HBM9378/WIN378, a Long-Acting, Fully Human Anti-TSLP Antibody, Enters Global Phase 2 POLARIS Trial for Asthma

HBM9378/WIN378, a Long-Acting, Fully Human Anti-TSLP Antibody, Enters Global Phase 2 POLARIS Trial for Asthma

• Phase 2 POLARIS trial will evaluate the dosing, safety, and efficacy of HBM9378/WIN378 in patients with asthma, with an initial data readout expected in mid-2026
• HBM9378/WIN378 has the potential to be the first-to-market long-acting anti-TSLP antibody with twice-yearly dosing for asthma
  
• Extended dosing intervals could reduce treatment burden and improve outcomes for patients with advanced respiratory diseases 
  
• Global COPD clinical program planned to start in mid-2026

CAMBRIDGE, Mass. and ROTTERDAM, Netherlands and SHANGHAI, July 23, 2025 /PRNewswire/ -- Harbour BioMed (the "Company"; HKEX: 02142), a global biopharmaceutical company focused on the discovery and development of novel antibody therapeutics in immunology and oncology, today announced that its partner, Windward Bio AG ("Windward Bio"), has initiated the POLARIS clinical study, a global, randomized, double-blind, placebo-controlled Phase 2 study evaluating the dosing, safety, and efficacy of HBM9378/WIN378 in patients with asthma. Initial data are expected in mid-2026.

Asthma is a chronic respiratory condition affecting approximately 300 million people worldwide, with prevalence continuing to rise. Despite the availability of treatment options, many patients experience persistent symptoms, frequent exacerbations, and reduced quality of life. Current therapies - mainly inhaled corticosteroids (ICS) and bronchodilators - are inadequate for some patients, underscoring the urgent need for more effective, long-acting treatments that address the underlying disease mechanisms.

HBM9378/WIN378 is a potentially best-in-class, long-acting monoclonal antibody targeting thymic stromal lymphopoietin (TSLP), a well-validated cytokine that plays a key role in the development and progression of a wide array of immunological diseases, including asthma and chronic obstructive pulmonary disease (COPD). This molecule has fully human sequences, offering a lower risk of immunogenicity and improved bioavailability compared to other TSLP-targeting therapies. It has been engineered to achieve a half-life extension and a silenced effector function and is subcutaneously administered. In a Phase 1 trial, HBM9378/WIN378 demonstrated an extended half-life, showed a low incidence of antidrug antibodies, and was safe and well tolerated up to the highest tested dose.

"We are pleased to see HBM9378/WIN378 advancing rapidly into global clinical development," said Dr. Jingsong Wang, Founder, Chairman and CEO of Harbour BioMed. "This long-acting, fully human anti-TSLP antibody has demonstrated strong potential in previous preclinical and clinical studies. We believe it has the potential to address significant unmet needs for patients with asthma."

HBM9378/WIN378 (also known as SKB378) started as a co-development project jointly conducted by Harbour BioMed and Kelun-Biotech, with both parties equally sharing global rights. Earlier this year, Harbour BioMed and Kelun-Biotech entered into a strategic partnership with Windward Bio, granting Windward Bio an exclusive license to research, develop, manufacture, and commercialize this antibody globally, excluding Greater China and several Southeast and West Asian countries.

In addition to asthma, HBM9378/WIN378 is also being evaluated in clinical trials for COPD, another major respiratory condition. In November 2024, the Company submitted an Investigational New Drug (IND) application for HBM9378/WIN378 in COPD to the National Medical Products Administration (NMPA) of China, which was approved in January 2025. Additionally, Windward Bio plans to initiate global clinical trials in COPD in 2026. The continued progress of HBM9378/WIN378 in both asthma and COPD highlights the versatility and potential of this innovative therapy.

About Harbour BioMed
Harbour BioMed (HKEX: 02142) is a global biopharmaceutical company committed to the discovery and development of novel antibody therapeutics in immunology and oncology. The company is building a robust and differentiated pipeline through internal R&D capabilities, strategic global collaborations in co-discovery and co-development, and selective acquisitions.

Harbour BioMed's proprietary antibody technology platform, Harbour Mice^®, generates fully human monoclonal antibodies in both the conventional two heavy and two light chain (H2L2) format and the heavy chain-only (HCAb) format. Building upon HCAb antibodies, the HCAb-based immune cell engagers (HBICE^®) bispecific antibody technology enables tumor-killing effects that traditional combination therapies cannot achieve. Additionally, the HCAb-based bispecific immune cell antagonist (HBICA^TM) technology empowers the development of innovative biologics for immunological and inflammatory diseases. By integrating Harbour Mice^®, HBICE^®, and HBICA^TM with a single B-cell cloning platform, Harbour BioMed has built a highly efficient and distinctive antibody discovery engine for developing next-generation therapeutic antibodies. For more information, please visit www.harbourbiomed.com.

About Windward Bio AG
Windward Bio is a clinical-stage biotechnology company with deep discovery, development and commercialization expertise committed to transforming the treatment of people living with advanced immunological conditions. Its lead program is WIN378, a potential best-in-disease, long-acting, anti-TSLP monoclonal antibody in Phase 2 for asthma. The company is planning additional clinical studies of WIN378 in COPD and other respiratory indications and is also building a pipeline of long-acting bi-specific antibodies targeting validated biology in respiratory and dermatological conditions. Windward Bio launched earlier this year with a $200M Series A led by top-tier investors.

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SOURCE Harbour BioMed