Study: Universal dengue vaccine may be possible thanks to antibody discovery

Dengue mosquito--Courtesy of CDC

So far, Sanofi's ($SNY) dengue candidate, the furthest along in the clinic, has struggled to ward off all four dengue viruses. But now, researchers have discovered new antibodies that could lead to a vaccine that does just that.

In findings published on Monday in Nature Immunology, scientists studied 145 human antibodies and found new ones that neutralize all four types of dengue virus--including serotype 2, which has given the Sanofi prospect trouble.

The discovery could eventually lead to a more effective vaccine that helps cut down on the 20,000 deaths dengue causes each year. "Without a vaccine, it's unlikely that this disease will ever be controlled," lead paper author and Imperial College London professor Gavin Screaton said, as quoted by Bloomberg. Imperial College has filed a patent for this discovery, but it may license or sell its intellectual property, Screaton told the news service.

Lead author Gavin Screaton--Courtesy of Imperial College London

In 2012, Sanofi conducted a Phase IIb trial in Thailand of its tetravalent dengue candidate, which successfully defended against serotypes 1, 3 and 4, but faltered against serotype 2. It didn't do much better in Phase III trials held this year in Asia, posting a 35% efficacy in serotype 2, just a little higher than the approximately 30% efficacy it registered in the 2012 trial.

While results from a Phase III trial conducted in Latin America showed improvement against serotype 2--42% efficacy--they still didn't come close to Sanofi's initial estimate, which was more than 70% efficacy.

Despite its lackluster performance against serotype 2, the vaccine, by blocking three out of the four dengue viruses, lowered the overall risk of contracting dengue as well as reduced hospitalization. Following the announcement of the Latin American trial results, the company said it could have the vaccine to market by the second half of 2015. It could be the world's first dengue vaccine.

Takeda and Merck ($MRK) are also working on dengue jabs, with the former on track to release its vaccine in 2015, pending approval, and eyeing U.S. and EU approvals for its candidate in the 2017-18 fiscal year.

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