World’s first dengue vaccine extends human studies in Asia
Sanofi Pasteur’s tetravalent vaccine –effective against all the 4 types of dengue virus -will hit markets by 2015
First vaccine against dengue fever developed by Sanofi Pasteur will now be testing in children from Vietnam and Singapore.
Sanofi Pasteur, the vaccine division of France’s largest drug maker Sanofi-Aventis SA started human studies of vaccine against dengue in Thailand and Philippines in February.
“Dengue has emerged as a serious public health problem in Asia-Pacific in the last decades. There are 1.8 billion people in the region at risk of dengue fever,” said Chusak Prasittisuk, coordinator Communicable Diseases Control at the World Health Organization South East- Asia Region.
Currently, there is no specific treatment available against dengue fever, which is the most widespread tropical disease after malaria, affecting two-fifths of the world’s population.
Sanofi Pasteur is collaborating with the Communicable Disease Center in Singapore and the Pasteur Institute in Vietnam to conduct these clinical studies in children and adults.
“Controlling the mosquitoes that transmit dengue is necessary but not sufficient to fight against the disease. A safe and effective vaccine has been long awaited to prevent dengue epidemics,” said professor Leo Yee Sin, director of the Communicable Disease Center in Singapore.
Clinical studies in Singapore are critical steps to advance the development of a vaccine for the prevention of dengue in Asia, he added.
The dengue vaccine’s new human trials are the second of three stages of tests regulators usually require.
“Fighting against dengue is a main public health priority in Vietnam. About 100,000 people are infected each year, mostly children,” said Dr. Tran Ngoc Huu, director of Pasteur Institute in Ho Chi Minh City.
Sanofi is leading an effort begun by scientists in the U.S. in the 1940s to develop a vaccine capable of protecting against the four types of dengue that cause severe flu-like illness. The disease can trigger a potentially lethal complication called dengue hemorrhagic fever. About 2.5 billion people live in areas prone to the mosquito-borne virus, which the World Health Organization says causes about 50 million infections every year.
Dengue is characterised by sudden onset of fever, severe headache, and muscle and joint ache lasting a week to 10 days. It can also lead to a drop in white blood cells and platelets, leading to excessive bleeding. Before 1970, nine countries had experienced epidemics of dengue hemorrhagic fever, and the number had more than quadrupled by 1995, WHO said.
Dengue is mostly transmitted by Aedes aegypti, a domesticated mosquito which is infesting more areas because of global trade and bans on pesticides such at DDT. There is no specific treatment for the illness.
A vaccine for dengue is clearly seen as a priority as dengue is a debilitating disease which is increasing in terms of numbers, stated Marie-Paule Kieny, director of the Initiative for Vaccine Research at WHO.
Sanofi will test its tetravalent vaccine in 1,200 children and adults in Singapore and about 180 people in Vietnam to assess the vaccines safety and ability to produce protective antibodies against all four dengue types, said Melanie Saville, head of Sanofi’s clinical dengue programme, said.
Sanofi will select the volunteers randomly to receive either the dengue shot or an inoculation against hepatitis A or flu. The vaccinations will be repeated after 6 and 12 months, and the recipients followed for a further four years.
The new dengue vaccine is based on four live yellow fever viruses that have been modified to include key dengue genes. Sanofi is using the same technique to produce a vaccine for Japanese encephalitis.
Sanofi will proceed to a final round of human trials involving tens of thousands of people, if the data from the new dengue vaccine emerge positive. Sanofi may seek regulatory approval of the product as early as 2015, more than 20 years after beginning work on dengue in collaboration with Bangkok’s Mahidol University.
Sanofi expects the dengue vaccines to generate annual revenue of more than $1 billion.
Dengue is the most widespread tropical disease after malaria. It is an endemic disease in more than 100 countries. Complications from dengue cause about 500,000 hospitalizations annually, mostly involving children. About 2.5 percent get affected with dengue hemorrhagic fever – a form of the disease that weakens blood vessels die as a result of spontaneous bleeding and shock.
Complications are more common as a result of subsequent infection with a different dengue serotype because the virus is more likely to evade the body’s immune response. Sanofi’s vaccine is formulated to provide even levels of antibodies across all four serotypes.
Sanofi will spend about 350 million euros ($453 million) on a factory near Lyon, southeastern France, to support mass production of the dengue vaccine, said Benoit Rungeard, a company spokesman. The plant would take about five years to commission, he said.