ACT-709478 is a potent, selective T-type calcium channel blocker that is orally active and capable of penetrating the brain. It is currently utilized in research focusing on generalized epilepsies[1].

Cav 3.3:7.5 nM, Cav 1.2:2410 nM, Cav 3.1:6.4 nM, Cav 3.2:18 nM

ACT-709478 (Compound 66b) blocks Cav3.1, Cav3.2, Cav3.3, Cav1.2 with IC50s of 6.4, 18, 7.5 and 2410 nM, respectively. ACT-709478 blocks recombinant channel hCav3.3 potently with marked voltage-dependency (Kr≈1500 nM and Ki≈20 nM). ACT-709478 blocks currents through hKv11.1-hERG channels with an IC50 of 5.5 μM[1]. ACT-709478 also inhibits P450 enzymes with IC50s of 14, 15, 22, 25, 51 and 52 μM for CYP2C8,CYP2D6 CYP2C9, CYP2C19, CYP3A4, and CYP2B6, respectively[1].

ACT-709478 ( 100, 300 mg/kg, p.o., 12 hours) can decreas the cumulative duration of absence-like seizures in mice[1].