NEW DELHI – As India grapples with its annual bouts of post-monsoon dengue outbreaks, Sanofi Pasteur said it hopes to roll out the world's first dengue vaccine in the second half of 2015.

Stephan Barth, Sanofi's India head, said in Mumbai recently that, subject to regulatory approval, the company would file for registration and licensing in countries where the mosquito-borne disease is a public health problem.

The vaccine, CYD-TDV, is a genetically engineered, live attenuated tetravalent vaccine effective against all four serotypes of dengue. Sanofi Pasteur, the vaccines unit of Paris-based Sanofi SA, first announced in June that it had successfully completed late-stage trials. (See BioWorld Today, June 25, 2014.)

"Dengue is a serious health concern in India, causing a significant but underreported burden. Over recent months we have seen a worrying increase in cases in many parts of the country, putting a huge strain on health care systems," Barth said.

Barth told Bioworld Today: "India is part of Sanofi Pasteur's global development strategy for dengue vaccine. The results of CYD15 [the vaccine ready for registration] are very encouraging and in line with the results of the phase III study results in Asia and the phase II study results in India.

"We have recently completed the phase II study and are planning to conduct a phase III study in India," he added.

Dengue is transmitted by the mosquito Aedes aegypti and has no specific treatment. A major public health problem in India, dengue has seen a sharp rise in incidence and severity in recent years linked to urbanization, increased air travel, shoddy public health infrastructure and even climate change. Cases of dengue are being grossly underreported in India, according to a recent study funded by Sanofi Pasteur.

Researchers from Brandeis University's Schneider Institute for Health Policy in Waltham, Mass., the INCLEN Trust International in New Delhi and the Indian Council of Medical Research's Centre for Research in Medical Entomology (CRME) in Madurai, Tamil Nadu, reported in the American Journal of Tropical Medicine and Hygiene in 2014 that there were 6 million cases during 2006, about 282 times more than what was officially reported.

The researchers claimed that theirs was the "first study to estimate the disease burden and direct medical cost of dengue in India using empirical data."

The World Health Organization (WHO) estimated that each year about 500,000 people, including children, have severe dengue requiring hospitalization, putting a huge strain on health care systems during outbreaks.

Dengue has dramatically increased over the past 30 years, particularly in the past decade. The number of reported cases in the Americas has increased fivefold from 517,617 in 2003 to 2.3 million in 2013. One of WHO's key goals is to reduce dengue deaths by at least 50 percent and morbidity by at least 25 percent by 2020.

POSITIVE DATA IN ASIA, LATIN AMERICA

The Sanofi Pasteur announcement follows publication of results of studies in 20,869 children in Latin America, which included dengue endemic areas of Brazil, Colombia, Mexico, Honduras and Puerto Rico, published in the Nov. 3 issue of The New England Journal of Medicine.

The company said the vaccine gave 95.5 percent protection against severe dengue and 80.3 percent reduction in the risk of hospitalization in children given a three-dose vaccination schedule.

"For the first time ever, after 20 years of research and industrial commitment, dengue is set to become a vaccine preventable disease," said Sanofi Pasteur's CEO Oliver Charmeil.

Rivaldo Cunha, associate professor at the faculty of medicine, de Mato Grosso do Sul, Brazil, and a principal investigator in the study, said, "These compelling phase III results demonstrate the efficacy and good safety profile of this vaccine candidate against dengue. For the first time, we have a vaccine candidate that has the potential to offer protection to people who are at risk of dengue."

The results from Latin America tallied with previously released results from Asian phase III studies, published in The Lancet in July. The study involved 10,275 children and adolescents from Indonesia, Malaysia, the Philippines, Thailand and Vietnam. The trials recorded 56.5 percent efficacy.

"These new positive phase III results from Latin America are very encouraging because they are consistent with the results reported in July in the Asian phase III trial. Together, the results of these trials suggest that for the first time, a vaccine solution that can help control dengue, is on the horizon." said Duane Gubler, professor and founder of the Signature Research Program on Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore, and chairman of the Partnership for Dengue Control.

But some senior vaccine scientists in India say the efficacy of the vaccine against two of the four serotypes of dengue is on the low side.

An India spokeswoman for Sanofi Pasteur, however, maintained that results from the Asian phase III showed a "clinically important reduction in the risk of hospitalization due to dengue by 67 percent over 25 months of the study.

"The results of this second phase III efficacy study confirm the high efficacy against severe dengue and the reduction in hospitalization," the spokeswoman said.