OBJECTIVES : This study aimed to compare healthcare resource utilization (HRU) and costs of Medicare patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) who received ibrutinib versus chemoimmunotherapy (CIT) in first-line (1L).

METHODS : The Chronic Conditions Data Warehouse de-identified 100% Medicare database (1/1/2005-12/31/2017) was used to identify adults with a CLL/SLL diagnosis initiating 1L ibrutinib single-agent or CIT between 3/4/2016 and 9/30/2017 (index date). Patients' baseline characteristics were balanced using inverse probability of treatment weighting (IPTW). HRU and costs (Medicare spending) were evaluated during 1L Oncology Care Model (OCM) episodes (defined as the first 6 months post-index) and over the observed 1L duration. Mean monthly cost differences (MMCDs) obtained from ordinary least square regressions (bootstrapped to obtain p-values) and rate ratios (RRs) obtained from Poisson regressions (bootstrapped to obtain p-values) were used to compare costs and HRU, respectively, between ibrutinib and CIT cohorts.

RESULTS : After IPTW, the weighted sample size was 2,014 in the ibrutinib cohort and 2,050 in the CIT cohort (median follow-up: 10.9 vs. 10.7 months). Baseline characteristics were well-balanced. During 1L OCM episode and observed 1L duration, ibrutinib patients had significantly fewer monthly days with outpatient services compared to CIT patients (1L OCM: RR= 0.74, P<0.0001; 1L duration: RR= 0.86, P<0.0001). Ibrutinib patients incurred significantly higher monthly pharmacy costs (1L OCM: MMCD= $4,878, P<0.0001; 1L duration: MMCD= $4,892, P<0.0001) that were fully offset by lower monthly medical costs (1L OCM: MMCD= -$8,289, P<0.0001; 1L duration: MMCD= -$5,888, P<0.0001), yielding a monthly total cost reduction (1L OCM: MMCD= -$3,411, P<0.0001; 1L duration: MMCD= -$996, P<0.0001) versus CIT patients.

CONCLUSIONS : During 1L OCM episodes and observed 1L duration, continuous ibrutinib treatment was associated with lower outpatient HRU and total cost reduction compared to CIT in Medicare patients with CLL/SLL. The total cost reduction was driven by fewer outpatient days.