X0306 4 2021-12-08 0 0001582313 Xenon Pharmaceuticals Inc. XENE 0001283535 PATOU GARY 200 - 3650 GILMORE WAY BURNABY A1 V5G 4W8 BRITISH COLUMBIA, CANADA 1 0 0 0 Common Shares 2021-12-08 4 M 0 2057 3.67 A 25630 D Common Shares 12500 I See Note Stock Option (Right to Buy) 3.67 2021-12-08 4 M 0 2057 0.00 D 2021-12-31 Common Shares 2057 0 D The exercise price was converted from $3.74 CAD using the closing rate of exchange of the Bank of Canada on the date of grant. The actual exercise price is the Canadian dollar amount regardless of the exchange rate on the date of exercise. By Gary & Karen Barbara Patou TTEE Patou Family Trust FBO Gary Patou Karen Barbara Patou. 1/3 of the shares subject to the Option vested on January 1, 2013 (the "2012 Vesting Commencement Date") and thereafter the remaining 2/3 of the shares subject to the Option vest each monthly anniversary of the 2012 Vesting Commencement Date over the following 2 years. /s/ Cassandra Robinson, Attorney-in-fact 2021-12-10