Long-acting Neuraminidase Inhibitor Laninamivir Octanoate as Post-exposure Prophylaxis for Influenza

Clin Infect Dis. 2016 Aug 1;63(3):330-7. doi: 10.1093/cid/ciw255. Epub 2016 Apr 26.


Background: 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.

Methods: 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.

Results: 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.

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

Clinical trials registration: JapicCTI-142679.

Keywords: influenza; laninamivir; neuraminidase inhibitor; post-exposure; prophylaxis.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Administration, Inhalation
  • Adolescent
  • Adult
  • Antiviral Agents / administration & dosage*
  • Child
  • Double-Blind Method
  • Enzyme Inhibitors / administration & dosage*
  • Family Characteristics
  • Female
  • Guanidines
  • Humans
  • Influenza, Human / prevention & control*
  • Male
  • Middle Aged
  • Neuraminidase / antagonists & inhibitors*
  • Post-Exposure Prophylaxis
  • Pyrans
  • Sialic Acids
  • Young Adult
  • Zanamivir / administration & dosage
  • Zanamivir / analogs & derivatives*


  • Antiviral Agents
  • Enzyme Inhibitors
  • Guanidines
  • Pyrans
  • Sialic Acids
  • laninamivir
  • Neuraminidase
  • Zanamivir