High-dose melphalan and autologous stem-cell transplantation in patients with AL amyloidosis: an 8-year study.

BACKGROUND AL amyloidosis is a fatal disease resulting from tissue deposition of amyloid fibrils derived from monoclonal immunoglobulin light chains. Treatment with oral chemotherapy is minimally effective. OBJECTIVE To test survival and organ response in a large sample of patients treated with high-dose intravenous melphalan (100 to 200 mg/m2) and autologous blood stem-cell transplantation. DESIGN 8-year longitudinal analysis of clinical effectiveness. SETTING University-affiliated specialty referral clinic. PATIENTS 701 consecutive new patients with AL amyloidosis. INTERVENTION High-dose chemotherapy and autologous stem-cell transplantation for patients who met eligibility requirements based on organ involvement and clinical status. MEASUREMENTS Survival analysis of all patients evaluated and a detailed analysis of treatment outcome in the subgroup that received high-dose melphalan and stem-cell transplantation. RESULTS Among 701 patients with AL amyloidosis, 394 (56%) were eligible for high-dose melphalan and stem-cell transplantation; 82 did not proceed with treatment because of patient choice or disease progression. Median survival of the 312 patients who initiated treatment was 4.6 years. A complete hematologic response, defined as no evidence of an underlying plasma cell dyscrasia 1 year after treatment, was achieved in 40% of patients and was associated with prolonged survival. Statistically significant improvements occurred in end-organ disease and were greater in patients with a complete hematologic response. Mortality rate within 100 days of treatment with high-dose melphalan and stem-cell transplantation was 13%; patients with cardiomyopathy had the highest mortality rates. CONCLUSIONS Treatment of selected patients with AL amyloidosis by using high-dose melphalan and stem-cell transplantation resulted in hematologic remission, improved 5-year survival, and reversal of amyloid-related disease in a substantial proportion.