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

Abstract

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. 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, with extra clinical information collected through a secondary survey. The primary endpoint was overall survival (OS). Hematologic response, organ response, and transplantation-related mortality were analyzed as secondary endpoints. The database search identified 330 patients (median age, 57 years; range, 31 to 74), and the secondary survey provided details for the 110 patients (33.3%) included in the study cohort. Fewer than 3 organs were involved in 56.4% of the patients, with cardiac involvement in 57.3%. Performance status (PS) was 0 to 1 in 83.6%. The conditioning melphalan dose was reduced in 54.6%. Overall hematologic response was a partial response or better in 77.6% of the patients and a complete response in 49.3%. The 5-year OS was 70.1%. A PS of 0 to 1 was associated with a significantly better prognosis in terms of OS. Although survival after ASCT for AL amyloidosis improved over time, poor PS and cardiac involvement had negative impacts on prognosis. The early mortality after ASCT was 6.4%. Poor PS and cardiac involvement led to high early mortality. A brain natriuretic peptide (BNP) level of 400 pg/mL was associated with worse OS. Our study has several limitations inherent to a retrospective analysis using a questionnaire. The depth of response and biomarker responses were significantly limited by the degree of missing data. Nonetheless, our data support the importance of careful patient selection for good outcomes of ASCT in patients with AL amyloidosis. In our cohort, poor PS and cardiac involvement had a negative impact on prognosis, and BNP level was a useful prognostic factor.