Hansoh Pharma Initiates First Global Phase III Trial of B7-H4 ADC HS-20089 (GSK5733584)

On March 3, the Drug Clinical Trial Registration and Information Disclosure Platform showed that Hansoh Pharma initiated the first Phase III clinical trial of HS-20089 (GSK5733584). This is the first B7-H4 ADC drug to enter the Phase III clinical stage.

HS-20089 is a B7-H4 ADC developed by Hansoh Pharma, with a topoisomerase inhibitor (TOPOi) as its payload and a drug-to-antibody ratio (DAR) of 6. B7-H4 is a transmembrane glycoprotein in the B7 superfamily, showing limited expression in normal tissues but high expression across various cancers. In October 2023, GSK reached an agreement with Hansoh Pharma to acquire overseas rights to HS-20089 for a total deal worth $1.57 billion.

This study is a multicenter, randomized, open-label, active-controlled clinical trial (n=468) designed to evaluate the efficacy and safety of HS-20089 compared with investigator’s choice of chemotherapy (topotecan, paclitaxel, or liposomal doxorubicin) in patients with platinum-resistant recurrent epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer. The primary endpoint of the study is progression-free survival (PFS) assessed by an independent imaging review committee (BICR) according to RECIST v1.1 criteria.