Venetoclax Effectiveness, Safety, and Treatment Patterns in Chronic Lymphocytic Leukemia Patients: Results from the CLL Collaborative Study of Real-World Evidence (CORE)

Introduction: Venetoclax has demonstrated deep responses and sustained progression-free survival and is well tolerated in patients (pts) with previously untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia/small lymphocytic leukemia (CLL/SLL) in clinical trials. Some early studies provided initial insight of venetoclax utilization in the real-world (RW), but RW evidence focusing on venetoclax effectiveness and safety is still limited. This study assessed venetoclax effectiveness, safety, and treatment patterns in CLL pts treated in clinical practice. Methods: The CLL Collaborative Study of Real-World Evidence (CORE), a large multicenter chart review across 21 institutions in 4 countries, enrolled adult pts who initiated a first line (1L) therapy on/after 01/01/2012 or a new line of therapy (LOT) for R/R CLL/SLL on/after 02/12/2014 (current data cut through 06/08/2020). Clinical responses were abstracted from the medical records as assessed by treating physicians or investigators (iwCLL criteria were provided as reference). Overall response rate (ORR) was calculated as the proportion of pts with complete response (CR) or partial response (PR) out of pts with documented response assessments. Treatment patterns included choice of regimens and sequences, dose interruption, dose reduction, and discontinuation. Treatment discontinuation was defined as ending therapy for any reason(s) other than the completion of planned duration of therapy. Interruption was defined as a gap in the same LOT. All analyses were descriptive. Results: Of the 1231 CLL pts in the CORE data, 155 received venetoclax (21 in 1L and 134 in R/R) and were included in this study. Most of the sample were male (65%) and the median age at venetoclax initiation was 67.5 (range 37-91). For high-risk features among pts with available data, 33% (43/132 pts) had del(17p) or TP53 mutation, 24% (31/131 pts) had complex karyotype (≥ 3 abnormalities), and 77% (61/79 pts) had unmutated IGHV. At venetoclax initiation, 46%, 40%, and 14% of 151 pts with available data had low, medium, and high tumor burden, respectively. Median follow-up time from venetoclax initiation across all lines was 7.0 (0.1-43.1) months. Median number of prior LOT for R/R pts was 2 (1-5); the largest proportion of pts (36%) received venetoclax in 2L followed by 3L (26%). In 1L, venetoclax was most frequently used (62%) in combination (Figure 1), while in R/R setting venetoclax monotherapy was more commonly used (61%) fo