Effect of severe hypoalbuminemia on toxicity of high-dose melphalan and autologous stem cell transplantation in patients with AL amyloidosis.

High-dose melphalan with stem cell transplantation (HDM/SCT) extends survival and induces hematologic and clinical responses in patients with light chain (AL) amyloidosis. Eighty percent of melphalan is bound to plasma proteins (60% albumin-bound). We hypothesized that patients with profound hypoalbuminemia have a greater free melphalan fraction and more toxicity. Patients with AL amyloidosis treated with HDM/SCT between 2011 and 2014 with severe hypoalbuminemia (SH), defined as serum albumin ⩽2 g/dL were studied retrospectively. Sixteen patients with SH were identified. Forty-one patients without severe hypoalbuminemia (WSH) treated between 2011 and 2012 served as control. The incidence of acute renal failure requiring hemodialysis was 25% among patients with SH, compared with 5% among patients WSH (P=0.05). Not all patients who needed dialysis required it long term; 6.25% for SH and 2.44% for WSH (P=0.49). The rates of grade 3 or 4 febrile neutropenia and gastrointestinal toxicities were not significantly different between the groups. Engraftment kinetics were similar for both groups. Grade 4 renal toxicity and grade 3 lightheadedness were more frequent in patients with SH undergoing HDM/SCT for AL amyloidosis. Further studies into the mechanism of increased renal toxicity in patients with SH are warranted.