Abstract 11818: Daratumumab Containing Regimens Improved Survival in Patients With Light-Chain Cardiac Amyloidosis

Background: Immunoglobulin light-chain (AL) amyloidosis is a lethal condition resulting from misfolded immunoglobulin ALs produced by clonal CD38-positive plasma cells. Daratumumab, an anti-human CD38 monoclonal antibody, led to higher frequencies of complete hematologic responses and better clinical outcomes compared to conventional treatment. Therefore, daratumumab-containing regimens has become the standard of care in patients with systemic AL amyloidosis and multiple myeloma. This study sought to evaluate the survival benefit of daratumumab-containing regimens in patients with AL cardiac amyloidosis. Methods and Results: We examined 65 consecutive patients with AL cardiac amyloidosis (mean age: 67.2±10.4 years old, male: 69%) who underwent chemotherapy. We divided the patients into two groups, daratumumab group (n=32: treated with daratumumab containing regimens within the first two lines of chemotherapy) and conventional treatment group (n=33). Compared to conventional treatment group, daratumumab group tended to be older (69.2±9.6 vs. 65.2±11.0; p=0.12), while no significant differences in biomarkers and echocardiographic parameters were observed. A total of 26 patients (40%) were deceased (median follow up period: 395 days). Kaplan-Meier survival curves showed that daratumumab group had significantly lower mortality compared to conventional treatment group (p=0.04; log-rank test; Figure). Cox hazard analysis revealed that daratumumab containing regimens were associated with lower mortality after adjustment for revised Mayo staging system for AL amyloidosis (hazard ratio: 0.32; 95% confidence interval: 0.12 to 0.85; p=0.02). Conclusion: Daratumumab containing regimens might be associated with improved survival in AL cardiac amyloidosis.