Sanofi's investigational dengue vaccine hits main goal showing efficacy in late-stage trial

Study data published Monday in the NEJM revealed that Sanofi's experimental tetravalent dengue vaccine met its main goal and displayed efficacy in a Phase III study of healthy children and adolescents aged 9 to 16 years. "We plan to submit the vaccine for licensure in 2015 in endemic countries where dengue is a public health priority," remarked Sanofi Pasteur CEO Olivier Charmeil, adding "our goal is to help meet the [World Health Organization's] objectives to reduce dengue mortality by 50 percent and morbidity by 25 percent by 2020." Sanofi indicated that assuming approval, the vaccine could be launched in the second half of next year in endemic countries.

In the late-stage study, 20 869 children and adolescents from dengue endemic areas of Brazil, Colombia, Mexico, Honduras and Puerto Rico were randomised to receive immunisation with three doses of the vaccine or placebo, with 79.4 percent of an immunogenicity subgroup of 1944 children exhibiting seropositivity for at least one dengue subtype. In the pre-protocol population, the researchers observed 176 cases of virologically confirmed dengue in the vaccine group and 221 cases of dengue in the control group, resulting in the vaccine overall efficacy rate against any symptomatic dengue disease of 60.8 percent.

Meanwhile, in the intent-to-treat population, the vaccine was 64.7 percent effective against infection with the virus in children who received at least one dose. The researchers also noted that only one of 12 cases of severe dengue occurred in a subject in the vaccine group, giving an efficacy rate of 95.5 percent against severe dengue, while the vaccine efficacy against hospitalisation due to dengue was 80.3 percent. Further, the safety profile of the vaccine was consistent with that of placebo, with no marked differences in adverse event rates observed between the groups.

Sanofi remarked that data from the study will be presented this month at the American Society of Tropical Medicine and Hygiene annual meeting. In September, the French drugmaker announced that the vaccine met its primary goal in a late-stage study of children and adolescents in Latin America, while the company previously revealed detailed results of another Phase III study.

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