Phase I/II BRUIN PROs: Pirtobrutinib in CLL/SLL and MCL

Results from the final analysis of the phase I/II BRUIN (NCT03740529) study, evaluating patient-reported outcomes (PROs) in patients with chronic lymphocytic leukemia / small lymphocytic lymphoma (CLL/SLL) and mantle cell lymphoma (MCL) receiving pirtobrutinib after prior covalent Bruton tyrosine kinase inhibitor (cBTKi) therapy, were published in Current Medical Research and Opinion by Coombs et al. PRO‑related endpoints included determination of the association of tumor response categories with the improvement of cancer-related symptoms and with improvements in physical functioning, change in PROs from baseline, time to worsening (TTW), and longitudinal analyses of PROs throughout treatment. 

Key data: At a median follow-up of 46.5 months and 39.7 months, 263 and 124 patients with CLL/SLL and MCL, respectively, were included in the PRO analysis. In the CLL/SLL cohort, the proportion of patients who improved or remained stable from baseline to Cycle 31 ranged 83.1–94.1% for physical function, 88.0–94.7% for CLL/SLL-related symptoms, 82.3–90.5% for fatigue, and 85.6–92.0% for global health status / quality of life (GHS/QoL). In the MCL cohort, the proportion of patients who improved or remained stable from baseline to Cycle 20 ranged 87.5–100.0% for physical function, 82.4–94.1% for MCL-related symptoms, 70.6–94.1% for fatigue, and 82.2–95.0% for GHS/QoL. Median TTW was not reached in either cohort. Longitudinal analyses showed statistically significant improvements from baseline in physical function, CLL/SLL-related symptoms, fatigue, and GHS/QoL in the CLL/SLL cohort, while PRO assessments remained stable for MCL.

Key learning: Results indicate that PROs remain stable or improve throughout pirtobrutinib treatment in patients with CLL/SLL or MCL, supporting the use of pirtobrutinib in this patient population.