Tandem cycles of high-dose melphalan and autologous stem cell transplantation increases the response rate in AL amyloidosis

Clinical outcomes of patients with AL amyloidosis treated with high-dose melphalan and stem cell transplantation (HDM/SCT) are tightly linked to the achievement of a hematologic complete response (HCR). We conducted a prospective trial to determine whether a second cycle of HDM/SCT could induce HCR in patients in whom the plasma cell dyscrasia persisted following initial treatment with HDM/SCT. Sixty-two patients were enrolled. Nine patients (15%) were removed from the protocol. Of the 53 patients continuing in this study, four died within 100 days of treatment (8%), and 27 (55%) achieved an HCR at 6 months after the first cycle of HDM/SCT. Of the 22 patients who did not achieve an HCR after initial treatment, 17 received a second HDM/SCT, 1 died within 100 days of treatment (6%), while 5 (31%) achieved an HCR. Thus, the HCR rate was 67% (32/48) for surviving patients on study, 60% (32/53) for all patients who received initial cycle of HDM/SCT, and 56% (35/62) by intention-to-treat. The median survival for all patients enrolled on the trial has not yet been reached. Thus, tandem cycles of HDM/SCT can increase the proportion of patients who achieve an HCR.