Clinical tools to guide in the appropriate treatment selection in immunoglobulin light chain (AL) amyloidosis are not well developed. We evaluated the response and outcome for various regimens at first-line treatment (n=681) and first progression (n=240) stratified by the immunoparesis status at diagnosis. Immunoparesis was assessed by the average relative difference of the uninvolved immunoglobulins, classifying patients into a negative average relative difference (i.e. significant immunoparesis) or a positive average relative difference (no/modest immunoparesis). Treatment was categorized as autologous stem cell transplant and four non-transplant regimens (melphalan-based; bortezomib-based, immunomodulatory drug-based and dexamethasone alone). Patients with significant immunoparesis who underwent stem cell transplant had a significantly lower rate of very good partial response or better response (58%), progression-free survival (median 30 months) and overall survival (108 months), compared to those without significant immunoparesis (80%, 127 months, median not reached, respectively; P
