Retrospective Analysis of Autologous Stem Cell Transplantation for AL Amyloidosis: A Study from the Multiple Myeloma Working Group of the Japan Society for Hematopoietic Cell Transplantation

Background Autologous stem-cell transplantation (ASCT) is the standard of care for eligible patients with light-chain (AL) amyloidosis, but little is known about it in Asian populations. Objective and Study Design To investigate the outcome of and prognostic factors for ASCT, we retrospectively analyzed ASCT cases registered to the Transplant Registry Unified Management Program between December 1999 and December 2015 and extra clinical information collected through a secondary survey. The primary endpoint was overall survival (OS). Hematological response, organ response, and transplant-related mortality were analyzed as secondary endpoints. Results The database search found 330 patients (median age, 57 years; range, 31-74), and the secondary survey provided details of 110 cases (33.3%) finally included. Less than three organs were involved in 56.4%, with cardiac involvement in 57.3%. Performance status (PS) was 0-1 in 83.6%. Conditioning melphalan (MEL) dose was reduced in 54.6%. Overall hematological response was partial response or better in 77.6% and complete response in 49.3%. The 5-year OS was 70.1%. A PS of 0-1 was a factor for a significantly better prognosis in terms of OS. Although survival after ASCT for AL amyloidosis improved over time, poor PS and cardiac involvement had a negative impact on prognosis. The early mortality after ASCT was 6.4%. Poor PS and cardiac involvement led to high early mortalities. A brain natriuretic peptide (BNP) level of 400 pg/ml was associated with worse OS. Our study had several limitations of a retrospective analysis using questionnaire. The depth of response and biomarker responses is significantly limited by the degree of missing data. Conclusion Careful patient selection is important for a good outcome of ASCT in patients with AL amyloidosis. Poor PS and cardiac involvement had a negative impact on prognosis and the BNP level was a useful prognostic factor for AL amyloidosis patients who received ASCT.