Overview : BSI-500 is a novel bispecific antibody that shows anti-neoplastic activity by acting as CD40 agonist and CD47/SIRPα antagonist. It shows higher binding affinity and bioactivity compared to selicrelumab analog on CD40 part and similar binding affinity and blocking activity to SIRPα-fusion protein on CD47 part. CD47 is upregulated in essentially every cancer type to inhibit innate immune cells from phagocytosing the tumor cells. By blocking this signal though SIRPα-ECD binding, the surface of the tumor cells is coated with the BSI-500, allowing the CD40 activation, which can license dendritic cells to promote antitumor T cell activation and re-educate macrophages to destroy tumor. BSI-500 was created by Biosion under a collaboration with CTTQ in Nov 2021. Biosion owns ex-Greater China rights for development and commercialization while CTTQ owns Greater China rights.

Development status : Pre-clinical development, CTTQ plans to file an IND in 2H 2023.