Autologous hematopoietic stem cell transplantation for non-AL amyloidosis monoclonal gammopathy of renal significance.

Background: The treatment strategy for non-immunoglobulin light chain (AL) amyloidosis monoclonal gammopathy of renal significance (MGRS) remains unstandardized. Autologous hematopoietic stem cell transplantation (ASCT) has shown favorable results in a limited number of studies.

Methods: This single-center, retrospective case-control study included non-AL amyloidosis MGRS patients diagnosed between February 2012 and July 2024; these patients were divided into the ASCT group and non-ASCT group. Baseline characteristics, ASCT characteristics and complications, treatment responses, survival outcomes, and risk factors for progression-free survival (PFS) were analyzed.

Results: A total of 53 patients with non-AL amyloidosis MGRS were enrolled in this study, comprising 23 patients who received ASCT and 30 patients who did not receive ASCT. The baseline characteristics were comparable between the ASCT and non-ASCT groups, with exceptions of serum albumin and C3 levels. The median overall survival (OS) and renal survival were not reached in either group. The median PFS was significantly longer in the ASCT group compared to the non-ASCT group (58.4 vs 16.4 months, P = .004). The overall response rate (ORR) and deep response rates of the ASCT group were higher than those of the non-ASCT group, both in hematological and renal responses. In the ASCT group, 18 patients (78.3%) achieved a hematological very good partial response (VGPR) or better, and 21 patients (91.3%) achieved a renal partial response or better after transplantation. Moreover, the ASCT group exhibited higher long-term cumulative incidences of OS and renal survival. The toxicity of ASCT was manageable, and no transplantation-related deaths occurred. There was no statistically significant difference in the median PFS between monoclonal immunoglobulin deposition disease and light chain proximal tubulopathy (P = .539). High serum albumin level at diagnosis, and hematological response ≥VGPR after ASCT were protective factors of PFS.

Conclusions: This study confirmed that ASCT was an effective and safe treatment for patients with non-AL amyloidosis MGRS, thereby offering long-term hematological remission and survival benefits.