Xenon stock plunges as B.C. drug developer pauses enrolment in depression study — SkimNews
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- Xenon Pharmaceuticals (XENE-Q) shares fell roughly 30% to US$39.91 from Thursday's US$57.35 close after the company paused enrolment in its late-stage major depressive disorder efficacy trial of azetukalner following adverse events in a small number of patients.
- Chief medical officer Chris Kenney disclosed that a "small percentage" of patients experienced confusion, aphasia and ataxia, with one case of psychosis; CEO Ian Mortimer called the side effects mostly mild or moderate and "consistent with the known profile" of the drug.
- The trial pause overshadowed Xenon's new drug application to the FDA for azetukalner to treat focal-onset seizures, the most common type of epileptic seizure, which would mark the 15th B.C.-developed therapy to win regulatory approval if greenlit.
- RBC Capital Markets analyst Brian Abrahams cut his price target to US$70 from US$81 but said the "main value-driving" epilepsy indication and its expected 2025 market launch remain intact.
- Xenon's March Phase 3 data showed a 53.2% median seizure reduction at a 25mg daily dose over 12 weeks — 42.7 percentage points better than placebo — in patients most resistant to other treatments, prompting the company to raise over $1 billion in equity that month.
- Azetukalner, acquired from Bausch Health in 2017, distinguishes itself by requiring no gradual dose escalation and is taken at night to minimize side effects such as dizziness, headaches and sleepiness.
Why it matters: The 30% plunge erased all stock gains since Xenon's March epilepsy results, but analysts say the FDA epilepsy filing and expected 2025 launch remain on track. Investors who priced in a depression expansion thesis lost roughly a third of their position in a day; the core value now hinges on the FDA's review of a drug that cut seizures 53% in drug-resistant patients.
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