Chugai and GSK Sign Exclusive License Agreement for Anti-Dengue Virus Antibody AID351

• Exclusive license agreement signed granting GSK rights to develop, manufacture, and commercialize a new antibody drug “AID351”, which is being developed for dengue fever, one of the major neglected tropical diseases prevalent in developing countries
• Under this agreement, GSK will be responsible for the clinical development and manufacturing of AID351

TOKYO, August 18, 2026 -- Chugai Pharmaceutical Co., Ltd. (TOKYO: 4519) announced that it has signed an exclusive license agreement with GSK for the anti-dengue virus antibody “AID351” on August 17, 2026. This agreement follows the collaboration agreement for AID351 signed between the two companies on January 30, 2025.

Under this agreement, GSK obtains an exclusive, worldwide license from Chugai to develop, manufacture, and if successful commercialize with respect to AID351, which is expected to be used to manage flavivirus infections, including dengue fever. GSK will be responsible for the clinical development, including Phase I clinical trials, and the manufacturing of the asset. Chugai is eligible to receive royalties based on future product sales by GSK, if successful, as well as a percentage of any sublicensing income received by GSK from third parties.

This agreement builds on a joint development initiative for an anti-dengue virus antibody aimed at overcoming dengue fever, which is classified by the World Health Organization (WHO) as one of the Neglected Tropical Diseases (NTDs). The project has been advanced through collaboration between Chugai Pharmabody Research (CPR), the Chugai Pharmaceutical Group’s research base in Singapore, and A*STAR Singapore Immunology Network (A*STAR SIgN), using an antibody derived from A*STAR SIgN and the National University of Singapore (NUS) as the lead. During this period, the project received grant funding twice from the Global Health Innovative Technology (GHIT) Fund.

“This agreement reflects GSK’s ambition to change the trajectory of high-burden infectious diseases in lower-income countries. With between 100 and 400 million people globally estimated to be infected by dengue each year and a gap in solutions, AID351 offers a potential solution for vulnerable communities. I am proud of GSK’s partnership, scientific courage and commitment to take this innovation forward in an area of substantial unmet need,” said GSK Chief Global Health Officer, Dr. Harmony P. Garges.

“We are committed to contributing to global health through the continuous discovery of innovative medicines and efforts to improve access to healthcare. This exclusive license agreement with GSK represents a significant milestone and a major step forward from the collaboration agreement signed in January 2025. By combining GSK’s global development capabilities with our innovative antibody engineering technologies, we sincerely hope that new solutions for dengue fever, a serious global health challenge, will reach patients around the world as quickly as possible,” said Chugai’s President and CEO, Dr. Osamu Okuda.

Through this partnership, Chugai and GSK aim to further accelerate the development of an innovative new drug for dengue fever, bringing hope to patients and contributing to the resolution of social challenges.

[Reference Information]
Chugai and GSK Sign Collaboration Agreement for Anti-Dengue Virus Antibody AID351
News release issued on January 30, 2025
https://www.chugai-pharm.co.jp/english/news/detail/20250130170001_1126.html

Chugai - A*STAR Joint Development Project for Anti-Dengue Virus Antibody Continuously Selected as Grant Recipient by GHIT Fund
News release issued on March 29, 2019
https://www.chugai-pharm.co.jp/english/news/detail/20190329150000_607.html

Chugai - A*STAR Joint Development Project for Anti-Dengue Virus Antibody Selected as Grant Recipient by the GHIT Fund
News release issued on March 30, 2017
https://www.chugai-pharm.co.jp/english/news/detail/20170330090100_91.html

About Dengue Fever
Dengue fever is a mosquito transmitted febrile disease that is rapidly spreading in tropical and subtropical urbanized regions. In severe cases, it progresses to the serious and lethal dengue hemorrhagic fever or dengue shock syndrome. This disease is a leading cause of hospitalization and death in many countries in Asia and Latin America. According to the World Health Organization (WHO), about half of the world’s population is now at risk of dengue, with an estimated 100-400 million infections occurring each year¹, but there is currently no effective drug for the treatment of dengue fever.

About AID351
Dengue virus, which causes dengue fever, is known to have four different serotypes. In 2017, A*STAR SIgN and NUS have discovered a new human antibody that shows high neutralizing activity against all of the dengue virus serotypes. AID351 is an antibody drug that was developed through drug discovery where CPR undertook the optimization of the antibody by applying Chugai’s proprietary antibody engineering technologies.

Trademarks used or mentioned in this release are protected by law.

Sources:

1. WHO Dengue Information Page [Internet; cited August 2026]: https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue