Suzhou Zelgen Biopharmaceuticals Co., Ltd (SHA: 688266) announced the successful completion of a pivotal Phase IIb clinical trial (ZGJAK006) for its in-house Janus kinase (JAK) inhibitor, jacktinib, in patients with ruxolitinib-intolerant, medium- to high-risk myelofibrosis. The study met its primary endpoint, with 43.2% of subjects achieving ≥35% spleen volume reduction at 24 weeks.
Study Results
The trial, conducted across 45 centers including Zhejiang University’s First Affiliated Hospital, demonstrated jacktinib’s efficacy in reducing spleen volume—a key marker of disease progression in myelofibrosis. The 43.2% response rate underscores the drug’s potential to address unmet needs in ruxolitinib-intolerant patients.
Previous Milestones
In June, Zelgen reported Phase III success in medium- to high-risk myelofibrosis, meeting primary endpoints. The company plans to file two New Drug Applications (NDAs) for jacktinib: one for first-line treatment and another for ruxolitinib-intolerant patients.
Mechanism and Pipeline
Jacktinib inhibits JAK/STAT signaling pathways to reduce immune-related inflammation. It is under investigation for multiple indications, including severe alopecia areata, idiopathic pulmonary fibrosis, and COVID-19. The U.S. FDA granted orphan drug designation for myelofibrosis, while China approved Phase II trials for severe COVID-19.-Fineline Info & Tech
