By Esther Nakkazi
A multinational Phase III clinical trial of a promising dengue treatment is set to begin in early 2027, marking one of the most advanced efforts yet to develop the first targeted therapy for a disease that threatens more than half of the world’s population.
The trial follows a licensing agreement between the Serum Institute of India and the non-profit Drugs for Neglected Diseases initiative (DNDi) to advance the development of a monoclonal antibody treatment against dengue. The study will enrol about 1,000 participants in Malaysia, Thailand and Brazil, countries that are part of the Dengue Alliance, a partnership of dengue-endemic nations working to develop affordable treatments.
While dengue now puts 5.6 billion people at risk globally, there is currently no specific treatment for the virus. Patient management relies entirely on symptomatic care, which can quickly overwhelm health systems during massive outbreaks. This new partnership aims to change that by developing a therapeutic that is not only effective but also globally accessible and affordable.
Fuelled by climate change and globalization, dengue is no longer confined to tropical regions and is increasingly affecting Europe. In 2024, Brazil experienced its most devastating outbreak on record, with over 6.5 million cases and 5,000 deaths.
“Climate change is reshaping the epidemiology of dengue, driving epidemics of unprecedented magnitude, extended duration, and expanding geographic distribution,” noted Viviane Boaventura, a researcher at Fiocruz in Brazil. She emphasized that if successful, this trial would mark a “historic milestone—the first approved specific therapy for dengue”.
“Treatments will be essential to tackling dengue,” said Dr André Siqueira, head of dengue at DNDi. “We need therapeutics that can prevent progression to the severe stage of the disease to save lives and reduce economic strain, not only on patients but also on public health systems.”
Monoclonal antibodies are among the most advanced dengue treatment candidates under development. The antibody being evaluated, formerly known as VIS513, has already completed preclinical studies and Phase I and II clinical trials that showed encouraging safety and efficacy results. Serum Institute of India is also conducting a separate Phase III trial in India, while DNDi will lead the multinational study in partnership with research institutions in Brazil, Malaysia and Thailand.
The initiative is backed by a EUR 20 million investment from the European Commission’s DG HERA and supported by the Dengue Alliance, a partnership of endemic countries utilizing “South-South cooperation” to solve local health crises.
The Serum Institute of India, the world’s largest vaccine manufacturer, has committed to ensuring the treatment remains affordable for low- and middle-income countries. Dr. Rajeev Dhere, Senior Scientific Advisor at SII, stated:
“Serum Institute of India is committed to go all out in controlling dengue… we will make all attempts to develop, produce, and distribute the vaccine and monoclonal antibodies all over the globe in an affordable manner”.
Once largely confined to tropical regions, the virus is expanding into new areas as climate change, urbanization and global travel increase the range of the Aedes mosquitoes that transmit it.
Children younger than 15 years are at greater risk of developing severe dengue, while infection during pregnancy increases the risk of maternal death and pregnancy loss. Yet current control efforts still rely largely on mosquito control and vaccines, whose effectiveness varies depending on previous infection and the circulating virus strain.
Researchers say an effective treatment could become an important addition to existing control measures by preventing severe illness, reducing hospital admissions and easing pressure on health systems during outbreaks.
The licensing agreement includes provisions to improve access in low- and middle-income countries, where dengue causes the greatest burden. Under the agreement, the treatment would be supplied to the public sector at the lowest sustainable price if it proves safe and effective.
