UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 9, 2017

CELLDEX THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Perryville III Building, 53 Frontage Road, Suite 220,
Hampton, New Jersey 08827

(Address of principal executive offices) (Zip Code)

(908) 200-7500

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o                        Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o                        Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                        Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                        Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 8.01.  Other Events.

Previously, on May 19, 2016, Celldex Therapeutics, Inc. (the “Company”) entered into a Controlled Equity OfferingSM Sales Agreement (the “Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor Fitzgerald”), as sales agent, pursuant to which the Company may offer and sell, from time to time, through Cantor Fitzgerald shares of its common stock, par value $0.001 per share. On November 9, 2017, the Company filed a prospectus supplement registering the offer and sale of shares of common stock of up to $75.0 million pursuant to the Sales Agreement.

The Company is not obligated to sell any shares under the Sales Agreement. Subject to the terms and conditions of the Sales Agreement, Cantor Fitzgerald will use commercially reasonable efforts consistent with its normal trading and sales practices, applicable state and federal law, rules and regulations and the rules of the Nasdaq Global Market to sell shares from time to time based upon the Company’s instructions, including any price, time or size limits specified by the Company. Under the Sales Agreement, Cantor Fitzgerald may sell shares by any method deemed to be an “at the market offering” as defined in Rule 415(a)(4) under the U.S. Securities Act of 1933, as amended, or any other method permitted by law. Cantor Fitzgerald’s obligations to sell shares under the Sales Agreement are subject to satisfaction of certain conditions, including customary closing conditions. The Company will pay Cantor Fitzgerald a commission equal to 3.0% of the aggregate gross proceeds from each sale of shares and has agreed to provide Cantor Fitzgerald with customary indemnification and contribution rights. The Company has also agreed to reimburse Cantor Fitzgerald for certain specified expenses.

Sales of shares of common stock under the Sales Agreement will be made pursuant to the registration statement on Form S-3 (File No. 333-214882), which was declared effective by the U.S. Securities and Exchange Commission (the “SEC”) on February 13, 2017, and a related prospectus supplement filed with the SEC on November 9, 2017, for an aggregate offering price of up to an additional $75,000,000.

The foregoing summary of the Sales Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Sales Agreement, which is included as Exhibit 1.1 hereto.

This Current Report on Form 8-K shall not constitute an offer to sell or the solicitation of an offer to buy any shares under the Sales Agreement, nor shall there be any sale of such shares in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

Item 9.01                                           Financial Statements and Exhibits.

(d)

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

3

Exhibit 5.1

[Lowenstein Sandler LLP letterhead]

November 9, 2017

Celldex Therapeutics, Inc.

Perryville III Building

53 Frontage Road, Suite 220

Hampton, NJ 08827

Ladies and Gentlemen:

We have acted as counsel to Celldex Therapeutics, Inc., a Delaware corporation (the “Company”), in connection with the offer and sale by the Company of up to an aggregate of $75,000,000 of shares of its common stock, par value $0.001 per share (the “Shares”), pursuant to the Controlled Equity OfferingSM Sales Agreement (the “Sales Agreement”), dated May 19, 2016, by and between the Company and Cantor Fitzgerald & Co., as sales agent.  The Shares are being offered for sale pursuant to the Company’s registration statement on Form S-3 (File No. 333-214882) (the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), and the rules and regulations promulgated thereunder, the prospectus, dated February 13, 2017 (the “Prospectus”) and the Prospectus Supplement filed pursuant to Rule 424(b) under the Securities Act, dated November 9, 2017 (the “Prospectus Supplement”).

We understand that the Shares are to be issued by the Company and sold by Cantor Fitzgerald & Co. pursuant to the Sales Agreement, as described in the Registration Statement, the Prospectus and the Prospectus Supplement.

In connection with this opinion, we have examined the Sales Agreement, the Registration Statement, the Prospectus and the Prospectus Supplement. In addition, we have reviewed such corporate records and documents and made such examination of law as we have deemed appropriate to give the opinion expressed below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinion set forth below, on the representations and warranties set forth in the Sales Agreement and certificates of officers of the Company. In making our examination, we have assumed that all signatures on documents examined by us are genuine, the authenticity of all documents submitted to us as originals and the conformity with the original documents of all documents submitted to us as certified, conformed or photostatic copies.

We have also assumed the legal capacity for all purposes relevant hereto of all natural persons and, with respect to all parties to agreements or instruments relevant hereto other than the Company, that such parties had the requisite power and authority (corporate or otherwise) to execute, deliver and perform such agreements or instruments, that such agreements or instruments have been duly authorized by all requisite action (corporate or otherwise), executed and delivered by such parties and that such agreements or instruments are the valid, binding and enforceable obligations of such parties.

Based on the foregoing, and subject to the assumptions, limitations and qualifications set forth herein, we are of the opinion that, upon the issuance and sale of the Shares in accordance with the Sales Agreement, and as described in the Registration Statement, the Prospectus and the Prospectus Supplement, the Shares will be validly issued, fully paid and non-assessable.

The opinion expressed above is limited to the federal laws of the United States and to the General Corporation Law of the State of Delaware (including reported judicial decisions interpreting the General Corporation Law of the State of Delaware). We express no opinion as to the effect of the law of any other jurisdiction. Our opinion is rendered as of the date hereof, and we assume no obligation to advise you of changes in law or fact (or the effect thereof on the opinions expressed herein) that hereafter may come to our attention.

We hereby consent to the inclusion of this opinion as an exhibit to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the Prospectus Supplement. In giving our consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations thereunder.