WHO Adds ArkBio's Ziresovir to Pediatric RSV Drug Priority List

On July 15, 2025, the World Health Organization (WHO) announced that Ziresovir, a novel antiviral developed by Shanghai Ark Biopharmaceutical Co., Ltd. (ArkBio), has been included in its Pediatric Drug Optimization for Respiratory Syncytial Virus (PADO-RSV) priority list. This significant inclusion marks a milestone as Ziresovir becomes the first RSV antiviral drug originating from China to be recognized on this global platform, aimed at enhancing pediatric healthcare.

Ziresovir is a small-molecule fusion protein inhibitor targeting respiratory syncytial virus (RSV), which is a leading cause of lower respiratory tract infections in infants and young children. According to WHO data, RSV accounts for approximately 33 million cases of lower respiratory tract infections annually, resulting in 3.6 million hospitalizations and an estimated 101,400 deaths, predominantly in low- and middle-income countries (LMICs). This stark reality underscores the pressing need for effective treatment options for a virus that poses severe health risks to vulnerable populations.

The PADO-RSV project, part of WHO's Global Accelerator for Pediatric Formulations (GAP-f), aims to identify and prioritize the development of essential pediatric medicines. This initiative seeks to systematically review the research and development pipeline for RSV treatments and enhance accessibility to effective therapies for children. As stated in the WHO report, Ziresovir's inclusion signifies its clinical value and potential to address significant health gaps in RSV treatment.

Dr. Jim Wu, CEO of ArkBio, emphasized the significance of this recognition, stating, "The inclusion of Ziresovir in the WHO PADO-RSV priority list is an affirmation of the years of effort by ArkBio scientists. This recognition will allow us to expedite its global development and ensure its availability for patients worldwide."

Ziresovir's mechanism of action involves binding to the pre-fusion conformation of the RSV F protein, effectively preventing the virus from entering human cells and inhibiting its replication. The drug has successfully completed pivotal Phase 3 clinical trials, with positive results published in reputable journals such as The New England Journal of Medicine and The Lancet Child & Adolescent Health.

ArkBio's commitment to global health is further underscored by plans to ensure affordable access to Ziresovir, particularly in LMICs, where the burden of RSV is most acutely felt. The company aims to collaborate with international health organizations and scientific institutions to facilitate the drug's global registration and distribution.

Ziresovir's designation as a Breakthrough Therapy by the National Medical Products Administration (NMPA) in China highlights its potential impact on public health. By developing this innovative therapeutic, ArkBio aligns its corporate mission with the broader goal of improving healthcare outcomes for children worldwide.

The PADO-RSV initiative, supported by WHO, emphasizes the importance of targeted R&D in addressing pediatric health needs. This program has successfully identified priority products for various diseases, including HIV, hepatitis C, and tuberculosis, showcasing the potential for optimized formulations to significantly improve children's health outcomes.

As ArkBio moves forward with its strategic plans for Ziresovir, the implications for pediatric RSV treatment are substantial. The drug's inclusion in the WHO's priority list is expected to catalyze further research, enhance collaboration among stakeholders, and ultimately improve access to vital treatments for one of the most challenging pediatric health issues globally. The future of RSV treatment may be transformed by innovations such as Ziresovir, paving the way for improved health outcomes for children affected by this viral infection.