Abstract

We evaluated bone marrow minimal residual disease (MRD) negativity in 44 patients with light chain (AL) amyloidosis using next generation flow cytometry (sensitivity > 1x 10-5 ; median events analyzed: 8.7 million, range: 4.8 to 9.7 million). All patients underwent MRD testing in two years from start of therapy (median: 7 months). Overall MRD negative rate was 64% (n=28). MRD-negative rate after one-line of therapy was 71% (20/28). MRD negative rates were higher with stem-cell transplant as first-line therapy (86%, 18/21) vs. chemotherapy alone as first-line treatment (29%, 2/7), p=0.005. MRD negative rate amongst patients in complete response were 75% (15/20); in very good partial response: 50% (11/22) and there were two patients in partial response/rising light chains (with renal dysfunction) who were MRD negative. There were no differences in baseline characteristics of MRD negative vs. MRD positive patients, except younger age among MRD-negative patients. MRD negative patients were more likely to have achieved cardiac response at the time of MRD assessment, 67% (8/12) vs. 22% (2/7), p=0.04. Renal response rates were similar in both groups. Progression free survival was assessed in the 42 patients achieving CR or VGPR. After median follow-up of 14 months, the estimated 1-year progression free survival in MRD negative vs. MRD positive patients was 100% (26 patients, 0 events) vs. 64% (16 patients, 5 events), p=0.006, respectively. MRD assessment should be explored as a surrogate endpoint in clinical trials and MRD risk-adapted trials may help optimize treatment in AL amyloidosis. This article is protected by copyright. All rights reserved.

View details for DOI 10.1002/ajh.25746

View details for PubMedID 32010993