Efficacy and Safety of Ibrutinib Therapy in Patients with Chronic Lymphocytic Leukemia: Retrospective Analysis of Real-Life Data

OBJECTIVE: This study aimed to retrospectively evaluate the efficacy, safety, and survival outcome of single-agent ibrutinib therapy in chronic lymphocytic leukemia patients. MATERIALS AND METHODS: A total of 136 patients (mean age ± standard deviation: 64.6±10.3 years, 66.9% males) who had received at least one dose of ibrutinib were included in this retrospective multicenter, noninterventional hospital-registry study conducted at 33 centers across Turkey. Data on patient demographics, baseline characteristics, laboratory findings, and leukemia-cell cytogenetics were retrieved. Treatment response, survival outcome including overall survival (OS) and progression-free survival (PFS), and safety data were analyzed. RESULTS: Overall, 36.7% of patients were categorized as Eastern Cooperative Oncology Group (ECOG) class 2-3, while 44.9% were in Rai stage 4. Fluorescence in situ hybridization revealed the presence of del(17p) in 39.8% of the patients. Patients received a median of 2.0 (range: 0-7) lines of pre-ibrutinib therapy. Median duration of therapy was 8.8 months (range: 0.4-58.0 months). The 1-year PFS and OS rates were 82.2% and 84.6%, respectively, while median PFS time was 30.0 (standard error, 95% confidence interval: 5.1, 20.0-40.0) months and median OS time was 37.9 (3.2, 31.5-44.2) months. Treatment response (complete or partial response), PFS time, and OS time were better with 0-2 lines versus 3-7 lines of prior therapy (p<0.001, p=0.001, and p<0.001, respectively), with ECOG class 0-1 versus class 2-3 (p=0.006, p=0.011, and p=0.001, respectively), and with Rai stage 0-2 versus 3-4 (p=0.002, p=0.001, and p=0.002, respectively). No significant difference was noted in treatment response rates or survival outcome with respect to the presence of comorbidity, bulky disease, or del(17p). While 176 adverse events (AEs) were reported in 74 (54.4%) patients, 46 of those 176 AEs were grade 3-4, including pneumonia (n=12), neutropenia (n=11), anemia (n=5), thrombocytopenia (n=5), and fever (n=5). CONCLUSION: This real-life analysis confirms the favorable efficacy and safety profile of long-term ibrutinib treatment while emphasizing the potential adverse impacts of poorer ECOG performance status, heavy treatment prior to ibrutinib, and advanced Rai stage on patient compliance, treatment response, and survival outcomes.