High Dose Melphalan with Autologous Stem Cell Transplantation Overcomes Poor Prognosis of Primary Amyloidosis

Systemic Primary AL Amyloidosis is a rare but potentially fatal disease resulting from tissue deposits of amyloid fibrils derived from monoclonal immunoglobulin light chains. High-dose melphalan followed by autologous hematopoietic stem cell transplant (auto HCT) is associated with hematologic and organ responses and improved survival.

In this retrospective analysis we identified 46 patients with primary AL amyloidosis who received auto HCT between 01/1998 to 05/2010 at MDACC. Organ responses were determined using Amyloidosis Consensus Criteria.

The median age at auto HSCT was 56 years (34-74) where 61% were males and 35% were older than 60 years of age. 61% had lambda light chain restriction and only 4% had cytogenetic abnormalities. Disease characteristics are summarized in Table 1. The median time from diagnosis to auto HCT was 6.6 months (2.2-29.4 months). 22 pts (47.8%) had one organ, 19 pts (41.3%) had 2 organ and 4 pts (8.7%) had 3 organ involvement. 11 pts (23.9%) had heart and 35 pts (76.1%) had kidney involvement. The median follow up from the time of diagnosis was 22.4 months and from time of auto HCT was 16.7 months. High dose Melphalan dose was 200mg/m² in 24 pts (52%) and 140mg/m² in 22 (47.8%). There were 4 early deaths and 4 pts whose follow up was less than 3 months and their response was not assessed. Out of the 38 evaluable patients, the post-transplant organ responses were as follows ≥PR 25(66%), ≥stable disease 35(92%) (Table2). The hematologic responses were: CR=5 (13%), ≥VGPR=10(26%), ≥PR=26 (68%), ≥SD=37(97%). One patient had progressive disease. There was a correlation between organ response and hematologic response (chi square;p<10^-3). The day-100 treatment related mortality (TRM) was 8.7% and 1-yr TRM was 13%. The median progression-free (PFS) and overall survival (OS) from auto HCT was 73.8 months and not reached (from transplant). The median PFS and OS from diagnosis were 93 months and 59.8 months respectively. In multivariate analysis, heart involvement (p=0.01), female sex (p=0.011), age ≥60 years (p=0.002), bone marrow plasma cells≥10% (p=0.043) and Beta-2 microglobulin>3.5mg/l (p=0.02) were associated with poor OS. Improved OS correlated with organ response (52.6 vs 11.4 months; p=0.01) and hematologic response (52.6 vs.6.1months; p=0.002). Hemoglobin <10 g/dl (p=0.047), bone marrow plasma cells≥10% (p=0.043) and age≥60 years (p=0.075) were associated with shorter PFS. Hematologc response (p=0.48) and organ response (p=0.12) were not associated with improved PFS.

In this analysis the outcome of patients with primary systemic AL amyloidosis was durable with auto HCT with acceptable mortality risk and improved survival.

Table 1.

Disease characteristics

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Table 2.

Organ Response Distribution

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No relevant conflicts of interest to declare.