The safety and efficacy of quadrivalent live attenuated influenza vaccine in Japanese children aged 2‐18 years: Results of two phase 3 studies |
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Authors: | Raburn M Mallory Jing Yu Sachiko Kameo Michio Tanaka Ki Rito Yohji Itoh Filip Dubovsky |
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Affiliation: | 1. MedImmune, Gaithersburg, MD, USA;2. AstraZeneca Japan, Osaka, Japan;3. Formerly of AstraZeneca Japan, Tokyo, Japan |
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Abstract: | Background Quadrivalent live attenuated influenza vaccine (Q/LAIV) has not been assessed in Japanese children. Objectives Evaluate safety and efficacy of Q/LAIV in Japanese children. Patients/methods Two phase 3 studies were conducted in the 2014‐2015 influenza season. Study 1 was an open‐label, uncontrolled single arm, multicenter study of Q/LAIV safety in subjects aged 2‐6 years. Study 2 was a randomized, double‐blind, placebo‐controlled multicenter study of Q/LAIV safety and efficacy; subjects aged 7‐18 years were randomized 2:1 to receive Q/LAIV or placebo. Primary efficacy endpoint was laboratory‐confirmed symptomatic influenza infection caused by vaccine‐matched strains; secondary endpoint evaluated efficacy against all strains regardless of match. Both studies reported solicited symptoms, adverse events (AEs), and serious AEs. Results In Study 1, 100 subjects received Q/LAIV. In Study 2, 1301 subjects received Q/LAIV (n = 868) or placebo (n = 433). Treatment‐emergent AEs occurred in 42% of subjects in Study 1, and in 24.3% of subjects in the Q/LAIV arm and in 25.9% of subjects in the placebo arm in Study 2. In Study 2, a single infection by a vaccine‐matched strain was reported in the placebo arm, resulting in a vaccine efficacy estimate of 100% (95% CI: ?1875.3, 100.0); efficacy for all strains regardless of match to the vaccine was 27.5% (95% CI: 7.4, 43.0). Conclusions Quadrivalent live attenuated influenza vaccine did not meet its primary efficacy endpoint as only a single infection by a vaccine‐matched strain was detected; however, efficacy for the secondary endpoint, all strains regardless of match, was achieved. Q/LAIV was generally well tolerated in the Japanese pediatric population. |
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Keywords: | Japan LAIV pediatric seasonal influenza |
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