Adverse event clusters present at dose-reduction in CLL patients on ibrutinib in the U.S. Veterans Health Administration.

Abstract

252 Background: Previously, we reported that adverse events (AEs) were the top reason for dose reductions in VHA patients on novel agents. Some AEs might be problematic but might not directly lead to dose reduction; however, these concomitant AEs should not be overlooked. This study describes AE clusters that occurred with the primary AE that led to dose reduction in VHA CLL patients receiving ibrutinib. Methods: This is a retrospective chart review study of CLL patients treated with ibrutinib in the VHA from October 2013 to March 2018. Variables included the presence of dose reduction, the reasons for dose reduction, primary AEs leading to dose reduction, and concomitant AEs present at the time of dose reduction. Descriptive statistics were used to summarize AE clusters. Results: Out of 1069 CLL patients on ibrutinib, 285 patients experienced dose reduction due to AEs and were included in this analysis. The most common AEs leading to dose reduction were: musculoskeletal (11%), bleeding (11%), fatigue (10%), infection (9%), atrial fibrillation (8%), diarrhea (8%), and rash (8%). Fatigue was the leading concomitant AE present at dose reduction among patients who were dose reduced due to musculoskeletal (18%), infection (12%), diarrhea (18%), and rash (25%). Fatigue was also the second-leading or third leading concomitant AE among those who were dose reduced due to atrial fibrillation (13%) or bleeding (10%). Musculoskeletal was the leading or second-leading concomitant AE present at dose reduction among those who were dose reduced due to fatigue (17%), infection (12%), or diarrhea (14%). Bleeding was the leading concomitant AE among those who were dose reduced due to atrial fibrillation (17%) and vice versa. Conclusions: This study provides evidence that fatigue and musculoskeletal AEs are problematic in CLL patients on ibrutinib in the VHA. These were not only among the most common primary AEs but also the leading concomitant AEs present at dose reduction. Although not directly leading to dose reduction, these ‘nuisance’ AEs can greatly affect quality of life among CLL patients and warrant more attention from clinicians. A better understanding of all AEs present at dose reduction may help clinicians better manage patients on novel agents. These data also highlight the unmet need for novel agents with a ‘cleaner’ safety profile.