Posttreatment dFLC less than 10 mg/L predicts superior organ response and longer time to next treatment in newly diagnosed light-chain amyloidosis patients treated with bortezomib.

Recently, a difference between involved and uninvolved free light chains (dFLC) less than 10 mg/L after treatment (stringent dFLC response) was reported to be associated with superior survival in light-chain (AL) amyloidosis. We conducted a retrospective study of AL amyloidosis patients treated with bortezomib to investigate the predictive value of a stringent dFLC response. Two hundred and thirty-five patients were included. The cardiac and renal responses were much higher in patients achieving a stringent dFLC response (86.5% versus 42.7% and 75.9% versus 38.2%, p < .001). Patients with a stringent dFLC response had significantly longer overall survival and time to next treatment (TNT). Among the very good partial response (VGPR) patients, the TNT of stringent dFLC responders was superior to those of the remaining VGPR patients (p = .045) and comparable to those of complete response patients. In conclusion, a stringent dFLC response might be added to current response criteria for AL amyloidosis.