Real-world analysis of infusion-related reactions in patients receiving subcutaneous daratumumab in Nova Scotia, Canada.

IntroductionThis study aimed to characterize the incidence, grade, onset, duration and management of infusion-related reactions (IRRs) in patients receiving their first cycle of subcutaneous daratumumab and to evaluate the duration of the observation period.MethodsThis retrospective observational study included adult patients diagnosed with MM or AL amyloidosis who received their first cycle of subcutaneous daratumumab in Nova Scotia, Canada, between October 2021 and April 2025.ResultsSix IRRs were identified in 5 out of 140 patients (3.6%); 5 of the 6 reactions were categorized as low-grade and one patient developed grade 3 hypoxia which was managed with supplemental oxygen and diphenhydramine. The median time to IRR onset was 49.5 min (range 2-245) and the median time to resolution after intervention was 73.5 min (range 10-101). The IRR rate in patients who received 20 mg of dexamethasone or less was 5.8% versus 0% in patients who received greater than 20 mg.ConclusionsThis real-world analysis of patients receiving subcutaneous daratumumab for the first time revealed a low rate of IRRs and fewer IRRs in patients who received higher doses of dexamethasone prior to treatment. These findings suggest an important role for dexamethasone in IRR prophylaxis and support a reduction in the duration of the observation period post-subcutaneous daratumumab. Based on these results, the duration of the observation period in Nova Scotia was reduced from 4 h to 1 h, which saves chair time and has implications for cost savings, and the patient experience.