CLL/SLL Therapy Initiation at Specialty Pharmacies May Increase Treatment Adherence Rates


Patients with chronic lymphocytic leukemia who initiated therapy through an integrated health-system specialty pharmacy had high therapy adherence rates.

Houston Wyatt

Houston Wyatt

Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who initiated therapy through an integrated health-system specialty pharmacy had high therapy adherence rates, according to findings from a real-world study presented at the 28th International Congress on Hematologic Malignancies.

Patients who had 3 or more prescription fills were evaluable for adherence (n = 137) and persistence (n = 135). Regarding adherence, the mean proportion of days covered (PDC) was 0.92 (standard deviation, 0.12). Notably, 44, 69, 22, and 2 patients had 100%, 80% to less than 100%, 50% to less than 80%, and less than 50% adherence, respectively. The median PDC was 0.98 (IQR, 0.9-1.0).

Patients who were identified as nonpersistent after 2 prescription fills were considered to only have 2 fills in the persistence calculation and were excluded from the persistence analysis. In total, 53.3% of patients were non-persistent, and the median time to non-persistence was 375 days (IQR, 180-526). Reasons for non-persistence included treatment progression (31%), adverse effects (AEs; 28%), treatment completion (32%), death (6%), and unknown reasons (13%). Multiple reasons for non-persistence could be reported.

This single-center, retrospective cohort study assessed treatment outcomes, including adherence, persistence, switching, and treatment discontinuation, in patients with CLL/SLL receiving an oral oncolytic therapy at an integrated health-system specialty pharmacy focused on patient outcomes. Investigators collected data from specialty pharmacy management systems and electronic medical records from Vanderbilt Health System outpatient oncology and hematology clinics in Nashville, Tennessee, from January 1, 2019, to June 30, 2022. Patients were included if they had at least 6 months of follow-up.

This study evaluated patients who were prescribed acalabrutinib (Calquence), ibrutinib (Imbruvica), or venetoclax (Venclexta) for the treatment of CLL/SLL. Patients were excluded if they participated in a clinical trial, underwent off-label drug use, were lost to follow-up, received a stem cell transplant, or transferred their care outside of Vanderbilt University Medical Center.

A total of 157 patients were identified for inclusion, 12 of whom were excluded because of off-label drug use (n = 2), loss to follow-up (n = 1), stem cell transplant (n = 1), and transfer of care outside of Vanderbilt University Medical Center (n = 5).

The outcomes of this study were adherence, calculated as the PDC; persistence, defined as a more than 30-day gap in treatment; therapy switch or discontinuation; and reasons for therapy switch or discontinuation. Patients with 3 or more prescription fills were analyzed for adherence and persistence. The PDC was calculated as the number of days patients had medication available between the date of their first fill and the last fill in the study period. Excess medication supply from fill overlap was carried forward and truncated at the date of the last fill.

Patients had a median age of 69 years (IQR, 60-76 years). Most were male (66%) and White (90%). At the start of medication use, patients had been diagnosed with their disease for a median of 6 years (IQR, 2-10), and 51% of patients had Medicare. CLL/SLL treatments included ibrutinib (53%), venetoclax (32%), and acalabrutinib (15%). Comorbidities included hypertension (51%), gastroesophageal reflux disease (31%), atrial fibrillation/arrhythmia (18%), cerebrovascular disease (5%), headache (5%), and migraine (2%). Genetic testing results showed that 53%, 17%, and 10% of patients had 13q, 11q, and 17p deletions, respectively. Thirty-two percent of patients had no available genetic testing results.

Among all patients included in the study, 81 patients discontinued treatment, irrespective of the number of fills. Patients could have had more than 1 documented reason for discontinuation. Reasons for discontinuation included AEs (36%), treatment completion (35%), treatment progression (31%), and death (6%). Among patients who discontinued ibrutinib because of AEs (n = 21), the primary AEs leading to discontinuation were atrial fibrillation (14%), bruising (10%), fatigue (10%), nail splitting (10%), and rash (10%). Among patients who discontinued acalabrutinib because of AEs (n = 2), the primary AEs leading to discontinuation were bruising (50%) and diarrhea (50%). Among patients who discontinued venetoclax because of AEs (n = 6), the primary AEs leading to discontinuation were pancytopenia (66%), itching (17%), and nausea (17%).

Eighteen patients switched medications, and some patients switched medications more than once. Among patients who received ibrutinib, acalabrutinib, and venetoclax, 16, 5, and 4 switched medications, respectively. Reasons for medication switch included AEs (60%), progressive disease (PD; 20%), multiple reasons (16%; including no clinical response plus AEs; no clinical response plus PD; no clinical response plus AEs and PD; and PD plus AEs [n = 1 each]), and unknown reasons (4%). Patients switched to receive acalabrutinib (56%), venetoclax (28%), multiple medications (8%; including acalabrutinib plus venetoclax and venetoclax plus obinutuzumab [n = 1]), or other medications (8%).

“AEs contributed to 36% of therapy discontinuations and 72% of therapy switches, indicating a continued opportunity for specialty pharmacists to help manage and mitigate AEs,” lead study author Houston Wyatt, of Vanderbilt Specialty Pharmacy, Vanderbilt Health, and coauthors, concluded in a poster presentation of the data.


Wyatt H, White S, Zuckerman A, et al. Real-world outcomes of patients receiving oral specialty therapy for the treatment of chronic lymphocytic leukemia/small lymphocytic leukemia at an integrated health system in the United States. Presented at: 28th International Congress on Hematologic Malignancies; February 29 to March 3, 2024. Miami, FL.

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