ArkBio's Ziresovir Included into Pediatric RSV Drug Priority List by WHO

SHANGHAI, July 16, 2025 /PRNewswire/ -- In the newly released "Paediatric drug optimization for respiratory syncytial virus (PADO-RSV) meeting report" by Global Accelerator for Paediatric formulations (GAP-f), the World Health Organization (WHO) host network, ziresovir (10mg) has been included in the PADO-RSV priority list. Ziresovir, developed by Shanghai Ark Biopharmaceutical Co., Ltd. ("ArkBio"), is the first and only RSV antiviral drug to be included in the list. This is the first time WHO has included an anti-RSV drug developed from China in the paediatric drug optimization priority list.

Filling a Global Gap: Ziresovir Leads RSV Antiviral Development

RSV is the leading pathogen of lower respiratory tract infections (LRTIs) in infants and young children globally, causing approximately 33 million cases of LRTIs, 3.6 million hospitalizations, and 101,400 deaths annually, with 97% of deaths occurring in low- and middle-income countries (LMICs). Despite the severe threat, current specific treatment options for RSV are extremely limited, and there is a clinical urgent need for safe, effective, and child-appropriate innovative drugs. The "Paediatric drug optimization for respiratory syncytial virus (PADO-RSV)" project initiated by WHO/GAP-f aims to systematically review the global R&D pipeline, clarify R&D priorities, and promote the development and accessibility of RSV prevention and treatment tools more suitable for the paediatric population. With its clear clinical value, child-friendly design, and good safety profile, ziresovir becomes the only product in the antiviral drug category selected for the PADO-RSV priority list, demonstrating its huge potential in the paediatric RSV treatment globally.

WHO pointed out in the report that ziresovir's research results are of great significance to the global RSV treatment field and recommended conducting diverse clinical studies in broader populations to further verify its applicability and effectiveness.

ArkBio will actively respond to WHO's advice with a plan to expand ziresovir's clinical development in other countries and regions. By collaborating with international scientific institutions and public health organizations, ArkBio aims to rapidly advance the drug's global registration and accessibility. Simultaneously, ArkBio is deeply aware of the importance of global public health, particularly concerned about the challenges faced by low- and middle-income countries. The company will formulate drug accessibility plans specifically for these countries to ensure ziresovir can be supplied at reasonable prices globally wherever it is needed, contributing to the prevention and treatment of RSV infection.

"ArkBio has a mission to 'help patients inspire and thrive'", Dr. Jim Wu, CEO of ArkBio, stated. "The inclusion of ziresovir in the WHO PADO-RSV priority list is not only an affirmation of the years of effort by ArkBio scientists, but also an inspiration for our corporate mission. The recognition of ziresovir would allow us to expedite its global development and realize the potential on the global stage. We will ensure the innovation can not only benefit patients in China but the very needed patients worldwide. This is not just our goal but our social responsibility. ArkBio will strive to contribute more to address global public health issues."

About GAP-f

GAP-f stands for the Global Accelerator for Paediatric Formulations Network. Hosted by WHO, it operates throughout the drug development lifecycle to accelerate the research, development, and dissemination of optimized pediatric formulations. Identifying priorities is the first step toward a targeted R&D approach. Establishing a priority list of the most urgently needed pediatric formulations is crucial, as it helps focus the efforts and resources of researchers and suppliers on specific dosage forms and formulations that address children's most critical needs.

About PADO

PADO stands for Paediatric Drug Optimization. It is a WHO's legally binding international priority (based on WHA69.20 resolution) that accelerates the development of high-demand pediatric drugs by building consensus among regulators, funders, and manufacturers. It aims to identify priority products for R&D and define their ideal characteristics. It has been successfully implemented in areas including human immunodeficiency virus (HIV), hepatitis C, tuberculosis, COVID-19, antibiotics, neglected tropical diseases, and childhood cancers. These initiatives demonstrate that, against the backdrop of a fragmented and small pediatric drug market, such efforts hold potential and deliver tangible impacts in accelerating access to optimized formulations.

About Ziresovir

Ziresovir is a novel small-molecule RSV fusion (F) protein inhibitor. It binds to the pre-F protein conformation of the virus and prevents viral entry into human cells. Ziresovir can also suppress RSV viral transmission by blocking cell-to-cell fusion through the formation of "syncytia", a characteristic event of RSV infection of host cells. It is the first oral anti-RSV drug that has completed a phase 3 pivotal clinical study with positive results. The phase 3 results have been published in The New England Journal of Medicine and The Lancet Child & Adolescent Health. Ziresovir has received Breakthrough Therapy designation by the National Medical Products Administration (NMPA) of China.

About ArkBio

ArkBio is a global biotech company focused on developing innovative therapeutics for respiratory, infectious, and pediatric diseases. Founded in 2014, it has built core technology platforms and a differentiated R&D pipeline through in-house R&D efforts and external collaboration. Key drug assets include ziresovir (AK0529), the first direct-acting RSV antiviral with positive pivotal phase III results, and Azstarys (AK0901), an FDA-approved ADHD therapeutic drug.

ArkBio has established strategic partnerships with several multinational pharmaceutical companies and academic institutes, including Roche, Genentech, the Scripps Research Institute, the Institute of Microbiology of Chinese Academy of Sciences, domestic and international biotechnology companies, as well as venture capital institutions.

For more information, please visit: www.arkbiosciences.com
Investor Inquiries: IR@arkbiosciences.com

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