Rebastinib

• CAT Number: I000144
• CAS Number: 1020172-07-9
• Molecular Formula: C30H28FN7O3
• Molecular Weight: 553.59
• Purity: ≥95%
• Synonyms: 4-[4-[(5-tert-butyl-2-quinolin-6-ylpyrazol-3-yl)carbamoylamino]-3-fluorophenoxy]-N-methylpyridine-2-carboxamide
• InChI: InChI=1S/C30H28FN7O3/c1-30(2,3)26-17-27(38(37-26)19-7-9-23-18(14-19)6-5-12-33-23)36-29(40)35-24-10-8-20(15-22(24)31)41-21-11-13-34-25(16-21)28(39)32-4/h5-17H,1-4H3,(H,32,39)(H2,35,36,40)
• InChIKey: WVXNSAVVKYZVOE-UHFFFAOYSA-N
• SMILES: CC(C)(C)C1=NN(C(=C1)NC(=O)NC2=C(C=C(C=C2)OC3=CC(=NC=C3)C(=O)NC)F)C4=CC5=C(C=C4)N=CC=C5

Rebastinib (DCC-2036) is an orally active, non-ATP-competitive Bcr-Abl inhibitor for Abl1WT and Abl1T315I with IC50s of 0.8 nM and 4 nM, respectively. Rebastinib also inhibits SRC, KDR, FLT3, and Tie-2, and has low activity to seen towards c-Kit.
Rebastinib potently (IC50 0.82 nM) inhibits u-ABL1native, which is thought to exist predominantly in the inactive type II conformation. In addition, Rebastinib also strongly inhibits p-ABL1native (IC50 2 nM), which more readily adopts an active, Type I conformation[1].
Rebastinib potently inhibits both u-ABL1T315I (IC50 5 nM) and p-ABL1T315I (IC50 4 nM), both of which exist predominately in the Type I conformation due to stabilization of an activating hydrophobic spine by the T315I mutation[1].
In addition to ABL1, Rebastinib also inhibits the SRC family kinases LYN, SRC, FGR, and HCK, and PDGFRα, and PDGFRβ with IC50 of 29±1, 34±6, 38±1, 40±1, 70±10 and 113±10 nM, respectively. Notably, Rebastinib spared c-KIT (IC50 481 nM)[1].
Rebastinib effectively inhibits the proliferation of Ba/F3 cells expressing native BCR-ABL1native (IC50 5.4 nM). Rebastinib also inhibits proliferation of the Ph+ cell line K562 (IC50 5.5 nM)[1].
Rebastinib also inhibits proliferation of several common TKI-resistant mutants of BCR-ABL1, including G250E, Q252H, Y235F, E255K, V299L, F317L, and M351T, at IC50s ranging from 6-150 nM. Rebastinib effectively inhibits autophosphorylation of BCR-ABL1native (IC50 29 nM) and BCR-ABL1T315I (IC50 18 nM), as well as the phosphorylation of STAT5 in both cell lines (IC50 28 nM and 13 nM, respectively)[1].
A single dose of Rebastinib (DCC-2036; oral; 100 mg/kg) affords circulating plasma levels that exceeds 12 μM for up to 24 hours, and effectively inhibits BCR-ABL1 signaling for up to 8 hours in Ba/F3-BCR-ABL1T315I leukemia cells isolated from BM and spleen of tumor-bearing mice[1].
Treatment of mice bearing Ba/F3-BCR-ABL1T315I leukemia cells with Rebastinib at 100 mg/kg once daily by oral gavage significantly prolonged their survival, while STI571 at 100 mg/kg twice daily is ineffective[1].
In this aggressive allograft model, Rebastinib is as effective for treatment of BCR-ABLT315I leukemia as STI571 at 100 mg/kg twice daily in BCR-ABL1native leukemia, and reduces the leukemia cell burden in the spleens of treated mice[1].

Reference

[1]. Chan WW, et al. Conformational control inhibition of the BCR-ABL1 tyrosine kinase, including the gatekeeper T315I mutant, by the switch-control inhibitor DCC-2036. Cancer Cell. 2011, 19(4), 556-568.
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