Safety and Immunogenicity of the Japanese Encephalitis Vaccine IC51 (IXIARO®) in a Pediatric Population

Open-label, randomized, active controlled Phase 3 study in children aged ≥ 2 months to < 18 years. Subjects aged ≥ 2 months to < 12 months were randomized in a 2:1 ratio to receive IC51 (0.25 ml dose) or Prevnar® as a safety comparator. Children aged ≥ 12 months to < 3 years and ≥ 12 years to < 18 years were randomized in a 3:1 ratio to receive IC51 (0.25 ml dose < 3 years, 0.5 ml ≥ 12 years) or HAVRIX®720 as safety comparator.

For subjects aged ≥ 3 years to < 12 years, a dose finding run-in phase was performed. A total of 200 subjects were randomized 1:1 to receive either the 0.25 ml or the 0.5 ml dose of IC51, and the appropriate dose was determined based on an interim analysis. After this run-in phase, 300 further children in this age group were randomized 2:1 to receive either 0.5 ml of IC51 or HAVRIX®720.

Immunogenicity was be studied in a subgroup of 30 children aged ≥ 2 months to < 12 months; 125 children aged ≥ 12 months to < 3 years and 140 children ≥ 12 years to < 18 years. For the age group of ≥ 3 to < 12 years immunogenicity was assessed in the 200 children enrolled during the dose-finding run-in phase.

Inclusion criteria

• Male or female healthy children and adolescents aged > 2 months to < 18 years at the time of first vaccination.
• Written informed consent by the subject's legal representative(s), according to local requirements, and written informed assent of the subject, if applicable.
• Female subjects: either no childbearing potential or negative pregnancy test, for females after menarche willingness to practice a reliable method of contraception.

Exclusion criteria

• Clinical manifestation of Japanese Encephalitis
• History of Flavivirus vaccination (including any investigational vaccines)
• History of vaccination with HAVRIX®720 and/or Prevnar®
• History of immunodeficiency or immunosuppressive therapy
• Known HIV, HBV or HCV infection
• History of hypersensitivity reactions to other vaccines
• Acute febrile infection at each visit during which the subject receives a vaccination
• Active or passive immunization within 2 weeks prior to the first IC51 vaccination and up to the second IC51 vaccination.