Venetoclax in Relapsed/Refractory Chronic Lymphocytic Leukemia: A Retrospective, Single-Institution Analysis Based on Risk Features and Debulking Strategy with Anti-CD20 Monoclonal Antibody

• Published in: Blood 2019-11, Vol.134 (Supplement_1), p.5484-5484
• Main Authors: Grajales-Cruz, Ariel F, Chavez, Julio, Volpe, Virginia Olivia, Sandoval-Sus, Jose, Shah, Bijal, Bello, Celeste, Sokol, Lubomir, Fisher, Shanel, Nair, Rajesh R, Seongseok, Yun, Saeed, Hayder, Isenalumhe, Leidy, Turba, Elyce P., Nodzon, Lisa, Pinilla Ibarz, Javier
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2019-129260

Background: The treatment of Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) has continued to evolve in recent years, offering the patients different therapeutic options. Venetoclax (ven) is a selective, small molecule inhibitor of B-cell receptor-2 (BCL-2) approved by the FDA for patients with newly diagnosed and relapsed/refractory CLL. Stratification based on tumor lysis syndrome (TLS) risk is recommended and may guide debulking strategies. Methods: We retrospectively analyzed 36 patients with relapsed/refractory (RR) CLL who received treatment with ven at the Moffitt Cancer Center between January 2016 and July 2019. Objective response to therapy was determined based on iwCLL. Progression free survival (PFS) and overall survival (OS) were evaluated via Kaplan-Meier method; overall response rate (ORR) and complete response (CR) via Fisher's exact test. Adverse events (AEs) were graded by CTCAEv5. Results: The median age was 58.5 years (28-82). Median follow up was 12.97 months. The vast majority of patients had high risk disease; Chromosomal analysis by Fluorescence In Situ Hybridization (FISH) reported Del17p and Del11q (+/- others, except Del17p) in 18 (50%) patients and 6 (16.7%) patients respectively. Twenty one (58.3%) patients had a TP53 mutation by next generation sequencing. Twenty five (80.6%) patients had unmutated IGHV status, and 24 (79.9%) patients had high or very high CLL-International prognostic Index (CLL-IPI) score. Twenty-four patients (66.7%) had been previously treated with Ibrutinib, 11 of those progressing on it. Further characteristics are described in table 1. Median OS was not reached. Median PFS was 23.93 months, figure 1a. Median duration of response was 25.97 months. The ORR (PR+CR) at the time of analysis was 63.9%, with CR rate of 33.3%, and PR rate of 30.6%. Nine patients (25%) had stable disease (SD), while four patients (11.1%) progressed on treatment. Minimal residual disease (MRD) was evaluated as part of the response assessment in 7 patients (19.4%) by flow cytometry (1 patient) and by clonoSEQ (6 patients), and 4 (11.1%) had achieved undetectable disease. Response rates were also based on risk stratification; OS and PFS were not affected by the presence of TP53 mutation (p=0.1145) as described in figure 1b, IGHV unmutated status, or NOTCH1 mutation. PFS was inferior in patients with high-very high CLL-IPI score (p=0.0414), figure 1c. The presence of bulky lymphadenopathy (≥5 cm) did not affect outco