title: Laninamivir octanoate for post-exposure prophylaxis of influenza in household contacts: a randomized double blind placebo controlled trial.
abstract: Laninamivir octanoate, a long-acting neuraminidase inhibitor, is an effective treatment for influenza. However, its effectiveness for the prevention of influenza has not yet been demonstrated. We conducted a double-blind, multicenter, randomized, placebo-controlled trial to determine whether laninamivir octanoate was superior to a placebo for post-exposure prophylaxis of influenza in household contacts. Eligible participants, who were household members who did not have influenza and were in contact with an influenza-infected index patient, were randomly assigned (1:1:1) to one of three groups: 20 mg of laninamivir octanoate once daily for 2 days (LO-2), 20 mg of laninamivir octanoate once daily for 3 days (LO-3), or a placebo. The primary endpoint was the proportion of participants who developed clinical influenza during a 10-day period. A total of 1711 participants were enrolled, and 1451 participants were included in the primary analysis. The proportion of participants with clinical influenza was 3.9 % (19/487) in the LO-2 group, 3.7 % (18/486) in the LO-3 group, and 16.9 % (81/478) in the placebo group (P < 0.001 for each of the laninamivir octanoate group). The relative risk reductions, compared with the placebo group, were 77.0 % [95 % confidence interval (CI) 62.7-85.8] and 78.1 % (95 % CI 64.1-86.7 %) for the LO-2 and LO-3 groups, respectively. The incidences of adverse events in the laninamivir octanoate groups were similar to that in the placebo group. The inhalation of 20 mg of laninamivir octanoate once daily for 2 or 3 days was well tolerated and effectively prevented the development of influenza in household contacts.
authors.affiliation: Kashiwagi Clinic, SS Building Hakata-Ekimae 4F, 3-21-15 Hakataekimae, Hakata-ku, Fukuoka, 812-0011, Japan. s-kashiwagi@daido-g.jp
authors.forename: Seizaburo
authors.initials: S
authors.lastname: Kashiwagi
authors.forename: Akira
authors.initials: A
authors.lastname: Watanabe
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ikematsu
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Awamura
authors.forename: Takako
authors.initials: T
authors.lastname: Okamoto
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Uemori
authors.forename: Katsuyasu
authors.initials: K
authors.lastname: Ishida
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D018562:Disease Transmission, Infectious / Q000517:prevention & control; D004311:Double-Blind Method; D005191:Family Characteristics; D005260:Female; D006146:Guanidines; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000188:drug therapy / Q000517:prevention & control* / Q000635:transmission; D008297:Male; D008875:Middle Aged; D010919:Placebos; D056990:Post-Exposure Prophylaxis / Q000379:methods; D011714:Pyrans; D012794:Sialic Acids; D053243:Zanamivir / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000998:Antiviral Agents; D006146:Guanidines; D010919:Placebos; D011714:Pyrans; D012794:Sialic Acids; C546918:laninamivir; D053243:Zanamivir