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XENE's Depression Trial Setback: Is Its Pipeline Still Attractive?

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Key Takeaways

  • Xenon paused enrollment in phase III depression trials after unexpected side effects emerged.
  • Xenon is reviewing dose adjustments, with top-line X-NOVA2 results expected in the first quarter of 2027.
  • Azetukalner's FDA application for FOS and ongoing epilepsy trials offer potential growth opportunities.

Xenon Pharmaceuticals (XENE - Free Report) is facing investor concerns after a safety-related setback in its late-stage depression program. The company is evaluating its lead pipeline asset, azetukalner, in phase III X-NOVA2 and X-NOVA3 studies for the treatment of patients with major depressive disorder (MDD) and in the X-CEED study for bipolar depression (BPD) I or II.

Azetukalner is an experimental oral drug designed to open Kv7 potassium channels, which help regulate electrical activity in the brain. Xenon is studying the drug for both depression and epilepsy.

In September 2026, Xenon voluntarily paused enrollment of new patients temporarily in its ongoing phase III depression studies after unexpected neurological and psychiatric side effects were observed. The side effects included confusion, speech difficulties and problems with muscle coordination, along with a small number of cases classified as psychosis. These events had not been observed in the earlier phase II depression study. However, the setback does not mean the drug failed to demonstrate efficacy in these trials. The company took this precaution after reviewing the safety data and consulting its independent safety monitoring board.

Xenon is reviewing potential dose adjustments, while patients already enrolled in the studies remain active. The development raises questions about the drug's safety and commercial potential, but the company's epilepsy program still offers growth opportunities.

Meanwhile, Xenon plans to complete the six-week treatment period for patients already enrolled in the X-NOVA2 study and release topline results in the first quarter of 2027.

Year to date, XENE's shares have lost 23.1% against the industry’s 2.9% growth.

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Epilepsy Pipeline Remains the Key Growth Driver for XENE

Xenon's prospects are not limited to psychiatric disorders. The company has submitted a new drug application to the FDA for azetukalner to treat focal onset seizures (FOS), a common form of epilepsy. The application is supported by positive clinical results, including statistically significant reductions in monthly seizure frequency compared with placebo in the phase IIb X-TOLE and phase III X-TOLE2 studies. If approved, azetukalner could become Xenon's first commercial product.

Xenon is also evaluating azetukalner in the phase III X-TOLE3 study for focal onset seizures and the X-ACKT study for primary generalized tonic-clonic seizures. These programs could expand the drug's potential market if they produce favorable results.

Other Pipeline Candidates Offer Longer-Term Potential

Beyond azetukalner, Xenon is developing early-stage candidates targeting ion channels involved in pain. These include XEN1701 and XEN1720, which target the Nav1.7 sodium channel, and XEN1120, a Kv7 potassium channel opener. The company is investigating these candidates for pain-related conditions, although they remain in early clinical development and are much less advanced than azetukalner. Positive results could eventually diversify Xenon's pipeline.

XENE’s Competitive Landscape in Depression Market

Xenon faces competition from established drugmakers in both depression and epilepsy. Vanda Pharmaceuticals (VNDA - Free Report) is evaluating Bysanti (milsaperidone) as a once-daily adjunctive treatment for MDD in an ongoing phase III study, with top-line data expected in the first half of 2027. Earlier this year, Vanda’s Bysanti received FDA approval for bipolar I disorder and schizophrenia in adults. Johnson & Johnson (JNJ - Free Report) is another key competitor to Xenon in the depression market. Its drug Spravato (esketamine) is FDA-approved for adults with treatment-resistant depression. Hence, Johnson & Johnson could pose a tough competition to Xenon if azetukalner receives approval for depression.

XENE's Zacks Rank

Xenon stock currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 (Strong Buy) Rank stocks here.

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