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Evaluation of the serum free light chain (sFLC) analysis in prediction of response in symptomatic multiple myeloma patients: rapid profound reduction in involved FLC predicts achievement of VGPR
Author(s) -
Hansen Charlotte T.,
Pedersen Per T.,
Nielsen Lars C.,
Abildgaard Niels
Publication year - 2014
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/ejh.12376
Subject(s) - medicine , multiple myeloma , myeloma protein , immunoglobulin light chain , gastroenterology , urology , surgery , antibody , immunology
Background Observational data from clinical studies indicate that the goal of first‐line therapy in newly diagnosed patients with symptomatic multiple myeloma ( MM ) should be very good partial response ( VGPR ) or better, preferably before high‐dose treatment. We evaluated the value of early measurements of involved free light chains (i FLC ) in prediction of high‐quality responses. Measuring i FLC has a potential advantage due to a short half‐life compared to the half‐life of the M‐protein. Methods In 36 multiple myeloma ( MM ) patients, we measured serial changes in i FLC and M‐protein after start of treatment. i FLC and M‐protein were measured before treatment, the following 5 wk days, 2, 3 and 6 wks after start of treatment. Results Median i FLC and M‐protein half‐life was 2.75 and 11.9 d, respectively. All patients with an i FLC >75 mg/L had an initial significant reduction (>20%) in i FLC , even patients with no response to treatment. The mean per cent reduction in i FLC 3 d after start of treatment was 52.3% and 23.6% ( P = 0.021) in patients achieving ≥ VGPR and PR , respectively. The mean per cent reduction in M‐protein in patients achieving ≥ VGPR and PR was not significantly different in the 6‐wk study period. As a predictor of VGPR , an 80% reduction in i FLC at day 21 resulted in a sensitivity of 87.5% and a specificity of 100%. Conclusion Changes in i FLC could be a tool for early identification of responders to anti‐myeloma therapy. Early, sequential measurements of i FLC within the first week after start of treatment are not meaningful.