NVP-BSK805 trihydrochloride trihydrochloride is an ATP-competitive JAK2 inhibitor, with IC50s of 0.48 nM, 31.63 nM, 18.68 nM, and 10.76 nM for JAK2 JH1 (JAK homology 1), JAK1 JH1, JAK3 JH1, and TYK2 JH1, respectively[1].
NVP-BSK805 is a selective, ATP-competitive (Ki = 0.43 nM) Janus kinase 2 (JAK2) inhibitor (IC50 = 0.58 and 0.56 nM against full-length wild-type and V617F JAK2, respectively) with greatly reduced potency against TYK2, JAK3, JAK1 (IC50 = 10.76, 18.68, 31.63 nM against respective JAK homology domain 1) and >300-fold selectivity over a panel of 36 other kinases. BSK805 potently inhibits STAT5 phosphorylation (by >90% at 100 nM; MB-02 & SET-2 cells) and proliferation in JAK2V617F mutant cultures in vitro (GI50= 39-331 nM; 75% SET-2 growth inhibition at 150 nM) and in Ba/F3 JAK2V617F-bearing mice in vivo (150 mg/kg p.o.). BSK805 daily oral administration is also efficacious against rhEpo-induced splenomegaly and polycythemia in mice (50-100 mg/kg) and rats (25-50 mg/kg) with good pharmacokinetics and oral avilability.
NVP-BSK805 trihydrochloride (BSK 805; 150 mg/kg, p.o.) blocks STAT5 phosphorylation, splenomegaly, and leukemic cell spreading in a Ba/F3 JAK2V617F cell-driven mouse model[1].
NVP-BSK805 trihydrochloride (50, 75, and 100 mg/kg, p.o.) also suppresses rhEpo-mediated polycythemia and splenomegaly in BALB/c mice[1].
JAK2 JH1: 0.48 nM (IC50); JAK2(V617F): 0.56 nM (IC50); FL JAK2 wt: 0.58 nM (IC50); TYK2 JH1: 18.68 nM (IC50); JAK1 JH1: 31.68 nM (IC50)
[1] Baffert F, et al. Potent and selective inhibition of polycythemia by the quinoxaline JAK2 inhibitor NVP-BSK805. Mol Cancer Ther. 2010 Jul;9(7):1945-55. DOI:
10.1158/1535-7163.MCT-10-0053[2] [2].Cheon JH, et al. The JAK2 inhibitors CEP-33779 and NVP-BSK805 have high P-gp inhibitory activity and sensitize drug-resistant cancer cells to vincristine. Biochem Biophys Res Commun. 2017 Sep 2;490(4):1176-1182. DOI:
10.1016/j.bbrc.2017.06.178
