Retrospective Analysis of High-Dose Melphalan and Autologous Stem Cell Transplantation for Systemic Light-Chain Amyloidosis: A Single Center 63 Cases

[Background]

High-dose melphalan and autologous stem cell transplantation (HDM/ASCT) show significant efficacy in systemic immunoglobulin light-chain (AL) amyloidosis. However, there have been few reports demonstrating efficacy of HDM/ASCT for AL amyloidosis patients in Asia, because of scarcity of AL amyloidosis. We retrospectively analyzed 63 cases of AL amyloidosis who received HDM/ASCT.

[Patients and methods]

We retrospectively analyzed 63 patients with AL amyloidosis who received HDM and ASCT between 2006 and 2017. Patients with plasma BNP<1000 pg/ml and <IVST 15mm were determined transplant eligible from 2007. The median age was 54 years old (range, 32-70). Cardiac, renal and gastrointestinal involvement were 24(38.1%), 42(66.7%) and 29(48%) patients, respectively. The percentage of more than 2 organ involvement was 69.8%. Cardiac response was defined as more than 30% of BNP decline. Because NTproBNP was measured only in limited number of patients, we used BNP instead of NTproBNP to analyze cardiac response. Also, BNP was well correlated to NTproBNP (spearman correlation = 0.922). Hematological and kidney response was defined as previously described (Comenzo RL et al, Leukemia, 2012). Briefly, a difference between the involved FLC and uninvolved FLC of 50mg/dl and more than 0.5g of 24-hour urine protein were defined as measurable for hematological and renal response.

[Results]

2-year and 4-year overall survival was 88.2% and 80.9%, respectively. Cardiac response was achieved in 9 of 22(40.9%). Hematological responses were evaluated in 25 cases and were 15(60%) sCR, 3(12%) VGPR and 6(24%) PR. More than 11mm of IVST affected worse OS(p=0.032) in line with previous reports. Also, more than 1mg/dl of serum creatinine (sCre) showed worse OS (p=0.022).

Mortality within 100 days after ASCT was observed in 5 patients (1 MOF, 1 arrhythmia, 1 heart failure and 2 infection). 4 out of 5 patients showed cardiac involvement (median BNP value = 732.3).

[Conclusions]

Our analysis revealed comparable OS rate with other institutions in US and EU countries. Patients with cardiac involvement and higher sCre level showed worse prognosis. More than 11 mm of interventricular septum thickness (IVST) affected worse OS. Careful patient selection and experienced management are important for HDM/ASCT for AL amyloidosis.