Safety and efficacy analysis of long-term follow up real-world data with ibrutinib monotherapy in 58 patients with CLL treated in a single-center in Greece.

Ibrutinib (IB) revealed high efficacy and safety profile in phase 2/3 chronic lymphocytic clinical trials. Emerging real-world-data shows similar response and survival, but higher discontinuation rates due to adverse events (AEs). We present retrospective real-world data from 58 chronic lymphocytic leukemia (CLL) patients (August 2014-January 2019) treated with IB monotherapy, according to standard instructions, in a Greek single-center, focusing on safety and efficacy. Eleven untreated first line (1st L) and 47 relapsed/refractory(R/R) CLL patients received IB for 6.6(0.7-46.8) and 16.3(0.4-53.7) months, respectively. Nine percent of 1stL and 10.6% of R/R patients discontinued IB due to AEs. Atrial fibrillation (AF) was the most common discontinuation AE cause (3.5% of patients). Thirteen patients (24.5%) discontinued due to disease progression: 6 Richter transformation (RT) cases, after 10.6 months (1-35.9) and 7 CLL-progression cases, after 30.3 months (5.4-43.4) of IB initiation. IB had minimal impact on immunoglobulin G (IgG)-levels, CLL-related autoimmunity, and second primary malignancies (SPM). Our real-world data show that CLL patients present similar to clinical trials' outcomes if treated homogenously according to standard guidelines, resulting in fewer unneeded discontinuations and shrinkage of treatment armamentarium.