A Phase II/III, Multicenter, Observer-blinded, Randomized, Non-inferiority and Safety, study of typhoid conjugate vaccine (EuTCV) compared to Typbar-TCV® in healthy 6 Months-45 years aged participants

The typhoid conjugate vaccine (TCV) ensures a long-lasting protective immune response, requires fewer doses and is fit for children under 2 years of age. From Phase I study, EuTCV displayed considerable immunogenicity and reliable safety, thus endorsing further examination in Phase II/III trials. Therefore, a clinical Phase II/III study (NCT04830371) was conducted to evaluate its efficacy in healthy Filipino participants aged 6 months to 45 years through administration of the test vaccine (Arm A, B, and C) or comparator vaccine Typbar-TCV (R) (Arm D). Sera samples were collected pre-vaccination (Visit 1) and postvaccination (Visit 4, Day 28) to assess the immunogenicity of EuTCV and Typbar-TCV (R). During the study, participants were regularly monitored through scheduled visits to the clinic to report any adverse events associated with the vaccine. For vaccine safety, the proportion of solicited and unsolicited TreatmentEmergent Adverse Events was all comparable between EuTCV and Typbar-TCV (R) groups. A single dose of EuTCV produced seroconversion in 99.4% of treated participants, with seroconversion rates noninferior to that of Typbar-TCV (R). Batch-to-batch consistency was concluded based on the 90% Confidence Interval of the geometric mean ratio (EuTCV Arm A, B, and C) at Week 4, lying within the equivalence margin of 0.5 to 2.0 for all batches. Results from this Phase II/III clinical trial of EuTCV in healthy volunteers show comparable safety and considerable immunogenicity, compared to TypbarTCV (R), meeting the objectives of this pivotal study. ClinicalTrials.gov registration number: NCT04830371.

Automated summary

The typhoid conjugate vaccine (TCV) has long-lasting protective immune response and is suitable for young children. The EuTCV displayed good immunogenicity and safety in Phase I study, leading to further evaluation in Phase II/III trials. The clinical trial conducted in healthy Filipino participants showed that EuTCV had comparable safety and immunogenicity to Typbar-TCV (R), meeting the study objectives.