KARYOPHARM THERAPEUTICS INC.
85 WELLS AVENUE, SECOND FLOOR
NEWTON, MA 02459
February 13, 2018
Via EDGAR
Securities and Exchange Commission
Division of Corporation Finance
100 F Street, N.E.
Washington, D.C. 20549
| Re: | Karyopharm Therapeutics Inc. |
| Registration Statement on Form S-3 |
| File No. 333-222726 |
| Request for Acceleration |
Ladies and Gentlemen:
Karyopharm Therapeutics Inc. (the “Registrant”) hereby withdraws its earlier request dated the date hereof requesting acceleration of the effective date of its Registration Statement on Form S-3 (File No. 333-222726) (the “Registration Statement”) to February 15, 2018.
Pursuant to Rule 461 promulgated under the Securities Act of 1933, as amended, the Registrant hereby requests acceleration of the effective date of the Registration Statement so that it may become effective at 4:00 p.m. Eastern time on February 14, 2018, or as soon thereafter as practicable.
Very truly yours,
Karyopharm Therapeutics Inc.
| By: | /s/ Christopher B. Primiano | |
| Name: | Christopher B. Primiano | |
| Title: | Executive Vice President, Chief Business Officer, General Counsel and Secretary |