The inhaled neuraminidase inhibitor laninamivir has been shown to significantly reduce the likelihood of developing influenza among children exposed to a family member with the infection, according to a study recently published in Pediatrics.
In a double-blind, placebo-controlled study, researchers randomized 343 children under 10 years old – who had an influenza-infected family member – to a single 20-mg dose of inhaled laninamivir octanoate or placebo.
After 10 days, there were 18 cases of influenza in the laninamivir group (11%), compared with 33 (19%) in the placebo group, representing a risk reduction of 45.8% (P = .02).
Subgroup analyses suggested the treatment was more effective in children under 7 years old, with a relative risk reduction of 64%, compared with a non–statistically significant 28% reduction in those aged 7-10 years (Pediatrics. 2016 Nov 2. doi: 10.1542/peds.2016-0109 ).
The treatment was also effective among children where the index case was infected with influenza A (H3N2).
Dr. Takashi Nakano, from Kawasaki Hospital in Okayama, Japan, and coauthors reported a similar incidence of adverse events in the laninamivir and placebo groups, with no serious adverse events and no withdrawals due to adverse events. However, the authors noted that there were very few study participants considered at high risk, such as patients with chronic respiratory disease, and suggested further studies of the impact and efficacy of treatment in high-risk groups.
The researchers noted that, despite increasing rates of influenza vaccination and the availability of other neuraminidase inhibitors, such as oseltamivir and peramivir, pandemic outbreaks of influenza are still occurring. There has also been evidence of resistance to both oseltamivir and peramivir, for example, in the 2013/2014 outbreak of influenza A (H1N1) in Japan. “Given the limitations of vaccination, extensive variations in the option for antiinfluenza prophylaxis are desirable as an adjunct to influenza vaccine,” the researchers wrote.
Laninamivir has been studied in adults and children and shown to be effective at treating influenza infection, but its efficacy as prophylaxis in children under 10 years old had not previously been studied.
“Since a single 20-mg dose of laninamivir octanoate revealed prophylactic effect, the regimen in the current study is a highly user-friendly option,” the researchers wrote. “Although the numbers of infected individuals may differ by season, the number needed to treat based on the incidence of clinical influenza for the two groups in the current study was 11.”
The study was funded by Daiichi Sankyo. Two of the study authors reported being consultants for Daiichi Sankyo, as well as having financial relationships with other pharmaceutical companies. The other study authors are employees of Daiichi Sankyo.