# EDGAR Filing Document

**Accession Number:** 0001503802
**File Stem:** 0001193125-26-219351
**Filing Date:** 2026-5
**Character Count:** 2052
**Document Hash:** 4b06794352b99e64d795eaba97a7393c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-219351.hdr.sgml**: 20260616

**ACCESSION NUMBER**: 0001193125-26-219351

**CONFORMED SUBMISSION TYPE**: CORRESP

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260512

**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:** CORRESP

**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

May 12, 2026

**<u>VIA EDGAR SUBMISSION</u>**

Securities and Exchange Commission

Division of Corporation Finance, Office of Life Sciences

100 F Street, NE

Washington, DC 20549

Attention: Alan Campbell

Re: Karyopharm Therapeutics Inc. <br> Registration Statement on Form S-3 Filed May 4, 2026 File No. 333-295535 <u>Request for Acceleration</u>

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, as amended, Karyopharm Therapeutics Inc. (the "Registrant") hereby requests acceleration of the effective date of its Registration Statement on Form S-3 (File No. 333-295535), so that it may become effective at 4:30 p.m., Eastern Time, on May 14, 2026, or as soon as practicable thereafter, or at such later time as the Registrant or its counsel may orally request via telephone call to the staff.

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| | |
|:---|:---|
| Very truly yours,<br>KARYOPHARM THERAPEUTICS INC. | Very truly yours,<br>KARYOPHARM THERAPEUTICS INC. |
| By: | /s/ Michael Mano |
| Name: | Michael Mano |
| Title: | Executive Vice President, Chief Legal Officer and Secretary |

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cc: Jason Kropp, *Sidley Austin LLP* <br> Craig Hilts, *Sidley Austin LLP*