Comparison of bortezomib with dexamethasone and thalidomide with dexamethasone in the treatment of patients with monoclonal immunoglobulin deposition disease.

BACKGROUND: There is currently no standardized treatment strategy for monoclonal immunoglobulin deposition disease, and anti-plasma cell therapy is considered an effective method for treating patients with this pathology. METHODS: This retrospective study included 72 patients with biopsy-confirmed monoclonal immunoglobulin deposition -disease from 2005 to 2025, divided by first-line therapy into bortezomib/dexamethasone (BD, n = 37) and thalidomide/-dexamethasone (TD, n = 35) groups. The bortezomib/dexamethasone group was further divided into those who received autologous stem cell transplantation (bortezomib/dexamethasone with autologous stem cell transplantation, n = 8) and those who did not (bortezomib/dexamethasone-only, n = 29). Efficacy was analyzed in evaluable patients, and risk factors for renal survival, time to next treatment, and overall survival were assessed in the entire cohort. RESULTS: The two groups had comparable baseline characteristics. The entire bortezomib/dexamethasone cohort showed superior rates of hematological complete response/very good partial response (63% vs. 46%), and renal complete response/very good partial response (57% vs. 32%) than the thalidomide/dexamethasone group, with superior 5-year renal survival (73% vs. 51%) and a favorable trend in 5-year overall survival (85% vs. 64%). The bortezomib/dexamethasone-only subgroup showed a significantly higher complete response rate (52% vs. 25%) and favorable trends in 5-year renal survival (74% vs. 51%) and overall survival (79% vs. 64%) compared with thalidomide/dexamethasone. In the 8 autologous stem cell transplantation patients, the hematological complete response rate increased from 25% post-induction to 75% post-transplant. Multivariate analysis identified chronic kidney disease (CKD) stage ≤3, hematological complete response/very good partial response, and the bortezomib/dexamethasone regimen as independent protective factors for renal survival. Regarding safety, neurotoxicity occurred in 19% of bortezomib/dexamethasone patients and in 29% of thalidomide/dexamethasone patients, while anemia and peripheral edema were more frequent in the thalidomide/dexamethasone group; no treatment-related deaths occurred. CONCLUSIONS: The bortezomib/dexamethasone regimen yields deeper hematological response and improved renal survival in monoclonal immunoglobulin deposition disease patients. Bortezomib/dexamethasone followed by autologous stem cell transplantation is recommended for transplant-eligible patients, while bortezomib/dexamethasone alone remains effective for those who are ineligible, which supports bortezomib/dexamethasone as first-line therapy.