Brief report: Clinical experiences after emergency use of daratumumab monotherapy for relapsed or refractory multiple myeloma in real practice.

Despite the recently reported efficacy of daratumumab monotherapy for patients with relapsed or refractory multiple myeloma, outcomes in real practice following daratumumab monotherapy have yet to be investigated. A multi-center retrospective study of 16 Korean patients receiving daratumumab monotherapy for relapsed or refractory multiple myeloma was conducted. The overall response rate was 56.3%. Three patients with creatinine clearance <30 ml/min even achieved an overall response. The median progression-free survival was 2.7 months with 28.9% (95% CI, 9.0-52.8) of 6-month progression-free survival. All infusion-related reactions, including ≥Grade 3 back pain (6.3%) and dyspnea (6.3%), were manageable. The most common hematologic and non-hematological adverse events were anemia (62.5%) and upper respiratory infection (43.8%). ≥Grade 3 bacterial infectious adverse events were identified, including upper and lower respiratory infection (12.5% and 18.8%) and death following sepsis (6.3%). We observed acceptable outcomes of daratumumab monotherapy on relapsed or refractory multiple myeloma patients including even a few subjects with high comorbidity, despite relatively frequent infectious adverse events.