Integrated health system pharmacy role in adherence, persistence, and adverse effect management for oral chronic lymphocytic leukemia therapy.

Background: Oral oncolytic therapy for the management of chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL), such as ibrutinib, acalabrutinib, and venetoclax, have vastly changed CLL treatment. Although effective, adverse effects of these agents remain challenging. Pharmacists have an important role in managing oral chemotherapy, educating patients, and intervening to reduce adverse effects.

Objective: To evaluate medication utilization patterns (adherence, persistence, discontinuation, and switching therapy) and pharmacists' management of adverse effects in patients initiated on an oral oncolytic therapy for CLL/SLL at an integrated health system specialty pharmacy.

Methods: This single-center, retrospective review of data collected from electronic health records and a specialty pharmacy management system was conducted at the institution's outpatient oncology and hematology clinics from January 1, 2019, through June 30, 2022. Patients were included if they were prescribed acalabrutinib, ibrutinib, or venetoclax for treatment of CLL/SLL. Patients were followed through December 2022, with all patients having at least 6 months of follow-up. Primary outcomes were adherence (calculated as proportion of days covered [PDC] for patients with ≥3 fills), persistence (defined as absence of a ≥30-day gap in treatment), discontinuation or therapy switch, and reasons for discontinuation or therapy switch. A secondary analysis evaluated pharmacist interventions and intervention outcomes for patient-reported adverse effects. Descriptive statistics were used for analyses.

Results: There were 145 patients included in the study; among the 137 with at least 3 fills, the median PDC was 0.98 (interquartile range [IQR] 0.90-1.00) and 51 patients (37%) were found to be nonpersistent with median time to nonpersistence of 10 (IQR 6-19) months. Among 53 patients (39%) who discontinued therapy, common reasons included adverse effects (n = 26, 49%) and disease progression (n = 25, 47%). Common reasons for switching therapy among patients with a switch (n = 25; 17%) included adverse effects (n = 18, 72%) and progressive disease (n = 8, 32%). Pharmacists completed 141 interventions in 69 patients (43%) and most often acted by reviewing or updating the patient's chart (n = 85, 60%) and counseling patients (n = 50, 35%). Intervention outcomes included identified issue resolved (n = 79, 56%), follow-up care scheduled (n = 9, 6%), medication administration held (n = 2, 1%), dose adjustment made (n = 4, 3%), or medication discontinued (n = 4, 3%).

Conclusions: In a population of patients initiating oral CLL/SLL therapy through an integrated health system specialty pharmacy, adherence and persistence to therapy was high. Adverse effects were attributed in 36% of therapy discontinuations and 72% of therapy switches, indicating a continued opportunity for specialty pharmacists to help manage and mitigate adverse effects. Pharmacist interventions were common and sometimes resulted in therapy changes.