# EDGAR Filing Document

**Accession Number:** 0001582313
**File Stem:** 0001193125-26-102666
**Filing Date:** 2026-3
**Character Count:** 13360
**Document Hash:** 878e641cb0d4ba1057470f6a0303c4c2
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-102666.hdr.sgml**: 20260311

**ACCESSION NUMBER**: 0001193125-26-102666

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260309

**FILED AS OF DATE**: 20260311

**DATE AS OF CHANGE**: 20260311

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** MORTIMER IAN
- **CENTRAL INDEX KEY:** 0001619961

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-36687
- **FILM NUMBER:** 26745043

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** C/O XENON PHARMACEUTICALS INC.
- **STREET 2:** 200 - 3650 GILMORE WAY
- **CITY:** BURNABY
- **PROVINCE COUNTRY:** A1
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Xenon Pharmaceuticals Inc.
- **CENTRAL INDEX KEY:** 0001582313
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 980661854
- **STATE OF INCORPORATION:** A1
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 200 - 3650 GILMORE WAY
- **CITY:** BURNABY
- **PROVINCE COUNTRY:** A1
- **BUSINESS PHONE:** (604) 484-3300

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 200 - 3650 GILMORE WAY
- **CITY:** BURNABY
- **PROVINCE COUNTRY:** A1

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[x] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>MORTIMER IAN<br><sub>(Last) (First) (Middle)</sub><br>3650 GILMORE WAY<br><sub>(Street)</sub><br>BURNABY, A1 V5G 4W8<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-09 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_PRESIDENT & CEO_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Xenon Pharmaceuticals Inc. [ XENE ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Shares | 2026-03-09 |  | M |  | 75000 | A | $8.40 | 81000 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 21791 | D | 58.81<sup>(2)</sup> | 59209 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 31694 | D | 59.88<sup>(3)</sup> | 27515 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 21515 | D | 60.49<sup>(4)</sup> | 6000 | D |  |
| Common Shares | 2026-03-09 |  | M |  | 25000 | A | $3.10 | 31000 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 12479 | D | 59.50<sup>(5)</sup> | 18521 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 10072 | D | 60.47<sup>(6)</sup> | 8449 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 2449 | D | 61.26<sup>(7)</sup> | 6000 | D |  |
| Common Shares | 2026-03-09 |  | M |  | 105000 | A | $4.75 | 111000 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 43348 | D | 59.26<sup>(8)</sup> | 72652 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 61652 | D | 60.08<sup>(9)</sup> | 6000 | D |  |
| Common Shares | 2026-03-09 |  | M |  | 65000 | A | $9.44 | 71000 | D |  |
| Common Shares | 2026-03-09 |  | S<sup>(1)</sup> |  | 65000 | D | 62.06<sup>(10)</sup> | 6000 | D |  |
| Common Shares | 2026-03-09 |  | M |  | 20000<sup>(11)</sup> | A | <sup>(11)</sup> | 26000 | D |  |
| Common Shares | 2026-03-10 |  | S<sup>(12)</sup> |  | 11269 | D | $60.108 | 14731 | D |  |
| Common Shares |  |  |  |  |  |  |  | 14300 | I | By Spouse |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Stock Option | $8.40 | 2026-03-09 |  | M |  |  | 75000 | <sup>(13)</sup> | 2027-03-12 | Common Shares | 75000 | $0 | 0 | D |  |
| Stock Option | $3.10 | 2026-03-09 |  | M |  |  | 25000 | <sup>(13)</sup> | 2027-10-22 | Common Shares | 25000 | $0 | 0 | D |  |
| Stock Option | $4.75 | 2026-03-09 |  | M |  |  | 105000 | <sup>(13)</sup> | 2028-03-11 | Common Shares | 105000 | $0 | 0 | D |  |
| Stock Option | $9.44 | 2026-03-09 |  | M |  |  | 65000 | <sup>(13)</sup> | 2029-09-15 | Common Shares | 65000 | $0 | 0 | D |  |
| Performance Share Units | <sup>(11)</sup> | 2026-03-09 |  | A |  | 20000<sup>(11)</sup> |  | <sup>(11)</sup> | <sup>(11)</sup> | Common Shares | 20000 | $0 | 20000 | D |  |
| Performance Share Units | <sup>(11)</sup> | 2026-03-09 |  | M |  |  | 20000 | <sup>(11)</sup> | <sup>(11)</sup> | Common Shares | 20000 | $0 | 0 | D |  |

---

### Footnotes:

(1) The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 27, 2024.

(2) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $58.16 to $59.1425, 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 sold at each separate price within the range set forth herein.

(3) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $59.16 to $60.15, 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 sold at each separate price within the range set forth herein.

(4) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $60.16 to $61.00, 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 sold at each separate price within the range set forth herein.

(5) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $59.03 to $60.02, 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 sold at each separate price within the range set forth herein.

(6) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $60.05 to $61.035, 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 sold at each separate price within the range set forth herein.

(7) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $61.055 to $61.555, 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 sold at each separate price within the range set forth herein.

(8) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $58.745 to $59.735, 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 sold at each separate price within the range set forth herein.

(9) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $59.75 to $60.60, 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 sold at each separate price within the range set forth herein.

(10) The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price (rounded to two decimal places), respectively, or shares sold. These shares were sold in multiple transactions at prices ranging from $62.00 to $62.30, 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 sold at each separate price within the range set forth herein.

(11) Represents shares earned and vested under a performance share unit ("PSU") award granted to the reporting person on March 11, 2024. The number of shares earned is based on a determination by the issuer's Board of Directors of the achievement of one or more prescribed milestones under the terms of the PSU award agreement. The PSUs vested immediately upon such determination.

(12) The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading arrangement, in the form of a durable sell-to-cover instruction, adopted by the reporting person on December 3, 2025, solely to satisfy tax withholding obligations related to the vesting of PSUs granted on March 11, 2024.

(13) The shares subject to this option are fully vested and exercisable.

**Signature:** /s/ Nathaniel Adams, Attorney-in-fact  
**Date:** 2026-03-11

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**