Treatment outcomes of multiple myeloma in patients requiring renal replacement therapy

Introduction: Renal impairment is a recognised complication of multiple myeloma (MM). Bortezomib and dexamethasone are used as first line therapy but are associated with important side effects. Objectives: We investigated outcomes of patients with MM requiring renal replacement therapy (RRT), assessed renal and haematological responses, and compared effects of different chemotherapy regimens. Patients and Methods: Retrospective study of 67 patients with MM with associated renal impairment managed at our centre from 2007–2017. Approximately 29 patients required RRT and were included in the final analysis. Results: Bortezomib was administered to treat 65.5% patients; overall response rate was 84.2% (complete 21.1%, partial 63.1%). The remaining patients were treated with other agents; of these 50% responded to therapy, all with partial response. Bortezomib was associated with improved survival (P=0.02), however a higher proportion of patients experienced side effects (P=0.02). Of the patients who received bortezomib, 47% came off RRT, compared to 10% of patients who did not (P=0.04). Independence from RRT had the best association with survival (P=0.07). Patients who came off RRT had significant reduction in serum free light chains after two cycles of chemotherapy; those remaining dialysis-dependent showed variable changes in free light chain levels (P=0.02). Conclusion: Bortezomib treatment resulted in a significant improvement in survival, albeit with more side effects. Gaining independence from RRT was associated with better patient survival. A greater degree of reduction of free light chains corresponded to an increased likelihood of being independent of dialysis; this could be used as a marker for renal recovery and overall prognosis.