Following investigation of the drug delivery vehicle Ex1, patient recruitment for Arrowhead Pharmaceuticals’ ongoing ARC-520, ARC-521, and ARC-AAT trials has been halted.
The products in question are RNAi based therapies being examined for chronic Hepatitis B infection (Ph I for ARC-520 & Phase IIb for ARC-521) and alpha-1 antitrypsin deficiency (ARC-AAT).
The decision comes after an investigation into the deaths of non-human primates in a toxicological dosing study of Ex1, reported earlier this month.
Ex1 is Arrowhead’s proprietary synthetic dynamic polyconjugate (DPC) iv drug delivery vehicle.
Instead, the firm has announced a switch of development priority from Ex1 to subcutaneous (subQ) and extra-hepatic delivery methods.
In a statement, the firm claims the decision is because it believes there will be a regulatory delay for Ex1. It also claimed its partnership deal with Amgen on some of the other ARC products will not be affected.
The firm’s stocks have dropped over 28% since the investigation announcement on Nov 8, and following as of today 30% of workforce at Arrowhead has also been let go.