- Pirtobrutinib reduced disease progression risk by 80% in treatment-naïve CLL/SLL patients.
- The Phase 3 BRUIN CLL-313 trial enrolled 282 patients without 17p deletions.
- Median follow-up was 28.1 months, showing improved progression-free survival.
- Overall survival trend favored pirtobrutinib despite crossover to the drug.
Study Overview
The Phase 3 BRUIN CLL-313 trial evaluated the efficacy and safety of pirtobrutinib, a non-covalent BTK inhibitor, in treatment-naïve patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) without 17p deletions. The study compared pirtobrutinib to bendamustine plus rituximab (BR) in 282 patients.
Key Findings
Pirtobrutinib significantly reduced the risk of disease progression or death by 80% compared to BR, with a hazard ratio of 0.20. The median follow-up was 28.1 months, and progression-free survival (PFS) results favored pirtobrutinib across all pre-specified subgroups, including those with high-risk molecular features.
Safety Profile
The safety profile of pirtobrutinib was consistent with previous trials, showing fewer grade ≥3 treatment-emergent adverse events (40.0% vs. 67.4% with BR). Pirtobrutinib also had fewer adverse event-related dose reductions and discontinuations compared to BR.
Overall Survival
While overall survival (OS) data remains immature, a trend favoring pirtobrutinib was observed, despite 52.9% of patients in the BR group crossing over to pirtobrutinib after disease progression. Final OS testing is planned for a future date.
