XENE Xenon Pharmaceuticals Inc

Xenon Pharmaceuticals Inc. (Nasdaq: XENE), a neuroscience-focused biopharmaceutical company dedicated to discovering, developing, and delivering life-changing therapeutics for patients in need, today announced multiple presentations at the upcoming American Epilepsy Society Annual Meeting (AES 2024), taking place December 6-10, 2024 at the Los Angeles Convention Center in Los Angeles, CA. Five posters will be presented, featuring new long-term data from the ongoing X-TOLE open-label extension study of azetukalner in patients with focal onset seizures (FOS), the mental health burden and comorbidity burdens of focal onset seizures, as well as new pre-clinical data from the Company’s early-stage Nav1.1 program.

• Poster Presentation #2.361: Long-term Safety and Efficacy of Azetukalner, a Novel, Potent Kv7 Potassium Channel Opener in Adults With Focal Epilepsy: Update From the Ongoing 7-year Open-Label Extension of X-TOLEJacqueline A. French, MD, New York University Grossman School of Medicine and NYU Langone HealthAuthor Session: Sunday, December 8 from 12 pm – 2 pm PT in South Hall H, Level 1

• Poster Presentation #2.347: Is the Mental Health Burden of Epilepsy Under-Recognized in Patients Reporting Focal Onset Seizures? A Patient-Reported Outcomes StudyAuthor Session: Sunday, December 8 from 12 pm – 2 pm PT in South Hall H, Level 1

• Poster Presentation #2.338: A Targeted Literature Review of Comorbidity Burden in Focal Onset SeizuresAuthor Session: Sunday, December 8 from 12 pm – 2 pm PT in South Hall H, Level 1

• Poster Presentation #3.389: Nav1.1 Potentiators Modulate Brain Rhythms Measured Through Quantitative Electrocorticography (qECoG) in a Dravet Mouse ModelAuthor Session: Monday, December 9 from 12 pm – 2 pm PT in South Hall K, Level 1

• Poster Presentation #3.395: Selective Potentiation of Nav1.1 Channels in Dravet Mice Restores Interneuron Function and Improves Motor FunctionAuthor Session: Monday, December 9 from 12 pm – 2 pm PT in South Hall K, Level 1

Scientific Exhibit

Xenon is hosting a Scientific Exhibit to provide an overview of its clinical and research programs on Sunday, December 8, 2024 from 2 pm – 5 pm PT in Room 406A on level 2.

Exhibit Hall

Xenon is hosting booths #1721 and #1827 in the Exhibit Hall, which is scheduled to open at 12 pm PT on Saturday, December 7 and close on Monday, December 9, 2024 at 2 pm PT.

About Xenon Pharmaceuticals Inc.

Xenon Pharmaceuticals (Nasdaq: XENE) is a neuroscience-focused biopharmaceutical company dedicated to discovering, developing, and delivering life-changing therapeutics. We are advancing an ion channel product portfolio to address areas of high unmet medical need, including epilepsy and depression. Azetukalner, a novel, highly potent, selective Kv7 potassium channel opener, represents the most advanced, clinically validated potassium channel modulator in late-stage clinical development for multiple indications. For more information, please visit www.xenon-pharma.com.

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 timing of and potential results from clinical trials; the potential efficacy, safety profile, future development plans in current and anticipated indications, 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 azetukalner and other pipeline and development programs; and our ability to successfully develop and obtain regulatory approval of azetukalner 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; our assumptions regarding our planned expenditures and sufficiency of our cash to fund operations may be incorrect; our ongoing discovery and pre-clinical efforts may not yield additional product candidates; any of our or our collaborators’ product candidates, including azetukalner, 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 market, industry, and regulatory conditions on clinical trial enrollment; 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; as well as the other risks identified in our filings with the U.S. 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.

“Xenon” and the Xenon logo are registered trademarks or trademarks of Xenon Pharmaceuticals Inc. in various jurisdictions. All other trademarks belong to their respective owner.

Contacts: For Investors:Chad FugereVice President, Investor Relations(857) 675-7275investors@xenon-pharma.com

For Media:Colleen AlabisoSenior Vice President, Corporate Affairs(617) 671-9238media@xenon-pharma.com