ABSTRACT
INTRODUCTION: Daratumumab, a monoclonal antibody targeting CD38, is approved to treat multiple myeloma. Red blood cells express low levels of CD38, which can result in a false-positive antibody screen in daratumumab-treated patients. Educational materials were developed to inform healthcare professionals (HCPs) and blood transfusion management department personnel (BTMDP) about this risk and recommended measures to mitigate that risk. Materials were distributed in European countries where daratumumab was commercially available. This post-authorization safety study was designed to evaluate whether HCPs and BTMDP understood the materials. METHODS: An anonymous, cross-sectional, non-interventional, web-based survey was distributed in 12 European countries. Four key questions were identified, for which a correct answer from at least 80% of respondents was considered indicative of satisfactory effectiveness. RESULTS: A total of 408 participants completed the questionnaires (62.3% (n = 254) HCPs and 37.7% (n = 154) BTMDP). Responses were consistent between groups. All respondents were aware of the educational materials (the first key question) and at least 80% correctly answered three of the four key questions. A key question regarding which blood typing test(s) daratumumab interferes with did not achieve satisfactory effectiveness (60% correct responses). In a weighted analysis, 79% of respondents correctly identified the recommended measures for daratumumab-treated patients requiring transfusion. This was attributed to an error in the survey's German translation; in a sensitivity analysis, 90% of participants correctly responded to this question. CONCLUSIONS: Results suggest that participants were aware of the educational materials, the risk of daratumumab interference with blood testing, and recommended measures to mitigate that risk.
Subject(s)
Blood Grouping and Crossmatching , Multiple Myeloma , Antibodies, Monoclonal/adverse effects , Cross-Sectional Studies , Delivery of Health Care , Europe , Humans , Surveys and QuestionnairesABSTRACT
INTRODUCTION: Daratumumab is a human IgGκ monoclonal antibody targeting CD38. Despite the demonstrated benefit of daratumumab in multiple myeloma, not all patients have access to commercially available daratumumab. Here we report a pooled analysis of patients from the UK, Spain, Italy, and Russia enrolled in an open-label, early access treatment protocol (EAP) that provided daratumumab (16 mg/kg) monotherapy to patients with heavily pre-treated relapsed or refractory multiple myeloma (RRMM). METHODS: Intravenous daratumumab 16 mg/kg was administered to patients who had received ≥ 3 prior lines of therapy, including a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD), or who were double refractory to both a PI and an IMiD. Safety and patient-reported outcomes data were collected. RESULTS: A total of 293 patients received ≥ 1 dose of daratumumab. The median duration of daratumumab exposure was 4.2 (range 0.03-24.1) months, with a median number of 13 (range 1-37) infusions. The overall response rate was 33.1%, and the median progression-free survival was 4.63 months. Grade 3/4 treatment-emergent adverse events occurred in 60.1% of patients, of which the most common were thrombocytopenia (18.8%), anemia (11.9%), and neutropenia (11.6%). The most common serious adverse events were pneumonia (4.4%) and pyrexia (4.1%). Infusion-related reactions occurred in 45.1% of patients. The median change from baseline in all domains of patient-reported outcome instruments (European Quality of Life Five Dimensions Questionnaire [EQ-5D-5L], European Organisation for Research and Treatment of Cancer [EORTC] Quality of Life Questionnaire [QLQ-C30], and EORTC Multiple Myeloma Module [QLQ-MY20]) was generally 0 or close to 0. CONCLUSION: These EAP results are consistent with those from previous trials of daratumumab monotherapy and confirm its safety in patients from Europe and Russia with heavily pre-treated RRMM. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT02477891.
