Molecular Imaging of the Underlying Mechanism of Cardiotoxicity in Patients With Light Chain Amyloidosis Using PET/CT

Molecular Imaging of the Underlying Mechanism of Cardiotoxicity in Patients With Cardiac Amyloidosis Using Positron Emission Tomography (PET/CT)

The research study is being conducted to test how two different types of Positron Emission Tomography (PET/CT) scans could be used to image a type of heart disorder called amyloidosis (AL). There will be two groups in the study. One group will have PET/CT scans using an imaging drug called 18F-NOS and the other group will have PET/CT scans using a drug called Florbetaben. subject will be assigned to one of the groups when she/he agrees to be in the study.

Immunoglobulin light chain (LC) amyloidosis (AL) is an underdiagnosed monoclonal plasma cell proliferative disorder caused by extracellular deposition of AL fibrils in various tissues and organs, causing disease by progressively damaging the structure and function of the affected tissue/organ. The heart is the most commonly involved organ (~75%),9 and the extent and severity of cardiac involvement continue to be the main limitation for successful treatment. Although it remains high, the 6-month mortality rate has improved significantly over the last decade (24% vs. 37%; P<0.001) due to earlier diagnosis, better treatment options, and the advent of sensitive serologic biomarkers to assess for early treatment response,10 in particular serum free light chains (FLC), which permit the differentiation of patients who achieve complete response (CR) and very good partial response (VGPR) from those with partial or no response. N-terminal fragment of the pro-brain natriuretic peptide (NT-proBNP) has also become a key biomarker for detection and risk-stratification of patients with cardiac AL amyloidosis, and is now routinely employed in clinical trials as a surrogate end point for survival. A large retrospective landmark analysis established that achievement of a CR or VGPR at 6 months post-initiation of therapy, or achievement of an NTproBNP response 6 months post-initiation of therapy, defined as a 30% reduction and absolute reduction ≥ 300 pg/mL from baseline for subjects with baseline levels ≥ 650 pg/mL, was strongly associated with improved overall survival (insert Palladini et al, JCO 2012).

Inclusion Criteria:

1. Participants will be at least 18 years of age

2. Have an established diagnosis of AL amyloidosis based on standard criteria and planning to start systemic therapy.

3. Have cardiac involvement as defined by all of the following:

   • Past documented or presently noted clinical signs and symptoms supportive of a diagnosis of heart failure in the setting of a confirmed diagnosis of AL amyloidosis in the absence of an alternative explanation for heart failure
   • Either an endomyocardial biopsy demonstrating AL amyloidosis or an echocardiogram demonstrating a mean left ventricular wall thickness at diastole >12mm in the absence of other causes (e.g. severe hypertension, aortic stenosis), which would adequately explain the degree of wall thickening
   • NT-proBNP ≥ 650 pg/mL

4. Participants should fall into 1 of the following 2 categories:

   1. Treatment-naïve or have completed no more than 1 cycle of initial therapy, OR
   2. Relapsed after 1 or more prior therapies, and at least 6 months from last treatment

5. Have serum free light chain (FLC) differential (defined as amyloid-forming FLC minus non-amyloid-forming FLC) ≥ 50 mg/L.

6. Participants must be informed of the investigational nature of this study and be willing to provide written informed consent and participate in this study in accordance with institutional and federal guidelines prior to study-specific procedures.

Exclusion Criteria:

1. Females who are pregnant or breast feeding at the time of the PET/CT scan will not be eligible for this study; a urine pregnancy test will be performed in women of child-bearing potential before the injection of radiotracer.
2. Inability to tolerate imaging procedures in the opinion of an investigator or treating physician
3. Any current medical condition, illness, or disorder as assessed by medical record review and/or self-reported that is considered by a physician investigator to be a condition that could compromise participant safety or successful participation in the study
4. Less than 6 months life expectancy as deemed by a treating physician