A Retrospective Claims Analysis of Real-World Treatment Patterns and Economic Burden Among Patients with Marginal Zone Lymphoma in the US

BACKGROUND: There is limited research on real-world treatment patterns and economic burden associated with marginal zone lymphoma (MZL), despite it being the second-most common indolent non-Hodgkin's lymphoma in the US. AIMS: To assess treatment patterns and economic burden in patients with MZL in the US. METHODS: Adult patients newly diagnosed with MZL were included in a retrospective analysis. Patients with ≥2 diagnosis codes for small cell B-cell lymphoma or mucosa-associated lymphoid tissue (MALT) lymphoma on distinct dates within 12 months, from October 2015 to June 2021, were identified in Optum's de-identified Clinformatics® Data Mart Database. Patients were required to have continuous enrollment and no malignancies in the baseline period (i.e., 12 months prior to the index date, defined as the first occurrence of small cell B-cell lymphoma or MALT lymphoma) and ≥1 month of enrollment post-index. Demographic and clinical characteristics were reported during baseline. The study period was defined as time from the index date through the end of continuous enrollment or data availability. A line of therapy (LOT) algorithm was applied to a subsample of patients with no National Comprehensive Cancer Network recommended systemic agents, stem cell transplant, or chimeric antigen receptor T-cell therapy during baseline and ≥1 treatment during the study period. The algorithm identified first (1L), second (2L) and third (3L) line therapies. Healthcare resource use (HRU) in terms of monthly incidence rates, and per patient per month (PPPM) costs were assessed during the study period as well as during 1L, 2L, and third and subsequent line (3L+) periods. RESULTS: A total of 2,207 patients were included in the final sample (average follow-up time 26 months). Patients were on average 71 years old with 53% being female and 75% covered by Medicare Advantage. Mean National Cancer Institute Comorbidity Index was 2.1, with cardiovascular disease (31%) and chronic obstructive pulmonary disease (26%) being the most common comorbidities. A subset of 510 patients was identified for the LOT analysis, of which 23% had at least 2 LOTs and 7% had 3+ LOTs. Rituximab monotherapy and bendamustine-based therapies were the most common regimens in 1L (48% and 24%, respectively) and 2L (34% and 21%, respectively), followed by ibrutinib-based therapies (9% in 1L and 13% in 2L). In 3L, rituximab monotherapy (51%) was the most common, followed by ibrutinib-based therapies (16%). Overall, patients had 0.06 inpatient (IP), 2.4 outpatient (OP), 0.05 emergency room (ER), and 0.19 other all-cause visits per patient-month. MZL-related visits made up less than a third of all-cause visits across all settings. All-cause total costs averaged $9,580 PPPM, 95% of which were medical costs ($9,089). IP costs ($5,132) were the main driver of all-cause costs, followed by OP costs ($3,630), with 60% of IP costs and 50% of OP costs being MZL-related. All-cause HRU in all settings peaked in 2L. MZL-related OP and ER visits were highest in 2L, while MZL-related IP visits remained constant across lines. For both all-cause and MZL-related costs, medical costs were highest in 1L. All-cause medical costs were driven by OP costs in 1L (62%) and 2L (64%) and by IP costs in 3L+ (59%), while MZL-related medical costs were driven by OP costs across lines (62%-78%). Pharmacy costs were lowest in 1L and highest in 2L. CONCLUSION:The current study describes treatment patterns and economic burden among MZL patients in the US. Results show that rituximab monotherapy is highly utilized across LOTs, but that bendamustine- and ibrutinib-based therapies are also common. MZL has a high economic burden, driven by medical costs across LOTs, emphasizing an area of unmet need.