Etiological Treatment of Cardiac Amyloidosis: Standard of Care and Future Directions

Cardiac amyloidosis (CA) is a condition caused by interstitial infiltration of misfolded proteins structured into amyloid fibrils. Transthyretin (ATTR) and immunoglobulin light chain (AL) amyloidosis represent the most common forms of CA. CA was traditionally perceived as a rare and incurable disease, but diagnostic and therapeutic advances have undermined the conventional paradigm.

The standard of care for ATTR-CA include agents capable of selectively stabilizing the precursor protein (e.g., tafamidis), whereas the plasma cell clone is the main target of chemotherapy for AL-CA. For long, tafamidis represented the only drug approved for patients with ATTR-CA. Recent data from ATTRibute-CM led to the approval of acoramidis, whereas patisiran received refusal based on the APOLLO-B trial. Novel CRISPR-Cas9-based drugs (i.e., NTLA-2001) hold great potential in the setting of ATTR-CA. Several hematological regimens are available to treat AL-CA. The main limit of current therapies is their inability to trigger removal of amyloid from tissues. However, the investigation of monoclonal antibodies targeting misfolded ATTR (e.g., PRX004, NI301A) or AL (e.g., birtamimab, anselamimab) has led to encouraging results. Various cutting-edge strategies are being tested for treatment of CA and may change the prognostic landscape of this condition in the next years.