Evaluation of blood purification and bortezomib plus dexamethasone therapy for the treatment of acute renal failure due to myeloma cast nephropathy

Aggressive removal of circulating free light chains (FLC) by blood purification accompanied by chemotherapy is a promising approach for the treatment of acute renal failure due to myeloma cast nephropathy. Plasma exchange has been performed to remove serum FLC; in order to examine an alternative strategy we performed hemodiafiltration using protein-leaking dialyzers for the treatment of dialysis-dependent acute renal failure due to myeloma cast nephropathy. In the first case with κ-light chain cast nephropathy, the pre-treatment serum creatinine was 9.65 mg/dL, and the serum κ-FLC was 27 100 mg/L. Plasma exchange or hemodiafiltration was performed from Monday to Friday during the first several weeks. Chemotherapy was started with high-dose dexamethasone and then switched to bortezomib plus dexamethasone. The mean removal rates of κ-FLC were 45.8% (one plasma volume) and 66.9% (one-and-a-half plasma volumes) by plasma exchange. The removal rates of κ-FLC by hemodiafiltration (66.9%, FB210UHβ; 71.6%, PES210Dα; 75.2%, FXS220) were comparable to those by plasma exchange. In the second case with γ-light chain cast nephropathy, the pre-treatment serum creatinine was 4.14 mg/dL, and the serum γ-FLC was 4140 mg/L. The mean removal rates of γ-FLC were 60.2% (FXS140) and 64.2% (FB210UHβ) by hemodiafiltration. Both cases became dialysis-independent. The combination of an intense blood purification regimen and bortezomib plus dexamethasone therapy appears to be an efficient approach to renal recovery. Hemodiafiltration using protein-leaking dialyzers could become an alternative to plasma exchange as a method of removing FLC.