X0306 4 2020-06-09 0 0001582313 Xenon Pharmaceuticals Inc. XENE 0001263647 TARNOW MICHAEL M 200 - 3650 GILMORE WAY BURNABY A1 V5G 4M1 BRITISH COLUMBIA, CANADA 1 0 0 0 Common Shares 2020-06-09 4 M 0 5144 3.52 A 69713 D Stock Option (Right to Buy) 3.52 2020-06-09 4 M 0 5144 0.00 D 2020-07-01 Common Shares 5144 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. The shares subject to the option fully vested on June 30, 2013. The date the options became fully vested was incorrectly reflected on the Reporting Person's Form 3. /s/ Cassandra Robinson, Attorney-in-fact 2020-06-10