X0306 4 2019-12-04 0 0001582313 Xenon Pharmaceuticals Inc. XENE 0001283535 PATOU GARY 200 - 3650 GILMORE WAY BURNABY A1 BRITISH COLUMBIA, CANADA 1 0 0 0 Common Shares 2019-12-04 4 M 0 2057 3.56 A 21516 D Common Shares 12500 I See Note Stock Option (Right to Buy) 3.56 2019-12-04 4 M 0 2057 0.00 D 2019-12-31 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. The shares subject to the option fully vested on December 31, 2012. The date the options became fully vested was incorrectly reflected on the Reporting Person's Form 3. /s/ Cassandra Robinson, Attorney-in-fact 2019-12-06