Identifying clinical response to daratumumab therapy in relapsed/refractory multiple myeloma using a patient-derived in vitro model.

Response to daratumumab in patients with relapsed/refractory multiple myeloma is heterogeneous, and a reliable biomarker of response is lacking. We aimed to develop a method that identifies response to daratumumab therapy. Patient-derived MM cells were collected before start of daratumumab treatment and were cultured in a hydrogel-based culture system. The extent of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro was associated with both clinical response and progression-free survival in corresponding patients. Together, our results demonstrate that in vitro sensitivity to daratumumab therapy in a hydrogel culture with primary MM cells might be used to identify patients most likely to benefit from treatment.