Lilly's Jaypirca Sees 80% Risk Of Disease Progression Or Death In Front-Line CLL/SLL Phase 3 Trial

(RTTNews) - Eli Lilly and Co. (LLY) announced Tuesday results from the Phase 3 BRUIN CLL-313 clinical trial of Jaypirca (pirtobrutinib), a non-covalent Bruton tyrosine kinase (BTK) inhibitor, versus bendamustine plus rituximab (BR), in treatment-naïve patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) without 17p deletions.

Pirtobrutinib met its primary endpoint demonstrating a reduction in the risk of disease progression or death by 80%. The risk reduction observed in BRUIN CLL-313 is among the most compelling observed for a single agent BTK inhibitor in a front-line CLL study.

BRUIN CLL-313 is the first prospective, randomized Phase 3 study examining the efficacy and safety of a non-covalent BTK inhibitor, pirtobrutinib, exclusively in patients with treatment-naïve CLL/SLL.

BRUIN CLL-313 enrolled 282 patients with previously untreated CLL/SLL without del(17p), who were randomized 1:1 to receive continuous pirtobrutinib monotherapy. Crossover to the pirtobrutinib arm was allowed after independent review committee (IRC)-confirmed disease progression. The efficacy results are based on a July 11, 2025, data cutoff.

At a median follow-up of 28.1 months, the primary endpoint of IRC-assessed progression-free survival (PFS) was significantly improved with pirtobrutinib compared to BR. PFS results favored pirtobrutinib across all pre-specified subgroups.

Overall survival (OS), a key secondary endpoint, remains immature, but a trend favoring pirtobrutinib was observed, despite over half of patients treated with BR crossing over to receive pirtobrutinib after IRC-confirmed disease progression. Final testing of OS superiority is planned at a future date.

Lilly has begun submitting results from BRUIN CLL-313 and BRUIN CLL-314 studies to regulatory authorities with the goal of further expanding Jaypirca's label into earlier lines of therapy. Lilly is studying Jaypirca in CLL/SLL in multiple Phase 3 studies.