This study aims to evaluate the use of teclistamab in systemic AL amyloidosis and answer whether teclistamab can improve the rate of complete hematological response.

This is a single-arm, multi-center, prospective study. Participants will receive the single drug teclistamab, which the investigator deems the best choice.

The treatment of amyloidosis should focus more on complete hematological response (CHR) and organ response rate. We hypothesize that teclistamab can deeply eliminate cloned plasma cells in AL patients, achieving a high proportion of complete hematological response.

In clinical practice, if daratumumab, bortezomib, and venetoclax (for patients with t(11;14)）have been used, the outcome is poor. Also, CHR is correlated with better clinical outcomes. In clinical routine practice, we use teclistamab, a more effective treatment to eliminate clonal plasma cells.

To further explore efficacy and safety, we designed this prospective study.

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.