Dengue Vaccine Candidate Provides 62% Efficacy for Children & Adolescents at 3 Years

A dengue vaccine candidate has shown continued protection against virus-specific illness and hospitalization without safety concerns at 3 years, according to new findings from an ongoing phase 3 study.

The Tetravalent Immunization against Dengue Efficacy Study (TIDES) program, a phase 3 assessment of the Takeda Pharmaceutical vaccine product TAK-003 in 20,000-plus healthy children and adolescents, now has 36-month follow-up data available showing a vaccine efficacy of 62.0% (95% CI, 56.6 – 66.7) against virologically-confirmed dengue.

Outcomes from the ongoing trial, which is observing the prophylactic candidate in participants aged 4-16 years old in Latin American and Asian countries where dengue is endemic, will support the company’s regulatory application for indicated use of TAK-003 in prevent dengue among persons aged 4-60 years old.

The new data, presented at the 2021 Conference of the International Society of Travel Medicine (CISTM) this weekend, additionally showed greater vaccine efficacy among seropositive children and adolescents (65.0%; 95% CI, 58.9 – 70.1) than among their seronegative counterparts (54.3%; 95% CI, 41.9 – 64.1).

Additionally, the tetravalent, live-attenuated dengue serotype 2 virus vaccine provided 83.6% prevention of dengue hospitalization (95% CI, 76.8 – 88.4) at 36 months—again more greatly among seropositive participants.

Investigators also reported good tolerance in relation to the vaccine in participants, with no new safety risks observed at 36 months. They believe the results “reinforce the potential of TAK-003 to help protect those who are living in or traveling to dengue-endemic countries.”

TAK-003 had previously met the TIDES trial primary endpoint of overall vaccine efficacy against dengue virus at 12 months follow-up (80.2%; 95% CI, 73.3 – 85.3; P <.001), as well as secondary endpoints. The trial is now assessing a booster dose in response to gradually reducing vaccine efficacy observed from 12-36 months, administered in the same time period. The company intends to publish results on the analysis this year.

In the meantime, Takeda intends to include the 36-month safety and efficacy data in regulatory submissions to the European Union and dengue-endemic countries. They will also include the findings in planned submission to the US Food and Drug Administration (FDA) later this year.

One of the World Health Organization’s (WHO) top 10 global health threats of 2019, dengue cases are estimated to be near 400 million globally, and drive about 500,000 hospitalizations every year.

The mosquito-borne viral disease spreads quickly, TIDES trial primary investigator LakKumar Fernandoi, MD, of the Center for Clinical Management of Dengue and Dengue Haemorrhagic Fever at Negombo General Hospital, said in a statement. A reliable vaccine indicated across broad age populations would be valuable tool in curbing outbreak risk.

“Dengue epidemics occur suddenly, and hospitals can become overwhelmed with severe disease cases and people seeking testing,” Fernandoi said. “Results from the long-term analysis of Takeda’s dengue vaccine candidate suggest that it could help with outbreak prevention, reduce rates of hospitalization and protect people from dengue regardless of their previous exposure. Importantly, no important safety risks were identified.”