ARC-520: Development hold

Arrowhead said FDA verbally informed the company of a partial clinical hold of IV ARC-520 to treat chronic HBV infection. Arrowhead said the agency will allow the company to begin a multiple-dose study at 1 mg/kg ARC-520, instead of its proposed parallel study design of 2 and 4 mg/kg doses. FDA also requested final data from an ongoing single-dose Phase IIa trial in patients who received 1-4 mg/kg ARC-520 and final data from a multiple-dose non-clinical study. Arrowhead said neither study showed evidence of end-organ toxicity and that no serious adverse events were reported in the Phase IIa trial, which is evaluating the compound in hepatitis B e antigen (HBeAg)-negative patients receiving long-term Baraclude entecavir. The company expects an official letter from FDA in 30 days. ...