SMO-IN-4 (Compound 24) serves as a potent, orally active antagonist of smoothened, exhibiting an IC50 of 24 nM. It demonstrates antitumor activity [1].

SMO-IN-4 (10 µM) exhibits minimal inhibition across all CYP isoforms and shows low inhibition of hERG (IC 50 = 38 µM) [1].

In a murine model of medulloblastoma with subcutaneous xenografts in Ptch1 +/- mice, SMO-IN-4 administered orally at 50 mg/kg daily can lead to tumor regression [2]. The pharmacokinetic properties of SMO-IN-4 (Compound 24) are as follows [2]: In mice, a 10 mg/kg oral dose results in an AUC0-24h of 4183 ng·h/mL, Cmax of 4132 ng/mL, half-life of 1.0 hours, and bioavailability of 49%. In rats, the same oral dose yields an AUC0-24h of 5541 ng·h/mL, Cmax of 2180 ng/mL, half-life of 2.3 hours, and bioavailability of 62%. In dogs, a 5 mg/kg oral dose demonstrates an AUC0-24h of 7656 ng·h/mL, Cmax of 1300 ng/mL, half-life of 5.4 hours, and bioavailability of 72%.