FIVE PRIME THERAPEUTICS, INC.
Two Corporate Drive
South San Francisco, California 94080
May 19, 2016
VIA EDGAR
Mr. Jim B. Rosenberg, Senior Assistant Chief Accountant
Office of Healthcare and Insurance
Division of Corporation Finance
Securities and Exchange Commission
100 F Street N.E., Mail Stop 4720
Washington, DC 20549
| Re: | Five Prime Therapeutics, Inc. |
| Form 10-K for the Year Ended December 31, 2015 |
| Filed on March 11, 2016 |
| File No. 001-36070 |
Dear Mr. Rosenberg:
We have received the comment letter dated May 16, 2016 from you regarding the comments of the Staff with respect to the above-referenced Form 10-K. Confirming Jaime Chase’s phone conversation on May 19, 2016 with Mr. Jacob Luxenburg, Staff Accountant, we have requested an extension for our response to the comment letter to June 15, 2016.
If you have any questions regarding this extension request, please contact me at (415) 365-5796, Francis Sarena at (415) 365-5632 or Jaime L. Chase at (202) 728-7096.
Very truly yours,
/s/ Marc Belsky
Marc Belsky
Senior Vice President and Chief Financial Officer
