Background: Chronic lymphocytic leukemia (CLL) is a B-cell neoplasm with clonal expansion of small lymphocytes. Ibrutinib, an irreversible inhibitor of Bruton tyrosine kinase (BTK), is a first-line treatment option, and recent data suggest that strict adherence is directly related to clinical outcomes. Objectives: The primary objective of this study was to quantify ibrutinib adherence rates in real-world patients with CLL on ibrutinib; secondary outcomes included progression-free survival and overall survival. Methods: This retrospective study included subjects who were treated at a large academic medical center over approximately 5 years. Subjects were at least 18 years, diagnosed with CLL or small lymphocytic lymphoma, and treated with ibrutinib monotherapy for at least 6 months. Adherence was quantified using the medication possession ratio (MPR), which is the ratio of the sum of days' supply of medication in a period over the number of days in that period, and was based on fill history from the medical center's specialty pharmacy. Results: For the 32 subjects in this study, the mean ibrutinib adherence rate was 91.7% (range, 84.4%-100%). Only 3 subjects had disease progression, and 1 death was recorded while on therapy (all with MPR < 95%); therefore, analyses of clinical outcomes were unable to be assessed due to a low number of events. There were no statistically significant differences in rates of adherence based on baseline characteristics and adverse drug events. Conclusion: In patients with CLL treated with ibrutinib, mean adherence was 91.7%, which is lower than rates seen in clinical trials.

Venetoclax is a BCL-2 inhibitor approved for treatment of adult patients with chronic lymphocytic leukemia (CLL). Due to significant risk of tumor lysis syndrome (TLS) upon treatment initiation, a 5week dose ramp-up is recommended. University of North Carolina Medical Center (UNCMC) utilizes a novel interdisciplinary model of care involving clinical pharmacists (CPs) who oversee the 5-week rampup to minimize treatment-related adverse events. The aim of this study was to investigate the effects of a pharmacist-led venetoclax initiation protocol on patient outcomes. The primary objective was to determine the incidence of venetoclax-induced TLS during dose ramp-up in patients managed by a CP. In this cohort (n=39), there were no cases of TLS during the venetoclax ramp-up. Significantly lower TLS rates were observed in CP-managed real-world patients compared to a previous real-world report (0% vs 13.4%, p=0.014). This real-world analysis supports the utilization of CPs for intensive monitoring of patients initiating venetoclax.