Ultragenyx shares fall 40% as Angelman study misses key endpoints

Ultragenyx shares plunged over 40% after its Phase 3 Aspire study for apazunersen in Angelman syndrome failed to meet primary and key secondary endpoints, raising concerns about the rare disease specialist's pipeline. The company faces ongoing heavy losses, a $1.45 billion market cap, and $436 million in cash, with limited near-term revenue growth despite recent approval of Genglycos. Analysts assign a Hold rating, citing uncertain pipeline prospects and imminent cost-cutting needs. A potentially pivotal FDA decision on UX411 for Sanfilippo syndrome looms, offering optionality if approved. Commercial execution improvements could also support the stock, though setbacks currently dominate the outlook.