X0306 4 2017-08-14 0 0001582313 Xenon Pharmaceuticals Inc. XENE 0001574579 Svoronos Dawn C/O XENON PHARMACEUTICALS INC. 200 - 3650 GILMORE WAY BURNABY A1 V5G 4W8 BRITISH COLUMBIA, CANADA 1 0 0 0 Common Shares 2017-08-14 4 P 0 50000 2.8154 A 50000 D The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares purchased. These shares were purchased in multiple transactions at prices ranging from $2.80 to $2.85, 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 purchased at each separate price within the ranges set forth herein. /s/ Joanne Smartt, Attorney-in-fact 2017-08-15