A 72-year-old woman from Delhi with a 15-year history of rheumatoid arthritis presents with progressive renal dysfunction (serum creatinine 3.2 mg/dL, proteinuria 4.8 g/24 hours) and hepatosplenomegaly. She has never required hemodialysis. Renal biopsy shows amyloid deposits in the glomeruli and blood vessel walls. Immunofluorescence microscopy reveals strong staining with anti-serum amyloid A (SAA) antibodies. Which of the following is the MOST appropriate next step in management?