Laninamivir, a potent
neuraminidase (NA) inhibitor, is an active metabolite of
laninamivir octanoate (code name:
CS-8958) which is a long acting NA inhibitor and is commercially available under the brand name Inavir in Japan to complete the treatment of
influenza by a single inhalation. It is supposed that the long acting character is provided by the long retention of
laninamivir in the respiratory tract after
intranasal administration of
laninamivir octanoate in mice and with stable binding of
laninamivir to NA of various influenza viruses such as N1, N2 subtypes and NA of B virus.
Peramivir, another NA inhibitor, is also approved in Japan as a single
intravenous infusion. In spite of the quick disappearance of
peramivir from the blood after injection, the reason treatment can be completed by a single administration is thought to be that
peramivir showed stable binding to NA with N9 subtype. Therefore, the stable binder,
laninamivir is possibly effective by a single
intravenous administration in the mouse model infected with influenza viruses. A single
intravenous administration of
laninamivir and
peramivir at 30mg/kg significantly prolonged mice survival at a comparable level in the mouse lethal model infected with the A/PR/8/34 (H1N1) virus. Also, a single
intravenous administration of
laninamivir and
peramivir significantly suppressed virus proliferation in the lungs of mice infected with influenza B virus. Thus,
laninamivir may be effective by a single
intravenous infusion in treating
influenza, the same as
peramivir.