Arrowhead Stock Drops After RNAi Therapeutic Shows Lung Inflammation In Animal Models

Arrowhead Pharmaceuticals Inc ARWR has voluntarily paused the AROENaC1001 Phase 1/2 study evaluating ARO-ENaC for cystic fibrosis.
ARO-ENaC is the company's investigational RNA interference (RNAi) therapeutic.
The decision comes after receiving a preliminary update from an ongoing chronic toxicology study in rats that showed unexpected signals of local lung inflammation.
The company has instructed investigators to pause new screening, enrollment, and any further dosing pending additional data from the ongoing chronic rat toxicology study and another ongoing chronic primate toxicology study.
Price Action: ARWR shares are down 26.7% at $62.25 during the premarket session on the last check Friday.