A Follow-Up Study to Monitor Therapeutic Response in Light Chain Cardiac Amyloidosis Using Beta-amyloid PET/CT

Light chain (AL) amyloidosis is a clonal plasma cell disorder that involves the deposition of misfolded monoclonal immunoglobulin light chains in the interstitial area, resulting in amyloid fibril aggregation. Despite advances in diagnostic work-up and treatment, AL amyloidosis frequently manifests as infiltrative cardiomyopathy, a particularly lethal form of heart failure. The diagnosis of cardiac amyloidosis (CA) is often overlooked and delayed due to nonspecific clinical symptoms and comorbidities. AL-CA is highly fatal without therapy; even with state-of-the-art therapies, including daratumumab, mortality remains high in the first year. Moreover, despite successful therapy, progressive heart failure, remains a significant clinical challenge in some patients and is attributed to residual amyloid fibril infiltration degree. Early and accurate assessment of changes in amyloid burden in response to therapy remains a challenge.

Currently, evaluation of response to plasma cell therapy relies on circulating AL biomarkers, which are not specific for reduction in amyloid burden. Echocardiography and CMR are used to evaluate myocardial functional and structural changes in AL amyloidosis after plasma cell-directed therapy. However, these measures lack specificity for amyloid fibrils. By contrast, beta-amyloid-binding tracers, such as 11C-PIB, 18F-Florbetapir, are emerging as quantitative and specific molecular markers of cardiac amyloid. These tracers have demonstrated high sensitivity and specificity for cardiac amyloid in preclinical and clinical studies. The investigators hypothesis that, changes in amyloid-binding tracer uptake may signal early molecular changes in myocardial amyloid.