Used in the treatment of relapsed or refractory diffuse large B-cell lymphoma (DLBCL). It targets CD19, a protein found on the surface of B-cells, including malignant B-cells. By binding to CD19, it activates immune-mediated cell killing, including antibody-dependent cellular cytotoxicity (ADCC). Often used in combination with lenalidomide to enhance therapeutic effect. Also serves as a reference standard in bioanalytical assays and drug development for evaluating CD19-targeting therapeutics.