# EDGAR Filing Document

**Accession Number:** 0001503802
**File Stem:** 0001193125-26-242083
**Filing Date:** 2026-5
**Character Count:** 18342
**Document Hash:** f9884981d8a09c4d1af760ac952ae4de
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-242083.hdr.sgml**: 20260622

**ACCESSION NUMBER**: 0001193125-26-242083

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 15

**FILED AS OF DATE**: 20260527

**DATE AS OF CHANGE**: 20260527

**EFFECTIVENESS DATE**: 20260527

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Karyopharm Therapeutics Inc.
- **CENTRAL INDEX KEY:** 0001503802
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 263931704
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-296280
- **FILM NUMBER:** 261027266

**BUSINESS ADDRESS:**
- **STREET 1:** 85 WELLS AVENUE
- **STREET 2:** SECOND FLOOR
- **CITY:** NEWTON
- **STATE:** MA
- **ZIP:** 02459
- **BUSINESS PHONE:** 617-658-0600

**MAIL ADDRESS:**
- **STREET 1:** 85 WELLS AVENUE
- **STREET 2:** SECOND FLOOR
- **CITY:** NEWTON
- **STATE:** MA
- **ZIP:** 02459

**As filed with the Securities and Exchange Commission on May 27, 2026** 

**Registration No. 333-** 

**UNITED STATES** 

**SECURITIES AND EXCHANGE COMMISSION** 

**Washington, D.C. 20549** 

**FORM S-8** 

**REGISTRATION STATEMENT** 

***UNDER***

***THE SECURITIES ACT OF 1933***

## Karyopharm Therapeutics Inc.
**(Exact name of registrant as specified in its charter)** 

---

| | |
|:---|:---|
| **Delaware** | **26-3931704** |
| **(State or other jurisdiction of**<br> **incorporation or organization)** | **(I.R.S. Employer**<br> **Identification No.)** |
| **85 Wells Avenue, 2nd Floor**<br> **Newton, MA** | **02459** |
| **(Address of Principal Executive Offices)** | **(Zip Code)** |

---

**Karyopharm Therapeutics Inc. 2022 Equity Incentive Plan, as amended** 

**(Full title of the plan)** 

**Richard Paulson** 

**President and Chief Executive Officer** 

**Karyopharm Therapeutics Inc.** 

**85 Wells Avenue, 2nd Floor** 

**Newton, MA 02459** 

**(Name and address of agent for service)** 

**(617) 658-0600** 

**(Telephone number, including area code, of agent for service)** 

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

---

| | | | |
|:---|:---|:---|:---|
| Large accelerated filer | ☐ | Accelerated filer | ☐ |
| Non-accelerated filer | ☒ | Smaller reporting company | ☒ |
|  |  | Emerging growth company | ☐ |

---

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

------

**EXPLANATORY NOTE** 

This Registration Statement on Form S-8 is being filed to register an additional 3,950,000 shares of Common Stock, $0.0001 par value per share, of Karyopharm Therapeutics Inc., a Delaware corporation (the "Registrant"), that may be issuable under the Registrant's 2022 Equity Incentive Plan, as amended (the "2022 Plan"). Pursuant to General Instruction E to Form S-8, except as otherwise set forth below, this Registration Statement on Form S-8 incorporates by reference the contents of (i) the Registration Statement on [<u>Form S-8</u>](http://www.sec.gov/Archives/edgar/data/1503802/000119312522166718/d319784ds8.htm), File No. 333-265386, filed by the Registrant with the Securities and Exchange Commission (the "SEC") on June 3, 2022 relating to the 2022 Plan, (ii) the Registration Statement on [Form S-8](http://www.sec.gov/Archives/edgar/data/1503802/000119312523201207/d712199ds8.htm), File No. 333-273593, filed by the Registrant with the SEC on August 2, 2023 relating to the 2022 Plan, (iii) the Registration Statement on [Form S-8](http://www.sec.gov/Archives/edgar/data/1503802/000119312524150328/d843249ds8.htm), File No. 333-279823, filed by the Registrant with the SEC on May 30, 2024 relating to the 2022 Plan, and (iv) the Registration Statement on [Form S-8](http://www.sec.gov/Archives/edgar/data/1503802/000119312525177472/d943947ds8.htm), File No. 333-289466, filed by the Registrant with the SEC on August 11, 2025 relating to the 2022 Plan.

------

**PART II** 

**INFORMATION REQUIRED IN THE REGISTRATION STATEMENT** 

**Item 8. Exhibits.** 

---

| | |
|:---|:---|
| Number | Description |
| 4.1 (1) | [Restated Certificate of Incorporation of the Registrant, as amended](http://www.sec.gov/Archives/edgar/data/1503802/000119312526222827/kpti-ex3_1.htm) |
| 4.2 (2) | [Third Amended and Restated By-Laws of the Registrant](http://www.sec.gov/Archives/edgar/data/1503802/000119312522297530/d423713dex31.htm) |
| 5.1\* | [Opinion of Sidley Austin LLP, counsel to the Registrant](d133029dex51.htm) |
| 23.1\* | [Consent of Sidley Austin LLP (included in Exhibit 5.1)](d133029dex51.htm) |
| 23.2\* | [Consent of Ernst & Young LLP, independent registered public accounting firm for the Registrant](d133029dex232.htm) |
| 24.1\* | [Power of attorney (included on the signature pages of this registration statement)](#sig) |
| 99.1 (3) | [2022 Equity Incentive Plan, as amended](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001503802/000150380226000023/kpti-20260413.htm) |
| 99.2\* | [Amendment No. 5 to 2022 Equity Incentive Plan of Karyopharm Therapeutics Inc.](d133029dex992.htm) |
| 107\* | [Filing Fee Table](d133029dexfilingfees.htm) |

---

\* Filed herewith.

(1) Previously filed with the SEC as Exhibit 3.1 to the Registrant's Quarterly Report on Form 10-Q (File No. 001-36167) filed with the SEC on May 14, 2026 and incorporated herein by reference.

(2) Previously filed with the SEC as Exhibit 3.1 to the Registrant's Current Report on Form 8-K (File No. 001-36167) filed with the SEC on December 2, 2022 and incorporated herein by reference.

(3) Previously filed with the SEC as Appendix A to the Registrant's Definitive Proxy Statement on Schedule
14A (File No. 001-36167) filed with the SEC on April 13, 2026 and incorporated herein by reference.

------

**SIGNATURES** 

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Newton, Commonwealth of Massachusetts, on this 27th day of May, 2026.

---

| | |
|:---|:---|
| **KARYOPHARM THERAPEUTICS INC.** | **KARYOPHARM THERAPEUTICS INC.** |
| By: | /s/ Richard Paulson |
| Name: | Richard Paulson |
| Title: | President and Chief Executive Officer |

---

------

**POWER OF ATTORNEY AND SIGNATURES** 

We, the undersigned officers and directors of Karyopharm Therapeutics Inc., hereby severally constitute and appoint Richard Paulson, Lori Macomber and Michael Mano, and each of them singly, our true and lawful attorneys with full power to them, and each of them singly, to sign for us and in our names in the capacities indicated below, the registration statement on Form S-8 filed herewith and any and all subsequent amendments to said registration statement, and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Karyopharm Therapeutics Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or any of them, to said registration statement and any and all amendments thereto.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

---

| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| /s/ Richard Paulson<br> Richard Paulson | President and Chief Executive Officer and Director (principal executive officer) | May 27, 2026 |
| /s/ Lori Macomber<br> Lori Macomber | Executive Vice President, Chief Financial Officer and Treasurer (principal financial officer) | May 27, 2026 |
| /s/ Kristin Abate<br> Kristin Abate | Vice President, Chief Accounting Officer and Assistant Treasurer (principal accounting officer) | May 27, 2026 |
| /s/ Garen G. Bohlin<br> Garen G. Bohlin | Director | May 27, 2026 |
| /s/ Barry E. Greene<br> Barry E. Greene | Director | May 27, 2026 |
| /s/ Christy J. Oliger<br> Christy J. Oliger | Director | May 27, 2026 |
| /s/ Deepika R. Pakianathan<br> Deepika R. Pakianathan, Ph.D. | Director | May 27, 2026 |
| /s/ Chen Schor<br> Chen Schor | Director | May 27, 2026 |
| /s/ Zhen Su<br> Zhen Su, M.D. | Director | May 27, 2026 |

---

## Exhibit 5.1

**Exhibit 5.1** 

---

| | |
|:---|:---|
| <br> ![LOGO](g133029dsp07.jpg)  | SIDLEY AUSTIN LLP<br> ONE SOUTH DEARBORN STREET<br> CHICAGO, IL 60603<br> +1 312 853 7000<br> +1 312 853 7036 FAX<br>AMERICA • ASIA PACIFIC • EUROPE |

---

May 27, 2026

Karyopharm Therapeutics Inc.

85 Wells Avenue, 2nd Floor

Newton, MA 02459

---

| | |
|:---|:---|
| Re: | <u>3,950,000 shares of Common Stock, $0.0001 par value per share</u>  |

---

Ladies and Gentlemen:

We refer to the Registration Statement on Form S-8 (the "<u>Registration Statement</u>") being filed by Karyopharm Therapeutics Inc., a Delaware corporation (the "<u>Company</u>"), with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the "<u>Securities Act</u>"), relating to the registration of 3,950,000 shares of common stock, $0.0001 par value per share (the "<u>Common Stock</u>"), of the Company, which may be issued under the Karyopharm Therapeutics Inc. 2022 Equity Incentive Plan, as amended (the "<u>Plan,</u>" and the aggregate shares of Common Stock to be registered under the Registration Statement, the "<u>Registered Shares</u>").

This opinion letter is being delivered in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

We have examined the Registration Statement, the Company's Restated Certificate of Incorporation, the Company's Third Amended and Restated By-laws, the Plan, the resolutions adopted by the board of directors of the Company relating to the Registration Statement, the Plan, Amendment No. 4 to the Karyopharm Therapeutics Inc. 2022 Equity Incentive Plan ("<u>Amendment No.</u> <u>4</u>") (increasing the number of shares of Common Stock reserved for issuance under the Plan by 3,000,000 shares) and Amendment No. 5 to the Karyopharm Therapeutics Inc. 2022 Equity Incentive Plan ("<u>Amendment No.</u> <u>5</u>") (increasing the number of shares of Common Stock reserved for issuance under the Plan by 950,000 shares), and the proposal adopted by the stockholders of the Company relating to Amendment No. 4 at the Company's 2026 Annual Meeting of Stockholders. We have also examined originals, or copies of originals certified to our satisfaction, of such agreements, documents, certificates and statements of the Company and other corporate documents and instruments, and have examined such questions of law, as we have considered relevant and necessary as a basis for this opinion letter. We have assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures, the legal capacity of all persons and the conformity with the original documents of any copies thereof submitted to us for examination. As to facts relevant to the opinions expressed herein, we have relied without independent investigation or verification upon, and assumed the accuracy and completeness of, certificates, letters and oral and written statements and representations of public officials and officers and other representatives of the Company.

Sidley Austin LLP is a limited liability partnership practicing in affiliation with other Sidley Austin partnerships.

------

![LOGO](g133029dsp07.jpg)

Karyopharm Therapeutics Inc.

May 27, 2026

Based on the foregoing, we are of the opinion that each Registered Share that is newly issued pursuant to the Plan will be validly issued, fully paid and non-assessable when: (i) the Registration Statement, as finally amended, shall have become effective under the Securities Act; (ii) with respect to the portion of the Registered Shares subject to Amendment No. 5, Amendment No. 5 shall have been duly approved by the Company's stockholders; (iii) such Registered Share shall have been duly issued and delivered in accordance with the Plan; and (iv) a certificate representing such Registered Share shall have been duly executed, countersigned and registered and duly delivered to the person entitled thereto against payment of the agreed consideration therefor (in an amount not less than the par value thereof) or, if any such Registered Share is to be issued in uncertificated form, the Company's books shall reflect the issuance of such Registered Share to the person entitled thereto against payment of the agreed consideration therefor (in an amount not less than the par value thereof), all in accordance with the Plan.

This opinion letter is limited to the General Corporation Law of the State of Delaware. We express no opinion as to the laws, rules or regulations of any other jurisdiction, including, without limitation, the federal laws of the United States of America or any state securities or blue sky laws.

We hereby consent to the filing of this opinion letter as an exhibit to the Registration Statement and to all references to our Firm included in or made a part of the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act.

---

| |
|:---|
| Very truly yours, |
| /s/ Sidley Austin LLP |

---

## Exhibit 23.2

**Exhibit 23.2** 

**Consent of Independent Registered Public Accounting Firm** 

We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the 2022 Equity Incentive Plan, as amended, of Karyopharm Therapeutics Inc. of our reports dated February 12, 2026, with respect to the consolidated financial statements of Karyopharm Therapeutics Inc. and the effectiveness of internal control over financial reporting of Karyopharm Therapeutics Inc. included in its Annual Report (Form 10-K) for the year ended December 31, 2025, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Boston, Massachusetts

May 27, 2026

## Exhibit 99.2

**Exhibit 99.2** 

**AMENDMENT NO. 5 TO** 

**2022 EQUITY INCENTIVE PLAN OF** 

**KARYOPHARM THERAPEUTICS INC.** 

In accordance with Section 12(d) of the 2022 Equity Incentive Plan (the "Plan") of Karyopharm Therapeutics Inc. (the "Company"), the Plan is hereby amended, effective as of the date of approval by the Board of Directors of the Company, as follows (all capitalized terms used and not defined herein shall have the respective meanings ascribed to such terms in the Plan):

1. Section 4(a)(1)(A) of the Plan be and hereby is deleted in its entirety and the following is inserted in lieu thereof:

5,406,666 shares of Common Stock; and

2. Except as expressly amended herein, the Plan and all of the provisions contained therein shall remain in full force and effect.

\* \* \*

*Approved by the Board of Directors on May 22, 2026* 

*Approved by the Stockholders on ______ __, 202__\** 

*\** *If stockholder approval is not obtained on or prior to May 31, 2027, then the shares subject to this Amendment shall terminate and shall cease to be available under the Plan; provided, however, that if stockholders approve a lesser number of shares on or prior to May 31, 2027, then the amount listed above shall be reduced to reflect the approval of such lesser number of shares.*

## Ex-Filing

?xml version='1.0' encoding='ASCII'? EX-FILING FEES

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| |
|:---|
| **Calculation of Filing Fee Tables**  |
| &nbsp;&nbsp;&nbsp;&nbsp;**S-8**  |
| &nbsp;&nbsp;&nbsp;&nbsp;**Karyopharm Therapeutics Inc.**  |

---

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| | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| | **Security Type**  | **Security Class Title**  | **Fee Calculation Rule**  | **Amount Registered**  | **Proposed Maximum Offering Price Per Unit**  | **Maximum Aggregate Offering Price**  | **Fee Rate**  | **Amount of Registration Fee**  |
| 1 | Equity | Common Stock, par value $0.0001 per share | Other | 3950000 | $7.98 | $31521000.00 | 0.0001381 | $4353.05 |
| Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: |  | $31521000.00  |  | $4353.05  |
| Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  |  |  |  | $0.00  |
| Net Fee Due:  | Net Fee Due:  | Net Fee Due:  | Net Fee Due:  | Net Fee Due:  |  |  |  | $4353.05  |

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 **Offering Note** <br>

<sup>1</sup> (a) Karyopharm Therapeutics Inc., a Delaware corporation (the "Registrant"), is registering an additional 3,950,000 shares of common stock, par value $0.0001 per share (the "Common Stock"), that may be issued under the Karyopharm Therapeutics Inc. 2022 Equity Incentive Plan, as amended (the "Plan"). Pursuant to Rule 416 of the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement also covers such additional and indeterminate number of securities as may become issuable pursuant to the provisions of the Plan relating to adjustments for changes resulting from a stock dividend, stock split or similar change. (b) The offering price per unit and in the aggregate are estimated in accordance with Rule 457(h) under the Securities Act solely for the purpose of calculating the registration fee. The price of $7.98 per share represents the average high and low sales prices of the Common Stock as quoted on the Nasdaq Stock Market on May 21, 2026.

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| |
|:---|
| |
| **Rule 457(p)** |
| Fee Offset Claims |
| Fee Offset Sources |

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