Celldex Therapeutics Announces Proposed Public Offering of Common Stock HAMPTON, N.J.

Celldex Therapeutics Announces Proposed Public Offering of Common

HAMPTON, N.J., July 12, 2021 (GLOBE NEWSWIRE) - Celldex Therapeutics,

Inc. ("Celldex" or the "Company") (Nasdaq: CLDX) today announced that it is proposing to offer and sell, subject

to market conditions, $175 million of shares of its common stock in an underwritten public offering. Celldex expects to grant the

underwriters a 30-day option to purchase up to an additional $26.25 million of shares of common stock offered in the public offering.

All of the shares of common stock are being offered by the Company. Celldex intends to use the net proceeds from the offering to continue

clinical and preclinical development of its product candidates and for general corporate purposes. The final terms of the offering will

depend on market and other conditions at the time of pricing, and there can be no assurance as to whether or when the offering may be

completed, or as to the actual size or terms of the offering.

Jefferies, SVB Leerink, Guggenheim Securities and Cantor are acting as the joint book-running managers for the proposed offering.

The securities described above will be offered pursuant to a shelf

registration statement on Form S-3 (No. 333-249917), which was previously filed with the Securities and Exchange Commission ("SEC")

and deemed effective on November 6, 2020. A preliminary prospectus supplement and accompanying base prospectus relating to and describing

the terms of the offering will be filed with the SEC and will be available on the SEC's website located at http://www.sec.gov,

copies of which may be obtained, when available, from Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue,

2nd Floor, New York, NY 10022, by telephone at (877) 821-7388 or by e-mail at prospectus_department@jefferies.com; SVB Leerink LLC, Attention:

Syndicate Department, One Federal Street, 37th Floor, Boston, MA 02110, by telephone at (800) 808-7525, ext. 6105, or by e-mail at syndicate@svbleerink.com;

or Guggenheim Securities, LLC Attention: Equity Syndicate Department, 330 Madison Avenue, New York, NY 10017 or by telephone at (212)

518-9544, or by email at GSEquityProspectusDelivery@guggenheimpartners.com; or Cantor Fitzgerald & Co., Attn: Capital Markets, 499 Park Avenue, 4th Floor, New York, New York 10022 or by email at prospectus@cantor.com.

This offering will be made only by means of a prospectus. This press

release does not constitute an offer to sell or the solicitation of an offer to buy any of the securities described herein, nor shall

there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior

to the registration or qualification under the securities laws of any such state or other jurisdiction.

About Celldex Therapeutics, Inc.

Celldex is a clinical stage biotechnology company dedicated to developing

monoclonal and bispecific antibodies that address devastating diseases for which available treatments are inadequate. Our pipeline includes

antibody-based therapeutics which have the ability to engage the human immune system and/or directly affect critical pathways to improve

the lives of patients with inflammatory diseases and many forms of cancer.

Forward Looking Statement

This release contains "forward-looking

statements" made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements

are typically preceded by words such as "believes," "expects," "anticipates," "intends,"

"will," "may," "should," or similar expressions. These forward-looking statements reflect management's

current knowledge, assumptions, judgment and expectations regarding future performance or events. Although management believes that the

expectations reflected in such statements are reasonable, they give no assurance that such expectations will prove to be correct or that

those goals will be achieved, and you should be aware that actual results could differ materially from those contained in the forward-looking

statements. Forward-looking statements are subject to a number of risks and uncertainties, including, but not limited to, risks associated

with market conditions and the satisfaction of customary closing conditions related to the offering and uncertainties related to the

Company's expectations regarding the completion, timing and size of the proposed offering. For a further description of the risks

and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks

relating to the Company's business in general, please refer to the Company's prospectus supplement to be filed with the SEC,

and the documents incorporated by reference therein, including the Company's Form 10-K for the year ended December 31, 2020 and Form 10-Q for the quarter ended March 31, 2021.

All forward-looking statements are expressly

qualified in their entirety by this cautionary notice. You are cautioned not to place undue reliance on any forward-looking statements,

which speak only as of the date of this release. We have no obligation, and expressly disclaim any obligation, to update, revise or correct

any of the forward-looking statements, whether as a result of new information, future events or otherwise.

Senior Vice President, Corporate Affairs & Administration

Celldex Therapeutics, Inc.

Senior Director, Investor Relations & Corporate Communications

Celldex Therapeutics, Inc.

Source: Celldex Therapeutics, Inc.