Clinical Outcomes in Double-Exposed Chronic Lymphocytic Leukemia Patients in Italy

B-cell receptor inhibitors (BCRi) and B-cell lymphoma-2 inhibitor (BCL2i) improved outcomes of patients with chronic lymphocytic leukemia (CLL), but relapsing after two inhibitors still represent an unmet clinical need. This multicenter real-world study analyzes outcomes of a cohort treated in Italy between May 2017 and September 2023 following prior exposure to both BCRi and BCL2i. The median follow-up after venetoclax initiation was 47 months (IQR 28-56). Of 153 double-exposed patients, 104 (68%) discontinued venetoclax and 53 of them (51%) received a subsequent treatment. Venetoclax was discontinued due to progressive disease (PD) in 51/104 cases (49.0%), with nine deaths occurring rapidly after PD without the administration of any further treatment. Fifty-three patients received treatment after venetoclax: 29/53 (54.7%) received inhibitors (13 cBTKi, 11 idelalisib, 2 BCL2i, 3 non-covalent BTKi), 19/53 (35.8%) received chemoimmunotherapy (CT: 16 intensive, 3 palliative), 5/53 (9.4%) received hematopoietic stem cell transplantation (HSCT). Overall response rate was 50%; median event free survival (EFS) in the groups of inhibitors, CT and HSCT was 11, 2, and 10 months, respectively (p < 0.0001); median overall survival (OS) was 12, 5, and 10 months, respectively (p = 0.020). Disease progression during venetoclax treatment was associated with shorter subsequent EFS compared to discontinuation for other reasons, even if the finding did not reach statistical significance (median EFS 4 vs. 10 months; p = 0.11). No decrease in EFS was associated with del17p and/or TP53 mutations, the use of venetoclax monotherapy or a previous treatment with one versus multiple BCRi. Despite its limitations, this real-world study provides additional insights into double-exposed patients, who still pose a clinical challenge, demonstrating the superior efficacy of inhibitors over alternative treatment options. Enrollment in clinical trial and treatments with novel molecules, if available, may help address this unmet clinical need.