Project description:Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. While BTK inhibition does not impact humoral memory survival, antigen-driven clonal expansion of memory B cells and antibody secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of BTK inhibition. We used Affymetrix genechips to profile the transcriptional changes downstream of BTK inhibition after in vivo B-cell activation by anti-IgD Mice were injected with the novel BTK inhibitor PF-303 2 hours prior to anti-IgD mediated in vivo B-cell activation; B-cells where harvested 2 hours after anti-IgD activation and RNA isolated.
Project description:Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. While BTK inhibition does not impact humoral memory survival, antigen-driven clonal expansion of memory B cells and antibody secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of BTK inhibition. We used Affymetrix genechips to profile the transcriptional changes downstream of BTK inhibition after in vivo B-cell activation by anti-IgD
Project description:Purpose: to investigate the method of action (MOA) of BTK small molecule inhibitor, G7744, in a pre-clinical mouse lupus model (NZB/W F1). Hypothesis: BTK inhibition will affect B cell and myeloid cell pathways.
Project description:Inhibition of the B-cell receptor pathway, and specifically of Bruton tyrosine kinase (BTK), is a leading therapeutic strategy in chronic lymphocytic leukemia (CLL). Target occupancy has been measured as a pharmacodynamic parameter in clinical studies of covalent BTK inhibitors. However, the kinetics of BTK turnover, which determines occupancy, and the relationship between occupancy, pathway inhibition and clinical outcomes remains undefined. This randomized phase 2 study investigated the safety, efficacy, and pharmacodynamics of a selective BTK inhibitor acalabrutinib at 100 mg twice daily or 200 mg once daily in 48 patients with relapsed/refractory or high-risk treatment naïve CLL. Acalabrutinib was well tolerated and yielded an overall response rate (ORR) of partial response or better of 95.8% (95% CI 78.9%, 99.9%) and an estimated progression-free survival (PFS) rate at 24 months of 91.5% (95% CI 70.0%, 97.8%) with twice daily dosing and an ORR of 79.2% (95% CI 57.9%, 92.9%) and an estimated PFS rate at 24 months of 87.2% (95% CI 57.2%, 96.7%) with once daily dosing. BTK resynthesis was faster in CLL than in healthy volunteers. Twice daily dosing maintained higher BTK occupancy and achieved more potent pathway inhibition compared to once daily dosing. Additional follow-up is required to address the impact of dosing schedule and BTK occupancy on long-term clinical outcomes.
Project description:We used the cuprizone mouse model of multiple sclerosis to determine whether Bruton's tyrosine kinase (BTK) inhibition could attenuate disease-relevant changes to central nervous system gene expression.
Project description:We used the MOG35-55 peptide induction experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis to determine whether Bruton's tyrosine kinase (BTK) inhibition could attenuate disease-relevant changes to central nervous system gene expression.
Project description:We used the MOG35-55 peptide induction experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis to determine whether Bruton's tyrosine kinase (BTK) inhibition could attenuate disease-relevant changes to central nervous system gene expression.
Project description:We describe a previously unappreciated role for Bruton's tyrosine kinase (BTK) in fungal immune surveillance against aspergillosis, an unforeseen complication of BTK inhibitors (BTKi) used for treating B-cell lymphoid malignancies. We studied BTK-dependent fungal responses in neutrophils from diverse populations, including healthy donors, BTKi-treated patients, and X-linked agammaglobulinemia patients. Upon fungal exposure, BTK was activated in human neutrophils in a TLR2-, Dectin-1-, and FcgR-dependent manner, triggering the oxidative burst. BTK inhibition selectively impeded neutrophil-mediated damage to Aspergillus hyphae, primary granule release, and the fungus-induced oxidative burst by abrogating NADPH oxidase subunit p40phox and GTPase RAC2 activation. Moreover, neutrophil-specific Btk deletion in mice enhanced aspergillosis susceptibility by impairing neutrophil function, not recruitment nor lifespan. Conversely, GM-CSF partially mitigated these deficits by enhancing p47phox activation. Our findings underline the crucial role of BTK signaling in neutrophils for antifungal immunity and provide a rationale for GM-CSF use to offset these deficits in susceptible patients.