Duration of fever and other symptoms after the inhalation of laninamivir octanoate hydrate for influenza treatment; comparison among the four Japanese influenza seasons from 2011-2012 to 2014-2015

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.

Duration of fever and other symptoms after the inhalation of laninamivir octanoate hydrate in the 2016/17 Japanese influenza season; comparison with the 2011/12 to 2015/16 seasons

The duration of fever and symptoms after laninamivir octanoate hydrate (laninamivir) inhalation were investigated in the Japanese 2016/17 influenza season and the results were compared with those of the 2011/12 to 2015/16 seasons. A total of 1278 patients were evaluated for the duration of fever and symptoms in the six studied seasons. In the 2016/17 season, the influenza types/subtypes of the patients were 6 A (H1N1)pdm09 (2.9%), 183 A (H3N2) (87.6%), and 20 B (9.6%). The respective median durations of fever for A (H1N1)pdm09, A (H3N2), and B were 38.0, 33.0, and 38.5 h, without significant difference (p = 0.9201), and the median durations of symptoms were 86.5, 73.0, and 99.0 h, with significant difference (p = 0.0342). The median durations of fever and symptoms after laninamivir inhalation were quite consistent for the six studied seasons for A (H1N1)pdm09, A (H3N2), and B, without any significant differences. The percentage of patients with unresolved fever patients displayed a similar pattern through the six studied seasons for all these virus types. There was no significant difference in the duration of fever or symptoms between the Victoria and Yamagata lineages in the 2016/17 season and those of the previous studied seasons. Over the seasons tested, ten adverse drug reactions (ADRs) were reported from 1341 patients. The most frequent ADR was diarrhea and all ADRs were self-resolving and not serious. These results indicate the continuing clinical effectiveness of laninamivir against influenza A (H1N1)pdm09, A (H3N2), and B, with no safety issues.

Impact of the number of repeated inhalations and patient characteristics on the residual amount of inhaled laninamivir octanoate hydrate dry powder in pediatric patients with influenza

BACKGROUND

A dry powder inhaled formulation is used for the anti-influenza drug laninamivir octanoate hydrate (laninamivir). Although two successive inhalations (puffs) are recommended to minimize residual amounts of active ingredients, previous reports suggest that pediatric patients with low peak inspiratory flow are unable to inhale the active ingredient adequately. In the present study, we prospectively investigated the appropriate number of repeated inhalations of laninamivir dry powder and factors influencing the residual amount of ingredients in pediatric patients with influenza.

METHODS

The study enrolled 64 patients receiving laninamivir dry powder inhaler (Inavir®) between January and March 2016 at Tsu emergency medical center/pediatric clinic and dental clinic. All patients enrolled used a laninamivir dry powder inhaler in four repeated inhalations, as instructed by a pharmacist. The residual amount of laninamivir dry powder was calculated by measuring the device weight before and after each inhalation and a residual amount of >20% was defined as an unsuccessful inhalation.

RESULTS

The inadequate inhalation rate after two successive inhalations was 45%, and it decreased as number of inhalation repeats increased, reaching 23% after four successive inhalations. Peak inspiratory flow in patients with inadequate inhalation was significantly lower than that in patients with adequate inhalation, for all numbers of inhalation repeats analyzed. Receiver operating characteristic analyses indicated peak inspiratory flow cut-off values of 140, 120, 100, and 100 L/min at 1-4 successive inhalations, respectively.

CONCLUSIONS

The present findings suggest that a proportion of patients with low peak inspiratory flow were unable to inhale the active ingredient adequately when laninamivir dry powder inhaler was administered as two successive inhalations, as recommended in the instruction manual. Three or four repeated inhalations of laninamivir dry powder inhaler should be administered to pediatric patients with low peak inspiratory flow.

The intratracheal administration of locked nucleic acid containing antisense oligonucleotides induced gene silencing and an immune-stimulatory effect in the murine lung

Locked nucleic acid containing antisense oligonucleotides (LNA-ASOs) have the potential to modulate the disease-related gene expression by the RNaseH-dependent degradation of mRNAs. Pulmonary drug delivery has been widely used for the treatment of lung disease. Thus, the inhalation of LNA-ASOs is expected to be an efficient therapy that can be applied to several types of lung disease. Because the lung has a distinct immune system against pathogens, the immune-stimulatory effect of LNA-ASOs should be considered for the development of novel inhaled LNA-ASOs therapies. However, there have been no reports on the relationship between knock-down (KD) and the immune-stimulatory effects of inhaled LNA-ASOs in the lung. In this report, LNA-ASOs targeting Scarb1 (Scarb1-ASOs) or negative control LNA-ASOs targeting ApoB (ApoB-ASOs) were intratracheally administered to mice to investigate the KD of the gene expression and the immune-stimulatory effects in the lung. We confirmed that the intratracheal administration of Scarb1-ASOs exerted a KD effect in the lung without a drug delivery system. On the other hand, both Scarb1-ASOs and ApoB-ASOs induced neutrophilic infiltration in the alveoli and increased the expression levels of G-CSF and CXCL1 in the lung. The dose required for KD was the same as the dose that induced the neutrophilic immune response. In addition, in our in vitro experiments, Scarb1-ASOs did not increase the G-CSF or CXCL1 expression in primary lung cells, even though Scarb1-ASOs exerted a strong KD effect. Hence, we hypothesize that inhaled LNA-ASOs have the potential to exert a KD effect in the lung, but that they may be associated with a risk of immune stimulation. Further studies about the mechanism underlying the immune-stimulatory effect of LNA-ASOs is necessary for the development of novel inhaled LNA-ASO therapies.