UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-K/A

(AMENDMENT NO. 1)

(Mark One)

For the fiscal year ended December 31, 2015

OR

For the transition period from                      to                     

Commission File Number: 001-36508

KITE PHARMA, INC.

(Exact Name of Registrant as Specified in Its Charter)

(310) 824-9999

(Registrant’s Telephone Number, Including Area Code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  x    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    x

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

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant based on the closing price of the registrant’s common stock as reported on The NASDAQ Global Select Market on June 30, 2015, the last business day of the registrant’s most recently completed second quarter, was $1,863 million.

As of February 23, 2016, there were 48,839,557 shares of the registrant’s common stock, par value $0.001 per share, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive Proxy Statement relating to its 2016 Annual Meeting of Stockholders were incorporated by reference into Part III of the Annual Report on Form 10-K that this filing amends. Such Proxy Statement was filed with the U.S. Securities and Exchange Commission within 120 days after the end of the fiscal year to which such Annual Report relates.

EXPLANATORY NOTE

This Amendment No. 1 to Form 10-K/A (this “Amendment”) amends the Annual Report on Form 10-K of Kite Pharma, Inc. (the “Company”) for the year ended December 31, 2015, originally filed with the Securities and Exchange Commission on February 29, 2016 (the “Original Filing”). This Amendment is being filed solely to include revised Exhibits 31.1 and 31.2, which replace the previously filed versions of those exhibits, to include certain statements required by Item 601(b)(31) of Regulation S-K inadvertently omitted when previously filed.

Except as described as above, no changes have been made to the Original Filing. The Original Filing continues to speak as of the date of the Original Filing, and the Company has not updated the disclosures contained therein to reflect any events that have occurred as of a date subsequent to the date of the Original Filing. Accordingly, this Amendment should be read in conjunction with the Original Filing and the Company’s filings made with the SEC subsequent to the filing of the Original Filing. The filing of this Amendment is not an admission that the Original Filing, when filed, included any untrue statement of a material fact or omitted to state a material fact necessary to make a statement not misleading.

PART IV

Item  15. Exhibits, Financial Statement Schedules

The following documents are filed as exhibits to this Amendment:

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

EXHIBIT INDEX