Peramivir is the only intravenous formulation among anti-influenza neuraminidase inhibitors currently available. Peramivir was approved for manufacturing and marketing in Japan in January 2010. We conducted a drug use investigation of peramivir from October 2010 to February 2012 and evaluated its safety and effectiveness under routine clinical settings. We collected data of 1309 patients from 189 facilities across Japan and examined safety in 1174 patients and effectiveness in 1158 patients. In total, 143 adverse events were observed with an incidence rate of 7.33% (86/1174). Of these, 78 events were adverse drug reactions (ADRs) with an incidence rate of 4.34% (51/1174). The most frequently reported ADRs were diarrhea, vomiting, and nausea, with incidence rates of 1.87% (22/1174), 0.85% (10/1174), and 0.68% (8/1174), respectively. Moreover, no ADR was reported as serious. ADR onset was within 3 days after the start of peramivir administration in 91.0% (71 events) of the 78 ADRs, and ADRs were resolved or improved within 7 days after onset in 96.2% (75 events) of the 78 ADRs. Neither patient characteristics nor treatment factors appeared to significantly affect drug safety. With regard to effectiveness, the median time to alleviation of both influenza symptoms and fever was 3 days, including the first day of administration. The present study demonstrates the safety and effectiveness of peramivir under routine clinical settings.

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Background Baloxavir marboxil (baloxavir), an anti-influenza drug with a novel mechanism of action, is expected to reduce influenza transmission by rapid reduction of viral load. The incidence of household transmission was compared between index patients (IPs) treated with baloxavir and those with neuraminidase inhibitors. Methods Using a Japanese claims database provided by JMDC Inc., the first family members with influenza diagnosis during 2018/2019 influenza season were identified as IPs, and the diagnosis date was designated Day 1. According to the anti-influenza drug dispensed to the IP, their families were classified into oral baloxavir group and three controls; oral oseltamivir group (a primary control), inhaled zanamivir group, and inhaled laninamivir group. A household transmission was defined as influenza diagnosed for any non-IP family members during Days 3−8. The incidence of household transmission was compared between groups using a logistic regression model adjusting backgrounds of IPs. Results The proportion of families with household transmission was 17.98% (15,226/84,672) in the baloxavir group and 24.16% (14,983/62,004) in the oseltamivir group. The covariate-adjusted odds ratio (oseltamivir/baloxavir) was 1.09 [95% confidence interval, 1.05–1.12], which indicated significantly lower incidence in the baloxavir group. Adjusted odds ratios (controls/baloxavir) against zanamivir and laninamivir were 0.93 [0.89–0.97] and 0.99 [0.96–1.02], respectively. Conclusions Baloxavir may contribute to reduce the incidence of household transmission compared with oseltamivir, which is widely used for oral influenza treatment. In comparison between baloxavir and inhalants, a similar reduction was not shown and it might be due to unmeasured confounding by administration route differences.

Peramivir, the only injectable anti-influenza neuraminidase inhibitor medically available in Japan at present, is considered first-line treatment in patients with high risk factors for influenza exacerbation. We conducted a drug-use investigation of peramivir in inpatients with high risk factors (old age, pregnancy, and underlying disease such as chronic respiratory disease) from January 2010 to March 2013. Data of 772 patients from 124 facilities across Japan were collected; peramivir's safety in 770 patients and effectiveness in 688 patients were examined. In total, 412 adverse events were observed in 219 patients (28.4%). Of these, 155 events were adverse drug reactions (ADRs) observed in 98 patients (12.7%). Major ADRs (≥2%) were increased aspartate aminotransferase (5.1%), increased alanine aminotransferase (3.8%) and decreased white blood cell count (2.5%). Fourteen serious ADRs were observed in 12 patients (1.6%). All serious ADRs were resolved or improved except for two events for which outcomes were unknown. Multivariate analyses revealed that ADR incidences were significantly associated with these four backgrounds of patients: medical history, no influenza vaccination, renal impairment and other infection(s). With regard to its effectiveness, the median time to alleviation of both influenza symptoms and fever was 3 days, including the first day of administration, which was the same as in other previous surveillance studies. This surveillance study indicated the safety of peramivir in the treatment of influenza inpatients with high risk factors under routine clinical settings.