Key Information
The International Society of Amyloidosis (ISA)external link, opens in a new tab developed criteria for assessing the haematologic response to treatment in light chain (AL) amyloidosis in 2012. The criteria were identified and validated to discriminate groups with different overall survival rates based on a rigorous process. Eight hundred and sixteen patients from seven referral centers, randomly divided into a testing cohort and a validation cohort, plus an additional validation cohort of 374 patients from a single center, were included in the study. Quantification of circulating free light chains (FLC) and immunofixation electrophoresis of serum and urine were used to determine a haematologic response. The haematologic response categories-partial response, very good partial response, and complete response (CR)-were associated with increasing lengths of survival.
The ISA response criteria have been used as guidance for individual patient management and as surrogate endpoints in clinical trials. Two international phases III randomized clinical trials with the overall haematologic response (OHR) as the primary endpoint have recently concluded. One of them compared ixazomib/dexamethasone versus the physician's best choice in relapsed/refractory patients with AL amyloidosis, and no significant difference in the primary endpoint was observed between the two arms. The other study compared oral melphalan/dexamethasone (MDex) with the same regimen with the addition of bortezomib (BMDex).