Doxycycline to Upgrade Organ Response in Light Chain (AL) Amyloidosis Trial

Organ response to anti-plasma cell therapy in AL amyloidosis tends to lags behind hematologic
response as chemotherapy may not clear pre-formed organ amyloid. Doxycycline has been shown
to have inhibitory effects on amyloid fibril formation as well as de-fibrillogenic effects
and shown to be beneficial in in vitro, murine models and other preclinical studies. The
investigators will prospectively evaluate the safety and efficacy of doxycycline in AL
amyloidosis patients when used in conjunction with anti-plasma cell chemotherapy.

Inclusion Criteria:

1. Patients with biopsy proven AL amyloidosis.

2. Patients ≥ 18 years of age are eligible.

3. Patient must provide informed consent.

4. All patients must have measurable amyloid organ involvement of a vital organ (eg.
heart, liver, kidneys). Localized amyloidosis will also be eligible as long as the
amyloid involvement is radiologically measurable.

5. A negative pregnancy test will be required for all women of child bearing potential.
Breast feeding is not permitted.

6. Patients who have previously been taking doxycyline will be eligible as long as there
is no contraindication to stay on doxycycline 100 mg BID for 1 year in the opinion of
the treating physician.

7. Creatinine clearance of >25 ml/min.

Exclusion Criteria:

1. Patients with severe malabsorption syndrome precluding absorption of oral agents will
be excluded.

2. Known intolerance or allergic reactions with doxycycline.

3. Previous chemotherapy for AL amyloidosis.