Bortezomib-based induction followed by stem cell transplantation in light chain amyloidosis: results of the multicenter HOVON 104 trial

This prospective, multicenter, phase II study investigated the use of 4 cycles of bortezomibdexamethasone induction treatment, followed by high dose melphalan and autologous stem cell transplantation in patients with newly diagnosed light chain amyloidosis. The aim of the study was to improve the hematologic complete remission rate 6 months after stem cell transplantation from 30% to 50%. Fifty patients were enrolled and 72% had 2 or more organs involved. The overall hematologic response rate after induction treatment was 80% including 20% complete remission and 38% very good partial remission. Fifteen patients did not proceed to stem cell transplantation due to various reasons but mostly treatment related toxicity and disease related organ damage and death (2 patients). Thirty-one patients received melphalan 200 mg/m2 and 4 patients a reduced dose because of renal insufficiency. The stem cell transplantation procedure was without treatment related mortality. Hematologic responses improved at 6 months after stem cell transplantation to 86% with 46% complete remissions and 26% very good partial remissions. However, due to the high discontinuation rate before stem cell transplantation the primary endpoint of the study was not met and the complete remission rate on intention to treat analysis was 32%. Organ responses continued to improve after stem cell transplantation. We confirm the high efficacy of bortezomib-dexamethasone treatment in AL amyloidosis patients. However, because of both treatment related toxicity and disease characteristics, 30% of the patients could not proceed to stem cell transplantation after induction treatment.

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