Background: Real-world evidence on Bruton Tyrosine Kinase Inhibitor treatment vs chemoimmunotherapy (CIT) for patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) has been limited to certain practice settings; research using a large and more comprehensive data source is warranted. Methods: This retrospective cohort study evaluated treatment outcomes among patients with CLL/SLL treated with first-line (1L) ibrutinib (IBR) or CIT using the US claims data from the Komodo Health payer-complete dataset, derived from >150 private insurers and >140 million insured individuals from 2015 to 2022. This study included adult patients with CLL/SLL who initiated 1L single-agent IBR or CIT (defined as no prior CLL/SLL treatment for ≥12 months in the baseline period) on or after March 2016. Time to next treatment (TTNT) was defined as the time from initiation (index date) of 1L treatment to treatment add-on or switch to a next line of therapy ≥29 days post-index and was compared using Cox proportional hazards models. Cohorts were balanced on baseline characteristics using inverse probability of treatment weights. Results: A total of 3570 1L IBR- and 2391 CIT-treated patients were included, with the mean age 68 vs 64 years, 63% vs 66% male, and mean Quan-Charlson Comorbidity Index score 2.87 vs 3.05, respectively. Median follow-up was 26 vs 31 months, and 13% vs 26% of patients recorded a next treatment during the study period for IBR and CIT, respectively. At 1-, 3-, and 5-year post-index, the probabilities (95% confidence interval [CI]) of not initiating a new treatment were 92% (91%-93%), 83% (81%-84%) and 76% (73%-78%) vs 88% (87%-89%), 70% (68%-73%) and 56% (53%-60%) for the IBR and CIT cohorts, respectively. After controlling for baseline characteristics, 1L IBR patients were significantly less likely to initiate the next line of therapy during the study period (hazard ratio 0.61, 95% CI 0.54-0.69, p<0.001). Conclusions: 1L single-agent IBR was associated with a significantly lower risk of advancing to next line of treatment compared to CIT in this large claims-based data set, reinforcing real-world effectiveness of 1L IBR for CLL in an insured US patient population.

Abbreviations: 1L, first-line; CIT, chemoimmunotherapy; IBR, ibrutinib; TTNT, time to next treatment. * Adjusted for age, gender, region, year of 1L treatment initiation, baseline Quan-Charlson Comorbidity index, CLL-related symptoms, cardiovascular comorbidities, gastrointestinal disorders, and healthcare utilization.