Emricasan (PF 03491390; IDN-6556) is orally active that is retained in the liver for prolonged period of time. TUNEL-positive cells are considerably increased by five-fold in mice fed a HFD and are reduced under Emricasan treatment. In accordance with this observation caspase-3 and -8 are increased in HFD-fed mice by 1.5- and 1.3-fold respectively and are significantly decreased by Emricasan treatment.
When comparing efficacy by multiple routes of administration, Emricasan is administered i.p., p.o., i.m., or i.v. (0.03-3 mg/kg). Caspase 3-like activities, measured as DEVD-AMC cleavage, dose dependently decreased with a 92.5% reduction after the highest dose of Emricasan (3 mg/kg). Emricasan is initially tested in the α-Fas model of liver injury, marked hepatocellular apoptosis, and peak ALT activities within 6 h. Emricasan is administered i.p. immediately after administration of α-Fas, ALT activities, measured 6 h later, decreased in a dose-dependent manner with an ED50 value of 0.08 (0.06-0.12) mg/kg.
Emricasan is a highly selective pan-caspase inhibitor demonstrating irreversible inhibition and a significant first-pass effect. In both syngeneic mouse islets and human islets transplanted into immunodeficient mice, Emricasan (i.p., 20 mg/kg) given for 7 days post-transplant led to a significantly enhanced rate of diabetes reversal as compared to vehicle.