Windward Bio doses first patients in Phase 2 COPD study of WIN378
Windward Bio has dosed the first patients in SIRIUS, its Phase 2 randomised, double-blind, placebo-controlled study of WIN378 in moderate-to-severe chronic obstructive pulmonary disease. The Basel-based, clinical-stage company said the trial is designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of the antibody candidate in this population.
WIN378 is a fully human monoclonal antibody engineered to inhibit the thymic stromal lymphopoietin (TSLP) ligand — a cytokine that sits upstream of several inflammatory cascades implicated in both asthma and COPD. The compound incorporates half-life extension technology and silenced effector function, giving it a projected dosing interval of twice yearly based on Phase 1 data. That Phase 1 study also reported a low rate of anti-drug antibodies and an acceptable safety profile up to the highest dose tested.
Expanding the pipeline
The SIRIUS initiation broadens Windward Bio's respiratory franchise, which is anchored by the POLARIS Phase 2/3 asthma trial. The Phase 2 portion of POLARIS is fully enrolled, with initial readouts expected in the second half of 2026. The company has stated it intends to start its first Phase 3 asthma study in the fourth quarter of 2026, contingent on those Phase 2 results.
Chief medical officer Omar Khwaja said that while existing biologic options for COPD require frequent dosing, WIN378's extended half-life is designed to deliver "longer-lasting disease control with substantially less frequent dosing." The company positions the candidate as a potential first-to-market ultra long-acting anti-TSLP antibody in both asthma and COPD — a claim that carries promotional weight and will depend heavily on the Phase 2/3 readout timeline and competitive execution.
Windward Bio holds global development and commercialisation rights to WIN378, excluding Greater China and several Southeast and West Asian territories. The compound was originally licensed from Kelun-Biotech (also known as SKB378) and Harbour BioMed (also known as HBM9378), both of which retain rights in those excluded markets.
Market context
The COPD biologics landscape is markedly less crowded than asthma but is attracting increasing attention. AstraZeneca's dupilumab was approved for COPD in the United States in 2024 — the first biologic in the indication — while tezepelumab, which also targets TSLP but with a conventional dosing interval, is being explored in COPD by AstraZeneca and Amgen. Windward Bio's differentiation argument rests squarely on dosing convenience: a twice-yearly subcutaneous injection would represent a meaningful practical advantage over monthly or quarterly regimens if the efficacy and safety profile prove comparable.
Roughly three million patients with moderate-to-severe COPD remain at high risk of exacerbations despite available inhaled therapies, according to the company — a figure that underscores the commercial rationale for pursuing the indication even as the asthma programme remains the nearer-term catalyst. Investors and potential commercial partners will be watching the POLARIS Phase 2 data in the second half of 2026 as a read-across indicator for SIRIUS, given the shared mechanism and patient population overlap in eosinophilic inflammation.
Windward Bio's pipeline also includes WIN027, a long-acting anti-TSLP × IL-13 bispecific antibody currently in Phase 1, suggesting the company is building a platform strategy around extended half-life immunology assets rather than a single-asset bet.