Drug trial setbacks can still hit a company’s shares hard, even after recent good news. Investors often react strongly when a late-stage study disappoints.
Ultragenyx Pharmaceutical Inc (NASDAQ: RARE) (FRA: UP0) saw its stock fall more than 40 per cent in after-hours trading after it reported unfavourable results from its Phase 3 Aspire study of apazunersen for Angelman syndrome. The medicine is designed to help restore a missing protein in the brain. Doctors give it by injection into the spinal fluid.
In the trial, children who received the drug showed no clear improvement in thinking skills compared with those in the control group. They also failed to show benefits on a wider set of daily abilities. The groups looked much the same.
JPMorgan Chase & Co (NYSE: JPM) slashed its price target from US$80 to US$36 as a result. Baird also cut its target from US$40 to US$16 while Evercore ISI reduced its expectation from US$34 to US$16. Ultragenyx says it plans to review the program and implement significant expense cuts.
Angelman syndrome is a rare genetic condition that begins in early childhood. It occurs when a gene from the mother does not work properly. Children typically have delayed development, little or no speech, balance and movement problems, and seizures. Strikingly, many display a happy and excitable nature, with frequent smiling and laughter that stands out against the other challenges.
The condition lasts a lifetime and requires ongoing care. No approved treatments can fix the root cause.
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Ultragenyx（ウルトラジェニクス）の株価急落がウルトラえげつない件📝 pic.twitter.com/WgCyG9AJYC— 海里@製薬バイオベンチャーMRブロガー (@biovenMRkairi) September 2, 2026
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Recent approval offers lingering optimism
This setback follows a major success. The US Food and Drug Administration recently granted accelerated approval to Ultragenyx’s gene therapy GENGLYCOS for people aged eight and older with glycogen storage disease type Ia.
Patients with this rare condition must take large amounts of cornstarch throughout the day and night to keep blood sugar stable. A newly published 96-week study showed that those treated with the gene therapy cut their daily cornstarch use by an average of 61 per cent while keeping sugar levels safe. Many reduced or stopped nighttime doses.
Ultragenyx’s leading competitors are Biomarin Pharmaceutical Inc (NASDAQ: BMRN) (FRA: BM8) and Sarepta Therapeutics Inc (NASDAQ: SRPT) (FRA: AB3A). They are rivals because they all specialise in rare genetic diseases and compete in the same overall biotech space for investors, talent and attention — not because they sell drugs for the same conditions.
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