AsianScientist (Nov. 7, 2017) – An 18-month interim analysis of an ongoing Phase 2 trial for the TAK-003 vaccine candidate has shown promising results in children and adolescents. These findings were announced by Takeda Pharmaceutical Company Limited and published in The Lancet Infectious Diseases.
Dengue fever is a mosquito-borne viral disease endemic in many tropical regions, infecting an estimated 390 million people and causing some 500,000 hospitalizations each year. There is currently no treatment for dengue, and designing a vaccine against it has proven challenging due to the complexity of protecting individuals against all four serotypes of the virus.
The Phase 2 DEN-204 trial was designed to evaluate the safety and immunogenicity of TAK-003, with the primary objective of assessing the vaccine-induced antibody levels to all four types of dengue virus following different vaccine schedules. The study involves 1,794 children and adolescents ages 2 through 17 living in dengue-endemic areas, namely the Dominican Republic, Panama and the Philippines.
Consistent with data from previous clinical studies, TAK-003 was found to be safe and well-tolerated in terms of solicited local reactions and systemic adverse events, relative to the placebo control group. Importantly, the present study showed that the immune response against all four dengue serotypes was durable across all vaccinated groups, with antibody levels persisting out to 18 months regardless of vaccine schedule or previous exposure to the dengue virus.
When study participants who had not been infected with dengue before were given a single dose of TAK-003, 69 percent showed a positive antibody response against all four serotypes six months after vaccination. A second dose at three months after the first dose improved the tetravalent seropositivity to 86 percent, while a booster dose at 12 months further increased the response to 100 percent. In contrast, the first vaccine to be approved for dengue, Sanofi’s Dengvaxia, does not offer equal protection against all serotypes.
TAK-003 is currently under evaluation in the Tetravalent Immunization against Dengue Efficacy Study (TIDES), a large-scale Phase 3 efficacy trial being conducted in eight dengue-endemic countries.
“We are seeing an acceptable safety profile and sustained antibody responses out to 18 months in this trial. These data are an important step in the development of our dengue vaccine candidate,” said Dr. Derek Wallace, Global Dengue Program Lead at Takeda. “The reduced incidence of dengue in children and adolescents receiving TAK-003 is encouraging, however data from our ongoing Phase 3 efficacy trial, TIDES, are required to confirm these findings.”
TIDES will build on DEN-204 and other previous studies in continuing to assess the tolerability, safety and immunogenicity of the vaccine against all four dengue serotypes in multiple age groups and to determine whether the vaccine helps prevent symptomatic dengue. Data from TIDES will be available in late 2018.
The article can be found at: Sáez-Llorens et al. (2017) Immunogenicity and Safety of One Versus Two Doses of Tetravalent Dengue Vaccine in Healthy Children Aged 2–17 Years in Asia and Latin America: 18-month Interim Data from a Phase 2, Randomized, Placebo-controlled Study.
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Source: Takeda; Photo: Shutterstock.
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