Treatment patterns and effectiveness of patients with multiple myeloma initiating Daratumumab across different lines of therapy: a real-world chart review study

Background Daratumumab, a CD38 monoclonal antibody, has demonstrated efficacy as monotherapy and combination therapy across several indications, both among newly-diagnosed and refractory patients with multiple myeloma (MM). However, there is limited evidence on treatment patterns and effectiveness of daratumumab in the real-world setting, particularly in first line (1 L). This study aimed to describe real-world treatment patterns and clinical outcomes among patients initiating daratumumab across different lines of therapy. Methods A retrospective chart review of adult patients with MM initiating daratumumab between November 2015 and March 2021 was conducted at two clinical sites in the United States. De-identified patient-level data were abstracted in an electronic case report form. Patient characteristics and treatment patterns were described. Clinical outcomes including overall response rate (ORR), progression-free survival, and time to next line of therapy were reported using descriptive statistics and stratified by line of therapy (1 L, second line [2 L] or third line or later [3 L+]). A sub-group analysis evaluated treatment patterns and ORR among patients re-treated with daratumumab. Results A total of 299 patients were included in the study (mean age: 68 years; 55% male). Among them, 26 were 1 L patients, 66 were 2 L patients, and 207 were 3 L+ patients; 110 patients (36.8%) received a stem cell transplant prior to daratumumab initiation. The mean duration of follow-up was 10 months among 1 L patients and 19 months among 2 L and 3 L+ patients. Patients who initiated daratumumab in 1 L had a 100% ORR, while those initiating in 2 L and 3 L+ had an ORR of 78.8 and 65.2%, respectively. Among re-treated patients, ORR was 66.7% during the first treatment segment, and 52.9% during the second treatment segment. Kaplan-Meier rates of progression-free survival at 12 months were 89.9, 75.2, and 53.1% among patients who initiated daratumumab in 1 L, 2 L, and 3 L+, respectively. Kaplan-Meier rates of time to next line of therapy at 12 months were 94.1, 73.4, and 50.0% among patients who initiated daratumumab in 1 L, 2 L, and 3 L+, respectively. Conclusions These findings suggest that daratumumab-based regimens are an effective treatment option across all lines of therapy, with highest response rate in 1 L.