Abstract Ref Number = APCP402
Safety, and Humoral and Cell-mediated Immunity of Takeda's Dengue Vaccine Candidate in a Paediatric Population from Dengue Endemic Countries
Vianney Tricou,Xavier SaezLlorens,Delia Yu,Luis Rivera,Astrid Borkowski,Derek Wallace
Takeda Vaccines Pte Ltd Singapore Hospital del Nino Dr Jose Renan Esquivel, Panama City, Panama De La Salle Health Sciences Institute, Dasmarinas, Philippines Hospital Maternidad Nuestra Senora de La Altagracia, Santo Domingo, Dominican Republic Takeda Pharmaceuticals International AG, Zurich, Switzerland
Background : Takeda's live attenuated tetravalent dengue vaccine candidate (TDV) contains a molecularly characterized dengue serotype 2 virus (TDV-2), and three recombinant viruses expressing the pre-membrane and envelope structural genes for serotypes 1, 3, and 4 in the attenuated TDV-2 backbone.
Material : In an ongoing phase II randomized placebo-controlled trial (ClinicalTrials.gov: NCT02302066), the safety and immunogenicity of different TDV vaccination schedules are being evaluated in about 1800 subjects aged 2 to <18 years living in the Dominican Republic, Panama, and the Philippines. Here we present the 18-month interim data on safety, humoral and cell-mediated immunogenicity, and febrile illness surveillance.
Results : Over the first 18 months of this trial, TDV was well tolerated and elicited persisting dengue specific immune responses through the two main components of the adaptive immune system: the humoral immunity and the cell-mediated immunity, regardless of baseline serostatus. TDV notably elicited neutralizing antibodies against all four dengue serotypes and generated long-lived multifunctional cross-reactive CD8+ T cells against the non-structural dengue virus proteins in both seropositive and seronegative participants before vaccination. In addition, febrile illness surveillance showed a reduction of dengue in vaccinees compared with controls, with a relative risk of dengue in vaccinees compared with controls of 0.29 (0.13 - 0.72).
Conclusions : Data from the current large phase III efficacy trial (ClinicalTrials.gov: NCT02747927), in which TDV is being investigated as a two-dose regimen (0, 3 months), are required to confirm these encouraging results, and will be available in late 2018.
Keywords: Paediatric Infectious Diseases Dengue Vaccine