Long-acting Neuraminidase Inhibitor Laninamivir Octanoate as Post-exposure Prophylaxis for Influenza.
A single administration of laninamivir octanoate, a long-acting neuraminidase inhibitor, has been proven to be effective in the treatment of influenza but not for post-exposure prophylaxis.



We conducted a double-blind, multicenter, randomized, placebo-controlled study to determine if a single administration of laninamivir octanoate 40 mg was superior to placebo for post-exposure prophylaxis. Eligible participants who had cohabited with an influenza patient within 48 hours of symptom onset were randomly assigned (1:1:1) to 1 of 3 groups: 40 mg of laninamivir octanoate single administration (LO-40SD), 20 mg of laninamivir octanoate once daily for 2 days (LO-20TD), or placebo. The primary efficacy endpoint was the proportion of participants who developed clinical influenza (defined as influenza virus positive, an axillary temperature >37.5°C, and at least 2 symptoms) over a 10-day period.



A total of 803 participants were enrolled, with 801 included in the primary analysis. The proportions of participants with clinical influenza were 4.5% (12/267), 4.5% (13/269), and 12.1% (32/265) in the LO-40SD, LO-20TD, and placebo groups, respectively. A single administration of laninamivir octanoate 40 mg significantly reduced the development of influenza compared with placebo (P = .001). The relative risk reductions compared with the placebo group were 62.8% and 63.1% for the LO-40SD and LO-20TD groups, respectively. The incidence of adverse events in the LO-40SD group was similar to that of the LO-20TD and placebo groups.



A single administration of laninamivir octanoate was effective and well tolerated as post-exposure prophylaxis to prevent the development of influenza.



JapicCTI-142679.
Japan Physicians Association, Tokyo.
Seizaburo
S
Kashiwagi
Research Division for Development of Anti-Infective Agents, Institute of Development, Aging and Cancer, Tohoku University, Sendai.
Akira
A
Watanabe
Japan Physicians Association, Tokyo.
Hideyuki
H
Ikematsu
Biostatistics & Data Management Department.
Mitsutoshi
M
Uemori
Clinical Development Department, Daiichi Sankyo Co., Ltd., Tokyo, Japan.
Shinichiro
S
Awamura
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000008:administration & dosage*; D002648:Child; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D005191:Family Characteristics; D005260:Female; D006146:Guanidines; D006801:Humans; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D056990:Post-Exposure Prophylaxis; D011714:Pyrans; D012794:Sialic Acids; D055815:Young Adult; D053243:Zanamivir / Q000008:administration & dosage / Q000031:analogs & derivatives*
D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; C546918:laninamivir; D009439:Neuraminidase; D053243:Zanamivir
influenza; laninamivir; neuraminidase inhibitor; post-exposure; prophylaxis