Ultragenyx hit with FDA delay for gene therapy targeting rare childhood disorder

Ultragenyx Pharmaceutical (Nasdaq: RARE) has been dealt a regulatory setback, as the American medicines regulator has declined to approve its gene therapy UX111 (formerly ABO-102) for Sanfilippo syndrome type A. The decision, delivered in a complete response letter, will delay any potential approval until at least 2026.

The Food and Drug Administration (FDA) has requested additional information related to manufacturing and facility procedures, following recent inspections. While the agency did not raise concerns over the product's clinical data or trial conduct, Ultragenyx confirmed that the application cannot move forward until the manufacturing issues are addressed.