Depth of response prior to autologous stem cell transplantation predicts survival in light chain amyloidosis

The goal of therapy in AL amyloidosis is to inhibit further production of the amyloidogenic light chains, thereby allowing organ recovery and improving survival. We aimed to assess the impact of depth of hematologic response prior to ASCT on survival. We conducted a retrospective study of 128 newly diagnosed AL amyloidosis patients who received induction prior to ASCT between January 2007 and August 2017 at Mayo Clinic. The overall response rate to induction was 86% (CR 18%, VGPR 31% and PR 38%). With a median follow up of 52 months, the median PFS and OS was 48.5 months and not reached, respectively. Response depth to induction therapy was associated with improved PFS and OS. The median PFS was not reached for patients achieving ≥VGPR prior to ASCT and 34.1 months for patients achieving PR or less (P = 0.0009). The median OS was longer in patients with deeper responses (not reached for ≥VGPR vs. 128 months for PR or less (P = 0.02)). On multivariable analysis, independent predictors of OS were melphalan conditioning dose (RR = 0.42; P = 0.036) and depth of response prior to transplant (RR 0.37; P = 0.0295). Hematologic response prior to transplant predicts improved post transplant outcomes in AL amyloidosis.