TAK-659 hydrochloride is a potent, selective and orally available spleen tyrosine kinase (Syk) inhibitor with an IC50 of 3.2 nM.
In a cell proliferation assay, TAK-659 shows inhibition toward a SYK-dependent cell line (OCILY10). TAK-659 is shown to be sensitive toward FLT3-ITD dependent cell lines, MV4-11 and MOLM-13 while the WT FLT3 RS4-11 (ALL cell line) and RA1 (Burkitt’s Lymphoma cell line) are not sensitive toward TAK-659. The sensitivity to TAK-659 is associated with mutations impacting SYK activity in B cell lymphomas, whereas TAK-659 is not cytotoxic for adherent primary or solid tumor cell lines[1]. TAK-659 inhibits the microenvironment-induced activation of Syk and downstream signaling molecules, without inhibiting the protein homologue ZAP-70 in T cells. Importantly, the pro-survival, proliferative, chemoresistant and activation effects promoted by the microenvironment are abrogated by TAK-659, which furthermore blocks CLL cell migration toward BMSC, CXCL12, and CXCL13[2].
TAK-659 is currently undergoing Phase I clinical trials for advanced solid tumor and lymphoma malignancies, a Phase Ib study in advanced solid tumors in combination with nivolumab, and PhIb/II trials for relapsed/refractory AML. TAK-659 blocks anti-IgD (immune-globulin D antibody) stimulated CD86 expression in mouse peripheral B cells in vivo. In the OCI-LY10 xenograft and DLBCL PHTX-95L (primary human tumor graft from DLBCL patient) mouse models, TAK-659 demonstrates potent tumor growth inhibition (TGI) after 20 days of treatment. In the FLT3-dependent MV4-11 xenograft model, TAK-659 shows tumor regression at 60 mg/kg daily after 20 days of dosing[1].
References:
[1]. Lam B, et al. Discovery of TAK-659 an orally available investigational inhibitor of Spleen Tyrosine Kinase (SYK). Bioorg Med Chem Lett. 2016 Dec 15;26(24):5947-5950.
[2]. Purroy N, et al. Inhibition of BCR signaling using the Syk inhibitor TAK-659 prevents stroma-mediated signaling in chronic lymphocytic leukemia cells. Oncotarget. 2017 Jan 3;8(1):742-756.