Real-world analysis of adverse event rates after initiation of ibrutinib among Medicare beneficiaries with chronic lymphocytic leukemia

Abstract

Background: The first-generation BTK inhibitor ibrutinib is a standard-of-care therapy in the treatment of chronic lymphocytic leukemia (CLL) despite potential side effects that often lead to discontinuation.

Methods: This study used 2013-2019 claims data to describe the incidence rate of adverse events (AEs) among elderly Medicare beneficiaries newly initiating ibrutinib for CLL.

Results: The final sample contained 11,870 Medicare beneficiaries with CLL (mean age 77.2) newly initiating ibrutinib, of whom 65.2% discontinued over mean follow-up of 2.3 years. The overall incidence rate of AEs was 62.5 per 1000 patient-months for all discontinuers and 32.9 per 1000 patient-months for non-discontinuers. Discontinuers had a higher incidence rate of AEs per 1000 patient-months compared with non-discontinuers for all AEs examined, including infection (22.8 vs. 14.5), atrial fibrillation (15.1 vs. 7.0), anemia (21.9 vs. 14.5), and arthralgia/myalgia (19.5 vs. 13.6).

Conclusion: In this first real-world study of a national sample of elderly US patients treated with ibrutinib, we found a clear unmet need for improved management of ibrutinib-related AEs and/or new treatments to improve real-world outcomes in patients with CLL.

Keywords: Medicare; adverse event; chronic lymphocytic leukemia; discontinuation; elderly; ibrutinib.