Overall Survival Associated with Real-World Treatment Sequences in Patients with CLL/SLL in the United States

Background/Objectives: This study compared overall survival (OS) associated with common real-world treatment sequences in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in the United States. Methods: Utilizing the nationwide Flatiron Health electronic health record-derived de-identified database, adult CLL/SLL patients who initiated systemic therapy (JAN2016-NOV2023) and received at least two lines of therapy (LoTs) were analyzed. Treatment regimens were categorized based on drug class, and most frequent (n ≥ 50) sequences (first LoT followed by [→] second LoT) were compared. OS from initiation of the first LoT was compared using multivariable Cox proportional hazard models, and adjusted hazard ratios with 95% CIs were reported. Results: Among 2354 eligible patients, n = 1711 (73%) received the 16 most frequent treatment sequences. Sequencing chemoimmunotherapy (CIT) → CIT (HR: 2.29 [1.23–4.28]), anti-CD20 monoclonal antibody (anti-CD20mab) monotherapy → CIT (1.95 [1.03–3.69]), and covalent Bruton tyrosine kinase inhibitor (cBTKi) monotherapy → anti-CD20mab monotherapy (2.00 [1.07–3.74]) were associated with worse OS compared to patients treated with cBTKi monotherapy → B-cell lymphoma 2 inhibitors (BCL2i) + anti-CD20mab (reference). Conclusions: OS associated with other sequences were not significantly different from the reference sequence in adjusted analyses, suggesting a lack of evidence for the optimal standard of care for sequencing the first two LoTs in real-world settings. Future research should reassess sequencing outcomes as novel treatments become adopted into clinical practice.