Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995: This report on Form 10-Q contains forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 under Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements include statements with respect to our beliefs, plans, objectives, goals, expectations, anticipations, assumptions, estimates, intentions and future performance, and involve known and unknown risks, uncertainties and other factors, which may be beyond our control, and which may cause our actual results, performance or achievements to be materially different from future results, performance or achievements expressed or implied by such forward-looking statements. All statements other than statements of historical fact are statements that could be forward-looking statements. You can identify these forward-looking statements through our use of words such as "may," "will," "can," "anticipate," "assume," "should," "indicate," "would," "believe," "contemplate," "expect," "seek," "estimate," "continue," "plan," "point to," "project," "predict," "could," "intend," "target," "potential" and other similar words and expressions of the future.

There are a number of important factors that could cause the actual results to differ materially from those expressed in any forward-looking statement made by us. These factors include, but are not limited to:

† our ability to raise sufficient capital on terms acceptable to us, or at all;

† our ability to successfully integrate our and CuraGen's businesses, to integrate our and CuraGen's business without causing delays in the research and development necessary to select drug development candidates and/or delays in clinical trials, and to operate the combined business efficiently;

† our ability to adapt our APC Targeting Technology™ to develop new, safe and effective vaccines against oncology and infectious disease indications;

† our ability to adapt our vectoring systems to develop new, safe and effective orally administered vaccines against disease causing agents;

† our ability to successfully complete product research and further development, including animal, preclinical and clinical studies, and commercialization of CDX-110, CDX-1307, Ty800, CDX-1135 (formerly TP10), CDX-1401 and other products and the growth of the markets for those product candidates;

† the cost, timing, scope and results of ongoing safety and efficacy trials of CDX-110, CDX-1307, Ty800, CDX-1135, CDX-1401 and other preclinical and clinical testing, some of which are not managed by us;

† the ability to negotiate strategic partnerships or other disposition transactions for our non-core programs, including our cholesterol management vaccine, CETi;

† our ability to manage multiple clinical trials for a variety of product candidates at different stages of development;

† the strategies and business plans of our partners, such as Pfizer's plans for CDX-110, GlaxoSmithKline's plans with respect to Rotarix® and Vaccine Technologies' plans concerning the CholeraGarde® (Peru-15) and ETEC E. coli vaccines, which are not within our control, and our ability to maintain strong, mutually beneficial relationships with those partners;

† our ability to develop technological capabilities and expand our focus to broader markets for vaccines;

† the availability, cost, delivery and quality of clinical and commercial grade materials produced our own manufacturing facility or supplied by contract manufacturers and partners;

† the timing, cost and uncertainty of obtaining regulatory approvals for product candidates;

† our ability to develop and commercialize products before competitors that are superior to the alternatives developed by such competitors;

† the validity of our patents and our ability to avoid intellectual property litigation, which can be costly and divert management time and attention; and

† the factors listed under the headings "Business," "Risk Factors" and Management's Discussion and Analysis of Financial Condition and Results of Operations" in the Company's annual report on Form 10-K for the year ended December 31, 2008 and other reports that Celldex files with the Securities and Exchange Commission.

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 report or the date of the document incorporated by reference into this report. 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. We have expressed our expectations, beliefs and projections in good faith and we believe they have a reasonable basis. However, we cannot assure you that our expectations, beliefs or projections will result or be achieved or accomplished.

OVERVIEW

We are a biopharmaceutical company that uses novel applications of immunology to develop products for the prevention and treatment of diseases. Using our Precision Targeted Immunotherapy Platform, we are developing a broad portfolio of vaccines, therapeutic antibodies and other targeted immunotherapeutics addressing a wide range of applications including oncology, inflammatory and infectious diseases. These include therapeutic cancer vaccines, monoclonal antibodies, single-dose, oral vaccines that protect against important disease-causing infectious agents and a treatment to reduce complement-mediated tissue damage. We are advancing a robust pipeline of clinical and preclinical product candidates, the most advanced of which are for treatment of various cancers. Our lead programs are therapeutic cancer vaccines designed to instruct the patient's immune system to recognize and destroy cancer cells.

Our strategy is to demonstrate proof-of-concept for our product candidates before leveraging their value through partnerships or, in appropriate situations, continuing late stage development ourselves. Demonstrating proof-of-concept for a product candidate generally involves bringing it through Phase 1 clinical trials and one or more Phase 2 clinical trials so that we are able to demonstrate, based on human trials, good safety data for the product candidate and some data indicating its effectiveness. Our current collaborations encompass the commercialization of an oral human rotavirus vaccine, the development of oral cholera, ETEC and HIV vaccines, and a therapeutic brain cancer vaccine. Our product candidates generally address large market opportunities for which we believe current therapies are inadequate or non-existent.

We are targeting our efforts where we can add the greatest value to the development of our products and technologies. We out-license technology and programs that do not match our development focus or where we lack sufficient resources for the technology's or program's efficient development or where certain uses of the technology are outside of our focus. Our goal is to demonstrate clinical proof-of-concept for each product, and then seek excellent partners to help see those products through to commercialization. We thus leverage the value of our technology portfolio through corporate, governmental and non-governmental partnerships. This approach allows us to maximize the overall value of our technology and product portfolio while best ensuring the expeditious development of each individual product.

Merger between AVANT and Celldex

On March 7, 2008, we (formerly known as AVANT Immunotherapeutics, Inc.) ("AVANT") merged with and into Celldex Research Corporation (formerly known as Celldex Therapeutics, Inc.) ("Celldex Research"), a privately-held company, (the "AVANT Merger"). Effective October 1, 2008, we changed our name from AVANT Immunotherapeutics, Inc. to Celldex Therapeutics, Inc.

The AVANT Merger was accounted for using the purchase method of accounting and was treated as an acquisition by Celldex Research of AVANT even though AVANT was the issuer of common stock and the surviving legal entity in the transaction. Because Celldex Research was determined to be the acquirer for accounting purposes, the historical financial statements of Celldex Research became our historical financial as of the closing of the AVANT Merger. Accordingly, our financial statements prior to the AVANT Merger reflect the financial position, results of operations and cash flows of Celldex Research, which during the historical periods presented in the accompanying consolidated financial statements, was then majority-owned by Medarex, Inc. ("Medarex"). Following the AVANT Merger, the financial statements reflect the financial position, results of operation and cash flows of the combined companies. The results of operations of AVANT are included in our results of operations beginning March 8, 2008.

Merger between us and CuraGen

On October 1, 2009, CuraGen Corporation ("CuraGen"), a former publicly-traded company, merged with a wholly-owned subsidiary of us (the "CuraGen Merger") in accordance with a definitive merger agreement dated May 28, 2009 (the "CuraGen Merger Agreement"). In connection with the CuraGen Merger, effective October 1, 2009, we (i) issued 15,722,713 shares of our common stock, or 0.2739 shares, in exchange for each share of outstanding CuraGen common stock, plus cash in lieu of fractional shares (the "CuraGen Exchange Ratio"), (ii) assumed all of the CuraGen stock options outstanding under the CuraGen 2007 Stock Plan (the "CuraGen 2007

Options"), and (iii) assumed the obligations of the $12.5 million in CuraGen 4% convertible subordinated debt due in February 2011 (the "CuraGen Debt"). The CuraGen 2007 Options are exercisable into 931,315 shares of our common stock after applying the CuraGen Exchange Ratio.

In connection with the consummation of the CuraGen Merger, effective October 1, 2009, Celldex, CuraGen, and The Bank of New York Mellon (formerly the Bank of New York) (the "Trustee") amended the CuraGen Debt to provide that the CuraGen Debt shall be convertible into shares of Celldex common stock at the rate of 28.27823 shares of Celldex common stock per $1,000 principal amount of notes, or $35.36 per share.

Based on the closing price of the Company's common stock on October 1, 2009 of $5.43, the fair value of the shares issued was $85.4 million. The Company will apply acquisition accounting as of October 1, 2009. Accordingly, the results of operations of CuraGen will be included in the results of operations of the Company beginning October 1, 2009.

CURRENT PROGRAMS AND PARTNERSHIPS

Our products are derived from a broad set of complementary technologies which have the ability to utilize the human immune system and enable the creation of preventative and therapeutic agents. We are using these technologies to develop vaccines and targeted immunotherapeutics that prevent or treat cancer and disease caused by infectious organisms, and treatment vaccines that modify undesirable activity by the body's own proteins or cells. A number of our immunotherapeutic and vaccine product candidates are in various stages of clinical trials. We expect that a large percentage of our research and development expenses will be incurred in support of our current and future clinical trial programs.

Below is a table of our currently active programs:

Technology           Product           Indication/Field            Partner          Status

ONCOLOGY         CDX-110           Glioblastoma multiforme     Pfizer             Phase 2b
                 CDX-1307          Colorectal, bladder,                           Phase 1
                                   pancreas, ovarian and
                                   breast tumors               -
                 CDX-1401          Multiple solid tumors       -                  Phase 1/2
                 CDX-1127          Immuno-modulation,          -                  Preclinical
                                   multiple tumors
                 CR011*            Metastatic melanoma and     -                  Phase 1/2
                                   breast cancer
                 CR014*            Renal and ovarian cancer    -                  Preclinical

INFLAMMATORY     CDX-1135          Transplantation             -                  Phase 1/2
DISEASE          (formerly TP10)   Renal disease               -                  Preclinical
                 CDX-1189          Renal disease               -                  Preclinical

INFECTIOUS       CholeraGarde®     Cholera infection           Vaccine            Phase 2b
                                                               Technologies
DISEASE          ETEC              Enterotoxigenic E coli      Vaccine            Phase 1
                                   infection                   Technologies
                 Ty800             Typhoid fever infection     -                  Phase 2
                 CDX-2401          HIV infection               Rockefeller        Preclinical
                                                               University

MARKETED         Rotarix®          Rotavirus infection         GlaxoSmithKline    Marketed
PRODUCTS

The expenditures that will be necessary to execute our business plan are subject to numerous uncertainties. Completion of clinical trials may take several years or more, and the length of time generally varies substantially according to the type, complexity, novelty and intended use of a product candidate. It is not unusual for the clinical development of these types of product candidates to each take five years or more, and for total development costs to exceed $100 million for each product candidate. Our estimates that clinical trials of the type we generally conduct are typically completed over the following timelines:

                  Estimated
                 Completion
Clinical Phase     Period
Phase 1          1 - 2 Years
Phase 2          1 - 5 Years
Phase 3          1 - 5 Years

The duration and the cost of clinical trials may vary significantly over the life of a project as a result of differences arising during the clinical trial protocol, including, among others, the following:

†          the number of patients that ultimately participate in the trial;



†          the duration of patient follow-up that seems appropriate in view of
results;

† the number of clinical sites included in the trials;

† the length of time required to enroll suitable patient subjects; and

† the efficacy and safety profile of the product candidate.

We test potential product candidates in numerous preclinical studies for safety, toxicology and immunogenicity. We may then conduct multiple clinical trials for each product candidate. As we obtain results from trials, we may elect to discontinue or delay clinical trials for certain product candidates in order to focus our resources on more promising product candidates.

An element of our business strategy is to pursue the research and development of a broad portfolio of product candidates. This is intended to allow us to diversify the risks associated with our research and development expenditures. As a result, we believe our future capital requirements and our future financial success are not substantially dependent on any one product candidate. To the extent we are unable to maintain a broad range of product candidates, our dependence on the success of one or a few product candidates increases.

Regulatory approval is required before we can market our product candidates as therapeutic or vaccine products. In order to proceed to subsequent clinical trial stages and to ultimately achieve regulatory approval, the regulatory agency must conclude that our clinical data is safe and effective. Historically, the results from preclinical testing and early clinical trials (through Phase 2) have often not been predictive of results obtained in later clinical trials. A number of new drugs, biologics and vaccines have shown promising results in early clinical trials, but subsequently failed to establish sufficient safety and efficacy data to obtain necessary regulatory approvals.

Furthermore, our business strategy includes the option of entering into collaborative arrangements with third parties to complete the development and commercialization of our product candidates. In the event that third parties take over the clinical trial process for one of our product candidates, the estimated completion date would largely be under control of that third party rather than us. We cannot forecast with any degree of certainty which proprietary products, if any, will be subject to future collaborative arrangements, in whole or in part, and how such arrangements would affect our development plan or capital requirements. Our programs may also benefit from subsidies, grants, contracts or government or agency-sponsored studies that could reduce our development costs.

As a result of the uncertainties discussed above, among others, we are unable to estimate the duration and completion costs of our research and development projects or when, if ever, and to what extent it will receive cash inflows from the commercialization and sale of a product. Our inability to complete our research and development projects in a timely manner or our failure to enter into collaborative agreements, when appropriate, could significantly increase our capital requirements and could adversely impact our liquidity. These uncertainties could force us to seek additional, external sources of financing from time to time in order to continue with our business strategy. Our inability to raise additional capital, or to do so on terms reasonably acceptable to us, would jeopardize the future success of our business.

During the past five years through December 31, 2008, we incurred an aggregate of $55.6 million in research and development expenses. The following table indicates the amount incurred for each of our significant research programs and for other identified research and development activities during the year ended December 31, 2008 and the nine months ended September 30, 2009 and 2008. The amounts disclosed in the following table reflect direct research and development costs, license fees associated with the underlying technology and an allocation of indirect research and development costs to each program. Prior to 2008, the privately-held Celldex Research did not maintain records that allowed for quantification of research and development expenses by project.

                                                    Nine Months Ended September 30,        December 31,
                                                      2009                  2008               2008
                                                                     (In thousands)
Oncology:
CDX-110                                         $           3,483     $           6,353   $        8,072
CDX-1307                                                    5,341                 2,323            3,446
CDX-1401                                                    3,607                 3,337            5,562
CDX-1127                                                      639                   728            1,040

Inflammatory Disease:
CDX-1135                                                      371                   123              159
CDX-1189                                                      297                    25              104

Infectious Disease:
Bacterial Vaccines (CholeraGarde®/ETEC/Ty800)                 124                 1,391            1,481
CDX-2401                                                    2,342                   571              830

Marketed Products:
Rotarix®                                                    5,128                 1,915            3,260

Other Programs:                                             2,397                 1,977            2,393
Total R&D Expense                               $          23,729     $          18,743   $       26,347

Cancer Vaccine Development Programs

CDX-110: Our lead clinical development program, CDX-110, is a peptide-based immunotherapy that targets the tumor specific molecule called EGFRvIII, a functional variant of the naturally expressed epidermal growth factor receptor ("EGFR"), a protein which has been well validated as a target for cancer therapy. Unlike EGFR, EGFRvIII is not present in normal tissues, and has been shown to be a transforming oncogene that can directly contribute to the cancer cell growth. EGFRvIII is commonly present in glioblastoma multiforme, or GBM, the most common and aggressive form of brain cancer, and has also been observed in various other cancers such as breast, ovarian, prostate, colorectal, and head & neck cancer.

On April 16, 2008, we and Pfizer Inc. ("Pfizer") entered into a License and Development Agreement (the "Pfizer Agreement") under which Pfizer was granted an exclusive worldwide license to CDX-110. The Pfizer Agreement also gives Pfizer exclusive rights to the use of EGFRvIII vaccines in other potential indications. Pfizer funds all development costs for these programs. We and Pfizer are currently pursuing the development of CDX-110 for GBM therapy and plan to expand the clinical development into other cancers through additional clinical studies. The FDA has granted orphan drug designation for CDX-110 for the treatment of EGFRvIII expressing GBM as well as fast track designation.

We initiated a Phase 2b/3 randomized study (ACT III) of CDX-110 combined with standard of care, temozolomide, versus standard of care alone in patients with GBM in over 30 sites throughout the United States. In December 2008, we announced an amendment to convert the ACT III study to a single-arm Phase 2 clinical trial in which all patients will receive CDX-110 in combination with temozolomide. We expect to enroll approximately 60 patients. The decision, which follows the recommendation of the Independent Data Monitoring Committee, was based on the observation that the majority of patients randomized to the control (standard of care) arm withdrew from this open-label study after being randomized to the control arm. Patients currently participating on the control

arm of the study will be offered the option to receive treatment with CDX-110. Under this amendment, the ACT III study will provide a multi-center, non-randomized dataset for CDX-110 in patients with newly diagnosed GBM. These data will provide important additional information that can be used to better design the future development of CDX-110.

CDX-1307: Our lead APC Targeting Technology™ product candidate, CDX-1307, is in development for the treatment of epithelial tumors such as colorectal, pancreatic, bladder, ovarian and breast cancers. CDX-1307 targets the beta chain of human chorionic gonadotropin, known as hCG-Beta, which is an antigen often found in epithelial tumors. The presence of hCG-Beta in these cancers correlates with a poor clinical outcome, suggesting that this molecule may contribute to tumor growth. Normal adult tissues have minimal expression of hCG-Beta; therefore, targeted immune responses are not expected to generate significant side effects.

We are completing two Phase 1 studies at multiple centers that are designed to explore safety and dose/effect relationships via two administration routes-intradermal (ID), a traditional vaccine route that allows efficient access to local dermal dendritic cells and intravenous (IV), a novel systemic approach to vaccination that might target a much larger population of dendritic cells. In both studies, there are dose escalations of CDX-1307 alone and CDX-1307 with the adjuvant GM-CSF (known to increase mannose receptor expression on dendritic cells). At the highest dose levels planned, additional immune system modulators (Toll-Like Receptor Agonists, or TLR agonists) have been added to determine what effect they have in augmenting an immune response. Patients with an assortment of different tumor types that are known to express hCG-Beta are being accrued with retrospective analysis for hCG-Beta expression. A four dose regimen is utilized with the possibility of retreatment if patients demonstrate tumor regression or stable disease.

Over seventy (70) patients with epithelial cancers have been treated in the Phase 1 clinical trials and more than half have evidence of hCG-Beta expression by their tumor. The immunotherapy has been well tolerated with only minor adverse events observed (reddening at the injection site). Analysis of the initial cohorts with GM-CSF have revealed that several patients developed good humoral responses to hCG-Beta, and some have demonstrated enhancement of circulating hCG-Beta-specific CD8 T cells. Thus, we are encouraged that CDX-1307 is providing similar results as predicted in the preclinical studies. In addition, seven patients with breast, colorectal or pancreatic cancers experienced disease stabilization from 2.2 to over 6.5 months. The safety of CDX-1307 in combination with defined immune system modulators is now being evaluated with intent to enter Phase 2 clinical research in the first quarter of 2010.

CDX-1401: Our second APC Targeting Technology product candidate, CDX-1401, is a fusion protein consisting of a fully human monoclonal antibody with specificity for the dendritic cell receptor, DEC-205, linked to the NY-ESO-1 tumor antigen. In humans, NY-ESO-1 is one of the most immunogenic tumor antigens and has been detected in 20-30% of cancers, thus representing a broad opportunity. This product is intended to selectively deliver the NY-ESO-1 antigen to APCs for generating robust immune responses against cancer cells expressing NY-ESO-1. Unlike CDX-1307, which targets the mannose receptor expressing dendritic cells, CDX-1401 is the first APC product targeting DEC-205 expressing dendritic cells. We are developing CDX-1401 for the treatment of malignant melanoma and a variety of solid tumors which express the proprietary cancer antigen NY-ESO-1, which we licensed from the Ludwig Institute for Cancer Research in 2006. We believe that preclinical studies have shown that CDX-1401 is effective for activation of human T-cell responses against NY-ESO-1. In September 2009, we initiated enrollment in a Phase 1/2 study with a combination regimen, including TLRs, for multiple tumors that express NY-ESO-1.

. . .