• COPD study initiation expands SKB378/WIN378 development into a second major respiratory disease
• SKB378/WIN378 is currently being evaluated in the Phase 2/3 POLARIS asthma study, with initial Phase 2 data expected in the second half of 2026
• SKB378/WIN378 has the potential to be the first-to-market, ultra long-acting anti-TSLP antibody for asthma and COPD, with Phase 3 initiation in asthma planned for Q4 2026

CHENGDU, China, June 9, 2026 /PRNewswire/ -- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. ("Kelun-Biotech" or the "Company") today announced that its partner Windward Bio has dosed the first patients in the Phase 2 SIRIUS study of SKB378/WIN378 (also known as HBM9378) in patients with chronic obstructive pulmonary disease (COPD).

COPD is a progressive, irreversible lung disease and the third leading cause of death worldwide. Driven by immune-mediated airway inflammation and persistent airflow obstruction, the disease makes even routine daily activities a struggle. Its defining feature is exacerbations — sudden, severe flare-ups that lead to emergency room visits, hospitalizations, and lasting declines in lung function. Despite currently available inhaled background therapies, more than 3 million patients with moderate-to-severe COPD remain at high risk of recurrent exacerbations, underscoring an urgent need for better treatment options.

SIRIUS is a global, Phase 2 randomized, double-blind, placebo-controlled, dose-finding study. It is designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of SKB378/WIN378 in patients with moderate-to-severe COPD.

SKB378/WIN378 started as a co-development project jointly conducted by the Company and Harbour BioMed, with both parties equally sharing global rights.

About SKB378/WIN378 (also known as HBM9378)

SKB378/WIN378 is a next-generation, fully human monoclonal antibody that potently inhibits the TSLP ligand. This clinically validated target plays a key role in the development and progression of a wide array of immunological diseases, including asthma and COPD. SKB378/WIN378 has been engineered to achieve half-life extension (HLE) and silenced effector function. It has been studied in a Phase 1 trial, which confirmed an extended half-life suitable for twice-yearly dosing, demonstrated a low rate of antidrug antibodies, and was safe and well tolerated up to the highest dose tested. SKB378/WIN378 is administered subcutaneously. Windward Bio licensed the global rights (excluding Greater China and several Southeast and West Asian countries) for SKB378/WIN378 from Kelun-Biotech and Harbour BioMed (also known as HBM9378). WIN378 is currently being evaluated in the POLARIS Phase 2/3 asthma study with initial readouts expected in the second half of 2026. WIN378 is also being evaluated in the SIRIUS Phase 2 COPD study. The first Phase 3 study of WIN378 in asthma is expected to begin in the fourth quarter of 2026.

About Kelun-Biotech 

Kelun-Biotech (6990.HK) is a holding subsidiary of Kelun Pharmaceutical, which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. Kelun-Biotech focuses on major disease areas such as solid tumors, autoimmune, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. Kelun-Biotech is committed to becoming a leading global enterprise in the field of innovative drugs. At present, Kelun-Biotech has more than 30 ongoing key innovative drug projects, of which 4 projects with 8 indications have been approved for marketing, 1 project is in the NDA stage and more than 10 projects are in the clinical stage. Kelun-Biotech has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 2 ADC projects with 5 indications approved for marketing, and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit https://en.kelun-biotech.com/. 

About Windward Bio

Windward Bio is a clinical-stage biotechnology company with deep discovery, development, and commercialization expertise committed to transforming the treatment of people living with serious immunological conditions. Its lead program is WIN378, a potential best-in-disease, ultra long-acting anti-TSLP monoclonal antibody currently in a Phase 2/3 trial for asthma and in a Phase 2 study for COPD. The pipeline also includes WIN027, a clinical-stage, long-acting anti-TSLPxIL-13 bispecific with broad therapeutic potential across immunological diseases, which is currently in Phase 1. The company is building a discovery pipeline of long-acting bispecific antibodies, targeting validated biology in respiratory and dermatological conditions.