Safety and efficacy of risk-adapted cyclophosphamide, thalidomide, and dexamethasone in systemic AL amyloidosis

High-dose melphalan with stem-cell transplantation is believed to be the most effective treatment for systemic light-chain (AL) amyloidosis, but many patients are ineligible because of the extent of their disease, and treatment-related mortality (TRM) remains substantial. We report the use of a risk-adapted oral regimen of cyclophosphamide, thalidomide, and. dexamethasone (CTD) or attenuated CTD (CTDa) in 75 patients with advanced AL amyloidosis, including 44 patients with clonal relapse after prior therapy. Fifty-one (68%) patients received CTD and 24 (32%) received CTDa. A hematologic response occurred in 48 (74%) of 65 evaluable patients, including complete responses in 14 (21%)and partial responses in 34 (53%) cases. Median estimated overall survival (OS) from commencement of treatment was 41 months, and from diagnosis median was not reached with a median follow-up of 22 months. Three-year estimated OS was 100% and 82% among complete and partial hematologic responders, respectively. Toxicity necessitating cessation of therapy occurred in 8% and was at least grade 2 in 52% of patients. TRM was 4%. The clonal response rates to CTD reported here are higher than any previously reported non-transplantation regimen in AL amyloidosis, and risk adaptation allows its use in poorer risk patients. CTD merits prospective randomized study.