Ultragenyx climbs after US FDA approves gene therapy

The condition damages the brain and nervous system because the body cannot properly break down heparan sulfate, leading to a gradual loss of cognitive, speech and motor skills.

Children who received Fayuvi maintained or improved cognitive function compared with untreated patients, according to the FDA.

Including session's moves, the stock has fallen about 40% year to date.

Ultragenyx Pharmaceutical RARE.O shares rose 12.8% to $14.52 after the U.S. Food and Drug Administration approved the company's gene therapy, Fayuvi, as the first treatment for children with Sanfilippo syndrome Type A.