The purpose of this study is to assess the efficacy of this combination of drugs in light chain (AL) amyloidosis which has relapsed or become refractory to other treatments. Amyloidosis is a rare disease that is caused by a substance called amyloid. Amyloid is an abnormal protein produced by plasma cells in the bone marrow which cannot be broken down by the body and so accumulate over time in various organs. Amyloidosis can affect different organs in different people. The most commonly affected organs are the heart, kidney, liver, spleen, nervous system, and digestive tract.