Arrowhead Pharmaceuticals has dosed the first patient in the multiple ascending dose (MAD) portion of its ongoing phase I/II study of ARC-521, the company’s second RNAi-based investigational medicine for the treatment of chronic hepatitis B virus (HBV) infection. To date 24 healthy volunteers have been treated in the study, and the drug safety committee (DSC) approved initiation of the MAD after a planned review of safety data from cohort 3 of the healthy volunteer portion of the study. The MAD is designed to evaluate the safety, tolerability, and antiviral activity of single and multiple doses of ARC-521 in patients with chronic HBV.

Bruce Given, M.D., chief operating officer and head of R&D at Arrowhead said, “The innovative design for the first-in-man study of ARC-521 is intended to get to multiple dose data in patients rapidly. Arrowhead’s development staff and the experienced investigators working on the study are operating at best-in-class speeds, enabling us to begin the MAD portion of the study just three months into the clinical program. This study may have multiple readouts, including single dose safety data in healthy volunteers and single and multiple dose safety and antiviral activity data in HBV patients. These readouts should happen progressively, potentially starting during the first quarter of 2017.”

The MAD portion of the ARC-521 study (ARC5211001) is a multicenter, sequential, multiple dose, open label study in patients with chronic HBV. Up to 24 chronic HBV patients (eight patients per dose level) that are negative for Hepatitis B e-antigen (HBeAg) at screening will enroll sequentially into up to three dose levels (2mg/kg, 4mg/kg, 6mg/kg) to receive three monthly doses of open label ARC-521.