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Xenon Pharmaceuticals Showcases Its XEN1101 Epilepsy Program at the 2023 American Academy of Neurology (AAN) Annual Meeting

April 24, 2023

Oral presentation by Dr. Jacqueline French to outline sustained monthly reduction in focal onset seizures during open-label extension of X-TOLE study

Poster to present the trial design for Phase 3 X-ACKT clinical study evaluating XEN1101 in additional epilepsy indication of primary generalized tonic-clonic seizures

VANCOUVER, British Columbia and BOSTON, April 24, 2023 (GLOBE NEWSWIRE) -- Xenon Pharmaceuticals Inc. (Nasdaq:XENE), a neurology-focused biopharmaceutical company, today announced its upcoming oral and poster presentations at the 2023 American Academy of Neurology (AAN) Annual Meeting in Boston, MA.

Mr. Ian Mortimer, Xenon’s President and Chief Executive Officer, stated, “We are excited to showcase our XEN1101 epilepsy program at the 2023 AAN meeting. In particular, we are looking forward to the oral presentation by Dr. Jacqueline French, who will outline the promising results we are seeing in the ongoing open-label extension study of our Phase 2b X-TOLE clinical trial in focal onset seizures. XEN1101 represents the most advanced potassium channel modulator in clinical development for multiple indications, and our robust Phase 3 plans for XEN1101 include clinical trials already underway in focal onset seizures as well as primary generalized tonic-clonic seizures.”

Jacqueline A. French, MD, Professor in the Department of Neurology at NYU Langone Health and Co-director of Epilepsy Clinical Trials at NYU Langone's Comprehensive Epilepsy Center; Founder/Director of the Epilepsy Study Consortium; and Chair of the XEN1101 X-TOLE Steering Committee, stated, “The interim analysis from an ongoing open-label extension study with XEN1101 builds upon the strong efficacy data generated in the Phase 2b X-TOLE clinical trial. Importantly, patients with epilepsy are experiencing continued seizure reduction and extended periods of seizure freedom. These data are encouraging for prescribing physicians who continue to seek new, differentiated therapeutics that improve upon existing options. I believe, as XEN1101 progresses through Phase 3 studies, these results also provide further hope for the many patients who experience the debilitating impacts of focal seizures, even while taking multiple anti-seizure medications.”

2023 AAN Presentation Details:

Title: “XEN1101, a Novel Potassium Channel Modulator: Interim Data From an Ongoing, Long-Term, Open-Label Extension of a Phase 2b Study (X-TOLE) in Adults With Focal Epilepsy”

Format: Oral Presentation #008, Epilepsy/Clinical Neurophysiology (EEG): Epilepsy Outcomes

Presenter: Jacqueline French, New York University Grossman School of Medicine and NYU Langone Health, New York, NY, USA

Date/Time: Thursday, April 27, 2023 at 2:24 pm-2:36 pm ET


  • During the open-label extension (OLE), there was a sustained monthly reduction in seizure frequency (80%–90% seizure reduction as measured by median percent change) from the double-blind period baseline.
  • Seizure freedom for ≥6-month and ≥12-month consecutive durations was achieved in 17.5% and 10.5% of patients, respectively.
  • XEN1101 continues to be generally well-tolerated in the OLE with adverse events consistent with prior results and other anti-seizure medications.

Title: “A Randomized, Double-Blind, Placebo-Controlled, Phase 3 Study to Evaluate the Safety and Efficacy of XEN1101 as an Adjunctive Therapy in the Treatment of Primary Generalized Tonic-Clonic Seizures”

Format: Poster Session 11, #012

Lead Author: Antonio Gil-Nagel, Hospital Ruber Internacional, Madrid, Spain

Date/Time: Wednesday, April 26, 2023 at 11:45 am-12:45 pm


  • Xenon has initiated a Phase 3 clinical trial, called X-ACKT, to support potential regulatory submissions in an additional epilepsy indication of primary generalized tonic-clonic seizures (PGTCS).
  • This multicenter, randomized, double-blind, placebo-controlled study will evaluate the clinical efficacy, safety, and tolerability of XEN1101 administered as adjunctive treatment in approximately 160 patients with PGTCS.
  • The primary efficacy endpoint is the MPC in monthly PGTCS frequency from baseline through the double-blind period of XEN1101 compared to placebo.

Other AAN Activities:

On Sunday, April 23, 2023, Dr. Christopher Kenney, Xenon’s Chief Medical Officer, hosted a presentation entitled “XEN1101, a Novel Potassium Channel Opener in Clinical Trials for Epilepsy” on the Emerging Neurologic Care Presentation Stage in the Exhibit Hall.

In addition to the posters noted above, Xenon is hosting a booth (#1575) in the Exhibit Hall, which is scheduled to be open from 11:30 am ET on Sunday, April 23, 2023 until 4 pm ET on Wednesday, April 26, 2023.

About Xenon Pharmaceuticals Inc.
Xenon Pharmaceuticals (NASDAQ:XENE) is a clinical stage biopharmaceutical company committed to developing innovative therapeutics to improve the lives of patients with neurological disorders. We are advancing a novel product pipeline of neurology therapies to address areas of high unmet medical need, with a focus on epilepsy. For more information, please visit

Safe Harbor Statement

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995 and Canadian securities laws. These forward-looking statements are not based on historical fact, and include statements regarding the potential efficacy, safety profile, future development plans, addressable market, regulatory success and commercial potential of our and our partners’ product candidates; the efficacy of our clinical trial designs; our ability to successfully develop and achieve milestones in our XEN1101 and other development programs; and our ability to obtain regulatory approval of XEN1101 and our other product candidates. These forward-looking statements are based on current assumptions that involve risks, uncertainties and other factors that may cause the actual results, events, or developments to be materially different from those expressed or implied by such forward-looking statements. These risks and uncertainties, many of which are beyond our control, include, but are not limited to: clinical trials may not demonstrate safety and efficacy of any of our or our collaborators’ product candidates; promising results from pre-clinical development activities or early clinical trial results may not be replicated in later clinical trials; any of our or our collaborators’ product candidates, including XEN1101, may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; we may not achieve additional milestones in our proprietary or partnered programs; regulatory agencies may impose additional requirements or delay the initiation of clinical trials; the impact of competition; the impact of expanded product development and clinical activities on operating expenses; the impact of new or changing laws and regulations; the impact of the ongoing COVID-19 pandemic on our research and clinical development plans and timelines and results of operations, including impact on our clinical trial sites, collaborators, regulatory agencies and related review times, and contractors who act for or on our behalf, may be more severe and more prolonged than currently anticipated; the impact of unstable economic conditions in the general domestic and global economic markets; adverse conditions from geopolitical events; as well as the other risks identified in our filings with the Securities and Exchange Commission and the securities commissions in British Columbia, Alberta, and Ontario. These forward-looking statements speak only as of the date hereof and we assume no obligation to update these forward-looking statements, and readers are cautioned not to place undue reliance on such forward-looking statements.

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Investor/Media Contact:
Jodi Regts
Xenon Pharmaceuticals Inc.
Phone: 604.484.3353

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Source: Xenon Pharmaceuticals Inc.