Filing Details

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Xenon Pharmaceuticals Inc. (Name of Issuer) Common Shares (Title of Class of Securities) 98420N105 (CUSIP Number) December 31, 2018 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP: 98420N105 Page 1 of 4

1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) SMALLCAP World Fund, Inc. 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a) (b) 3 SEC USE ONLY 4 CITIZENSHIP OR PLACE OF ORGANIZATION Maryland 5 SOLE VOTING POWER NONE 6 SHARED VOTING POWER NUMBER OF SHARES NONE BENEFICIALL Y OWNED BY 7 SOLE DISPOSITIVE POWER EACH REPORTING NONE PERSON WITH: 8 SHARED DISPOSITIVE POWER NONE 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,900,900 See Additional information in Item 4. Under certain circumstances, SMALLCAP World Fund may vote the shares of the fund. These shares may also be reflected in a filing made by Capital Research Global Investors, Capital International Investors, and/or Capital World Investors 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.5% 12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IV CUSIP: 98420N105 Page 2 of 4 SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 Schedule 13G Under the Securities Exchange Act of 1934 Amendment No. Item 1(a) Name of Issuer: Xenon Pharmaceuticals Inc. Item 1(b) Address of Issuer's Principal Executive Offices: 200-3650 Gilmore Way Burnaby, British Columbia Canada V5G 4W8 Item 2(a) Name of Person(s) Filing: SMALLCAP World Fund, Inc. Item 2(b) Address of Principal Business Office or, if none, Residence: 6455 Irvine Center Drive Irvine, California 92618-4518 Item 2(c) Citizenship: N/A Item 2(d) Title of Class of Securities: Common Shares Item 2(e) CUSIP Number: 98420N105 Item 3 If this statement is filed pursuant to sections 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: (d) [X] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). Item 4 Ownership Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1. (a) Amount beneficially owned: (b) Percent of class: (c) Number of shares as to which the person has: (i) Sole power to vote or to direct the vote: (ii) Shared power to vote or to direct the vote: (iii) Sole power to dispose or to direct the disposition of: (iv) Shared power to dispose or to direct the disposition of: See page 2 SMALLCAP World Fund, Inc., an investment company registered under the Investment Company Act of 1940, which is advised by Capital Research and Management Company ("CRMC"), is the beneficial owner of 1,900,900 shares or 7.5% of the 25,240,348 shares believed to be outstanding. CRMC manages equity assets for various investment companies through three divisions, CUSIP: 98420N105 Page 3 of 4 Capital Research Global Investors, Capital World Investors, and Capital International Investors. These divisions generally function separately from each other with respect to investment research activities and they make investment decisions and proxy voting decisions for the investment companies on a separate basis. Item 5 Ownership of Five Percent or Less of a Class. If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following: [ ] Item 6 Ownership of More than Five Percent on Behalf of Another Person: N/A Item 7 Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person: N/A Item 8 Identification and Classification of Members of the Group: N/A Item 9 Notice of Dissolution of Group: N/A Item 10 Certification By signing below, I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. Signature After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: February 8, 2019 Signature: /s/ Michael W. Stockton Name/Title: Michael W. Stockton - Secretary SMALLCAP World Fund, Inc. CUSIP: 98420N105 Page 4 of 4