BACKGROUND: Waldenström macroglobulinemia (WM) is a rare, incurable non-Hodgkin Lymphoma. There is limited real-world evidence on WM treatment among US Veterans.
OBJECTIVE: This retrospective observational study aims to evaluate the real-world treatment patterns and associated outcomes among patients with WM in the Veteran Health Administration (VHA) population.
METHODS: Adults who had ≥2 visits with WM diagnosis codes and ≥1 WM treatment were identified in VHA database (2014-2018). Index date was defined as the first date of WM treatment. Patients included were newly diagnosed, initiating treatment, and enrolled continuously for 6 months prior to and ≥60 days following index date. Treatment regimens were categorized as: rituximab monotherapy, ibrutinib-based, chemotherapybased, proteasome inhibitor-based and other regimens. Healthcare resource utilization examined included hospitalization and length-of-stay (LOS). Total costs were calculated as sum of inpatient, outpatient and pharmacy costs per-patient-per-month (PPPM).
RESULTS: Prevalence and incidence of WM among Veterans ranged from 11.4-12.8 cases, and 0.4-1.6 cases per 100,000 persons, respectively. A total of 255 patients (median age: 72 years, 84% white, mean Charlson comorbidity index score: 1.1) received 1st line (mean duration: 289 days); 96 (38%) patients received 2nd line (mean duration: 267 days); and 34 (13%) received 3rd line therapy (mean duration: 253 days). Treatment pattern for each line of therapy were as follows, 1st line: ibrutinib-based (30%), chemotherapy- based (25%), rituximab monotherapy (25%), proteasome inhibitor-based (14%), and other (5%); 2nd line: chemotherapy-based (27%), ibrutinib-based (24%), rituximab monotherapy (23%), proteasome inhibitor- based (15%), and other (9%); 3rd line: ibrutinib- based (41%), rituximab monotherapy (32%), chemotherapy-based (18%), proteasome inhibitorbased (6%), and other (3%). The overall hospitalization rate was 29% with an average LOS of 12 days. Approximately 21% (LOS: 10.9 days), 18% (LOS: 6.9 days), and 24% (LOS: 7.3 days) of patients had a hospitalization, respectively, during 1st, 2nd, and 3rd line therapy. Average total PPPM costs overall were $13,007, and $13,154, $12,550, and $25,813 during 1st, 2nd, and 3rd line therapy, respectively.