Arrowhead Pharmaceuticals has announced that Janssen has started dosing in a REEF-1 Phase IIb study of different combination regimens, including JNJ-3989, and/or JNJ-6379, and a nucleos(t)ide analogue (NA) to treat patients with chronic hepatitis B virus (HBV) infection.

Janssen paid Arrowhead $25m in milestone payment for the study.

The liver-targeted investigational antiviral therapeutic JNJ-3989 is designed as a subcutaneous infusion to treat chronic HBV infection through the ribonucleic acid interference (RNAi) mechanism.

The investigational drug is an orally administered capsid assembly modulator of the class that forms normal capsid structures (CAM-N).

Last October, Arrowhead signed a collaboration agreement with Janssen to develop and commercialise JNJ-3989, which was then ARO-HBV.

“We are thrilled that JNJ-3989, formerly ARO-HBV, is one of the agents being investigated.”

Arrowhead president and CEO Christopher Anzalone said: “Patients with chronic hepatitis B infection are in need of new medicines that improve functional cure rates with finite treatment regimens.

“We are thrilled that JNJ-3989, formerly ARO-HBV, is one of the agents being investigated in Janssen’s REEF-1 triple combination Phase IIb study.”

The Phase IIb, multi-centre, double-blind, randomised REEF-1 trial will evaluate the safety and efficacy of the combination regimens and placebo in patients identified with chronic HBV infection.

The study is intended to include around 450 patients who will be randomised to receive treatment for up to 48 weeks.

HBV infects the liver and causes infectious hepatitis. The disease spreads from person to person through sharing needles or syringes, sexual intercourse and from mother to baby during birth.

According to the World Health Organization (WHO), more than 292 million people worldwide have hepatitis B.