Cyclophosphamide + Thalidomide + Dexamethasone Versus Melphalan + Dexamethasone for the Treatment of Amyloid Light-chain Amyloidosis With Kidney Involvement: A Retrospective Study in Chinese Patients.

Purpose: At present, a diverse array of treatment regimens are available for systemic amyloid light-chain (AL) amyloidosis. Both cyclophosphamide + thalidomide + dexamethasone (CTD) and melphalan + dexamethasone (MD) regimens have been recommended as first-line therapies, but no detailed comparative studies of the two have been performed. This study is the first to compare the efficacy and tolerability of the CTD and MD regimens in the treatment of AL amyloidosis.

Methods: We retrospectively reviewed data from consecutive patients with AL amyloidosis who were treated with MD or CTD as the initial regimen between June 2012 and January 2018.

Findings: In the final analysis, 38 patients received CTD, and 30 received MD. There were no significant differences in baseline characteristics, including age, sex, renal function, involved organs, level of free light chains, and Mayo Clinic amyloidosis prognostic staging. The overall hematologic response rates in the CTD and MD groups were 69.0% versus 68.0%, respectively (P = 0.94), including a complete response in 27.6% versus 8.0% (P = 0.14). Neither group reached the estimated median overall survival, and the difference between the 2 groups was not significant (P = 0.17). The median progression-free survival times were 36 versus 14 months (P = 0.24) in the CTD and MD groups, respectively. The CTD group achieved a numerically but not statistically higher prevalence of kidney response (52.9% vs 37.0%; P = 0.22). The most common adverse events in the 2 treatment groups were fatigue (48.5% vs 21.7%; P = 0.04) and constipation, anemia, nausea/vomiting, neutropenia, and syncope (all, P = NS). Deaths occurred in 6 patients in the CTD group and 9 patients in the MD group; none were considered by the investigators as related to the study treatments. There were no other serious adverse events observed in our study.

Implications: The CTD regimen may not be inferior to standard oral MD in terms of overall hematologic response and overall survival. Although this study was of retrospective and negative-control design with some additional limitations, it may provide a therapeutic option for use in developing countries where patients cannot afford bortezomib or melphalan.