Inclusion Criteria:

   - Diagnosis of primary systemic immunoglobulin light chain (AL) amyloidosis.

   - Eastern Cooperative Oncology Group (ECOG) performance status of <= 2.

   - Have at least 1 organ historically impacted by AL amyloidosis.

   - Considered AL amyloidosis risk stage 1, 2, or 3a and have measurable disease of AL
   amyloidosis as defined by difference between involved and uninvolved free light chains
   (dFLC) >= 50 mg/L.

   - Has previously been exposed to a proteasome inhibitor (PI) and an anti-CD38 monoclonal
   antibody.

Exclusion Criteria:

   - Known history of clinically significant (per investigator's judgment) drug or alcohol
   abuse within the last 6 months.

   - Known allergic reaction, significant sensitivity, or intolerance to constituents of
   the study drugs (and excipients) and/or other products in the same class.

   - Participant has the following conditions:

      - Other non-AL amyloid disease;

      - Previous or current diagnosis of symptomatic multiple myeloma (MM), including the
      presence of lytic bone disease, plasmacytomas, >= 60% plasma cells in the bone
      marrow, or hypercalcemia (defined as corrected calcium > 11 mg/dL);

      - Active plasma cell leukemia (i.e., either 20% of peripheral white blood cells or
      > 2.0 × 109/L circulating plasma cells by standard differential);

      - Waldenström's macroglobulinemia;

      - Acute diffuse infiltrative pneumopathy;

      - Major surgery within 28 days prior first dose or planned during study
      participation;

      - History of organ transplant requiring continued use of immunosuppressants;

      - Acute infections within 14 days prior first dose requiring parenteral therapy
      (antibiotic, antifungal, or antiviral);

      - Participant has received an autologous stem cell transplant (SCT) within 12 weeks
      or an allogeneic SCT within 1 year of the first dose of study drug treatment.