Interphase fluorescence in situ hybridization in untreated AL amyloidosis has an independent prognostic impact by abnormality type and treatment category.

Abstract

The significance of interphase fluorescence in situ hybridization (iFISH) by regimen type was assessed in 692 immunoglobulin light-chain (AL) amyloidosis patients with iFISH at diagnosis. First-line treatment was categorized as stem cell transplant and three non-transplant regimens. The most common abnormality was t(11;14) (49% of patients) followed by monosomy 13/del(13q) (36%) and trisomies (26%). A lower rate of very good partial response (VGPR) or better was observed in patients with t(11;14) treated with bortezomib-based (52% vs 77%; P=0.004) and IMiD-based regimens (13% vs 54%; P=0.04) compared with those lacking t(11;14). This corresponded to an inferior overall survival (OS) in t(11;14)-positive bortezomib-treated (median 15 vs 27 months; P=0.05) and IMiD-treated patients (median 12 vs 32 months; P=0.05). The inferior OS associated with t(11;14) bortezomib-treated patients was restricted to patients with favorable disease. Trisomies were associated with a shorter OS (median 29 vs 69 months; P=0.001), reaching statistical significance only for melphalan (median 15 vs 32 months; P=0.02). Multivariate analysis confirmed an independent survival impact for trisomies in the entire cohort and for t(11;14) among bortezomib-treated patients. iFISH is prognostic in untreated AL amyloidosis and may influence treatment selection. Patients with t(11;14) should be considered for ASCT or standard-dose melphalan at diagnosis because the survival disadvantage may be abrogated.