Ultragenyx rises after FDA clears human trial for rare muscle disease drug

Shares of drugmaker Ultragenyx Pharmaceutical RARE.O rise 2% to $19.76 premarket

Co says U.S. FDA cleared its application to start human testing of UX016 for GNE myopathy, a rare inherited muscle disease that causes worsening muscle weakness and disability

There are no approved treatments for the condition, which affects about 10,000 people in commercially accessible markets, co says

Co plans an early- to mid-stage trial starting in 2H 2026, enrolling about 24 adults in the United States

UX016 aims to replace sialic acid, a sugar patients cannot make enough of, and is designed to better reach muscle tissue - RARE

Trial will run for up to 48 weeks and is funded through patient groups and philanthropic support, co says

Shares fell ~45% in 2025