l  Phase 3 AirFLO study with ziresovir met primary and key secondary endpoints of significant reduction of sign-and-symptom score (p=0.002) and viral load (p=0.006) respectively, compared with placebo

l  Respiratory syncytial virus (RSV) infection is a leading cause of hospitalization and death in children under five years old

l  Ziresovir is the first antiviral drug successfully completing a pivotal phase 3 study in this patient population

l  Regulatory submission in China planned for Mid-2022

Shanghai April 7, 2022 – Ark Biopharmaceutical (ArkBio), a biopharma company dedicated to the discovery and development of drugs for pediatric and respiratory diseases, today announced the successful results of the multicenter Phase 3 AirFLO study with ziresovir in infants hospitalized with RSV. The trial met both primary endpoint of reduction in signs-and-symptoms (S&S) score (p=0.002) and key secondary endpoint of reduction in viral load (p=0.006) compared with placebo. The results represent the first successful phase 3 study for an oral RSV antiviral drug globally.

“Every year tens of thousands of young infants and children die from RSV infection, and we urgently need a safe and effective therapy”, commented Dr. Xin Ni, President of Beijing Children’s Hospital, Director of National Children’s Medical Center, and the leading investigator of the AirFLO study. “The AirFLO results give hope to patients, families, and physicians. With ziresovir they may finally get access to an effective treatment which has been lacking for so long.”

In the Phase 3 AirFLO trial, ziresovir demonstrated a rapid onset of clinical effects, showing a 30% additional S&S score reduction compared with placebo (p=0.002) after 2 days of treatment. In the study, patients under 6-month-old showed even more pronounced benefits, with 55% additional S&S score reduction compared with placebo (p<0.001). Ziresovir also showed significant anti-viral effect, with active drug group shown 77% additional viral load reduction compared with placebo (p=0.006) on day 5; and statistically significant viral load reductions were observed throughout the treatment period. Ziresovir has shown an excellent safety profile from the clinical studies conducted to date. Supported by the AirFLO results, regulatory submission of ziresovir for market approval in China is planned in Mid-2022.

“We are extremely excited about these results”, said Dr. Jim Wu, chairman and CEO of ArkBio. “I want to thank all parents and children who participated in this trial and congratulate the stellar team of investigators to the successful outcome of their hard work. We had high hopes after the international multicenter Phase 2 VICTOR study showed good efficacy and safety of ziresovir. The Phase 3 AirFLO results confirmed ziresovir’s clinical benefits.  We are particularly proud that ziresovir is the first pediatric drug that is discovered and developed in China before expanding to the rest of the world. We are continuing our efforts to bring clinically significant therapeutics to patients in China and globally.”

About RSV

It is estimated that in 2019, there were approximately 33 million cases of RSV-ALRTI (RSV viral infection with symptoms of acute lower respiratory tract infection) in children under 5 years old worldwide, which resulted in approximately 3.6 million hospitalizations and 100,000 deaths. Even in children with mild symptoms, untreated RSV infection may develop into chronic respiratory diseases, such as wheeze and asthma, and affect a child’s long-term growth and development.

RSV is a highly prevalent airborne RNA virus which enters the trachea and lungs through oral and nasal inhalation, invades epithelial cells and causes damage in respiratory tract, which can lead to excessive airway mucus, lumen blockage, and dyspnea. The common symptoms of RSV infection are runny nose, fever, cough, and wheeze. Under serious conditions, respiratory distress and complete airway blockage may occur, leading to respiratory failure and death.

The populations most susceptible to RSV infection are children, the elderly, and adults with impaired immune functions. Over 90% of children are infected with RSV before 2 years of age. At present, there are neither effective vaccine nor treatments available that specifically target RSV.

About ziresovir

Ziresovir is a novel small-molecule RSV fusion (F) protein inhibitor. It binds to the F protein of the virus and prevents viral entry into human cells and viral infection. Ziresovir can also suppress virus transmission by blocking cell fusion through the formation of “syncytia”, a characteristic event of RSV infection of host cells.

Ziresovir is the first anti-RSV drug that has successfully completed a phase 3 pivotal clinical study globally. It is the first pediatric drug discovered and developed in China before expanding to the rest of the world. Ziresovir is also the first non-oncology investigational product ever granted breakthrough designation by the Chinese National Medical Products Administration (NMPA).

About the AirFLO Study

The AirFLO study (NCT04231968) was a randomized, double-blind, placebo-controlled, multicenter, pivotal phase 3 clinical study evaluating the efficacy, safety, tolerability, pharmacokinetics, and antiviral effect of ziresovir for the treatment of RSV infection in hospitalized infants and children. A total of 302 patients were recruited from 30 pediatric clinical centers in China. Participants received ziresovir or placebo twice daily for five consecutive days. The primary endpoint was the change from baseline in bronchiolitis sign and symptom score; the key secondary endpoint was RSV viral load change from baseline.

About ArkBio

Ark Biopharmaceutical (ArkBio) is a biopharmaceutical company focusing on discovering and developing novel drugs for unmet medical needs, especially in pediatric and respiratory diseases. Since its inception in 2014, the company has established core technology platforms and discovered drug candidates with global patent protection. Through in-house R&D efforts and external collaborations, it has developed a promising and highly differentiated product pipeline. The core product, ziresovir, is the leading RSV antiviral drug that received a breakthrough designation from NMPA and successfully completed a pivotal phase 3 clinical trial. Another near-commercial asset is an ADHD drug AZSTARYS recently approved by FDA. ArkBio owns the right for development and marketing AZSTARYS in Greater China. The pipeline also includes a battery of clinical and pre-clinical stage drug candidates with first- or best-in-class potential for global market.

ArkBio has a track record of successful collaboration and partnership with multinational pharma companies such as Roche/Genentech, world-leading academic institutions such as The Scripps Research Institute, the Institute of Microbiology of Chinese Academy of Sciences, domestic and global biotech companies, as well as multinational investment institutions.

For investor relation please contact: IR@arkbiosciences.com