In a recent study, Kevin Lin, PhD, MD, Dana-Farber Cancer Institute, Boston, Massachusetts, investigated data on patients with chronic lymphocytic leukemia (CLL) that received first- or second-line Bruton tyrosine kinase inhibitors (BTKis) but eventually discontinued treatment. They presented their findings at the 2023 ASCO Annual Meeting in Chicago, Illinois. 

In this retrospective analysis, researchers reviewed charts on adult patients with CLL who were treated with a covalent BTKi at the Dana-Farber Cancer Institute. These patients were also found to be BTKi resistant or intolerant. Demographics, clinical characteristics, treatment patterns, reasons for treatment discontinuation, and cause of death were all factors of discontinuation included in the data. 

Altogether, the study included 104 patients with CLL. The researchers found that ibrutinib was the most-used BTKi among these patients, with 92% receiving it either as a monotherapy or in a combination treatment. The median duration for BTKi therapy was about 2 years, and 27% of patients received a BTKi in their first line of therapy, 32% received a BTKi in their second line of therapy, and 41% received a BTKi in a later line of treatment. About 98% (102 patients) stopped BTKi treatment, with 53% discontinuing because of adverse events and 40% because of disease progression. The most common adverse events were atrial fibrillation (26%) and bleeding (13%). In patients who discontinued because of adverse events, 74% received subsequent treatments, and in patients who discontinued due to disease progression, 100% received further treatment. Finally, data showed that 34% of patients passed away, and common causes of death were disease progression (62%), infection (17%), and secondary malignancy (7%).

Ultimately, Lin and colleagues found that for patients with CLL, adverse events and disease progression are the leading factors for BTKi discontinuation. “Following BTKi discontinuation, a high percentage of patients received venetoclax-based regimens, yet with a median follow-up of 6 years, 34% died,” the authors wrote. They added that the findings point to the need for novel treatment approaches for patients who have discontinued covalent BTKi treatment and have not received pretreatments for CLL.

Sources:
Lin K, Huynh L, Yang X, et al. Real-world evidence study of treatment patterns and outcomes following covalent BTKi discontinuation in a contemporary cohort of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) patients; June 2-6, 2023; Chicago, IL, and virtual; Abstract 19510.