December 12, 2019 Anthony S. Marucci President and Chief Executive Officer Celldex Therapeutics, Inc. Perryville III Building, 53 Frontage Road, Suite 220 Hampton, NJ 08827 Re: Celldex Therapeutics, Inc. Registration Statement on Form S-3 Filed December 6, 2019 File No. 333-235399 Dear Mr. Marucci: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Jeffrey Gabor at 202-551-2544 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Anthony O. Pergola, Esq.