Heplatinum Pharmaceutical-B (02142): Positive phase II clinical results of HBM9378/WIN378 for asthma treatment and commencement of phase III study

Zhitong Financial App News and Platinum Pharmaceutical-B (02142) announced that our partner Windward Bio AG (Windward Bio) has announced that HBM9378/WIN378 (an all-human ultra-long-lasting monoclonal antibody targeting thymic matrix lymphopoietin (TSLP)) achieved positive interim results in the phase II phase II clinical trial of POLARIS-1 for the treatment of asthma. The Phase III portion of POLARIS-1 has also been launched.

HBM9378/WIN378 is a novel all-human ultra-long-lasting monoclonal antibody. It has a unique binding pattern and can effectively inhibit TSLP. The antibody has been engineered to have stronger efficacy, extended half-life, and functional silencing. HBM9378/WIN378 is currently the only known drug under development that blocks its signaling pathway by binding TSLP at two sites, which can interfere with the binding of TSLP to its two co-receptors on the surface of epithelial cells.

POLARIS-1 (NCT07120503) is a seamless global phase II/III clinical study conducted by Windward Bio to evaluate the use of HBM9378/WIN378 in adult patients with uncontrolled asthma. The phase II portion of the study was a 48-week randomized, double-blind study that mainly assessed the pharmacokinetics, safety, immunogenicity, and pharmacodynamic activity of the three dose levels of subcutaneous HBM9378/WIN378 compared to placebo, and provided a basis for dose selection for the phase III study. The study also assessed the effects of HBM9378/WIN378 on lung function and biomarkers of airway inflammation. A total of 147 patients were enrolled in this phase II group, exceeding the initial enrollment target of 120 cases. The mid-term analysis was based on data from the first 98 patients. The phase III section is evaluating the efficacy of two doses of HBM9378/WIN378 given twice a year compared to placebo. The main end point was the annual rate of acute asthma attacks in patients with severe asthma.

The results of the interim analysis showed that at week 24 after a single dose of HBM9378/WIN378 administration:

(i) First-second force breathing volume (FEV1) showed a dose-dependent average increase of up to 174 mL (median increase of up to 256 mL after placebo correction, p=0.033);

(ii) Exhaled nitric oxide fraction (FeNO) showed a dose-dependent average reduction of up to 24 billion parts (43% reduction percentage, p=0.006); and

(iii) The average blood eosinophil count (EOS) decreased, with a maximum drop of 200 cells/µL (51% reduction percentage, p<0.0001).

FEV1 is a key indicator of lung function, while FenO and EOS are key inflammatory markers associated with acute asthma attacks. The above effects were observed as early as week 2 and continued until week 24. Mid-term analysis showed a half-life of up to 75 days. Interim analysis results and population pharmacokinetic models supported HBM9378/WIN378 to adopt a twice-yearly dosing regimen.

HBM9378/WIN378 is well tolerated and safe. As of the data cutoff date, no serious treatment-related adverse events, withdrawal or discontinuation were observed. The treatment group had a similar incidence of adverse events to the placebo control group. The incidence of reaction at the injection site is less than 1%, and the incidence of anti-drug antibodies is 2% (this indicator is used to evaluate immunogenicity and has no effect on the pharmacological characteristics of HBM9378/WIN378).

The phase III portion of POLARIS-1 has used two twice-yearly dosage regimens to evaluate the effects of HBM9378/WIN378 on the annual acute incidence rate of asthma and other key efficacy indicators in patients with severe asthma. The phase III portion of the study has already been initiated by Windward Bio, which plans to launch the second phase III clinical study Polaris-2 program in the first half of 2027. The data from the Phase II study of POLARIS-1 will be presented at an upcoming medical conference.