Progressive refractory light chain amyloidosis and multiple myeloma patients are responsive to the addition of clarithromycin to IMiD based therapy

Multiple myeloma (MM) and primary systemic light chain amyloidosis (AL) are both chronic plasma cell dyscrasias with different clinical expression but limited treatment options for relapsed refractory disease. We report the effect of the addition of clarithromycin on 31 MM and 17 AL with relapsed or refractory disease who had an insufficient response or disease progression while on an IMiD based therapy. In this high risk population, hematological response was reported in 48% of MM patients and 94% of AL patients. Responses were reported early in both groups (median 35 days) and were more sustained in AL patients. Adverse events were common and included mostly grade 1–2 fatigue, infections and abdominal discomfort. Cytopenias were common and cardiac complications were rare in both MM and AL patients. Clarithromycin-IMiD combination therapy appears to be both effective and safe in progressive MM and primarily in AL patients, although a prospective clinical trial is warranted to validate these results. Am. J. Hematol. 92:131–135, 2017.