61O First-in-human phase I evaluation of HCB101, a SIRPα–Fc innate checkpoint fusion protein: Safety, pharmacokinetics, and receptor occupancy

HCB101 is a rationally engineered SIRPα-Fc fusion protein designed to improve the safety and activity of CD47 pathway inhibition through reduced red-blood-cell binding, minimized cytopenias, and enhanced macrophage activation. Preclinical studies in >80 xenograft and PDX models demonstrated potent CD47–SIRPα blockade, strong innate immune activation, and a broad therapeutic window. This first-in-human study evaluates the safety, pharmacokinetics (PK), receptor occupancy (RO), and pharmacodynamic (PD) effects of HCB101 in advanced cancers.