Arrowhead Plans Return to Clinic With New Study of Hep B Drug

Xconomy Wisconsin — 

Arrowhead Pharmaceuticals is back in the clinic.

On Thursday, Pasadena, CA-based Arrowhead—which houses its research and development operations in Madison, WI—said regulators cleared the company to initiate a clinical study of a drug it’s developing to treat chronic hepatitis B virus.

Arrowhead (NASDAQ: ARWR) said it expects to enroll about 60 patients in the Phase 1/2 study. They’ll begin receiving the drug, ARO-HBV, by the end of March, the company said.

Arrowhead said it received approval from the New Zealand Medicines and Medical Devices Safety Authority to proceed with the trial. It is slated to take place in that country’s largest city, Auckland. Arrowhead may later open sites in Australia and Hong Kong and conduct parts of the study there, according to a company spokesperson.

The World Health Organization estimates that 257 million people worldwide are living with hepatitis B virus (HBV) infection, a virus that can lead to cirrhosis and liver cancer. Arrowhead was previously developing a drug for chronic HBV, called ARC-520. But in late 2016, when the drug candidate was in mid-stage studies, the company canceled the development of ARC-520 and two other experimental drugs for liver diseases. The decision to cancel followed an announcement from the FDA that it was putting a Phase 2 clinical trial of ARC-520 on hold due to deaths of nonhuman primates in a separate study.

Arrowhead is among the companies attempting to develop therapies using RNA interference (RNAi), which involves shutting down, or “silencing” a gene before it can make a potentially harmful protein. Arrowhead said in December that its goal with ARO-HBV is to mute the production of all HBV genes so that a patient’s immune system can reconstitute.

Likewise, last fall, Cambridge, MA-based Alnylam Pharmaceuticals (NASDAQ: ALNY) said it planned to file for FDA approval of its drug, patisiran. Patisiran has the chance to become the first RNAi therapy ever to reach the market

Arrowhead said its upcoming study of ARO-HBV is aimed at evaluating the drug candidate’s safety and tolerability in different patient populations. The company said it plans to enroll two patient groups of roughly the same size in the trial. One group, made up of healthy people, will receive either a single dose of ARO-HBV or a placebo. The other group, composed of patients with chronic HBV, will receive three doses of the drug.

Arrowhead projects it will complete the study by March 2019.

Liver Drug Gets ‘Orphan’ Status

Separately, Arrowhead also announced Wednesday that the FDA granted the company orphan drug status for ARO-AAT, a pre-clinical RNAi therapy it’s developing.

The drug is designed to treat rare liver diseases associated with alpha-1 antitrypsin (AAT) deficiency. AAT deficiency is a genetic disorder that involves a mutation of the gene that encodes the AAT molecule. With this mutation, AAT gets trapped inside the liver cells that produce it, rendering the molecule unable to perform functions such as protecting the lungs from inflammation. That can increase the odds of developing lung disease, while the buildup of AAT proteins in the liver can also lead to disease in that organ.

An estimated 100,000 people in the U.S. have AAT deficiency. The FDA created its Orphan Drug Designation program to incentivize organizations to develop therapies for diseases or disorders that affect fewer than 200,000 Americans.

One of the drug candidates Arrowhead scrapped in 2016, ARC-AAT, was made to treat patients with AAT deficiency. ARC-AAT was designated as an orphan drug in the U.S. and in Europe before Arrowhead decided to stop developing it.

Other companies with AAT deficiency drugs in development include Israel-based Kamada (NASDAQ: KMDA) and Cambridge, MA-based Intellia Therapeutics (NASDAQ: NTLA), which is working to create treatments with CRISPR-Cas9 gene editing technology.