Daratumumab for relapsed AL amyloidosis - when cumulative real-world data precedes clinical trials: A multisite study and systematic literature review.

Objectives Patients with relapsed/refractory AL amyloidosis (RRAL) have poor prognosis, but emerging data shows promising results with the use daratumumab. We evaluated daratumumab treatment in RRAL in real-world setting. Methods retrospective multi-site study of RRAL patients treated with daratumumab alone and in combinations. Results Forty-nine patients, diagnosed between 1.1.2008 and 1.2.2018 were included; 27% also had multiple myeloma. Revised Mayo score was ≥3 in 67%. Hematologic overall response rate was 81%, 64% achieved very good partial response (VGPR) or better. Concurrent active multiple myeloma was associated with lower rates of VGPR (OR 0.19, 95% CI 0.04-0.81; p=0.03) in a multi-variate analysis. Cardiac and renal responses were 74% and 73%, respectively. Median progression-free survival (PFS) was 28.4 months and median overall survival (OS) was not reached; two-years PFS and OS were 68.6±7.5% and 90.4±4.6%, respectively. Hematologic response correlated with prolonged PFS and OS. Daratumumab was safe and well tolerated, no patients discontinued therapy due to toxicity. Our data was aligned with outcomes from a systematic literature review, which identified 10 case-series (n=517) and 2 clinical trials (n=62) meeting pre-specified criteria. Conclusions Our data supports favorable safety tolerability and efficacy of daratumumab among nonselective RRAL patients in a real-world setting.