Treatment response among patients with multiple myeloma initiating daratumumab across different lines of therapy: A real-world chart review study

e18737 Background: Daratumumab (DARA), a CD38 monoclonal antibody, has been approved for the treatment of multiple myeloma (MM) among previously-treated patients since 2015, and among newly-diagnosed patients since 2018. This study aimed to describe real-world treatment response among patients initiating DARA across different lines of therapy since 2018. Methods: A retrospective chart review of adult patients with MM initiating DARA (monotherapy or as part of a combination regimen) between 1/2018 and 5/2020 was conducted at two clinical sites in the US (Levine Cancer Institute & Weill Cornell Medical College). De-identified patient-level data were abstracted in an electronic case report form. Treatment patterns, overall response rate (ORR) and proportion of patients with very good partial response (VGPR) or better were reported using descriptive statistics and stratified by line of therapy (first line [1L], second line [2L] or third line or later [3L+]). Results: A total of 202 patient charts were extracted. Patients were, on average, 65.3 years old at MM diagnosis and 68.1 years old at DARA initiation; 109 (54.0%) were male; 104 (51.5%) were White and 65 (32.2%) were Black or African American; 64 (31.7%) received a stem cell transplant (SCT) prior to the line of DARA initiation. Twenty-one (10.4%), 53 (26.2%) and 128 (63.4%) patients initiated DARA in 1L, 2L and 3L+, respectively. Median follow-up time was 6.2 months for 1L patients and 13.8 months for 2L+ patients. The most common 1L regimen was DARA with bortezomib, lenalidomide ± dexamethasone (DVRd; n=10, 47.6%) followed by DARA with lenalidomide ± dexamethasone (DRd; n=8, 38.1%). The most common 2L regimen was DRd (n=15, 28.3%) followed by DARA with pomalidomide ± dexamethasone (DPd, n=13, 24.5%) and DARA with bortezomib ± dexamethasone (DVd, n=13, 24.5%). The most common regimen in 3L+ was DPd (n=62, 48.4%). Among patients initiating DARA in 1L, 2L or 3L+ the ORR was 100.0%, 81.6% and 76.0%, and the proportion of patients achieving VGPR or better was 73.3%, 65.8% and 51.0%, respectively (Table 1). Median time to treatment response ranged between 2.6 and 2.8 months post-initiation. Conclusions: In this study, patients initiated on DARA had high ORR and rates of VGPR or better, including an ORR of 100% among 1L DARA users. These findings suggest that DARA-based regimens are an effective treatment option across all lines of therapy, with highest response rate in 1L. [Table: see text]