[Successful treatment with a combination of elotuzumab, lenalidomide and dexamethasone of extramedullary disease in a patient with refractory multiple myeloma].

: A 56-year-old man diagnosed with multiple myeloma was treated with CBD (cyclophosphamide, bortezomib, and dexamethasone; DEX), which was discontinued because of bortezomib-associated adverse events. Thereafter, he was treated with Ld (lenalidomide; LEN+DEX) followed by high-dose chemotherapy with autologous stem cell rescue, resulting in a complete response. Ld as maintenance therapy was discontinued because of immune thrombocytopenia, resulting in disease progression. Although treatment was switched to Pd (pomalidomide+DEX), DLd (daratumumab+LEN+DEX), and IRd (ixazomib+LEN+DEX); the patient's M protein level continued to increase and the extramedullary disease expanded despite radiotherapy. He was treated with E-Ld (elotuzumab+LEN+DEX) after 3 cycles of short VAD (vincristine, doxorubicin, and DEX). The extramedullary disease disappeared after 8 cycles of E-Ld. To the best of our knowledge, this is the first report showing the effectiveness of E-Ld treatment for extramedullary disease of a heavily treated patient for multiple myeloma. We believe that the clinical course of this patient provides useful insights about the antimyeloma mechanism of elotuzumab.