ALX Oncology Holdings Inc. is a clinical-stage immuno-oncology company. The Company is focused on enabling patients to fight cancer by developing therapies that block the cluster of differentiation 47 (CD47) checkpoint pathway and bridge the innate and adaptive immune system. The Company is developing a checkpoint inhibitor designed to have an affinity for CD47 and to avoid the limitations caused by hematologic toxicities inherent in other CD47 blocking approaches. Its lead product candidate, ALX148, is a CD47 blocking therapeutic. ALX148 is a fusion protein that combines a CD47 binding domain with its inactivated fragment crystallizable (Fc) domain. The CD47 binding domain of ALX148 is an affinity enhanced extracellular domain of signal regulatory protein alpha (SIRPa), a protein that is the natural receptor to CD47 found on myeloid cells. Its programs are focused on targeting CD47 across various oncology indications.