Daratumumab-Based Therapy for AL Amyloidosis: A Case Report

Introduction: AL amyloidosis is characterized by deposition of amyloid fibrils of light chains produced by clonal CD38+ plasma cells. One-third of patients have renal involvement with poor response to chemotherapy. We present a case of AL amyloidosis successfully treated with daratumumab followed by remission after two year follow-up. Case Description: 66-year-old male with history of CKD stage 3A presented with recurrent syncopal episodes. On exam, he had orthostatic hypotension and macroglossia. Labs showed serum creatinine (sCr) of 2.55mg/dL (baseline 1.2mg/dL), albumin 2.7 mg/dl. Urinalysis revealed >500 protein, 24hr urine protein of 8.5 g/24hr, and urine microalbumin of 5.7g/24hr. Urinary protein electrophoresis and immunofixation was positive for monoclonal IgA-lambda in the beta region. Diagnostic kidney biopsy was consistent with lambda restricted AL amyloidosis (Fig 1). Bone marrow biopsy revealed plasma cell neoplasm, IgA and lambda light chain restricted with associated focal amyloid deposition. Peripheral blood smear showed rouleaux with 12.4 % plasma cells. The was no speckled pattern on echocardiography; there was moderate concentric LVH (Ejection fraction 64%). He was treated with Dara-CyBorD (daratumumab, cyclophosphamide, bortezomib, and dexamethasone) for stage II systemic AL amyloidosis. Cyclophosphamide was then stopped due to side effects. He received 4 cycles of Dara-BorD, then monthly daratumumab for 2 years with ongoing remission. 24hr urine protein improved to 1.7g/day with stable sCr of 2.5 mg/dl at two year follow-up. Discussion: AL amyloidosis has overall poor prognosis leading to progressive disability and death. A challenge in the management has been the low response rates to CyBorD. This case highlights the promising efficacy and better survival outcomes when adding daratumumab as based therapy to achieve remission.