Blood Transfusion Management and Transfusion-Related Outcomes in Daratumumab-Treated Patients With Relapsed or Refractory Multiple Myeloma

Daratumumab binds CD38 on red blood cells (RBCs), resulting in panagglutination in blood compatibility tests. RBC transfusions and transfusion-related adverse events (AEs) from the phase 2 SIRIUS clinical trial were analyzed and, an in-depth analysis from 2 clinical study sites were performed. RBC transfusion–related AEs, including hemolysis, were not observed among daratumumab-treated patients, confirming that transfusions may be safely administered. Introduction Daratumumab, a human CD38 monoclonal antibody approved for multiple myeloma (MM) treatment, binds red blood cells (RBCs), resulting in panagglutination in compatibility tests. Published mitigation methods avoid additional testing, ensuring timely release of blood products. Blood transfusion management and transfusion-related outcomes of daratumumab-treated patients in the SIRIUS study are reported, with emphasis on 2 clinical sites. Patients and Methods Patients had MM treated with ≥ 3 prior lines of therapy, including a proteasome inhibitor and an immunomodulatory drug, or were refractory to a proteasome inhibitor and an immunomodulatory drug. RBC typing and alloantibody screening were performed in gel cards. Antibody identification using RBC panels was performed on patients with positive antibody screens. Hematology panels and serum chemistry were analyzed ≤ 2 days before each daratumumab infusion and the first daratumumab dose within each treatment cycle, respectively. Pre- and posttransfusion hemoglobin values were analyzed retrospectively. Results At clinical cutoff, patients received 236 transfusions; 47 (37.9%) of 124 patients received 147 packed RBC transfusions, and 17 (13.7%) received 89 platelet transfusions. No hemolysis was reported, and 1 platelet transfusion reaction was observed. At Mount Sinai, no transfusion adverse events were observed, no new unexpected RBC alloantibodies were identified, and transfusions increased hemoglobin values (median, 1.2 g/dL). At Levine Cancer Institute, 6 of 7 patients responded to transfusions, with a median hemoglobin change of 1.7 g/dL. Conclusion In SIRIUS, no RBC transfusion reactions, including hemolysis, were observed. Observations from Mount Sinai and Levine Cancer Institute confirm that transfusions may be administered safely to daratumumab-treated patients.