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In addition to meeting the primary endpoint of non-inferiority for overall response rate (ORR) in the BRUIN CLL-314 study, pirtobrutinib achieved a numerically higher ORR of 87.0% compared to 78.5% for ibrutinib in the intent-to-treat (ITT) population
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Progression-free survival data were immature but trended in favor of pirtobrutinib with a 43% reduction of the risk of disease progression or death in the ITT population, and the treatment-naïve subgroup, which had the longest follow up, showed a 76% reduction
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These data will be simultaneously published in the Journal of Clinical Oncology and presented at the 2025 American Society of Hematology Annual Meeting and Exposition, as well as featured as part of the meeting's press program
INDIANAPOLIS, Dec. 7, 2025 /PRNewswire/ -- Eli Lilly and Company (NYSE: LLY) today announced results from the Phase 3 BRUIN CLL-314 clinical trial evaluating Jaypirca (pirtobrutinib), a non-covalent (reversible) Bruton tyrosine kinase (BTK) inhibitor, versus Imbruvica (ibrutinib), a covalent BTK inhibitor, in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) who were treatment-naïve or were BTK inhibitor-naïve. Pirtobrutinib met its primary endpoint of non-inferiority on overall response rate (ORR) compared to ibrutinib (87.0% [95% CI, 82.90-90.44] versus 78.5% [95% CI, 73.73-82.85]; p<0.0001) in the intent-to-treat (ITT) population. Pirtobrutinib also had numerically higher ORR rates and, while immature, progression-free survival (PFS) was also trending in favor of pirtobrutinib compared to ibrutinib across all populations, including a 76% reduction in the risk of disease progression or death (HR=0.239 [95% CI, 0.098-0.586]) in treatment-naïve patients, the subgroup with the longest follow-up.
These data will be highlighted at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition taking place in Orlando, Florida and simultaneously published in the Journal of Clinical Oncology.
"These data from BRUIN CLL-314 are both novel and clinically significant, demonstrating an improved overall response rate and a favorable trend in progression-free survival outcomes with pirtobrutinib compared to ibrutinib across all populations, including treatment-naïve patients where covalent BTK inhibitors are a cornerstone of treatment," said Jennifer A. Woyach, M.D., professor, hematologist-oncologist, and Director of the Division of Hematology at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute. "BRUIN CLL-314 is the first randomized study to compare covalent and non-covalent BTK inhibitors and to directly compare any BTK inhibitors in the treatment-naïve setting, offering findings that are important for advancing the field and patient care. These efficacy results, along with pirtobrutinib's safety profile, offer strong evidence on the role of pirtobrutinib earlier in the treatment course for patients with CLL or SLL."
The BRUIN CLL-314 study enrolled 662 patients who were randomized to receive pirtobrutinib (n=331) or ibrutinib (n=331), with the ITT population consisting of 225 treatment-naïve and 437 relapsed/refractory patients. The efficacy results utilize a June 10, 2025, data cutoff date.
The study achieved its primary endpoint demonstrating that pirtobrutinib was statistically non-inferior to ibrutinib in independent review committee (IRC)-assessed ORR for the ITT population, and results numerically favored pirtobrutinib (87.0% [95% CI, 82.90-90.44] versus 78.5% [95% CI, 73.73-82.85]; nominal p = 0.0035). Additionally, ORR consistently favored pirtobrutinib versus ibrutinib across all populations evaluated, including relapsed/refractory and treatment-naïve, as well as across pre-specified subgroups such as patients with and without 17p deletions, IGHV status and complex karyotype.
PFS, a key secondary endpoint, was not yet mature at this analysis but was trending in favor of pirtobrutinib compared to ibrutinib in the ITT (HR=0.569 [95% CI, 0.388-0.834]), relapsed/refractory (HR=0.729 [95% CI, 0.471-1.128]), and treatment-naïve (HR=0.239 [95% CI, 0.098-0.586]) populations, with a median follow-up of 22.0 months, 18.4 months, and 22.5 months, respectively. Among all subgroups, the largest PFS effect size was observed in the treatment-naïve subgroup, which had the longest follow-up at this data cut, with a 76% reduction in the risk of disease progression or death. A formal PFS analysis testing for superiority is planned at a future analysis. There was no detriment in overall survival (OS) (HR=0.961 [95% CI, 0.55-1.69]) for the ITT population.
The overall safety profile for patients treated with pirtobrutinib in BRUIN CLL-314 was similar to previously reported trials, and the most common treatment-emergent adverse events were similar between arms. Most adverse events (AE) of interest were lower with pirtobrutinib compared to ibrutinib, including atrial fibrillation/flutter (2.4% versus 13.5%) and hypertension (10.6% versus 15.1%). Fewer AE-related dose reductions (7.9% versus 18.2%) and discontinuations (9.4% versus 10.8%) were seen with pirtobrutinib versus ibrutinib.
"We are excited to share these compelling new findings for pirtobrutinib with the scientific community at ASH and in the Journal of Clinical Oncology," said Jacob Van Naarden, executive vice president and president, Lilly Oncology. "These data build on additional results from the BRUIN development program and the recent FDA approval for pirtobrutinib in the post-covalent BTK inhibitor setting to reinforce the medicine's potential to deliver meaningful benefit for people living with CLL or SLL across various disease settings."
As part of the Late-Breaking Abstract Session on Dec. 9, Lilly will also share results from the Phase 3 BRUIN CLL-313 study of pirtobrutinib versus chemoimmunotherapy in patients with treatment-naïve CLL/SLL without del(17p). These data were also selected to be highlighted as part of the ASH Annual Meeting press program session on Dec. 8.
Lilly is studying Jaypirca in CLL/SLL in multiple Phase 3 studies. Details on the trials can be found by visiting clinicaltrials.gov.
About BRUIN CLL-314
BRUIN CLL-314 is a Phase 3, randomized, open-label study of Jaypirca (pirtobrutinib) versus Imbruvica (ibrutinib) in patients with CLL/SLL who were either treatment-naïve, or who were previously treated and were BTK inhibitor-naïve. The trial planned to enroll 650 patients who were randomized 1:1 to receive pirtobrutinib (200 mg orally, once daily) or ibrutinib (420 mg orally, once daily). The primary endpoint is ORR as assessed by blinded IRC. Secondary endpoints include investigator and IRC-assessed PFS, duration of response (DoR) and event-free survival (EFS), and time to next treatment (TTNT), OS, safety and tolerability, and patient-reported outcomes (PRO).
About Jaypirca (pirtobrutinib)
Jaypirca (pirtobrutinib, formerly known as LOXO-305) (pronounced jay-pihr-kaa) is a highly selective (300 times more selective for BTK versus 98% of other kinases tested in preclinical studies), non-covalent (reversible) inhibitor of the enzyme BTK.1 BTK is a validated molecular target found across numerous B-cell leukemias and lymphomas including mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL).2,3 Jaypirca is a U.S. FDA-approved oral prescription medicine, 100 mg or 50 mg tablets taken as a once-daily 200 mg dose with or without food until disease progression or unacceptable toxicity.
About Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma
Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are forms of slow-growing non-Hodgkin lymphoma that develop from white blood cells known as lymphocytes.4 CLL is one of the most common types of leukemia in adults.4 In the U.S., CLL accounts for about one-quarter of the new cases of leukemia and there will be approximately 23,690 new cases of CLL diagnosed this year.4,5 SLL is identical to CLL from a pathologic and immunophenotypic standpoint, with the main difference between them being the location of the cancer cells.4 In CLL, the cancer cells are present in the blood, and in SLL, the cancer cells are found in the lymph nodes.4
About Lilly
Lilly is a medicine company turning science into healing to make life better for people around the world. We've been pioneering life-changing discoveries for nearly 150 years, and today our medicines help tens of millions of people across the globe. Harnessing the power of biotechnology, chemistry and genetic medicine, our scientists are urgently advancing new discoveries to solve some of the world's most significant health challenges: redefining diabetes care; treating obesity and curtailing its most devastating long-term effects; advancing the fight against Alzheimer's disease; providing solutions to some of the most debilitating immune system disorders; and transforming the most difficult-to-treat cancers into manageable diseases. With each step toward a healthier world, we're motivated by one thing: making life better for millions more people. That includes delivering innovative clinical trials that reflect the diversity of our world and working to ensure our medicines are accessible and affordable.
Endnotes & References
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Mato AR, Shah NN, Jurczak W, et al. Pirtobrutinib in relapsed or refractory B-cell malignancies (BRUIN): a phase 1/2 study. Lancet. 2021;397(10277):892-901. doi:10.1016/S0140-6736(21)00224-5
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Hanel W, Epperla N. Emerging therapies in mantle cell lymphoma. J Hematol Oncol. 2020;13(1):79. Published 2020 Jun 17. doi:10.1186/s13045-020-00914-1
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Gu D, Tang H, Wu J, Li J, Miao Y. Targeting Bruton tyrosine kinase using non-covalent inhibitors in B cell malignancies. J Hematol Oncol. 2021;14(1):40. Published 2021 Mar 6. doi:10.1186/s13045-021-01049-7
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Mukkamalla SKR, Taneja A, Malipeddi D, et al. Chronic Lymphocytic Leukemia. [Updated
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]. Cancer Stat Facts: Leukemia—Chronic Lymphocytic Leukemia (CLL). Accessed on September 3, 2025. https://seer.cancer.gov/statfacts/html/clyl.html