A Clinical Study of Melphalan Flufenamide (Melflufen) and Dexamethasone for Patients With Immunoglobulin Light Chain (AL) Amyloidosis

Inclusion Criteria: (For full list of inclusion criteria, see study protocol) * Male or female, age 18 years or older at the time of signing the informed consent * Proven histochemical diagnosis of AL amyloidosis based on tissue specimens with Congo red staining * At least one prior line of therapy, defined as either one non-transplant regimen, one ASCT (autologous stem cell transplantation), or one regimen of induction therapy followed by a single ASCT. No more that 4 cycles of melphalan containing chemotherapy is allowed. * Measurable hematologic disease * Objectively measurable organ amyloid involvement * ECOG performance status ≤ 2 (ECOG = Eastern cooperative oncology group) * Women of child bearing potential must have a negative serum or urine pregnancy test * Less than 30% plasma cells in bone marrow aspirate or biopsy * Acceptable laboratory results met (absolute neutrophil count (ANC), platelet count, hemoglobin, total bilirubin,alkaline phosphatase, AST (aspartate aminotransferase) and ALT (alanine aminotransferase), renal function) * Male participant agrees to use contraception during treatment and 90 days after last dose of melflufen Exclusion Criteria: (For full list of exclusion criteria, see study protocol) * Amyloidosis due to known mutations of the transthyretin gene or presence of another non-AL amyloidosis * Evidence of gastro-intestinal bleeding * Cardiac risk stage 3 * Low platelets value with evidence of mucosal or internal bleeding * Medical documented cardiac syncope, NYHA Class 3 or 4 congestive heart failure, myocardial infarction, unstable angina pectoris, clinically significant ventricular arrhythmias (NYHA=New York Heart Association Functional Classification) * Clinically significant finding on 24 h Holter recording * Severe orthostatic hypotension * Clinically significant factor X deficiency * Clinically significant autonomic disease * Any medical condition that would impose excessive risk to the patient * Serious psychiatric illness, active alcoholism or drug addiction that may hinder or confuse compliance * Known HIV or active hepatitis B or C viral infections * Previous cytotoxic therapies, including cytotoxic investigational agents within 3 weeks prior to start of study treatment. Monoclonal antibodies within 4 weeks. Concomitant immunotherapy, investigational therapy and anticoagulation therapy are not permitted * Prior autologous or allogenic stem cell transplant within 12 weeks of initiation of therapy * Prior allogeneic stem cell transplant with active graft-host-disease * Prior major surgical procedure or radiation therapy within 4 weeks of the first dose of study treatment