Long-term event-free and overall survival after risk-adapted melphalan and SCT for systemic light chain amyloidosis

Stem cell transplantation (SCT), an effective therapy for amyloid light chain (AL) amyloidosis patients, is associated with low treatment-related mortality (TRM) with appropriate patient selection and risk-adapted dosing of melphalan (RA-SCT). Consolidation after SCT increases hematologic complete response (CR) rates and may improve overall survival (OS) for patients with <CR. We retrospectively analyzed outcomes for 143 patients who underwent RA-SCT with or without consolidation. Melphalan was administered at 100 (14%), 140 (52%) and 200 (34%) mg/m(2). The TRM rate at 100 days was 5%. RA-SCT resulted in CR in 24% (3 months) and 48% (12 months) of patients. The CR rate was particularly high (62%) in patients offered bortezomib consolidation. With a median follow-up among survivors of 7.7 years, median event-free survival (EFS) with RA-SCT was 4.04 years (95% confidence interval (CI): 3.41–5.01 years); median OS was 10.4 years (95% CI: 7.3–not achieved). Patients with CR at 12 months after SCT had significantly longer EFS (P=0.01) and OS (P=0.04). In a multivariate analysis, melphalan dose had no impact on EFS (P=0.26) or OS (P=0.11). For selected patients, RA-SCT was safe and was associated with extended long-term survival. With the availability of novel agents for consolidation, RA-SCT remains a very effective and important backbone treatment for AL amyloidosis.