Why RARE fell 46.1% on Sep 3 2026: phase 3 trial failure
RARE-46.1%on Thu Sep 3 2026
Ultragenyx Pharmaceutical Inc. was down 46.1% on the day at $14.29, ranked #5 on 61.1× its usual five-minute volume, when TapeRank recorded this drop at 04:02 ET during the pre-market session.
WHAT THE ROW LOOKED LIKE
LAST14.29
DAY▼ 46.1%
5 MIN▼ 3.45%
5M RVOL61.1×
5M $VOL$512K
FLOAT*98.6M
RANK#5
SESSIONPRE-MARKET
* FLOAT IS SHARES OUTSTANDING; TRUE FREE FLOAT IS NOT AVAILABLE
AI VERDICT
JUSTIFIEDCONFIDENCE5/5
Ultragenyx shares are collapsing after the company disclosed that its Phase 3 Aspire study of apazunersen in Angelman syndrome failed both its primary endpoint and key secondary endpoint. This was a pivotal, late-stage readout for a lead pipeline program, and the company is now signaling it will reassess the program's future and cut costs.
WHYA near-50% drop is proportionate to a outright Phase 3 failure of a flagship clinical program with no efficacy signal shown.
ANALYZED 04:02 ET · <1 MIN AGO · ANTHROPIC/CLAUDE-SONNET-5
FILINGS · 24H BEFORE THE MOVE
- WED 12:04 ET8-K — Other EventsSEC 8-K
SESSION LEVELS AT CAPTURE
VWAP14.71
HOD14.99
LOD14.20
OR HIGH—
OR LOW—
PREV CLOSE26.53
PM HIGH14.99
PM LOW14.20
GAP▼ 46.44% (indicated)
— MEANS THE LEVEL DID NOT EXIST YET AT THAT INSTANT, NOT ZERO