Effective Neutralization of Daratumumab Effects on Pre-Transfusion Testing: a Method Modification

Background: The anti-CD38 antibody daratumumab is a common multiple myeloma treatment. As the erythrocyte's membrane expresses CD38, Daratumumab-treated samples show agglutination in serological pre-transfusion tests, hindering detection of erythrocyte alloantibodies. Dithiothreitol interferes with erythrocyte antigens, affecting investigation of unexpected antibodies. DARAEx (R), an anti-CD38 neutralizing agent, overcomes daratumumab-induced effects, without dithiothreitol's interferences. DARAEx (R) is applied only in Biorad columns. This study aimed to provide a DARAEx (R) protocol for application with the Grifols platform. Methods: We introduced a modified DARAEx (R) protocol (AssutaBB protocol) and performed antibody screenings on samples from nineteen daratumumab-treated patients. Results: The AssutaBB protocol provided antibody screen results for all patients, exactly as established in the default manufacturing protocol. Eleven patients presented natural negative antibody screens; eight presented positive K/E antibodies. Conclusions: AssutaBB allows the use of the more widespread Grifols platform in daratumumab-treated patients.