Vertex Pharmaceuticals (NASDAQ:VRTX) has slipped 7.9% after new that it's discontinuing its Phase 2 study of VX-814 and dropping development.
That's based on safety and pharmacokinetic data, the company says.
The study of about 50 patients was designed to evaluate safety/PK in VX-814 and its ability to increase functional levels of alpha-1 antitrypsin over 28 days of dosing.
"Elevated liver enzymes (AST/ALT) were observed in several patients," Vertex says. "In four patients, across different doses studied, elevations greater than 8 times the upper limit of normal were noted; the elevated liver enzymes have either resolved or are resolving."
The company concluded that it's not feasible to safely reach targeted exposure levels (and thus meaningful increases in AAT levels).
A Phase 2 trial of VX-864 - structurally distinct from VX-814 - is still ongoing after its July start, the company says. It also continues to advance multiple small molecule correctors in late stage research with a goal of advancing at least one additional molecule into development in 2021.
Updated 4:55 p.m.: Arrowhead Pharmaceuticals (NASDAQ:ARWR) - also focused on liver diseases associated with alpha-1 antitrypsin deficiency - is up 14.9% after hours.