjustments made to their dosing interval to a more frequent interval. Ten (91%) patients were adjusted to an every‐12‐hour regimen and 1 (9%) patient was adjusted to an every‐8‐hour regimen. No adverse events were associated with peramivir treatment.

Conclusion

The pharmacokinetics of PRV demonstrated in this PICU cohort differs in comparison to healthy pediatric and adult patients, and alterations to dosing regimens may be needed in PICU patients to achieve pharmacodynamic exposures. Additional investigations in the PICU population are needed to confirm these findings.

Influenza

Influenza is an infectious respiratory disease that, in humans, is caused by influenza A and influenza B viruses. Typically characterized by annual seasonal epidemics, sporadic pandemic outbreaks involve influenza A virus strains of zoonotic origin. The WHO estimates that annual epidemics of influenza result in ~1 billion infections, 3–5 million cases of severe illness and 300,000–500,000 deaths. The severity of pandemic influenza depends on multiple factors, including the virulence of the pandemic virus strain and the level of pre-existing immunity. The most severe influenza pandemic, in 1918, resulted in >40 million deaths worldwide. Influenza vaccines are formulated every year to match the circulating strains, as they evolve antigenically owing to antigenic drift. Nevertheless, vaccine efficacy is not optimal and is dramatically low in the case of an antigenic mismatch between the vaccine and the circulating virus strain. Antiviral agents that target the influenza virus enzyme neuraminidase have been developed for prophylaxis and therapy. However, the use of these antivirals is still limited. Emerging approaches to combat influenza include the development of universal influenza virus vaccines that provide protection against antigenically distant influenza viruses, but these vaccines need to be tested in clinical trials to ascertain their effectiveness.

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.

Combating mutations in genetic disease and drug resistance: understanding molecular mechanisms to guide drug design

INTRODUCTION

Mutations introduce diversity into genomes, leading to selective changes and driving evolution. These changes have contributed to the emergence of many of the current major health concerns of the 21st century, from the development of genetic diseases and cancers to the rise and spread of drug resistance. The experimental systematic testing of all mutations in a system of interest is impractical and not cost-effective, which has created interest in the development of computational tools to understand the molecular consequences of mutations to aid and guide rational experimentation. Areas covered: Here, the authors discuss the recent development of computational methods to understand the effects of coding mutations to protein function and interactions, particularly in the context of the 3D structure of the protein. Expert opinion: While significant progress has been made in terms of innovative tools to understand and quantify the different range of effects in which a mutation or a set of mutations can give rise to a phenotype, a great gap still exists when integrating these predictions and drawing causality conclusions linking variants. This often requires a detailed understanding of the system being perturbed. However, as part of the drug development process it can be used preemptively in a similar fashion to pharmacokinetics predictions, to guide development of therapeutics to help guide the design and analysis of clinical trials, patient treatment and public health policy strategies.

Influenza viruses - antiviral therapy and resistance

Influenza is a serious and frequently underestimated, but vaccine preventable disease. The adamantane derivates rimantadine and amantadine and the neuraminidase inhibitors zanamivir and oseltamivir are the only antiviral drugs currently approved in Europe for therapy and prophylaxis of influenza infections. Resistance to these drugs occurs due to mutations within the therapeutic target proteins M2 ion channel protein and viral neuraminidase. An unexpected occurrence of oseltamivir-resistant seasonal A(H1N1) viruses was detected in winter 2007/2008. The prevalence of these viruses increased rapidly and nearby all viruses circulating during the following seasons were resistant to oseltamivir. The A(H1N1)pdm09 viruses replaced the former seasonal A(H1N1) subtype during the 2009-2010 influenza season. Fortunately, resistance to neuraminidase inhibitors was detected in A(H1N1)pdm09, A(H3N2) and influenza B viruses only sporadically and was treatment related mostly. Comprehensive analyses of circulating viruses showed a high prevalence of A(H3N2) influenza viruses that are resistant to adamantane derivates since 2004/2005 and a progressive trend in the prevalence of resistant viruses up to 100% in following seasons. The M2 ion channel protein of A(H1N1)pdm09 viruses is associated with the Eurasian avian-like swine lineage and thus show "natural" resistance to adamantane derivates. Therefore, only neuraminidase inhibitors are recommended for influenza treatment today. This manuscript summarizes the occurrence and spread of antiviral resistant influenza viruses and highlights the importance for developing and/or approving new antiviral compounds.

Influenza Virus Shedding in Laninamivir-Treated Children upon Returning to School

The current School Health and Safety Act in Japan states that children with influenza infection should stay home until day 6(th) after symptoms onset. This was an amendment of a previous version recommending school return on day 3 after defervescence. Here, we investigated the duration of fever and virus shedding after laninamivir treatment in 7 children infected with influenza A(H3N2) virus and 21 children with influenza B virus in relation to the school return timing recommended by the School Health and Safety Act during the 2011-2012 influenza season. Nasal discharge was collected on the first, second, and third hospital visits and virus titers were assessed by virus culture and real-time PCR. Duration of fever after laninamivir treatment was 1 day longer for influenza B than for influenza A(H3N2). Virus detection rates with 50% tissue culture infectious dose and viral RNA were highest at the first visit and gradually decreased at subsequent visits. Virus positivity rates were detectable at the time of defervescence in less than half of the enrolled patients (14.3-42.9%). Virus shedding rates were similarly low (0.0-19.0%) on day 3 or later from defervescence and on day 6 or later from fever onset (school return dates per the old and current School Health and Safety Act) regardless of the influenza type. In conclusion, despite the higher efficacy of laninamivir against A(H3N2) viruses than B viruses, viral shedding is low after return to school for both types, regardless of the version of the School Health and Safety Act.

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.

Opportunities for the development of novel therapies based on host-microbial interactions

Immune responses are fundamental for protecting against most infectious agents. However, there is now much evidence to suggest that the pathogenesis and tissue damage after infection are not usually related to the direct action of the replication of microorganisms, but instead to altered immune responses triggered after the contact with the pathogen. This review article discusses several mechanisms necessary for the host to protect against microbial infection and focuses in aspects that cause altered inflammation and drive immunopathology. These basic findings can ultimately reveal pathways amenable to host-directed therapy in adjunct to antimicrobial therapy for future improved control measures for many infectious diseases. Therefore, modulating the effects of inflammatory pathways may represent a new therapy during infection outcome and disease.

Antiviral therapy in seasonal influenza and 2009 H1N1 pandemic influenza: Korean experiences and perspectives

Influenza is a major cause of substantial morbidity and mortality in humans every year. Vaccination is the main strategy to prevent influenza infection, but antiviral agents also play an important role in the control of both seasonal and pandemic influenza. During the influenza A/H1N1 pandemic in 2009, early prompt antiviral therapy may have reduced the severity of the influenza outcomes including pneumonia, hospitalization and mortality in the Republic of Korea. Since the 2009 H1N1 pandemic, there have been increasing usages of antiviral agents for the treatment of patients with seasonal influenza. Although currently rare, antiviral resistance among influenza viruses may emerge and increase with increased use of neuraminidase inhibitors. New agents with different modes of action are under investigation, including favipiravir, DAS181, nitazoxanide and broad-spectrum neutralizing monoclonal antibodies. Data are limited with respect to high-dose and combination antiviral therapies. So, clinical trials are warranted to evaluate diverse antiviral combinations that may be synergistic and less likely to induce breakthrough resistance.

Rates and effectiveness of antiviral use among hospitalized influenza patients

The influenza virus is currently a global public health problem. There are several thousand cases of classic and newly emerging atypical influenza virus infections around the world annually. Prevention, early diagnosis and treatment are the keys to managing influenza outbreaks. Some influenza treatments have proven to be more useful than others. A standard antiviral drug has been developed and is recommended for the management of hospitalized influenza patients. This article briefly outlines the rates and effectiveness of antiviral use among hospitalized influenza patients. It also discusses some important considerations regarding controversial issues and future perspectives on antiviral use for the management of hospitalized influenza patients.

Optimizing antiviral therapy for influenza: understanding the evidence

Influenza is an important cause of annual epidemics of respiratory viral infection associated with significant morbidity and mortality. Three classes of drugs, the M2 ion channel, neuraminidase and RNA-dependent RNA polymerase inhibitors, are approved for the prevention and treatment of influenza. Due to widespread resistance to the class, the M2 ion channel inhibitors are not recommended currently for therapy. The only polymerase inhibitor, favipiravir, is approved only in Japan and its use is highly restricted. Despite significant data to support the early use of the neuraminidase inhibitors, their use in all patient populations is suboptimal. The data to support the early use of neuraminidase inhibitors will be reviewed, as will current data on the utilization rates in ambulatory and hospitalized populations.