Global clinical-stage biopharma giant Zenas BioPharma has announced a major development in the fight against autoimmune disease.

 

Thanks to its partner, InnoCare Pharma which has reported that orelabrutinib achieved the primary endpoint in a Phase 2b study for Systemic Lupus Erythematosus (SLE). InnoCare also received approval from China’s Center for Drug Evaluation (CDE) to move forward with a Phase 3 registrational trial.

 

In the Phase 2b study, 187 patients were randomized into three groups: orelabrutinib 75 mg once daily (QD), orelabrutinib 50 mg QD, and placebo. The primary endpoint was the SLE Response Index-4 (SRI-4) response rate at week 48. 

 

“At week 48, the orelabrutinib 75 mg QD group achieved a statistically significant improvement in SRI-4 response rate compared with placebo (57.1% vs. 34.4%, p < 0.05), meeting the primary endpoint,” the company reported.

 

The study also showed a clear dose-dependent trend, with the 75 mg QD group outperforming the 50 mg QD cohort. Secondary endpoints—including SRI-6 and the British Isles Lupus Assessment Group-based Composite Lupus Assessment (BICLA)—were also met, with “significantly higher response rates compared to the placebo group (p < 0.05).”

 

Orelabrutinib was “well tolerated with a safety profile consistent with the mechanism of action of BTK inhibition and the underlying disease biology of SLE,” the announcement noted. The drug had previously demonstrated promising results in a Phase 2a study, presented at the European Union Congress of Rheumatology (EULAR 2022).

 

In October 2025, Zenas and InnoCare sealed a transformational license agreement. Under the deal, Zenas “acquired the exclusive right to develop, manufacture and commercialize orelabrutinib in the field of Multiple Sclerosis (MS) globally, and non-oncology fields in all territories outside Greater China and Southeast Asia,” while InnoCare retained global oncology rights. Zenas also gained exclusive rights to develop ZB021, an oral IL-17AA/AF inhibitor, and ZB022, a brain-penetrant TYK2 inhibitor.

 

About orelabrutinib, Zenas noted: “Orelabrutinib is a late-stage, potentially best-in-class, highly selective CNS-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. In Multiple Sclerosis (MS), Zenas is advancing a Phase 3 trial in Primary Progressive MS (PPMS). 

 

"A Phase 3 trial in Secondary Progressive MS (SPMS) is expected to initiate in the first quarter of 2026. Orelabrutinib is approved for B cell malignancies in mainland China and Singapore, marketed by our partner InnoCare.”