(±)-Zanubrutinib is a potent, selective and orally available Bruton's tyrosine kinase (Btk) inhibitor.
In both biochemical and cellular assays, (±)-Zanubrutinib demonstrates nanomolar Btk inhibition activity. In several MCL and DLBCL cell lines, (±)-Zanubrutinib inhibits BCR aggregation-triggered Btk autophosphorylation, blocks downstream PLC-γ2 signaling, and potently inhibits cell proliferation. In comparison with ibrutinib, (±)-Zanubrutinib shows much more restricted off-target activities against a panel of kinases, including ITK. (±)-Zanubrutinib is at least 10-fold weaker than ibrutinib in inhibiting rituximab induced ADCC, consistent with its weak ITK inhibition activity[1].
(±)-Zanubrutinib induces dose-dependent anti-tumor effects against REC-1 MCL xenografts engrafted either subcutaneously or systemically via tail vein injection in mice. In the subcutaneous xenografts. Preliminary 14-day toxicity study in rats shows that (±)-Zanubrutinib is very well tolerated and maximal tolerate dose (MTD) is not reached when it is dosed up to 250mg/kg/day[1].
[1]. Na L, et al. BGB-3111 is a novel and highly selective Bruton's tyrosine kinase (BTK) inhibitor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2597. doi:10.1158/1538-7445.AM2015-2597