• Subject understands the study procedures and can give signed informed consent.

• Subject is willing and able to comply with this protocol and will be available for the entire duration of the study.

• Has a confirmed diagnosis of AL amyloidosis and meets the criteria below:

‣ Histologic confirmation with a biopsy containing deposits of apple-green birefringent, Congophilic material or other amyloid staining (i.e., thioflavin T or sulfated alcian blue) with confirmatory immunohistochemistry or mass spectrometry, AND

⁃ May be receiving maintenance daratumumab and must have achieved and maintained a hematologic very good partial response (VGPR) or complete response (CR), have completed chemotherapy therapy (ie, melphalan, bortezomib, thalidomide, lenalidomide, or cyclophosphamide) and be at least 6 months from first hematologic response (CR or VGPR), AND

⁃ Either

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‣ Screening eGFR ≥20 and ≤75 mL/min/1.73m2 based on CKD-EPI equation, OR

⁃ Proteinuria that is not improving (e.g., \<25% reduction in urine protein creatinine ratio (UPCR) in the last 12 months or since hematologic response, whichever is shorter) with screening urine albumin creatinine ratio (UACR) \>700 mg/g based on central lab assessment of first morning void urine collected at screening and confirmed by a separate Screening 24-hr urine protein \>1.0gm/day; 24-hr urine protein may be repeated once during Screening.

• Note: Participants may meet both eGFR and proteinuria criteria

• Women of childbearing potential (WOCBP):

‣ WOCBP must have a negative serum or urine pregnancy test within 24 hours prior to the start of study treatment.

⁃ Must not be breastfeeding, lactating, or planning a pregnancy during the study period.

⁃ WOCBP who are not exclusively in same-sex relationships must agree to remain abstinent (complete avoidance of heterosexual intercourse) or use adequate contraceptive methods, defined as use of a condom by the male partner combined with use of a highly effective method of contraception by the female partner, during the treatment period and for at least 105 days after the last dose of study intervention.

• Women of non-childbearing potential (WONCBP), and female participants with vasectomized male partners:

‣ WONCBP must agree to remain abstinent (complete avoidance of intercourse) or the male partners of WONCBP participants must wear a condom to protect against the transfer of study intervention through bodily fluids during the treatment period and for at least 105 days after the last dose of study intervention.

⁃ Postmenopausal females must have a documented serum FSH level \>40 mIU/mL at Screening to confirm menopause.

• Male participants:

‣ Male participants must inform their female sexual partners who are WOCBP of the contraceptive requirements of the protocol and are expected to adhere to using contraception with their partner.

⁃ Male participants with female sexual partners who are WOCBP must agree to remain abstinent (complete avoidance of heterosexual intercourse) or use adequate contraceptive methods, defined as use of a condom by the male partner combined with use of a highly effective method of contraception by the female partner, during the treatment period and for at least 165 days after the last dose of study intervention.

⁃ Male participants must not donate sperm for at least 165 days after the last dose of study intervention.

⁃ Male participants in same-sex relationships or in relationships with WONCBP, must agree to remain abstinent (complete avoidance of intercourse) or use a condom to prevent exposure of the partner to study intervention through ejaculate/seminal fluid during the treatment period and for at least 165 days after the last dose of study intervention.