Ultragenyx to lay off roughly 20% of staff as it halts two rare disease drug programs

Ultragenyx announced it will cut about 20% of its workforce as it ends development of two rare disease drug candidates.

The move follows a recent clinical study that failed to meet its primary endpoints, prompting the company to reassess its pipeline.

The layoffs affect employees across multiple sites and highlight the challenges of advancing rare‑disease therapies, where development costs are high and trial outcomes uncertain.

Ultragenyx did not name the programs or give a timeline for the restructuring, but said it will concentrate resources on its remaining portfolio.