SEC Form S-8 filed by Celldex Therapeutics Inc.

As filed with the Securities and Exchange Commission on June 26, 2026

Registration No. 333- [     ]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

CELLDEX THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Perryville III Building

53 Frontage Road, Suite 220

Hampton, New Jersey 08827

(908) 200-7500

(Address of principal executive offices; zip code)

Celldex Therapeutics, Inc. 2021 Omnibus Equity Incentive Plan

(Full title of the plan)

Sam Martin

Chief Financial Officer

CELLDEX THERAPEUTICS, INC.

Perryville III Building

53 Frontage Road, Suite 220

Hampton, New Jersey 08827

(908) 200-7500 

(Name, address and telephone number, including area code, of agent for service)

Copies to:

Anthony O. Pergola, Esq. 

Lowenstein Sandler LLP

1251 Avenue of the Americas

New York, New York 10020

(212) 262-6700

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

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 7(a)(2)(B) of the Securities Act. ¨

EXPLANATORY NOTE

This Registration Statement is being filed by the registrant, Celldex Therapeutics, Inc. (the “Company”), for the purpose of registering an additional 3,400,000 shares of common stock, par value $0.001 per share (“Common Stock”), to be issued under the Celldex Therapeutics, Inc. 2021 Omnibus Equity Incentive Plan (as amended, effective as of June 25, 2026) (the “2021 Plan”), pursuant to General Instruction E on Form S-8 (Registration of Additional Securities).

The contents of the original registration statement on Form S-8 for the 2021 Plan filed on June 16, 2021 (File No. 333-257137), the registration statement on Form S-8 for the 2021 Plan filed on June 21, 2023 (File No. 333-272804), the registration statement on Form S-8 for the 2021 Plan filed on June 14, 2024 (File No. 333-280207) and the registration statement on Form S-8 for the 2021 Plan filed on June 6, 2025 (File No. 333-287839) are hereby incorporated by reference and made a part hereof. Any items in the Company’s Registration Statements on Form S-8 (File No. 333-257137, File No. 333-272804, File No. 333-280207 and File No. 333-287839) not expressly changed hereby shall be as set forth in the Company’s Registration Statements on Form S-8 (File No. 333-257137, File No. 333-272804, File No. 333-280207 and File No. 333-287839)). The stockholders of the registrant approved amending the 2021 Plan for this purpose at the annual meeting of stockholders held on June 25, 2026.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

The Securities and Exchange Commission allows us to “incorporate” into this registration statement information we file with other documents. This means that we may disclose important information to you by referring to other documents that contain that information. The information incorporated by reference is considered to be part of this registration statement, and information we file later with the Securities and Exchange Commission will automatically update and supersede this information. We incorporate by reference the documents listed below, except to the extent information in those documents is different from the information contained in this registration statement:

All documents subsequently filed by us with the Securities and Exchange Commission pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, prior to the filing of a post-effective amendment to this registration statement, which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in this registration statement and to be a part hereof from the date of filing of such documents, except as to specific sections of such documents as set forth therein. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained in any subsequently filed document, which also is deemed to be incorporated by reference herein, modifies or supersedes such statement.

The exhibits accompanying this registration statement are listed on the accompanying exhibit index.

EXHIBIT INDEX

* Filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Hampton, State of New Jersey, on June 26, 2026.

KNOW ALL BY THESE PRESENTS that each individual whose signature appears below constitutes and appoints Anthony S. Marucci and Sam Martin, and each of them singly, as such person’s true and lawful attorney-in-fact and agent with full power of substitution and resubstitution, for such person in such person’s name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Securities and Exchange Commission, granting unto each said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that any said attorney-in-fact and agent, or any substitute or substitutes of any of them, may lawfully do or cause to be done by virtue hereof.