Dengue fever – a 30% breakthrough
13.09.2012 - Sanofi-Pasteur has suffered a setback with its dengue fever vaccine. It proved to be far less effective than originally hoped. But this is not the end of the story.
Results from a Phase IIb study conducted in Thailand revealed the vaccine had about 30% overall efficacy against dengue fever type 2. Originally, the French pharma hoped to achieve more than 70% efficacy. The compound did show strong results against types 1, 3 and 4 of the mosquito-borne disease. However patients with a type 2 infection, the most prevalent strain in Thailand at the time of the study, did not show a satisfactory response. The vaccine candidate is meant to protect against all four types viruses that cause dengue. The result leaves uncertainty on the future of a product that Sanofi estimates it could generate more than €1bn in annual sales. Sanofi has invested €350m in a site to manufacture the vaccine. Still, the vaccine shows promise and Phase III studies involving more than 31,000 children and adults are under way in 10 countries across Asia and Latin America.
Dengue fever, a mosquito-borne disease, also known as "breakbone fever", is a threat to nearly 3 billion people in tropical regions. "This result knocked me off my chair," Scott Halstead, a senior scientific adviser for the non-profit Dengue Vaccine Initiative, who was not involved in the study, told Reuters. Sanofi had already published topline data in July saying that the study had shown efficacy against three of the four strains. However, the company did not present any details. The full findings were published online in the The Lancet. If the Thai trial results had been as strong as expected, Sanofi could have filed for early approval in some countries. Instead, Sanofi now has to wait for the phase III results. A commercial launch can now happen in 2015 or later.