X0609 4 2026-08-28 0001582313 Xenon Pharmaceuticals Inc. XENE 0001880129 KENNEY CHRISTOPHER JOHN true 3650 GILMORE WAY BURNABY A1 V5G 4W8 BRITISH COLUMBIA, CANADA false true false false Chief Medical Officer true Common Shares 2026-08-28 4 S false 6368 60.1673 D 702 D Common Shares 2026-08-28 4 S false 700 60.9766 D 2 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 29, 2026. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, of shares sold. These share were sold in multiple transactions at prices ranging from $59.79 to $60.68, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, of shares sold. These share were sold in multiple transactions at prices ranging from $60.81 to $61.12, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein. The number of shares beneficially owned following the reported transactions reflects an upward adjustment of one share from the reporting person's previous Form 4 filed on March 13, 2026, based on updated tax withholding calculations for the transactions described on the previously filed Form 4. /s/ Nathaniel Adams, Attorney-in-fact 2026-08-31