Cambridge, Massachusetts – September 11, 2026 -- Harbour BioMed (HKEX: 02142) and partner Windward Bio reported positive Phase 2 interim results for HBM9378/WIN378, a twice-yearly TSLP-blocking antibody, from the 147-patient POLARIS-1 asthma trial, clearing the path for two Phase 3 studies.
Interim data show up to 174 mL lung-function gain after single dose
The Phase 2 interim analysis, conducted on the first 98 of 147 enrolled patients with uncontrolled moderate-to-severe asthma, found FEV1 increases of up to 174 mL, with a placebo-adjusted mean increase of 256 mL (p=0.033) at Week 24 after a single dose.
Biomarkers for airway inflammation drop sharply
FeNO fell by up to 24 ppb, a 43% reduction (p=0.006), while blood eosinophil counts dropped by up to 200 cells/μL, a 51% decline (p0.0001). Near-maximal effects appeared as early as Week 2 and were sustained through Week 24.
Half-life of up to 75 days supports twice-yearly dosing
Population pharmacokinetic modeling showed a half-life of up to 75 days, backing Windward Bio's plan for twice-yearly subcutaneous dosing -- a potential reduction in treatment burden compared with biologics requiring more frequent injections.
Safety profile shows no treatment-related serious adverse events
No treatment-related serious adverse events, withdrawals or discontinuations were recorded as of the data cut-off. Adverse events were balanced between active-dose arms and placebo; fewer than 1% of participants reported injection-site reactions and 2% developed anti-drug antibodies, which did not affect the drug's pharmacology.
Phase 3 trial already underway, second study planned for 2027
Windward Bio has initiated the Phase 3 portion of POLARIS-1, testing two twice-yearly doses against placebo with annualized asthma exacerbation rate as the primary endpoint in severe asthma patients. A second pivotal trial, POLARIS-2, is scheduled to start in the first half of 2027.
HBM9378/WIN378 -- also known as SKB378 -- originated as a co-development between Harbour BioMed and Kelun-Biotech, which share global rights equally. Windward Bio licensed rights outside Greater China and select Southeast and West Asian markets. Full Phase 2 data will be presented at an upcoming medical congress.