Renal outcome in patients with newly diagnosed multiple myeloma: results from the UK NCRI Myeloma XI trial.

Renal injury is a common complication of multiple myeloma (MM) and is associated with adverse outcome. Despite this, the natural history of renal injury in patients with MM remains uncertain especially in the context of intensive therapy and novel therapies. To address the lack of data, we evaluated the renal function of 2334 patients from the UK National Cancer Research Institute Myeloma XI trial at baseline and at 12 months to assess renal function over time and the factors associated with change. Patients who had severe acute kidney injury or a requirement for dialysis were excluded. At 12 months of the 1450 evaluable patients planned for autologous transplantation; 204 (14%) patients had a decline in estimated glomerular filtration rate (eGFR) ≥25% from baseline, 341 (23.5%) had an improvement and 905 (62%) had no significant change in eGFR. Renal outcome at 12 months for the 884 evaluable patients who were not planned for transplant was similar. Improved renal function was more likely if patients were <70 years old, male, had an average eGFR <60 mL per minute per 1.73 m2 and a higher baseline free light chain level >1000 mg/L, and/or a free light chain response of >90%. It did not correlate with monoclonal-protein response, transplantation, or use of a bortezomib-based regimen. We show that with current therapies the proportion of patients who have a significant decline in renal function in the first 12 months is small. The greatest relative improvement in eGFR is seen in patients with high free light chain at baseline and a high light chain response. This trial was registered at http://www.isrctn.com as #49407852.