26 April 2019 - - US-based Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) has begun dosing in a new triple combination cohort (cohort 12) that includes JNJ-3989 (formerly ARO-HBV) and additional undisclosed agents selected by Janssen Pharmaceuticals, Inc. in its ongoing Phase 1/2 study (AROHBV1001) in patients with chronic hepatitis B virus, the company said.

In connection with the start of this new cohort, Arrowhead has earned a USD 25m milestone payment from Janssen Pharmaceuticals, Inc., part of the Janssen Pharmaceutical Companies of Johnson and Johnson.

AROHBV1001 (NCT03365947) is a Phase 1/2 clinical study evaluating the safety, tolerability, and pharmacokinetic effects of single-ascending doses of ARO-HBV in healthy adult volunteers, as well as the safety, tolerability, and pharmacodynamic effects of multiple-ascending doses of ARO-HBV in patients with chronic HBV.

Arrowhead entered into a license and collaboration agreement with Janssen in October 2018 to develop and commercialise ARO-HBV.

Under the initial terms of the HBV license agreement, Arrowhead was eligible to receive a USD 50m milestone payment linked to a Phase 2 study.

Arrowhead and Janssen subsequently amended the HBV license agreement to accelerate the payment of USD 25m of the USD 50m Phase 2 milestone with the initiation of cohort 12 of the AROHBV1001 trial. Arrowhead is eligible to receive the remaining USD 25m upon the initiation of a Phase 2 study by Janssen.

Hepatitis B infection is a life-threatening viral infection of the liver, which can cause cirrhosis, scarring of liver tissue, and liver cancer if the infection becomes chronic.

The World Health Organization cites that hepatitis B is a global public health problem with 257m people living with the disease, resulting in 887,000 deaths in 2015.

While a preventive vaccine is available, cure rates for those infected remain low and most patients will endure lifelong therapy.

Arrowhead Pharmaceuticals develops medicines that treat intractable diseases by silencing the genes that cause them.

Using a portfolio of RNA chemistries and efficient modes of delivery, Arrowhead therapies trigger the RNA interference mechanism to induce rapid, deep, and durable knockdown of target genes.

RNA interference, or RNAi, is a mechanism present in living cells that inhibits the expression of a specific gene, thereby affecting the production of a specific protein.

Arrowhead's RNAi-based therapeutics leverage this natural pathway of gene silencing.