Sanofi Pasteur, the vaccines division of Sanofi, announced that the first of two pivotal phase III efficacy studies with its dengue vaccine candidate has achieved its primary clinical endpoint. The efficacy study showed a significant reduction of 56 per cent of dengue disease cases. Initial safety data are consistent with the good safety profile observed in previous studies. Full analysis of the data will be undertaken in the coming weeks and reviewed by external experts prior to disclosure at an upcoming international scientific congress and publication in a peer-reviewed journal later this year.

Dengue is a threat to nearly half the world's population and is a pressing public health priority in many countries in Asia and Latin America where epidemics occur. The annual incidence rate of 4.7 per cent observed in the control group demonstrates the very high burden of disease in Asia.

"This achievement is the result of more than 20 years of work in the field of dengue, collaborating with investigators, volunteers, authorities, scientific experts and international organizations," said Olivier Charmeil, president and CEO of Sanofi Pasteur. "Developing a dengue vaccine for the benefit of children and their parents is at the heart of our mission. Our goal is to make dengue the next vaccine-preventable disease and to support the WHO's ambition to reduce dengue mortality by 50 per cent and morbidity by 25 per cent by 2020."

"This is the first time ever a dengue vaccine successfully completed a phase III efficacy study," said Dr Capeding, principal investigator, Research Institute for Tropical Medicine, the Philippines. "These significant clinical results, associated with the good safety profile of the vaccine, bring real hope to more than 100 million people affected each year by dengue, a disease without any specific treatment today."  

The results of this first, large-scale efficacy study will be further complemented by results in Q3 2014 from a second, large-scale study currently conducted in Latin America, including more than 20,000 volunteers from Brazil, Colombia, Honduras, Mexico and Puerto Rico.

The phase III clinical study conducted in Asia is a randomized, observer-blind, placebo-controlled multicenter trial. A total of 10,275 children aged 2 to 14 years from dengue endemic areas of Indonesia, Malaysia, the Philippines, Thailand and Vietnam participated in the study from 2011-2013 and were randomized to either receive three injections of the dengue vaccine or a placebo (2 to 1 ratio) at 6-month intervals. The primary endpoint was measured by the number of symptomatic virologically-confirmed dengue cases caused by any serotype. The study will continue with a long term follow up of the population.

Sanofi Pasteur has been working on a dengue vaccine for more than 20 years. The company's goal is to provide a safe and effective dengue vaccine accessible in all regions of the world where dengue is a public health issue.

Over 40,000 volunteers are participating in the Sanofi Pasteur dengue vaccine clinical study programme (phase I, II and III). Sanofi Pasteur's dengue vaccine candidate is in phase III clinical studies. It is the most clinically and industrially advanced vaccine candidate in development and the first dengue vaccine in advance development.

The two, pivotal phase III efficacy studies involve more than 31,000 volunteers from Asia (Indonesia, Malaysia, the Philippines, Thailand and Vietnam) and Latin America (Brazil, Columbia, Honduras, Mexico and Puerto Rico). The phase III evaluations provide pivotal data on efficacy, safety, and immunogenicity of the vaccine candidate in a broad population and different epidemiological environments and assess the potential impact of the vaccine on the disease burden.