Arrowhead Pharma Reveals Data It Hopes Will Aid New Hepatitis B Drug

Xconomy Wisconsin — 

Arrowhead Pharmaceuticals (NASDAQ: ARWR) suffered a major setback last year after it canceled the development of three experimental drug candidates for liver disease.

On Wednesday, Pasadena, CA-based Arrowhead—which houses its research and development operations in Madison, WI—shared data from a study involving one of the canceled drug candidates that the company believes could bode well for a new compound it’s since begun developing.

The data Arrowhead made public on Wednesday were from a Phase 2 clinical trial of ARC-520, which is aimed at treating chronic hepatitis B virus (HBV). Arrowhead terminated the partially completed study after it canceled development of ARC-520. The decision to cancel followed an announcement from the FDA that it was putting the trial on hold due to deaths of nonhuman primates in a separate study. However, investigators continued to monitor and gather data about the health of human patients who participated in the ARC-520 trial for seven months afterward, according to a spokesperson for Arrowhead.

The company thinks results from certain patients could augur well for its newest form of viral treatment, ARO-HBV, which hasn’t yet been studied clinically. However, a word of caution: the data aren’t directly connected to the new compound and at this point Arrowhead’s comments are speculative.

Arrowhead is among the companies attempting to develop drugs using RNA interference (RNAi), which involves shutting down, or “silencing” a gene before it can make a potentially harmful protein.

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

Arrowhead said Wednesday that researchers observed a reduction in markers that indicate the presence of HBV among patients who participated in the Phase 2 trial of ARC-520. Those markers included HBV surface antigens and alanine aminotransferase enzymes in the liver, the company said. Taken together, the data “indicate that multiple doses of an RNAi-based therapy may lead to a host response that is sustained after therapy is concluded,” Arrowhead said in a press release.

Bruce Given, Arrowhead’s chief operating officer, said in a prepared statement the data give his company hope that its new RNAi-based drug compound, ARO-HBV, could prove to be effective in treating chronic HBV. The goal with ARO-HBV is to mute the production of all HBV genes so that a patient’s immune system can reconstitute, Arrowhead said.

Arrowhead is developing ARO-HBV using a new type of RNAi drug delivery platform that it first discussed publicly in September. It’s using the platform—known as Targeted RNAi Molecule, or TriM—to develop drugs for chronic HBV, cardiovascular disease, and other conditions.

The company said it plans to have the agreements that are necessary to begin clinical studies of ARO-HBV in place by June of 2018.