Induction therapy with bortezomib and dexamethasone followed by autologous stem cell transplantation versus autologous stem cell transplantation alone in the treatment of renal AL amyloidosis: a randomized controlled trial

Background: Although the use of bortezomib alone and in combination with steroids has shown efficacy in AL amyloidosis, its role in combination with high-dose melphalan and autologous stem cell transplantation (HDM/SCT) is unknown. In this study, we evaluated bortezomib in combination with dexamethasone (BD) for induction chemotherapy prior to HDM/SCT. Methods: This was a single-center, prospective, randomized controlled trial comparing induction therapy consisting of two BD cycles followed by HDM/SCT (BD + HDM/SCT) with HDM/SCT alone in the treatment of patients with newly diagnosed AL amyloidosis. The hematological and organ responses of the patients were assessed every three months post HDM/SCT. Results: Fifty-six patients newly diagnosed with renal (100%), cardiac (57.1%), liver (7.1%), or nervous system (8.9%) AL amyloidosis were enrolled in this study; 28 patients were assigned to each arm. Two patients died within 100 days of HDM/SCT (3.6% treatment-related mortality). The overall hematologic response rates in the BD + HDM/SCT arm and HDM/SCT arm at three, six and twelve months were 78.5% versus 50%, 82.1% versus 53.5% and 85.7% versus 53.5%, respectively. In the BD + HDM/SCT arm, 15 (53.5%) patients achieved a hematologic response after BD and before HDM/SCT. An intention-to-treat analysis revealed a higher rate of complete remission in the BD + HDM/SCT arm at both 12 and 24 months (67.9% and 70%, respectively) than with the HDM/SCT-only therapy (35.7% and 35%, respectively, P = 0.03). After a median follow-up of 28 months, the survival rates at 24 months post-treatment start were 95.0% in the BD + HDM/SCT group and 69.4% in the HDM/SCT alone group (P = 0.03). Conclusions: Our preliminary data suggest that the outcome of treating AL amyloidosis with BD induction and HDM/SCT was superior to the outcome of the HDM/SCT treatment alone.