Dengue vaccine tests 61% effective

Dengue vaccine tests 61% effective

PARIS — French drug maker Sanofi, developing the first vaccine against dengue fever, said its product reduced disease cases by 60.8% in a its large-scale and final clinical trial.

Employees work in the cell-culture unit at the French drug maker Sanofi Pasteur's vaccine unit plant in Neuville-sur-Saone, near Lyon, in this March 14, 2014 file picture. The first vaccine against dengue fever, from France's Sanofi, reduced disease cases by 60.8% in a its large-scale and final clinical trial. (Reuters photo)

Sanofi has invested more than 1.3 billion euros ($1.7 billion) in the project, undertaking two decades of research on the world's fastest-growing tropical disease. In 2013, Thailand alone saw more than 120,000 cases and an estimated 120 deaths.

The final study - conducted on 20,875 children aged 9-16 across five countries in Latin America - confirmed that the vaccine was safe, provided high protection against dengue haemorrhagic fever and cut by 80% the risk of hospitalization, the Paris-based company said Wednesday.

Thailand and four other Asean countries currently are developing their own dengue vaccine that could mitigate the disease's severity by 88.5%, the Pediatric Infectious Disease Society of Thailand said in July. However, the drug is at least three years away from market.

Sanofi's vaccine, in its final test, was 42.3% efficient in tackling serotype 2, one of the viral disease's four strains, compared to 35% in a previous Asian trial on some 10,000 children, a relatively weak rate that has puzzled scientists.

Overall, the findings were consistent and more reliable in the Latin American trial as it had twice as many patients as the Asian trial, said Nicholas Jackson, head of dengue research and development at Sanofi's vaccines unit Sanofi Pasteur.

"We're talking about different regions, different seasons, different demographics, and it's very important for a vaccine to perform consistently, so these results are extremely pleasing," he told Reuters in an interview.

The study was conducted in Brazil, Colombia, Mexico, Honduras and Puerto Rico. Sanofi will unveil its detailed findings at the American Society of Tropical Medicine and Hygiene's annual meeting at the beginning of November.

As in Asia, the results suggested the new vaccine acts best as an immune booster for patients with some previous exposure, and therefore may be most useful in tropical regions where dengue is common, rather than as a vaccination for tourists.

However, given how the vaccine drastically reduces the most severe cases of dengue - by close to 90%  - many countries and patients including tourists could see the point in using it, said Guillaume Leroy, head of Sanofi's dengue vaccine project.

He said Sanofi aimed to start filing regulatory applications for the vaccine early next year and ultimately reach out to 100 countries, but that it would target as a priority the countries where it led the trials.

Chief Executive Chris Viehbacher said in July that Mexico, Brazil and Colombia could be the first to market the vaccine.

The first batches - produced at a dedicated plant outside Lyon in southeastern France - will be ready next year and Sanofi aims to sell the first doses in the second half of 2015.

Leroy said Sanofi would apply for regulatory approval on a three-dose regimen to maximise the body's immune response to the jab, but declined to comment on pricing and sales estimates.

Nearly half the world's population is at risk of contracting dengue fever -also known as "breakbone fever" because of the severe pain it can cause. The disease infects some 100 million people each year, according to the World Health Organization, and some experts put the number at three times that level.

Most patients survive dengue but it kills an estimated 20,000 people each year, many of them children, and causes one hospitalisation every minute around the globe.

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