Concurrent Immunoglobulin Light Chain and Transthyretin Cardiac Amyloidosis Patient Treated With Daratumumab and Tafamidis: A Case Report.

Immunoglobulin light chain (AL) and wild-type transthyretin (ATTRwt) amyloidosis, while sharing similar clinical presentations, require distinct treatments. We report a rare case of a 75-year-old man with heart failure diagnosed with concurrent AL and ATTRwt cardiac amyloidosis. Immunohistochemistry and liquid chromatography-tandem mass spectrometry confirmed both AL and ATTR amyloid deposits in the heart. The patient was safely and effectively treated with daratumumab-based chemotherapy followed by tafamidis. This case underscores the necessity of precise amyloid typing for tailored therapy, suggesting sequential daratumumab and tafamidis as a viable strategy for this complex overlap. : The authors have confirmed clinical trial registration is not needed for this submission.