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XENE Files NDA for Epilepsy Drug, Falls on Depression Studies' Setback

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Key Takeaways

  • Xenon submitted an FDA application for azetukalner to treat focal onset seizures.
  • Azetukalner showed significant seizure reductions across all four doses in two global epilepsy studies.
  • Depression-study enrollment is paused, while nearly 80% of X-NOVA2 enrollment is complete.

Xenon Pharmaceuticals (XENE - Free Report) announced that it has submitted a new drug application (NDA) to the FDA for azetukalner, its lead investigational therapy for the treatment of focal onset seizures (FOS) in epilepsy. If approved, the company will gain its first commercial product.

The regulatory submission was supported by positive data from two global studies, phase IIb X-TOLE and phase III X-TOLE2, which evaluated azetukalner in patients with FOS. Both studies achieved strong seizure control by demonstrating a statistically significant reduction in monthly seizure frequency from baseline compared with placebo across all four doses of azetukalner. Azetukalner was generally well-tolerated, with a consistent safety profile across the studies.

Additional Epilepsy Studies Continue to Advance

Xenon continues to expand the azetukalner epilepsy program. While the X-TOLE2 study announced data in March, the identical phase III X-TOLE3 study is currently enrolling patients and is intended to support potential regulatory submissions for azetukalner for FOS in ex-U.S. jurisdictions. Patient enrollment outside of Japan is expected to be completed in 2026. XENE is evaluating azetukalner for primary generalized tonic-clonic seizures in a phase III X-ACKT study. Patient enrollment is ongoing.

Temporary Pause in Xenon’s Depression Studies

While the epilepsy program continues to progress, Xenon has temporarily paused enrollment of new patients in its ongoing late-stage clinical studies of azetukalner for major depressive disorder (MDD) and bipolar depression (BPD). The decision followed an analysis of neuropsychiatric adverse events observed in these studies.

The X-NOVA2 and X-NOVA3 studies are evaluating the candidate in patients with MDD and the X-CEED study is evaluating azetukalner in patients with BPD I or II.

Patients already enrolled in the studies will continue treatment. Per the company, the side effects are consistent with azetukalner’s known safety profile and mechanism of action, but they were not observed in the earlier phase II X-NOVA study in MDD. The pause is a precautionary step taken in consultation with the data safety monitoring board and is expected to be temporary. Xenon is evaluating potential dose modifications to reduce these side effects. The pause does not affect the ongoing epilepsy studies.

The temporary pause in enrollment across the MDD and BPD programs raised investor concerns, triggering a sharp 27% decline in XENE shares in premarket trading.

Year to date, the stock has gained 28% compared with the industry’s 8.7% growth.

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However, Xenon has completed nearly 80% of the planned patient enrollment in the X-NOVA2 study, which the company believes is enough to detect a meaningful improvement in the study’s primary endpoint, HAM-D17. Top-line data from the study are expected in the first quarter of 2027.

XENE's Zacks Rank & Stocks to Consider

Xenon currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are Precigen (PGEN - Free Report) , currently sporting a Zacks Rank #1 (Strong Buy), and AC Immune (ACIU - Free Report) and Aldeyra Therapeutics (ALDX - Free Report) , carrying a Zacks Rank #2 (Buy) each. You can see the complete list of today’s Zacks #1 Rank stocks here.

Over the past 60 days, estimates for Precigen’s 2026 bottom line have improved from a loss of 2 cents to earnings per share of 25 cents. Over the same period, earnings estimates for 2027 have risen from 25 cents to 86 cents per share. PGEN shares have surged 88.3% year to date.

Precigen’s earnings beat estimates in three of the trailing four quarters and missed in the remaining one, with the average surprise being 108.96%.

Over the past 60 days, estimates for AC Immune’s 2026 loss per share have narrowed from 84 cents to 60 cents. Over the same period, earnings estimates for 2027 remained unchanged at 17 cents per share. ACIU shares have lost 14.7% year to date.

AC Immune’s earnings beat estimates in each of the trailing four quarters, with the average surprise being 33.25%.

Over the past 60 days, loss per share estimates for Aldeyra Therapeuticshave narrowed from 43 cents to 39 cents for 2026. Over the same period, estimates for 2027 loss per share have narrowed from 22 cents to 16 cents. ALDX shares have plunged 73.4% year to date.

Aldeyra Therapeutics’ earnings beat estimates in each of the trailing four quarters, delivering an average surprise of 29.25%.

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