This is an exploratory study to assess the binding of CAEL-101/anselamimab to amyloid in vivo, recruitment of inflammatory cells and reduction of the amyloid mass.

Inclusion Criteria:

1. AL amyloid deposit confirmed by biopsy and IHC or mass spectrometry

2. Amyloid deposits are measurable by imaging (ultrasound or cross-sectional)

3. 18 years or older

4. ECOG performance status 0-3

5. Adequate bone marrow reserve, hepatic and renal function as demonstrated by:

   1. Absolute neutrophil count ≥ 1.0 × 109/L
   2. Platelet count ≥ 75 × 109/L
   3. Hemoglobin ≥ 9 g/dL
   4. Total bilirubin ≤ 2 times the upper limit of normal (× ULN) unless due to Gilbert's syndrome.
   5. Aspartate aminotransferase (AST) ≤ 3 × ULN
   6. Alanine aminotransferase (ALT) ≤ 3 × ULN

6. No evidence of cardiac, renal or hepatic involvement by amyloidosis

   1. Echocardiogram with mean wall thickness </= 12mm unless other cardiac cause
   2. 24 hour urine protein <500mg AND estimated glomerular filtration rate (eGFR) >50mL/min/1.73 sqm (Cockcroft-Gault formula)
   3. Alkaline phosphatase below upper limit of normal and total liver span </=15cm

7. Participants of childbearing potential agree to use contraception throughout study an

8. Ability to understand and willingness to provide written informed consent.

Exclusion Criteria:

1. Use of other investigational agents within 30 days of screening

2. Taking doxycycline within 30 days of screening

3. Current significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders, or psychiatric disorder.

4. Major surgery within 4 weeks of enrollment

5. Pregnant

6. Breast feeding

7. Participant is eligible and agreeable to standard of care chemotherapy.

8. Presence of active infection at the time of screening

9. Participant with a monoclonal protein or isotypic light chain predominance (increased level of the involved light chain and abnormal free light chain ratio (<0.26 or >1.65)) ☐

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10. Participant with known or suspected systemic AL amyloidosis, or suspicion of other organ involvement.

11. Lymph node involvement

12. Involvement of amyloidoma in more than one organ.

13. AL amyloidoma involving other disease locations except those specified in the protocol

14. Presence of solitary plasmacytoma

15. Participant with clinically significant lung disorder or disease

16. Not a candidate for definitive surgical treatment (i.e., complete resection) of amyloidoma.