Background: WM is a rare, indolent B-cell lymphoma with 1000 to 1500 new cases diagnosed annually in the US. The disease is incurable with current therapy. Prior to January 2015 when ibrutinib was approved by the US FDA for WM, there were no therapies approved in this indication. This study describes initial systemic anti-cancer therapy (SACT) and HRU among WM patients (pts). Methods: A retrospective study using a large, national US claims database from 1/2007-10/2013 was conducted. Adult WM pts ( ≥ 2 claims for WM) with ≥ 1 claim for SACT were identified; the first SACT claim date was the index date. Pts were required to have a WM diagnosis within 3 months (m) prior to the index date and be continuously enrolled (CE) in the health plan for 12m pre- and ≥ 6m post-index date. Pregnant pts and those with SACT in the pre-index period were excluded. The first line of therapy (LOT1) period was examined; the LOT started at index date and the regimen included all drugs received within 60 days. The LOT ended at the earliest of, start of a new drug, ≥ 60-day gap in receipt of initial drug regimen, death or CE end. All-cause HRU and costs during LOT1 were examined. Results: There were 161 WM pts identified. 66% of pts were ≥ 65 yrs (mean age 69), 55% were male, and by insurance type, 49% were Medicare Advantage pts vs. 51% commercially insured. Mean total follow-up time was 23m, and mean duration of LOT1 was 4.7m. The top 4 most common LOT1 regimens accounted for 71% of patients: Rituximab (R) only (39%); bortezomib+ R (14%); bendamustine+ R (9%) and cyclophosphamide+ R (9%). No other regimens identified accounted for more than 4% of pts. Overall, 96% and 81% of pts had ≥ 1 office or hospital outpatient visit with mean per patient per month (PPPM) visits of 3.55 (standard deviation, SD = 2.41) and 2.60 (SD = 3.06), respectively. Approximately 25% and 21% had ≥ 1 ER visit or inpatient stay with mean PPPM visits of 0.11 (SD = 0.24) and 0.06 (SD = 0.16), respectively. Total mean PPPM healthcare costs during LOT1 was $13,589 (SD = $13,404). Conclusions: HRU and costs were high among WM pts initiating SACT. Future studies should examine whether differences in LOT1 regimen choice are associated with differences in cost and outcomes.