Inarigivir (ORI-9020) is a dinucleotide that can significantly reduce liver HBV DNA.

Inarigivir (100 mg/kg/day, I.p.) significantly reduces viral DNA in the liver and shows anti-HBV activity similar to ADV positive control. Inarigivir does not affect levels of HBV RNA in the liver, levels of HBeAg in serum, or mean titers of HBsAg. The minimal effective dose is identified to be between 1.6 and 0.5 mg/kg/day using liver HBV DNA values.

For the first animal experiment, Inarigivir is prepared fresh daily at a dosage of 100 mg/kg of body weight /day, which is equal to 170 mol/kg/day and is injected intraperitoneally (i.p.) using cremaphor-ethanol-saline (CES) (10:10:80) or physiological saline as vehicles. ADV, the positive control, is prepared using the CES vehicle. A dosage of 10 mg/kg/day (19.9 mol/kg/day) is used. In the second experiment to determine the minimal effective concentration, Inarigivir is prepared in sterile saline in onehalf-log dilutions from 50 to 0.05 mg/kg/day. The drug is delivered i.p. in a volume of 0.1 ml. Liver samples are analyzed for HBV DNA, HBV RNA, and HBcAg, and serum samples are processed for HBV DNA, HBeAg, and HBsAg.