Melphalan and Dexamethasone With or Without Bortezomib in Treating Patients With Previously Untreated Systemic Light-Chain Amyloidosis

PRIMARY OBJECTIVES: I. To compare hematologic overall response (partial response \[PR\], very good PR, amyloid complete hematologic response \[ACR\], and stringent complete response \[sCR\]) after 3 courses of therapy in patients with previously untreated systemic light-chain amyloidosis treated with melphalan and dexamethasone with vs without bortezomib. SECONDARY OBJECTIVES: I. To evaluate the ACR rate after 3 courses of therapy and at completion of therapy. II. To evaluate organ response rates after 3 courses of therapy and at 6, 9, and 12 months. III. To evaluate treatment-related mortality. IV. To evaluate toxicity. V. To evaluate progression-free and overall survival. VI. To evaluate PR or better at completion of therapy. VII. To evaluate time to hematologic and organ response. VIII. To evaluate the duration of hematologic and organ response. IX. To assess quality of life (QOL) at baseline, at 3, 6, and 9 months during the therapy, at completion of therapy, and 3 and 6 months after therapy. TERTIARY OBJECTIVES: I. To determine the prognostic impact of t(11;14) translocation and cyclin D1 overexpression on response and overall survival. II. (Correlative) To compare sCR rates and to determine the impact of sCR on the outcomes. III. (Correlative) To perform a descriptive analysis of amyloid typing and proteomic composition of amyloid tissues. OUTLINE: This is a multicenter study. Patients are stratified according to amyloid cardiac stage (stage I/II vs. better risk stage III) and are randomized to 1 of 2 treatment arms. ARM A (Mel-Dex): Patients receive melphalan 0.22 mg/kg orally (PO) and dexamethasone 40 mg PO on days 1-4 every 4 weeks. Treatment repeats every 4 weeks for up to 9 courses in the absence of disease progression or unacceptable toxicity. ARM B (B-Mel-Dex): Patients receive melphalan 0.22 mg/kg PO and dexamethasone 40 mg PO on days 1-4 and bortezomib 1.3 mg/m2 intravenously (IV) on days 1, 4, 8, and 11 every 4 weeks. Treatment repeats every 4 weeks for 2 cycles. Patients then receive melphalan PO and dexamethasone PO on days 1-4 and bortezomib IV on days 1, 8, 15, and 22 every 5 weeks. Treatment repeats every 5 weeks for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Blood, urine, bone marrow, and fat samples may be collected periodically for laboratory analysis. Health-related quality of life is assessed periodically before, during, and after therapy. After completion of study treatment, patients are followed up periodically for 5 years.