Safety of the long-acting neuraminidase inhibitor laninamivir octanoate hydrate in post-marketing surveillance.

Laninamivir octanoate hydrate (laninamivir) is a long-acting neuraminidase inhibitor (NAI) that completes treatment with only a single inhalation. It was launched in Japan in October 2010 as an anti-influenza agent. A post-marketing surveillance study was conducted in the 2010/2011 influenza season to assess the safety of this drug in clinical settings. Adverse drug reactions (ADRs) were observed in 50 patients (59 events) out of 3542 patients subjected to safety evaluation (incidence 1.41%). Commonly reported ADRs were psychiatric disorders (abnormal behaviour, etc.), gastrointestinal disorders (diarrhoea, nausea, etc.) and nervous system disorders (dizziness, etc.), with incidences of 0.48% (n=17), 0.45% (n=16) and 0.17% (n=6), respectively. No serious ADRs occurred. ADRs usually emerged on the day on which laninamivir was inhaled (52.5%) and ADRs emerged within 3 days after inhalation in >90% of adversely affected patients. ADRs resolved or improved within 3 days in >85% of patients. The incidence of adverse events involving abnormal behaviour was 3.1% (30/959) among patients <10 years of age, 0.7% (8/1088) among patients aged 10-19 years, 0.1% (2/1431) among adult patients aged 20-64 years and 0.0% (0/64) among patients aged ≥65 years. It was confirmed that laninamivir is unlikely to cause delayed ADRs or a prolonged duration of ADRs despite this drug being a long-acting NAI. Furthermore, the incidence of ADRs was not found to have increased compared with that observed during clinical trials, and the types of ADR observed during this study were similar to those previously observed. Thus, laninamivir octanoate hydrate was confirmed to have no noticeable problem with safety.