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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

Amendment No. 2

(Mark one)

x      ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2009

or

o         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number 0-15006

CELLDEX THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

119 Fourth Avenue, Needham, Massachusetts 02494

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (781) 433-0771

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 o  No x

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 o  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 o

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 o  No o

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 definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

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

The aggregate market value of the voting and non-voting common stock held by non-affiliates as of June 30, 2009 was $100.8 million (excludes shares held by directors and executive officers). Exclusion of shares held by any person should not be construed to indicate that such person possesses the power, direct or indirect, to direct or cause the actions of the management or policies of the registrant, or that such person is controlled by or under common control with the registrant.

The number of shares of common stock outstanding at December 17, 2010 was 32,054,238 shares.

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CELLDEX THERAPEUTICS, INC.

ANNUAL REPORT ON FORM 10-K

YEAR ENDED DECEMBER 31, 2009

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EXPLANATORY NOTE

This Amendment No. 2 on Form 10-K/A (the “Amendment”) amends the Annual Report on Form 10-K of Celldex Therapeutics, Inc. (the “Company”, “our” or “we”) for the year ended December 31, 2009 that was originally filed with the Securities and Exchange Commission on March 12, 2010 and amended on March 31, 2010 (“Amendment No. 1”) is being filed to provide updated information required by Item 15 of Part IV.  This Amendment does not otherwise modify or update disclosures in the original filing, Amendment No. 1 or change our previously reported financial statements and other financial disclosure.

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PART IV

Item 15.  EXHIBITS, FINANCIAL STATEMENT SCHEDULES

(A)                              The following documents are filed as part of this Form 10-K/A:

(3)                           Exhibits:

*                                         Confidential treatment has been requested for certain provisions of this Exhibit pursuant to Rule 24b-2 promulgated under the Securities Exchange Act of 1934, as amended.

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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.

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