Takeda Pharmaceutical Company Limited announced that The Lancet published two papers related to Takeda’s dengue vaccine candidate (TAK 003), reporting on results from the 18-month analysis of the ongoing pivotal Phase III Tetravalent Immunization against Dengue Efficacy Study (TIDES) trial and results from the final 48-month analysis of the Phase II DEN-204 trial. The analyses are consistent with previously reported safety, immunogenicity and efficacy data for TAK 003.
The 18-month data analysis from the pivotal Phase III TIDES trial includes an update on overall vaccine efficacy (VE) and a formal assessment of secondary efficacy endpoints by serotype, baseline serostatus and disease severity (18 months after the second dose, which was administered three months after the first dose), demonstrating protection against virologically confirmed dengue (VCD) in children ages four to 16 years (overall VE was 73.3% [95% confidence interval (CI): 66.5% to 78.8%]. The TIDES trial met all secondary endpoints for which there were a sufficient number of dengue cases. TAK 003 was generally well tolerated, and there were no important safety risks identified within this analysis. The 18-month data were previously presented at the American Society of Tropical Medicine & Hygiene (ASTMH) 68th Annual Meeting in November 2019. VE and safety results from the 18-month analysis were generally consistent with the data reported in the previously published 12-month analysis.
The DEN-204 study enrolled 1,800 participants. In the 48-month data analysis, TAK 003 was shown to elicit antibody responses against all four dengue serotypes in children and adolescents ages two to 17 years, which persisted through four years post-vaccination, regardless of baseline serostatus. Three different dose schedules (one primary dose; one primary dose plus one-year booster dose; or two-dose primary series), and placebo were assessed. In baseline seropositive participants, no clear differences in geometric mean titers (GMTs) – an indication of immune response – were shown between the dosing schedules by Month 48. In the baseline seronegative participants, GMTs were generally lower against all four serotypes in those who received one dose compared with either the two-dose primary series or the one dose plus one-year booster series, further supporting the use of the two-dose primary series studied in the ongoing TIDES trial.
No important safety risks were identified throughout the four-year study period, providing insight into the long-term safety profile of TAK 003. While VE ( vaccine efficacy) was not assessed in this study, there was a significantly lower risk of VCD in the vaccine groups compared with placebo over the four-year study period (relative risk: 0.35; 95% CI: 0.19-0.65). Results of previous interim analyses of the DEN-204 study demonstrated persistence of immunogenicity along with tolerability and safety assessments at six and 18 months.
The TIDES trial is continuing, and safety and efficacy will be assessed over a total of four and a half years. Takeda plans to share results from the 24-month analysis of TIDES later this year.
See- Biswal S, et al. "Efficacy of a tetravalent dengue vaccine in health children aged 4-16 years: a randomized, placebo-controlled, phase III trial". Lancet. 2020. doi:10.1016/S0140-6736(20)30414-1. [epub ahead of print].
See- Tricou, V, Sáez-Llorens X, et al." Safety and immunogenicity of a tetravalent dengue vaccine in children aged 2-17 years: a randomised, placebo-controlled, phase II trial ". Lancet. 2020. doi:10.1016/S0140-6736(20)30556-0. [epub ahead of print].