Indianapolis, Indiana, U.S., October 2, 2026
Eli Lilly and Company announced that the U.S. Food and Drug Administration (FDA) has approved Jaypirca® (pirtobrutinib) as the first and only non-covalent Bruton’s tyrosine kinase (BTK) inhibitor specifically approved for adult patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who have received at least one prior line of therapy containing a covalent BTK inhibitor. The approval represents an important development in the treatment of CLL/SLL, particularly for patients whose disease has progressed following treatment with a covalent BTK inhibitor. Jaypirca is designed to bind BTK differently from covalent BTK inhibitors, potentially allowing continued targeting of the BTK pathway even when resistance develops through certain mechanisms. The FDA decision expands the clinical role of pirtobrutinib in B-cell malignancies and strengthens Lilly’s hematology portfolio.
Jaypirca Targets BTK Through a Different Mechanism
Pirtobrutinib is a highly selective, non-covalent BTK inhibitor. Unlike covalent BTK inhibitors, which bind irreversibly to BTK, pirtobrutinib binds reversibly to the enzyme. This distinction is important because certain genetic changes in BTK can interfere with the binding of covalent inhibitors and contribute to treatment resistance. By using a different binding mechanism, Jaypirca can continue inhibiting BTK activity in settings where covalent BTK inhibition may no longer provide adequate disease control. This mechanism has made non-covalent BTK inhibition an important area of research in hematologic cancers. CLL and SLL are B-cell blood cancers characterized by the abnormal accumulation of lymphocytes. Although treatment advances have significantly improved outcomes for many patients, disease progression following targeted therapy remains an important clinical challenge. The availability of another BTK-targeting strategy provides physicians with an additional treatment option for appropriately selected patients. The new FDA approval therefore represents a significant milestone for Lilly’s Jaypirca development program and for patients with previously treated CLL/SLL.
Clinical Evidence Supports FDA Approval
The approval was supported by clinical data evaluating Jaypirca in patients with previously treated CLL/SLL, including patients whose disease had progressed following treatment with a covalent BTK inhibitor. The clinical evidence demonstrated the ability of pirtobrutinib to provide antitumor activity in this treatment setting. The development program is particularly important because patients who experience progression after covalent BTK inhibitor therapy may have limited treatment options. The ability to selectively inhibit BTK through a non-covalent mechanism provides a potential strategy for maintaining pathway inhibition after resistance or intolerance to previous BTK-directed treatment. The FDA decision also builds on the broader clinical development of pirtobrutinib across B-cell malignancies. Jaypirca has been evaluated in several hematologic cancers, including mantle cell lymphoma and CLL/SLL, supporting Lilly’s efforts to develop the medicine across multiple patient populations. As with all cancer therapies, treatment decisions depend on individual patient characteristics, prior therapies, disease status, and the physician’s clinical judgment.
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Lilly Advances Hematology Treatment Portfolio
The approval strengthens Lilly’s position in hematology and demonstrates the company’s continued investment in targeted therapies for blood cancers. Jaypirca’s mechanism provides an important addition to the expanding range of precision medicines being developed for B-cell malignancies. The growing understanding of molecular mechanisms responsible for treatment resistance is also changing the development of cancer therapies. Rather than relying solely on broader cytotoxic approaches, researchers are increasingly designing medicines to target specific signaling pathways that cancer cells depend upon for survival and proliferation.
For CLL/SLL, BTK remains an important therapeutic target, and the development of non-covalent inhibitors represents a significant evolution in BTK-directed treatment. Jaypirca’s FDA approval provides another option for patients who have previously received a covalent BTK inhibitor and whose disease requires additional therapy. The approval highlights the continued progress of precision oncology and targeted hematology medicines, while reinforcing the importance of developing therapies capable of addressing treatment resistance. For patients with previously treated CLL/SLL, Jaypirca could provide a meaningful new therapeutic option as physicians seek effective approaches for managing disease progression.
Source: Eli Lilly press release
