Sanofi Dengue Vaccine Succeeds in Reducing Disease, Study Shows

Sanofi’s experimental dengue vaccine succeeded in a study in reducing the mosquito-borne disease, moving the company closer to introducing the first inoculation against an illness that threatens almost half of the world’s population.

Results from 10,275 children showed a 56 percent reduction of dengue-disease cases, Paris-based Sanofi said in an e-mailed statement today. The initial safety data from the late-stage study are consistent with previous trials, the company said. Sanofi didn’t disclose how well the vaccine protected against each of dengue’s four strains.

“This result is the achievement of more than 20 years of work in the field of dengue, collaborating with investigators, volunteers, authorities, scientific experts and international organizations,” Olivier Charmeil, the head of Sanofi’s vaccines unit, said in today’s statement.

Dengue, which has had outbreaks in the U.S. and Europe, is a flu-like illness that can develop into a rare and potentially fatal complication involving bleeding from the nose and gums, rapid breathing and severe abdominal pain. Over 2.5 billion people are at risk from dengue, according to the World Health Organization. About 500,000 people are hospitalized each year, a large proportion of them children, and about 2.5 percent of those affected die, according to the Geneva-based WHO.

Three Injections

Sanofi’s study was conducted in Indonesia, Malaysia, the Philippines, Thailand and Vietnam between 2011 and 2013 on children and adolescents from ages 2 to 14, the company said. The participants received either three injections of the vaccine or a placebo at six-month intervals.

Mid-stage trials of the vaccine had yielded mixed results, providing good protection against three of the four viruses that cause the disease in a trial among 4,000 children in Thailand last year. Yet it was ineffective against type 2, the dominant dengue strain in Thailand at the time of the trial.

A full analysis of the results announced today will be undertaken in the coming weeks and reviewed by external experts before being presented at a medical conference later this year, Sanofi said. Results from a second late-stage efficacy trial conducted in Latin America will be unveiled in the third quarter, the French drugmaker said.

Dengue isn’t confined to poor and developing countries. An outbreak in Key West, Florida, occurred in 2009 and 2010. Two locally acquired cases were reported in Nice, France, in 2010. On the Portuguese resort island of Madeira in 2012, dengue sickened more than 2,200 people, including tourists from 12 European nations.

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