ETC-159

Biological Activity

ETC-159 is a potent, selective and orally available PORCN inhibitor, which inhibits β-catenin reporter activity with an IC50 of 2.9 nM. ETC-159 blocks the secretion and activity of all Wnts. ETC-159 has robust activity in multiple cancer models driven by high Wnt signaling.

ETC-159 is remarkably effective in treating RSPO-translocation bearing colorectal cancer (CRC) patient-derived xenografts. ETC-159 inhibits mouse PORCN with an IC50 of 18.1 nM, whereas the IC50 for Xenopus Porcn is approximately four fold higher (70 nM). ETC-159 exhibits good oral pharmacokinetics in mice allowing preclinical evaluation via oral administration. After a single oral dose of 5 mg/kg, ETC-159 is rapidly absorbed into the blood with a Tmax of ~0.5 h and oral bioavailability of 100%

Protocol

Cell Experiment
Cell lines	HEK293 cells, STF3A cells
Preparation method	HEK293 cells stably transfected with STF reporter and pPGK-WNT3A plasmid (STF3A cells) are treated with varying concentrations of compounds. For Wnt secretion, STF3A cells are treated with ETC-159 diluted in 1% fetal bovine serum-containing media.
Concentrations	100 nm
Incubation time	24 h

Animal Experiment
Animal models	Mice
Formulation	Formulated in 50% PEG400 (vol/vol) in water
Dosages	10 μL/g
Administration	oral gavage

Conversion of different model animals based on BSA (Value based on data from FDA Draft Guidelines)

Species	Mouse	Rat	Rabbit	Guinea pig	Hamster	Dog
Weight (kg)	0.02	0.15	1.8	0.4	0.08	10
Body Surface Area (m2)	0.007	0.025	0.15	0.05	0.02	0.5
Km factor	3	6	12	8	5	20

Animal A (mg/kg) = Animal B (mg/kg) multiplied by	Animal B Km
	Animal A Km

For example, to modify the dose of Compound A used for a mouse (20 mg/kg) to a dose based on the BSA for a rat, multiply 20 mg/kg by the K_m factor for a mouse and then divide by the K_m factor for a rat. This calculation results in a rat equivalent dose for Compound A of 10 mg/kg.

Chemical Information

References

Wnt addiction of genetically defined cancers reversed by PORCN inhibition.
Madan B, et al. Oncogene. 2016 Apr 28;35(17):2197-207. PMID: 26257057.