Real-world patterns and sequences of targeted therapy use in chronic lymphocytic leukemia and small lymphocytic lymphoma in the United States: a longitudinal study

With increasing focus on novel targeted therapies for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), this longitudinal claims-based study evaluated real-world CLL/SLL treatment sequences, particularly sequential targeted therapy. Among patients with first-line (1L) treatment in 2014-2017 (N=2,612; median follow-up = 3years), the most common 1L treatment was chemoimmunotherapy (CIT; 44.6%), followed by CD20 (25.2%) and Bruton's tyrosine kinase inhibitors (BTKi; 21.7%). Among those with 1L in 2018-2021 (N=4,534; median follow-up = 1year), these were BTKi (45.5%), CD20 (20.4%), CIT (17.5%), and B-cell lymphoma 2 inhibitor (8.3%). In 2014-2017, the proportion of patients receiving sequential targeted therapy in the first 2 LOTs was 11.2% (80.2% was BTKi -> BTKi); in 2018-2021, this proportion was 34.3% (66.4% was BTKi -> BTKi). Over time, there was a substantial increase in targeted therapy use in 1L and sequential targeted therapy, particularly with BTKi -> BTKi. Future studies should assess clinical outcomes to determine optimal sequences for CLL/SLL and reasons for restarting BTKi.