Background: With recent advances in treatment of CLL, it is important to understand emerging treatment patterns and associated outcomes. A population-based study was undertaken to describe the management and survival of CLL patients in Ontario, Canada. Methods: Patients diagnosed with CLL between January 1, 2010 and December 31, 2017 were identified in the Ontario Cancer Registry and linked to provincial administrative databases. Treatment patterns by line of therapy were characterized, including analyses of time to initiation and between therapies. Overall survival was calculated. Results: 2,887 CLL patients were identified (median age 68yr; 67% male). The mean time from diagnosis to first line (1L) treatment was 651 days with 35% of patients receiving fludarabine-cyclophosphamide-rituximab (FCR) based treatment. During the study period, 71% of patients did not yet receive second line (2L) therapy and did not have subsequent follow up, while 19% received 2L ibrutinib. Median time to 2L initiation from 1L treatment discontinuation was 636 days. The table summarizes 1L and 2L therapies. Of the 827 patients on 2L therapy, 65% received ibrutinib. After the introduction of publicly funded novel agents in 2015, a shift in treatment patterns away from FCR and chlorambucil based regimens was observed. Overall mean survival for the cohort from diagnosis was 6.8yrs, and mean 5 year probability of survival was 72.4%. Conclusions: A shift in treatment patterns for CLL can be seen with the introduction of newer therapies, such as ibrutinib. The results can support healthcare decision-makers by characterizing the size of this patient population, real world treatment patterns and survival outcomes for patients with CLL.

* exact counts suppressed due to privacy reasons ** patients who were on other treatments with less than 1% market share were omitted from the table