Prospective Study of Teclistamab in the Treatment of Systemic AL Amyloidosis

Inclusion Criteria: 1. Diagnosis of systemic AL amyloidosis; 2. Patients must have received standard-of-care daratumumab, bortezomib, they do not have at least one organ response, and have not get complete hematological response; 3. Life expectancy greater than 12 weeks; 4. HGB ≥70g/L; 5. Blood oxygen saturation \> 90%; 6. Total bilirubin (TBil) ≤3×upper limit of normal (ULN); aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤3.0×ULN; 7. Informed consent explained to, understood by and signed by the patient. Exclusion Criteria: 1. Fulfill with the criteria of active multiple myeloma or active lymphoplasmacytic lymphoma. 2. Presence of other tumors which is/are in advanced malignant stage and has/have systemic metastasis; 3. Severe or persistent infection that cannot be effectively controlled; 4. Presence of severe autoimmune diseases or immunodeficiency disease; 5. Patients with active hepatitis B or hepatitis C (\[HBVDNA+\] or \[HCVRNA+\]); 6. Patients with HIV infection or syphilis infection; 7. Any situations that the researchers believe will increase the risks for the subject or affect the results of the study.