Impact of minimal residual negativity using next generation flow cytometry on outcomes in light chain amyloidosis

Am J Hematol. 2020 May;95(5):497-502. doi: 10.1002/ajh.25746. Epub 2020 Feb 14.


We evaluated bone marrow minimal residual disease (MRD) negativity in 44 patients with light chain (AL) amyloidosis using next generation flow cytometry (sensitivity ≥1 × 10-5 ; median events analyzed: 8.7 million, range: 4.8 to 9.7 million). All patients underwent MRD testing in 2 years from start of therapy (median: 7 months). The overall MRD negative rate was 64% (n = 28). The MRD-negative rate after one-line of therapy was 71% (20/28). And, 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 = .005. The MRD negative rate amongst patients in complete response was 75% (15/20), and in very good partial response, 50% (11/22). 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 amongst MRD-negative patients. Patients with MRD negativity were more likely to have achieved cardiac response at the time of MRD assessment, 67% (8/12) vs 22% (2/7), P = .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, five events), P = .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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Female
  • Flow Cytometry / methods*
  • Humans
  • Immunoglobulin Light-chain Amyloidosis / diagnosis*
  • Male
  • Middle Aged
  • Neoplasm, Residual / diagnosis*
  • Neoplasm, Residual / physiopathology
  • Treatment Outcome