Real-World Treatment Patterns, Healthcare Resource Use, and Costs Among Patients with Waldenstrӧm Macroglobulinemia: A Retrospective Analysis of US Claims Data

BACKGROUND: Waldenstrӧm macroglobulinemia (WM) is a rare, incurable, indolent B-cell lymphoma. WM represents a significant economic burden and an evolving treatment landscape; however, real-world data on WM burden and management is sparse and outdated.

AIMS: To evaluate treatment patterns and economic burden among patients with WM in the US.

METHODS: A retrospective study was conducted among adult patients newly diagnosed with WM. Optum’s de-identified Clinformatics® Data Mart Database from October 2015 to June 2021 was used to identify patients with ≥2 diagnosis codes for WM on distinct dates within 12 months. The first observed WM diagnosis was the index date. Patients were required to have continuous enrollment and no diagnosis code for WM, macroglobulinemia, or other malignancies 1 year pre-index (i.e., baseline period), and ≥1 month of continuous enrollment post-index. Demographic and clinical characteristics were assessed during baseline. To identify first (1L), second (2L), and third (3L) line treatments, a line of therapy (LOT) algorithm was applied to a subsample of patients with no claims for National Comprehensive Cancer Network-recommended systemic agents, stem cell transplant, and chimeric antigen receptor T-cell therapy in baseline and ≥1 treatment in the study period (i.e., from the index date through end of enrollment or data). The study outcomes included all-cause and WM-related healthcare resource use (HRU; in terms of monthly incidence rates) and per patient per month (PPPM) costs, which were assessed during the study period in the overall sample, as well as during 1L, 2L, and third and subsequent line (3L+) periods.

RESULTS: The final sample included 791 patients with a mean study period of 27 months. Average age was 74 years, with 58% of patients being male and 82% covered by Medicare Advantage. Mean National Cancer Institute Comorbidity Index was 2.2. The most common comorbidities were cardiovascular disease (35%) and chronic obstructive pulmonary disease (28%). The LOT algorithm was applied to a subsample of 196 patients, of whom 33% had 2 and 10% had 3 LOTs. In 1L, rituximab monotherapy (30%), bendamustine-based therapies (28%), and ibrutinib-based therapies (15%) were most common. Rituximab monotherapy (34%), bortezomib-based therapies (20%) and ibrutinib-based therapies (20%) were the most common in 2L, while rituximab monotherapy (40%) was the most common treatment in 3L. In the overall sample, patients experienced 0.08 inpatient (IP), 2.52 outpatient (OP), 0.05 emergency room (ER), and 0.25 other all-cause monthly visits on average. WM-related visits constituted a small portion of all-cause visits (38% for IP, 26% for OP, 20% for ER, and 20% for other visits). All-cause costs totaled $8,445 PPPM, driven mainly by medical costs ($7,782 PPPM). IP costs constituted 50% of total costs, followed by OP costs (37%). More than half of all-cause costs were WM-related. Among patients in the LOT analysis, all-cause HRU increased by LOT, while WM-related HRU tended to peak in 2L. All-cause OP and ER costs decreased from 1L to 3L+, while all-cause IP and pharmacy costs increased with increased LOTs. WM-related costs tended peak in 2L.

CONCLUSION: This study describes the current treatment landscape of WM in the US, highlighting that rituximab monotherapy is common across all lines, bendamustine-based therapies are favored in 1L, and bortezomib-based therapies and ibrutinib-based therapies are common in later LOTs. This study indicates that the burden of WM is significant, particularly in terms of medical costs in earlier lines of therapy, highlighting the need for novel therapeutic options in WM.