ALK5 inhibitor
BI-4659
BI-4659 is a potent ALK5 (TGFβ receptor I) inhibitor (IC50 = 19 nM). This compound showed good selectivity against a broad panel of other kinases. BI-4659 is able to block the phosphorylation of SMAD2 and SMAD3 in cells and is a suitable tool for in vitro studies1. However, it is not suited for in vivo experiments due to the very high clearance observed in rats.
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Transforming growth factor β (TGFβ) is a pluripotent cytokine involved in the regulation of various biological processes such as cell proliferation, differentiation, migration, adhesion, apoptosis, and epithelial-to-mesenchymal transition (EMT). Therapeutic approaches to inhibit its signaling by targeting TGFβ receptor I (TGFβRI/ALK5) are discussed for the treatment of diseases such as Idiopathic Pulmonary Fibrosis (IPF) and cancer2,3,4.
Crystal structure of ALK5 complexed with a close analog of BI-4659 (PDB code 2X7O)1.
| PROBE NAME / NEGATIVE CONTROL | BI-4659 | BI-4101 |
| MW [Da, free base]a | 440.5 | 418.5 |
| Inhibition of ALK5 (Kinase Glow assay, IC50) [nM]b | 19 | >50000 |
| Inhibition of phosphorylation of SMAD2 and SMAD3 in HaCaT cells (EC50) [nM] | 185 | n.d. |
a For the salt form you will get, please refer to the label on the vial and for the molecular weight of the salt, please refer to the FAQs
b For detailed assay conditions see reference 1
| PROBE NAME / NEGATIVE CONTROL | BI-4659 | BI-4101 |
| logD @ pH 2/11 | 0.7 / 3.1 | n.d. |
| Solubility @ pH 6.8 [µg/mL] | 2 | n.d. |
| Solubility @ pH 4 [µg/mL] | 84 | n.d. |
| Solubility @ pH 2 [µg/mL] | 71 | n.d. |
| Caco-2 permeability AB @ pH 7.4 [*10-6 cm/s] | 8 | n.d. |
| Caco-2 efflux ratio | 6 | n.d. |
| Microsomal stability (human/mouse/rat) [% QH] | 26 / 23 / <22 | n.d. |
| hERG [inh. % @ 10 µM] | 38.5 | n.d. |
| hERG IC50 [µM] | >10 | n.d. |
| CYP 3A4 (IC50) [µM] | >50 | n.d. |
| CYP 2C8 (IC50) [µM] | >50 | n.d. |
| CYP 2C9 (IC50) [µM] | >50 | n.d. |
| CYP 2C19 (IC50) [µM] | >50 | n.d. |
| CYP 2D6 (IC50) [µM] | >50 | n.d. |
BI-4659 showed very high clearance in rat and therefore is not suited for in vivo studies
| BI-4659 | Rat |
| Clearance [% QH] | 123 |
| Mean residence time after i.v. dose [h]a | 1.7 |
| tmax [h]b | 3.3 |
| Cmax [nM]b | 27.7 |
| F [%]b | 50 |
| Vss [L/kg]a | 9 |
a i.v. dose: 4.5 mg/kg
b p.o. dose: 45 mg/kg
BI-4101 shows no inhibition of ALK5 in the Kinase Glow assay (IC50 > 50 µM) and therefore is a suitable negative control for in vitro experiments1.(BI-4101 = Compound 48 in reference 1)
BI-4101 which serves as a negative control
BI-4659 shows good selectivity in kinase panels. The compound shows no inhibition of 218/232 kinases tested at 2 µM. Cross-reactive kinases (%inhibition data at 0.2 µM): ABL1 (67), BLK (85), CSF1R (FMS) (82), FGR (91), FLT3 (66), FYN (74), LCK (100), LYN A (79), LYN (78), MAP4K5 (KHS1) (77), MELK (80), NTRK3 (TRKC) (78), RET (79), SNF1LK2 (96), YES1 (90).
| SELECTIVITY DATA AVILABLE | BI-4659 | BI-4101 |
SafetyScreen44™ with kind support of  | Yes | Yes |
| Invitrogen® | Yes | No |
| DiscoverX® | Yes | No |
| Dundee | Yes | No |
Download selectivity data:
BI-4659_selectivityData_0.xlsx
BI-4101_selectivityData.xlsx
No in-house structure is available for BI-4659, but for related compound (PDB code 2x7o).
SB-505124, SB-525334, GK6604, SD-208, LY-2157299, EW-7197, GW788388 and others. For a review on ALK5 kinase inhibitors in oncology see reference 5.
BI-4659 inhibits ALK5 with an IC50 value of 19 nM and blocks the cellular phosphorylation of SMAD2/SMAD3 with an EC50 of 185 nM. BI-4659 is a suitable tool for testing biological hypotheses in vitro.
Inhibition of TGF- Signaling for the Treatment of Tumor Metastasis and Fibrotic Diseases
Fuchs O.
Current Signal Transduction Therapy 2011, 6, 29-43.
Phenocopy – A Strategy to Qualify Chemical Compounds during Hit-to-Lead and/or Lead Optimization
Baum P., Schmid R., Ittrich C., Rust W., Fundel-Clemens K., Siewert S., Baur M., Mara L., Gruenbaum L., Heckel A., Eils R., Kontermann R. E., Roth G. J., Gantner F., Schnapp A., Park J. E., Weith A., Quast K., Mennerich D.
PLoS One 2010, 5, e14272.
When you plan a publication, please use the following acknowledgement:
BI-4659 was kindly provided by Boehringer Ingelheim via its open innovation platform opnMe, available at https://www.opnme.com.