Consolidation with bortezomib and dexamethasone following risk-adapted melphalan and stem cell transplant in systemic AL amyloidosis

High-dose melphalan and autologous stem cell transplant (SCT) induce hematologic and clinical remissions in AL and results in prolonged survival. In a prior phase II study, we showed that post-SCT adjuvant thalidomide and dexamethasone improved hematologic responses in 42% of patients, resulting in a 39% strictly defined complete response (sCR) rate at 12 months post-SCT (Cohen et al., Br J Haematol 2007;139:224-233). With a median follow-up of 59 months, the overall survival of patients on that study is 69% (Comenzo, Blood 2009;114:3147-3157). We now report on a phase II trial in which we use bortezomib and dexamethasone (BD) following risk-adapted SCT in newly diagnosed patients with amyloidosis who had residual disease following SCT. We show that BD is welltolerated and effective for eradicating persistent clonal plasma cell disease. At 12 months post-SCT, consolidation with BD achieves high overall and unprecedented sCR rates with frequent organ improvement that continues to occur over time.