LOXO-305 is an investigational, novel, selective non-covalent Bruton’s tyrosine kinase (BTK) inhibitor. BTK plays a key role in the B-cell antigen receptor signaling pathway, which is required for the development, activation and survival of normal white blood cells known as B-cells and malignant B-cells. BTK is a validated molecular target found across numerous B-cell leukemias and lymphomas including chronic lymphocytic leukemia, Waldenstrom’s macroglobulinemia, mantle cell lymphoma and marginal zone lymphoma.

Currently available BTK inhibitors irreversibly inhibit BTK and the long-term efficacy of these therapies has been limited by acquired resistance and intolerance, due to off target inhibition of other cellular targets.[1],[2] LOXO-305 was designed to reversibly bind BTK, preserve activity in the presence of the acquired resistance, and avoid off-target kinases that have complicated the development of both covalent and investigational non-covalent BTK inhibitors.

LOXO-305 is currently being studied in a global Phase 1/2 clinical trial.

For more information about the LOXO-305 clinical trial, please refer to Interested patients and physicians can contact the Loxo Oncology Physician and Patient BTK Clinical Trial Hotline at 1-855-LOXO-305 or email

[1] Woyach, Amy D, et al. BTK C481S-Mediated Resistance to Ibrutinib in Chronic Lymphocytic Leukemia J Clin Oncol. 2015; 35:1437-1443.

[2] Mato, Anthony R., et al. Toxicities and outcomes of 616 ibrutinib-treated patients in the United States: a real-world analysis. Haematologica. 2018; 103(5):874-879