[Efficacy and safety of daratumumab in the treatment of advanced light chain amyloidosis].

Objective: The study investigated the efficacy and safety of daratumumab in the treatment of cardiac light chain (AL) amyloidosis. Methods: We retrospectively analyzed the clinical characteristics, hematologic response, organ response, long-term survival, and adverse events of 20 patients with newly diagnosed or relapsed/refractory cardiac AL amyloidosis treated with daratumumab in Peking Union Medical College Hospitalo from January 2017 to March 2021. Results: The overall median age of 20 patients was 62 (range, 45-73) yeas, with a male to female ratio of 2.3:1. Nine patients were newly diagnosed, while 11 patients had relapsed or refractory disease. Based on Mayo 2004 cardiac AL staging system, stages Ⅱ and Ⅲ diseases were present in 20 patients respectively. Four patients died during the first cycle of daratumumab, and the remaining 16 patients completed a median of 3 (range, 1-10) cycles of treatment. Overall hematologic response rates were 80% each at 1, 3, and 6 months after treatment initiation, and 45% , 60% , and 60% of the patients achieved at least a very good partial response at 1, 3, and 6 months respectively. The median duration to hematologic response was 13 (range, 6-28) days. At 3, 6, and 12 months, 20% , 30% , and 40% of the patients respectively achieved a cardiac response, and the median days to response was 91 (range, 30-216) days. As of the last follow-up, 9 (45% ) patients died. The 1-month mortality rate of all the patients and stage IIIb patients was 25% and 40% , respectively. The 1-year overall survival rate was 48.4% . Lymphocytopenia was the most common hematological adverse event (above grade 3) . Non-hematological adverse events were mainly infusion-related reactions and infections. Conclusion: Daratumumab could induce deep and rapid hematologic response in newly diagnosed and previously treated cardiac AL amyloidosis patients. However, daratumumab was not effective in preventing the high and early mortality rate in stage Ⅲb patients.