RecruitingDrug trialProspective Study of Teclistamab in the Treatment of Systemic AL AmyloidosisThis 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.