Refining amyloid complete hematological response: Quantitative serum free light chains superior to ratio
Year: 2020
Type: article
Abstract: Response assessment in light chain (AL) amyloidosis is based on serum and urine monoclonal protein studies. Newly diagnosed patients (n = 373) who achieved very good partial response or complete response (CR) to first line therapy were assessed for the survival impact of each of the monoclonal protein studies. At end of therapy (EOT), negative serum/urine immunofixation (IFE) was achieved in 61% of patients, 72% achieved normal serum free light chain ratio (sFLCR), and the median involved free light chain (iFLC) and difference between involved to uninvolved light chain (dFLC) were 17 mg/L and 5 mg/L, respectively. Overall, 46% of patients achieved a CR at EOT. At EOT, iFLC ≤20 mg/L and dFLC ≤10 mg/L were additive in survival discrimination to negative serum/urine IFE and were independent predictors of overall survival. In contrast, normalization of sFLCR did not add survival discrimination to serum/urine IFE and was not independent predictor of survival. We propose a new definition for hematological CR to include serum/urine IFE negativity plus iFLC ≤20 mg/L or dFLC ≤10 mg/L, instead of the current definition of serum/urine IFE negativity and normal sFLCR. Complete response using dFLC ≤10 mg/L had the best performance in those with significant renal dysfunction and by light chain isotype, making it the preferred partner to IFE. Validation of these results in a multicenter cohort is warranted.
Source: American Journal of Hematology
DOI: 10.1002/ajh.25940
Authors: Eli Muchtar, Morie A. Gertz, Martha Q. Lacy, Nelson Leung, Francis K. Buadi, David Dingli, Suzanne R. Hayman, Ronald S. Go, Prashant Kapoor, Wilson Gonsalves, Taxiarchis V. Kourelis, Rahma Warsame, Yi Lisa Hwa, Amie Fonder, Miriam Hobbs, Stephen Russell, John A. Lust, Mustaqeem Siddiqui, S. Vincent Rajkumar, Robert A. Kyle, Shaji K. Kumar, Angela Dispenzieri
Institution: Mayo Clinic
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
Funder: National Cancer Institute
Award: G1016754749
OpenAlex ID: W3042348197