Efficacy and safety of Daratumumab in relapse/refractory diffuse large B-cell lymphoma

Abstract Background: Daratumumab is a human immunoglobulin G1 monoclonal antibody that targets CD38 surface antigen, which is overexpressed in different hematologic malignancies. Many studies have shown that Daratumumab can effectively inhibit the growth of B cell tumors. Therefore, Daratumumab may has a positive therapeutic impact on Relapse/Refractory Diffuse large B-cell lymphoma(R/R DLBCL). We evaluated the safety and efficacy of Daratumumab in 3 R/R DLBCL patients with no/low expression in CD19, CD20, CD22 and high expression of CD38 in tumor sample, to explore the new treatment method for the disease. Methods: The study population comprised 3 patients with R/R DLBCL aged from 46 to 68, including 1 male and 2 females. Median line of prior regimens was 4. Patients had all taken immunohistochemical/flow-cytometry examination, results showed that they had no/low expression in CD19, CD20, CD22, with high expression of CD38 in tumor sample. Patients were treated with Daratumumab-based combination chemotherapy, and for eligible patients, CAR-T therapy was used afterwards. Results: Relevant evaluation showed that 3 patients who received Daratumumab combination chemotherapy had varying degrees of remission after treatment, including 2 CR, and 1 PR. Adverse effects were moderate and reversible, and no treatment-related deaths occurred. Patients experienced the following adverse effects: Anemia (3/3), Neutropenia (3/3), Thrombocytopenia (3/3), fever (1/3), and upper respiratory tract infection (1/3). Among three patients, two patients were treated with CAR-T therapy afterwards, and had grade 1 CRS. For all three patients, one-year OS rate was 100%, and one-year PFS rate was 67%. Conclusion: These cases demonstrated a good application prospect of Daratumumab in the treatment of R/R DLBCL with no/low expression in CD19, CD20, CD22 and high expression of CD38, and helped bridge CAR-T therapy. Disclosures: No relevant conflicts of interest to declare.