Dr Mulvey on Real-World Treatment Discontinuation Data for First-Line BTK Inhibitors in CLL

“[These data] can be very helpful in informing future studies and questions that we want to ask in a more prospective fashion.”

Erin Mulvey, MD, an assistant professor of Medicine at Weill Cornell Medical College and an assistant attending physician at NewYork-Presbyterian Hospital, discussed data from a real-world analysis of first-line BTK inhibitors, including zanubrutinib (Brukinsa), acalabrutinib (Calquence), and ibrutinib (Imbruvica), in the treatment of patients with chronic lymphocytic leukemia (CLL), which were presented at the 2026 EHA Congress. In addition to discussing the data, Mulvey explored their significance and important topics they resurface for the larger CLL field.

Data from the retrospective analysis showed a 24% lower adjusted risk of treatment discontinuation with zanubrutinib (n = 608) vs with acalabrutinib (n = 826; adjusted HR, 0.76; 95% CI, 0.59-0.97; P = .0257) and 49% lower than with ibrutinib (n = 416; adjusted HR, 0.51; 95% CI, 0.39-0.66; P < .0001). Moreover, 12-month treatment persistence rates were 82.8% (95% CI, 79.1%-85.9%) with zanubrutinib, 78.7% (95% CI, 75.4%-81.7%) with acalabrutinib, and 68.1% (95% CI, 62.8%-72.9%; P < .0001) with ibrutinib. Twenty-four-month treatment persistence rates with zanubrutinib, acalabrutinib, and ibrutinib were 74.7% (95% CI, 69.3%-79.3%), 66.3% (95% CI, 61.6%-70.6%), and 58.7% (95% CI, 52.7%-64.3%), respectively (P = .0002).

Mulvey noted that when conducting the analysis, factors including, age, gender, region, and insurance type were all controlled. Both time to treatment discontinuation, and treatment persistence rates at 6, 12, and 24 months were all higher with zanubrutinib, she noted. Mulvey then pointed out how findings from the study regarding improvements made with zanubrutinib were consistent among patients who were 65 years of age and older.

Mulvey concluded by underscoring how being mindful of the limitations is important when looking at data from retrospective studies, since information on other potential confounding factors may be limited.