CLL1 + CD38

**CLL1 + CD38** refers to a combination approach—either as an investigational bispecific antibody or a dual-targeting therapeutic modality—designed to simultaneously target both the CLL1 (also known as CLEC12A) and CD38 antigens, which are expressed on certain hematological cancer cells. CLL1 is a myeloid antigen highly expressed in acute myeloid leukemia (AML) stem and progenitor cells, while CD38 is broadly expressed on malignant plasma cells and some myeloid leukemias. Drugs that combine CLL1 and CD38 targeted mechanisms, such as bispecific antibodies, are under preclinical or early-phase clinical investigation primarily for AML, relapsed/refractory AML, or other blood cancers. The goal is to enhance tumor cell recognition and killing—by leveraging multiple immune effector pathways (e.g., T cell engagement, antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, phagocytosis) and to overcome antigen escape seen with single-targeted therapies.