Healthcare Business

Why This Interim Liver Study Is Huge for Arrowhead Pharma

Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) has announced positive interim 24-week liver biopsy results in four subjects from its midstage study of ARO-AAT. Shares rallied on the news early Wednesday.

ARO-AAT is the firm’s second-generation investigational RNA interference (RNAi) therapeutic being developed as a treatment for the rare genetic liver disease associated with alpha-1 antitrypsin deficiency.

The results demonstrated clear evidence of a meaningful pharmacodynamic effect by ARO-AAT, leading to improvements in relevant biomarkers, including substantial reductions in intra-hepatic mutant AAT protein (Z-AAT), both Z-AAT monomer and Z-AAT polymer; improvements in liver stiffness based on FibroScan; and, a decrease in alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), both serum biomarkers of liver injury.

After 24 weeks of treatment with ARO-AAT in the study, serum and total intra-hepatic Z-AAT decreased in all four patients by up to 93% and 95%, respectively. Three of four patients demonstrated reductions from baseline in intra-hepatic Z-AAT polymer, with a maximum reduction of 97%. All four patients showed reductions in ALT and GGT, with maximum reductions of 66% and 58%, respectively. All patients demonstrated improved transient elastography FibroScan values, with three of four patients exhibiting greater than 20% reductions.

Management noted that these are very exciting results so far and they provide the firm with increased confidence in the potential of this program. Based on these results, Arrowhead is actively assessing its clinical and regulatory path forward, including meeting with the U.S. Food and Drug Administration and other regulatory agencies, to identify areas in which the program could potentially be streamlined and accelerated.

Arrowhead Pharmaceuticals stock traded up more than 30% early Wednesday to $44.00, in a 52-week range of $19.51 to $73.72. The consensus price target is $64.27.