BACKGROUND: To determine the efficacy of immunoglobulin free light chain (FLC) removal by high cut-off haemodialysis (HCO-HD) as an adjuvant treatment to chemotherapy for patients with acute kidney injury complicating multiple myeloma (MM).METHODS: Sixty-seven patients with dialysis-dependent renal failure secondary to MM were treated with HCO-HD and chemotherapy.RESULTS: The population was predominately male (62.7%) with new presentation MM (75%) and did not have a history of chronic kidney disease (84%). The mean serum creatinine at presentation was 662 (SD = 349) μmol/L and of the 56.7% of patients who had a renal biopsy, 86.7% had cast nephropathy as the principal diagnosis. Eighty-five percent of patients were treated with a chemotherapy regime consisting of dexamethasone in combination with a novel agent (bortezomib or thalidomide). The median number of HCO-HD sessions was 11 (range 3-45), 97% received an extended dialysis regime. Seventy-six percent of the population had a sustained reduction in serum FLC concentrations by Day 12, of these 71% subsequently became independent of dialysis. In total, 63% of population became independent of dialysis. Factors which predicted independence of dialysis were the degree of FLC reduction at Days 12 (P = 0.002) and 21 (P = 0.005) and the time to initiating HCO-HD (P = 0.006).CONCLUSION: The combination of extended HCO-HD and chemotherapy resulted in sustained reductions in serum FLC concentrations in the majority of patients and a high rate of independence of dialysis.