Sanofi's Dengue Vaccine Hits Phase 3 Trial Primary Endpoint

Sanofi’s vaccine division unit Sanofi Pasteur announced that the final landmark Phase III study in Latin America investigating its dengue vaccine candidate has met its primary endpoint, registering an overall vaccine efficacy of 60.8 percent.

The dengue vaccine significantly reduced dengue disease in children and patients aged 9 to 16 years old following a three-dose inoculation schedule. Efficacy was shown in each of the four dengue serotypes. In addition, the vaccine showed a reduction of 80.3 percent in hospitalization risk connected with dengue. The vaccine also demonstrated improved protection in case of prior exposure to the disease.

“These new positive phase III results from Latin America are very encouraging because they are consistent with the results reported in July in the Asian phase III trial. Together, the results of these trials suggest that, for the first time, a vaccine solution that can help control dengue, is on the horizon,” said Professor Duane Gubler, Chairman of the Partnership for Dengue Control.

The company said it will complete and review efficacy as well as safety data from the Phase III study of the vaccine before publishing them in a peer-reviewed scientific journal. Sanofi Pasteur also revealed that it will present the study results at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting this coming November in New Orleans, Louisiana, U.S.

Olivier Charmeil, President and CEO of Sanofi Pasteur, said that the company hopes to relabel dengue as a vaccine preventable disease after devoting 20 years to research and development of a dengue vaccine. “The data generated from our comprehensive research and clinical program involving 40,000 children, adolescents, and adults from 15 countries, will be submitted to the health authorities in countries where dengue is a public health priority.”

Some experts caution, however, that the vaccine might end up making dengue worse in its endemic countries. The prevalence of dengue’s different serotypes varies from region to region, meaning that the dengue situation in Asia is not like that in Latin America and vice versa. Protecting against some dengue subtypes might strengthen another serotype of the infection. Another concern was the price the vaccine would command once it wins approval in the near future.

Sanofi Pasteur plans to commercialize the first doses of the vaccine in the second half of 2015. The company has designated a dedicated plant in southeastern France to produce up to 100 million doses of the vaccine per year.