Characteristics and Treatment of Patients with Multiple Myeloma Who Received Daratumumab in a Large Claims Database in the United States

Introduction: Daratumumab (DARA) is a human IgGk monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action. Since its approval for relapsed or refractory multiple myeloma (MM) in 2015 and newly diagnosed MM (NDMM) in 2018, DARA has become the foundation of treatment for MM. However, there is limited real-world evidence describing patients (pts) with MM treated with DARA-containing regimens in the US, especially for NDMM pts. Thus, using a large US claims database, we evaluated pt and treatment characteristics among MM pts who received DARA-containing regimens as first-line (1L) or second-line (2L) therapy, and separately for the subset who received DARA plus lenalidomide/dexamethasone (D-Rd) given its more recent approval in NDMM.

Methods: This retrospective, observational cohort study evaluated pts aged ≥18 years at the index date (first observed treatment date with ≥1 medical or pharmacy claim for DARA) from the Optum Clinformatics Data Mart database between January 1, 2013 and December 31, 2020, with ≥1 diagnosis code for MM before the index date, and who were continuously enrolled in a medical benefit plan and pharmacy plan from ≥6 months before the initial MM diagnosis date to the index date. Pts with a hematopoietic stem cell transplant from 6 months before the observed initial MM diagnosis date to the index date were excluded. Eligible pts were categorized into 4 cohorts: pts with (1) a DARA-containing regimen as 1L (1L DARA-based cohort), (2) a DARA-containing regimen as 2L (2L DARA-based cohort), (3) D-Rd as 1L (1L D-Rd cohort), and (4) D-Rd as 2L (2L D-Rd cohort) after the observed initial MM diagnosis. Demographics were assessed on the index date; clinical characteristics, all-cause healthcare resource utilization (HCRU), and total all-cause healthcare costs (medical + pharmacy costs) were measured during the 6-month baseline period before the index date.

Results: Among the 1L DARA-based cohort (n=235), 48 (20.4%) pts received D-Rd (1L D-Rd cohort). Overall, the most common 1L DARA-based regimens (with or without dexamethasone or prednisone) were D-R (28.5%), DARA plus bortezomib (V)/R (D-VR; 23.8%), D-V (18.7%), and D (14.9%). Among the 2L DARA-based cohort (n=310), 44 (14.2%) pts received D-Rd (2L D-Rd cohort). In the 1L DARA-based and 1L D-Rd cohorts, the mean (SD) age on the index date was 72.4 (9.0) and 76.1 (7.9) years, respectively. In the 2L DARA-based and 2L D-Rd cohorts, the mean (SD) age on the index date was 72.7 (9.3) and 70.5 (11.5) years, respectively. Mean baseline Quan-Charlson Comorbidity index was higher in the 2L cohorts versus 1L cohorts (1L DARA-based: 3.1; 1L D-Rd: 2.8; 2L DARA-based: 3.5; 2L D-Rd: 3.6). Hypercalcemia, renal impairment, anemia, and/or bone lesions (CRAB symptoms) were identified in about 50% of pts in all cohorts. Renal impairment was identified in 32.3%, 22.9%, 32.9%, and 34.1% of pts in the 1L DARA-based, 1L D-Rd, 2L DARA-based, and 2L D-Rd cohorts, respectively. Cardiovascular conditions (myocardial infarction, angina, peripheral vascular disease, and/or congestive heart failure) were found in 26.4% of pts in the 1L DARA-based cohort, 29.2% in the 1L D-Rd cohort, 34.5% in the 2L DARA-based cohort, and 47.7% in the 2L D-Rd cohort. The most common (>5% of pts) 1L regimens for pts in the 2L D-Rd cohort were VRd (17 [38.6%] pts), Vd (6 [13.6%]), V/cyclophosphamide (C)/d (4 [9.1%]), Rd (4 [9.1%]), and VC (3 [6.8%]). In the 1L DARA-based, 1L D-Rd, 2L DARA-based, and 2L D-Rd cohorts, 47.7%, 41.7%, 47.7%, and 54.5% of pts, respectively, had ≥1 hospitalization, and mean numbers of outpatient encounters were 26.4, 25.1, 50.6, and 52.8 within the 6-month baseline period. Mean 6-month baseline total healthcare cost (in 2020 USD) was $53,874 (medical: $51,837; pharmacy: $2,038) in the 1L DARA-based cohort, $39,695 ($35,896; $3,799) in the 1L D-Rd cohort, $131,832 ($96,737; $35,095) in the 2L DARA-based cohort, and $136,218 ($97,380; $38,838) in the 2L D-Rd cohort.

Conclusions: In this real-world assessment using claims data, pts with MM receiving DARA-based therapy in 1L or 2L had median age ≥70 years, with high clinical burden as observed by their comorbidities, HCRU, and costs. Understanding the characteristics of real-world pts with MM treated with DARA-based therapy can further aid in the understanding of effective use of DARA in the real world.