Celldex Therapeutics, Inc. (CLDX) FY 2021 MD&A

Item 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

OVERVIEW

We are a biopharmaceutical company dedicated to developing therapeutic monoclonal and bispecific antibodies that address diseases for which available treatments are inadequate. Our drug candidates include 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.

We are focusing our efforts and resources on the continued research and development of:

We routinely work with external parties to collaboratively advance our drug candidates. In addition to Celldex-led studies, we also have an Investigator Initiated Research (IIR) program with multiple studies ongoing with our drug candidates.

Our goal is to build a fully integrated, commercial-stage biopharmaceutical company that develops important therapies for patients with unmet medical needs. We believe our program assets provide us with the strategic options to either retain full economic rights to our innovative therapies or seek favorable economic terms through advantageous commercial 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. Currently, all programs are fully owned by Celldex.

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 drug candidate. It is not unusual for the clinical development of these types of drug candidates to each take five years or more, and for total development costs to exceed $100 million for each drug candidate. We estimate that clinical trials of the type we generally conduct are typically completed over the following timelines:

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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:

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

An element of our business strategy is to pursue the discovery, research and development of a broad portfolio of drug candidates. This is intended to allow us to diversify the risks associated with our research and development expenditures. To the extent we are unable to maintain a broad range of drug candidates, our dependence on the success of one or a few drug candidates increases.

Regulatory approval is required before we can market our drug candidates as therapeutic products. In order to proceed to subsequent clinical trial stages and to ultimately achieve regulatory approval, the regulatory agencies must conclude that our clinical data demonstrate that our product candidates are 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 and biologics 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 drug candidates. In the event that third parties take over the clinical trial process for one of our drug 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, it is difficult to accurately estimate the duration and completion costs of our research and development projects or when, if ever, and to what extent we 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, 2021, we incurred an aggregate of $301.1 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 years ended December 31, 2021, 2020 and 2019. The amounts disclosed in the

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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.

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Clinical Development Programs

The COVID-19 pandemic continues to have a major impact in the US and around the world. The availability of vaccines holds promise for the future, though new variants of the virus and potential waning immunity from vaccines may result in continued impact from this pandemic in the future, which could adversely impact our operations. To date, the Company has managed delays and disruptions without significant impact in planned and ongoing preclinical and clinical trials, manufacturing or shipping. Potential impacts to our business include delays in planned and ongoing preclinical and clinical trials including enrollment of patients, disruptions in time and resources provided by independent clinical investigators, contract research organizations, and other third-party service providers, temporary closures of our facilities, disruptions or restrictions on our employees’ ability to travel, and delays in manufacturing and/or shipments to and from third-party suppliers and contract manufacturers for APIs and drug product.

CDX-0159

CDX-0159 is a humanized monoclonal antibody that specifically binds the receptor tyrosine kinase KIT and potently inhibits its activity. KIT is expressed in a variety of cells, including mast cells, and its activation by its ligand SCF regulates mast cell growth, differentiation, survival, chemotaxis and degranulation. CDX-0159 is designed to block KIT activation by disrupting both SCF binding and KIT dimerization. Celldex believes that by targeting KIT, CDX-0159 may be able to inhibit mast cell activity and decrease mast cell numbers to provide potential clinical benefit in mast cell related diseases.

In certain inflammatory diseases, such as chronic spontaneous urticaria (“CSU”), also known as chronic idiopathic urticaria (“CIU”) and chronic inducible urticaria (“CIndU”), mast cell degranulation plays a central role in the onset and progression of the disease. In June 2020, we completed a randomized, double-blind, placebo-controlled, single ascending dose escalation Phase 1a study of CDX-0159 in healthy subjects (n=32; 8 subjects per cohort, 6 CDX-0159; 2 placebo). Subjects received a single intravenous infusion of CDX-0159 at 0.3, 1.0, 3.0, or 9.0 mg/kg or placebo. The objectives of the study included safety and tolerability, pharmacokinetics (PK) and pharmacodynamics (tryptase and stem cell factor) and immunogenicity. Tryptase is an enzyme synthesized and secreted almost exclusively by mast cells and decreases in plasma tryptase levels are believed to reflect a systemic reduction in mast cell burden in both healthy volunteers and in disease. Data from the study were featured in a late breaking presentation at the European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress 2020 in June. CDX-0159 demonstrated a favorable safety profile as well as profound and durable reductions of plasma tryptase, consistent with systemic mast cell suppression.

These data supported expansion of the CDX-0159 program into mast cell driven diseases, including initially in CSU and CIndU, diseases where mast cell degranulation plays a central role in the onset and progression of the disease. The prevalence of CSU and CIndU is approximately 0.5-1% of the total population or up to 1 to 3 million patients in the United States alone (Weller et al. 2010. Hautarzt. 61(8), Bartlett et al. 2018. DermNet. Org). CSU presents as itchy hives, angioedema or both for at least six weeks without a specific trigger; multiple episodes can play out over years or even decades. About 50% of patients with CSU achieve symptomatic control with antihistamines or leukotriene receptor antagonists. Omalizumab, an IgE inhibitor, provides relief for roughly half of the remaining antihistamine/leukotriene refractory patients. Consequently, there is a need for additional therapies. CIndUs are forms of urticaria that have an attributable cause or trigger associated with them, typically resulting in hives or wheals. Celldex is exploring cold-induced, dermographism (scratch-induced) and cholinergic (exercise-induced) urticarias.

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In October 2020, we announced that enrollment had opened and the first patient had been dosed in a Phase 1b multi-center study of CDX-0159 in CSU. This study is a randomized, double-blind, placebo- controlled clinical trial designed to assess the safety of multiple ascending doses of CDX-0159 in up to 40 patients with CSU who remain symptomatic despite treatment with antihistamines. Secondary and exploratory objectives include pharmacokinetic and pharmacodynamic assessments, including measurement of tryptase and stem cell factor levels and clinical activity outcomes (impact on urticaria symptoms, disease control, clinical response) as well as quality of life assessments. CDX-0159 is administered intravenously (0.5, 1.5, 3 and 4.5 mg/kg at varying dosing schedules) as add on treatment to H1- antihistamines, either alone or in combination with H2-antihistamines and/or leukotriene receptor agonists.

In December 2020, we announced that enrollment had opened and the first patient had been dosed in a second Phase 1b study in CIndU being conducted in Germany in patients who are refractory to antihistamines. This study is an open label clinical trial designed to evaluate the safety of a single dose (3 mg/kg) of CDX-0159 in patients with cold urticaria (n=10) or symptomatic dermographism (n=10). In March and June 2021, respectively, we added a third cohort (single dose, 3 mg/kg) in patients with cholinergic urticaria (n=10) and a fourth cohort at a lower dose (single dose, 1.5 mg/kg) in cold urticaria. Patient’s symptoms are induced via provocation testing that resembles real life triggering situations. Secondary and exploratory objectives include pharmacokinetic and pharmacodynamic assessments, including changes from baseline provocation thresholds, measurement of tryptase and stem cell factor levels, clinical activity outcomes (impact on urticaria symptoms, disease control, clinical response), quality of life assessments and measurement of tissue mast cells through skin biopsies. CDX-0159 is administered intravenously on Day 1 as add on treatment to H1-antihistamines.

In July of 2021, we reported positive interim data from the cold urticaria and symptomatic dermographism cohorts. As of the data cut-off on June 11, 2021, 20 patients had received a single intravenous infusion of CDX-0159 at 3 mg/kg, including 11 patients with cold urticaria and 9 patients with symptomatic dermographism. Patients had high disease activity as assessed by provocation threshold testing. In patients with cold urticaria and symptomatic dermographism baseline critical temperature thresholds were 18.9°C/66°F (range: 5-27°C/41-80.6°F) and FricTest® thresholds were 3.8 (range: 3-4) of 4 pins. Safety results were reported for all 20 patients; activity results were reported for the 19 patients who received a full dose of CDX-0159. 14 of 19 patients completed the 12-week study observation period and five were ongoing (range of 2-8 weeks) as of June 11, 2021.

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In September of 2021, we reported additional positive data from the study on measurements of symptom control and quality of life. A single dose of CDX-0159 (3 mg/kg) resulted in a rapid and sustained improvement in urticaria control and greatly reduced disease impact on quality of life, as measured by the Urticaria Control Test (UCT) and Dermatology Life Quality Index (DLQI).

Celldex has expanded clinical development of CDX-0159 into prurigo nodularis (“PN"). PN is a chronic skin disease characterized by the development of hard, intensely itchy (pruritic) nodules on the skin. Mast cells through their interactions with sensory neurons and other immune cells are believed to play an important role in amplifying chronic itch and neuroinflammation, both of which are a hallmark of PN. There are currently no FDA approved therapies for PN, representing an area of significant unmet need. Industry sources estimate there are approximately 154,000 patients in the United States with PN who have undergone treatment within the last 12 months and, of these, approximately 75,000 would be biologic-eligible. In December 2021, the first patient was dosed in a Phase 1b multi-center, randomized, double-blind, placebo-controlled study designed to assess the safety and treatment effects across multiple dosing cohorts of CDX-0159 in up to 30 patients with PN.

Manufacturing activities to support the introduction of the CDX-0159 subcutaneous formulation into the clinical program have been completed and, in September 2021, we initiated dosing in a randomized, double-blind, placebo-controlled, Phase 1 study designed to evaluate the safety of single ascending doses of the subcutaneous formulation of CDX-0159 in healthy volunteers. In February 2022, we reported that subcutaneous administration of CDX-0159 was well tolerated and that multiple dose levels have been identified that possess promising pharmacokinetic and pharmacodynamic properties. Importantly, subcutaneous delivery of CDX-0159 resulted in dose-dependent, rapid and sustained decreases in serum tryptase compared with placebo and achieved sufficient exposure to produce tryptase suppression levels comparable with the levels that generated impressive clinical activity observed in the Phase 1 CIndU intravenous study. Celldex anticipates the upcoming Phase 2 multi-dose studies in urticaria will evaluate 75mg and 150mg administered q4weeks and 300mg administered q8weeks. The planned doses support a 0.5 to 2 ml injection volume, allowing for a single injection as CDX-0159 advances towards potential commercialization. In 2022, we plan to initiate a transfer of our current CDX-0159 manufacturing process to a contract manufacturing organization to support late-stage trials and to prepare for potential commercialization.

In February 2022, we also reported interim data after completing the in-life dosing portion of our six month chronic toxicology study in non-human primates; a subset of the animals will continue to be followed beyond clearance of the CDX-0159 antibody to study completion. As expected and consistent with other KIT-targeting agents, impact on spermatogenesis was observed which is anticipated to be fully reversible upon clearance of the antibody. There were no other clinically adverse findings reported in the study. Celldex believes these data strongly support the Company’s planned Phase 2 studies in urticaria later this year and in future indications.

In February 2022, we announced that we will be expanding clinical development of CDX-0159 into eosinophilic esophagitis (“EoE”), the most common type of eosinophilic gastrointestinal disease. EoE is a chronic inflammatory disease of the esophagus characterized by the infiltration of eosinophils. This chronic inflammation can result in trouble swallowing, chest pain, vomiting and impaction of food in the esophagus, a medical emergency. Several studies have suggested that mast cells may be an important driver in the disease, demonstrating that the number and activation state of mast cells are greatly increased in EoE biopsies and that mast cell signatures correlate with markers of inflammation, fibrosis, pain and disease severity. Currently, there are limited treatment options for EoE. Individuals often participate in an elimination diet to identify potential food allergens that may contribute to EoE, avoid difficult to swallow foods and undergo esophageal dilation. While not approved for EoE, proton pump inhibitors and the swallowing of topical corticosteroids are also used to address the disease. Industry sources estimate there are approximately 160,000 patients in the United States with EoE who have undergone treatment within the last 12 months and, of these, approximately 48,000 would be biologic-eligible. Given the lack of effective therapies for EoE and CDX-0159’s potential as a mast cell depleting agent, we believe EoE is an important indication for future study.

We continue to assess potential opportunities for CDX-0159 in other diseases where mast cells play an important role, such as dermatologic, respiratory, allergic, gastrointestinal and ophthalmic conditions.

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CDX-1140

CDX-1140 is a fully human agonist monoclonal antibody targeted to CD40, a key activator of immune response, which is found on dendritic cells, macrophages and B cells and is also expressed on many cancer cells. Potent CD40 agonist antibodies have shown encouraging results in early clinical studies; however, systemic toxicity associated with broad CD40 activation has limited their dosing concentrations to levels that may not be optimal for engaging CD40 expressing cells in the tumor microenvironment. CDX-1140 has unique properties relative to other CD40 agonist antibodies: potent agonist activity is independent of Fc receptor interaction, contributing to more consistent, controlled immune activation; CD40L binding is not blocked, leading to potential synergistic effects of agonist activity near activated T cells in lymph nodes and tumors; and the antibody does not promote cytokine production in whole blood assays. CDX-1140 has shown direct anti-tumor activity in preclinical models of lymphoma. Preclinical studies of CDX-1140 clearly demonstrate strong immune activation effects and low systemic toxicity and support the design of the Phase 1 study to identify the dose for characterizing single-agent and combination activity.

In November 2017, we initiated a Phase 1 study of CDX-1140 in up to 260 patients with recurrent, locally advanced or metastatic solid tumors and B cell lymphomas. The study is designed to determine the maximum tolerated dose, or MTD, during a dose-escalation phase (0.01 to 3.0 mg/kg once every four weeks until confirmed progression or intolerance) and to recommend a dose level for further study in a subsequent expansion phase. Secondary objectives include assessments of safety and tolerability, pharmacodynamics, pharmacokinetics, immunogenicity and additional measures of anti-tumor activity, including clinical benefit rate. We believe that the potential for CDX-1140 will be best defined in combination studies with other immunotherapies or conventional cancer treatments. A combination cohort with CDX-301, a hematopoietic cytokine that uniquely expands dendritic cells and hematopoietic stem cells and a safety run-in combination cohort with gemcitabine/nab-paclitaxel in patients with previously untreated metastatic pancreatic adenocarcinoma have been completed. A combination of CDX-1140 with pembrolizumab has completed the safety run-in phase. Expansion cohorts in patients with checkpoint-refractory/resistant squamous cell head and neck cancer and non-small cell lung cancer are enrolling patients.

In November 2020, we reported interim Phase 1 data from patients treated at the maximum tolerated dose (MTD) and recommended dose of 1.5 mg/kg—one of the highest systemic dose levels in the CD40 agonist class. Interim data from the study were presented at the Society for Immunotherapy of Cancer’s (SITC) 35th Annual Meeting 2020 (n=41; 25 mono, 16 with CDX-301 and 29 with post-treatment scans). Preliminary safety data from the combination cohort with pembrolizumab (n=9; 4 at 0.72 mg/kg and 5 at 1.5 mg/kg CDX-1140) were also presented. CDX-1140 monotherapy and in combination with pembrolizumab was generally well tolerated with mostly grade 1 or 2 drug related adverse events. Activity at 1.5mg/kg dose of CDX-1140 included an ongoing complete response (CR; 18 months as of Oct 2021) in a patient with follicular lymphoma treated with CDX-1140 monotherapy. There was notable tumor shrinkage and/or necrosis in 6 patients with squamous cell head and neck cancer (SCCHN) treated with CDX-1140 alone or in combination with CDX-301 and stable disease (n=10) for 11 to 32 weeks. CDX-1140 provided good systemic exposure and resulted in marked changes in the tumor microenvironment.

In November 2021, we provided an update on the ongoing Phase 1 study. Emerging data from the safety run-in cohort of CDX-1140 with gemcitabine/nab-paclitaxel in patients with previously untreated metastatic pancreatic adenocarcinoma and external CD40 agonist data recently reported using the same regimen, suggest that simultaneous treatment with chemotherapy and CD40 activation may not be optimal. Alternative strategies for investigating CDX-1140 in pancreatic cancer in other regimens are being explored, including through investigator sponsored studies. The combination of CDX-1140 with pembrolizumab has completed the safety run-in phase. Expansion cohorts in patients with checkpoint-refractory/resistant squamous cell head and neck cancer and non-small cell lung cancer are enrolling patients. Of the six patients with squamous cell head and neck cancer treated with CDX-1140 at 1.5 mg/kg in combination with pembrolizumab, encouraging preliminary results have been observed including a confirmed partial response and durable stable disease. Of the six evaluable patients with non-small cell lung cancer, four have had stable disease as their best response. Adverse events, such as arthralgia, myalgia and fatigue, have occurred more frequently in combination with pembrolizumab relative to CDX-1140 monotherapy and the protocol has been amended to allow CDX-1140 dose reduction, if necessary, to help manage these toxicities. Enrollment to the study is ongoing.

CDX-527

CDX-527 is the first candidate from Celldex’s bispecific antibody platform. Bispecifics provide opportunities to engage two independent pathways involved in controlling immune responses to tumors. CDX-527 uses Celldex’s proprietary highly active anti-PD-L1 and CD27 human antibodies to couple CD27 co-stimulation with blockade of the PD-L1/PD-1 pathway to help prime and

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activate anti-tumor T cell responses through CD27 costimulation, while preventing PD-1 inhibitory signals that subvert the immune response.

Celldex’s prior clinical experience with combining CD27 activation and PD-1 blockade provide the rationale for linking these two pathways into one molecule. Preclinical data presented at the SITC 34th Annual Meeting in November 2019 demonstrated that CDX-527 is more potent at T cell activation and anti- tumor immunity than the combination of parental monoclonal antibodies.

In August 2020, we announced the initiation of a Phase 1 dose-escalation study. The study includes up to approximately 40 patients with advanced or metastatic solid tumors that have progressed during or after standard of care therapy to be followed by tumor-specific expansion cohorts. The study is designed to determine the maximum tolerated dose, or MTD, during a dose-escalation phase and to recommend a dose level for further study in the subsequent expansion phase. The expansion is designed to further evaluate the tolerability, and biologic and anti-tumor effects of selected dose level(s) of CDX-527 in specific tumor types. Enrollment to the dose escalation portion of the study has been completed and an expansion cohort in ovarian cancer is enrolling patients.

Interim data were presented at the American Society of Clinical Oncology (ASCO) 2021 Annual Meeting in June that demonstrated a good safety profile along with promising pharmacodynamic and pharmacokinetic activity, which are important key hurdles for the development of bispecific antibodies. As of the data cut-off (April 16, 2021), 11 patients were enrolled in the first 5 dose escalation cohorts, 0.03 mg/kg through 3 mg/kg.CDX-527 was well tolerated, with no dose-limiting toxicities or treatment related serious adverse events observed. Pharmacokinetics and receptor occupancy demonstrate good exposure starting at the 1 mg/kg dose and no evidence of significant anti-drug antibodies impact. Pharmacodynamic parameters demonstrate biological activity consistent with immune activation including: transient increase in pro inflammatory cytokines/chemokines, upregulation of activation marker on T cells and particularly NK cells and a decrease in regulatory T cells.

CRITICAL ACCOUNTING POLICIES AND ESTIMATES

Our significant accounting policies are described in Note 2 to the financial statements included in Item 8 of this Form 10-K. We believe our most critical accounting policies include accounting for contingent consideration, revenue recognition, intangible and long-lived assets, research and development expenses and stock-based compensation expense.

The methods, estimates and judgments we use in applying our most critical accounting policies have a significant impact on the results we report in our financial statements. We evaluate our estimates and judgments on an ongoing basis. We base our estimates on historical experience and on assumptions that we believe to be reasonable under the circumstances. Our experience and assumptions form the basis for our judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may vary from what we anticipate and different assumptions or estimates about the future could materially change our reported results. We believe the following accounting policies are the most critical to us in that they are important to the portrayal of our financial statements and they require our most difficult, subjective or complex judgments in the preparation of our financial statements:

Contingent Consideration

We record contingent consideration resulting from a business combination at its fair value on the acquisition date. We determine the fair value of the contingent consideration based primarily on the following factors:

Our contingent consideration liabilities arose in connection with our acquisition of Kolltan. On a quarterly basis, we revalue these obligations and record increases or decreases in their fair value as an adjustment to operating earnings. Changes to contingent consideration obligations can result from adjustments to discount rates, accretion of the discount rates due to the passage of time, changes in our estimates of the likelihood or timing of achieving development or commercial milestones, changes in the probability of certain clinical events or changes in the assumed probability associated with regulatory approval.

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The assumptions related to determining the value of contingent consideration include a significant amount of judgment, and any changes in the underlying estimates could have a material impact on the amount of contingent consideration adjustment recorded in any given period.

Revenue Recognition

Revenues are recognized when performance obligations under agreements or contracts are satisfied, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those services.

The Company determines revenue recognition through the following steps:

Revenue for the Company is derived from product development agreements with collaborative partners for the research and development of therapeutic drug candidates. The terms of the agreements may include nonrefundable signing and licensing fees, funding for research, development and manufacturing, milestone payments and royalties on any product sales derived from collaborations. The Company assesses the multiple obligations typically within product development contracts to determine the distinct performance obligations and how to allocate the arrangement consideration to each distinct performance obligation. Under product development agreements, revenue is generally recognized using a cost-to-cost measure of progress. Revenue is recognized based on the costs incurred to date as a percentage of the total estimated costs to fulfill the contract. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Due to the nature of the work performed in these arrangements, the estimation of cost at completion is complex, subject to many variables, such as expected clinical trial costs, and requires significant judgements. Circumstances can arise that change original estimates of costs or progress toward completion. Any revisions to estimates are reflected in revenue on a cumulative catch-up basis in the period in which the change in circumstances became known.

Revenue for the Company is also derived from manufacturing and research and development arrangements. The Company owns and operates a cGMP manufacturing facility in Fall River, Massachusetts, to produce drug substance for its current and planned early-stage clinical trials. In order to utilize excess capacity, the Company has, from time to time, entered into contract manufacturing and research and development arrangements in which services are provided on a time-and-material basis or at a negotiated fixed- price. Revenue from time-and-material contracts is generally recognized on an output basis as labor hours and/or direct expenses are incurred. Under fixed-price contracts, revenue is generally recognized on an output basis as progress is made toward completion of the performance obligations using surveys of performance completed to date.

Intangible and Long-Lived Assets

We evaluate the recoverability of our long-lived assets, including property and equipment when circumstances indicate that an event of impairment may have occurred. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written-down to their estimated fair values.

IPR&D assets acquired in a business combination initially are recorded at fair value and accounted for as indefinite-lived intangible assets. These assets are capitalized on our balance sheets until either the project underlying them is completed or the assets become impaired. If a project is completed, the carrying value of the related intangible asset is amortized over the remaining estimated life of the asset beginning in the period in which the project is completed. If a project becomes impaired or is abandoned, the carrying value of the related intangible asset is written down to its fair value and an impairment charge is taken in the period in which the

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impairment occurs. Discounted cash flow models are typically used in these tests, and the models require the use of significant estimates and assumptions including but not limited to:

Each IPR&D asset is assessed for impairment at least annually or when impairment indicators are present. During the fourth quarter of 2020, we decided that although we had developed promising data for the AxL target within the TAM program, we would focus our efforts on out-licensing opportunities for the TAM program. As a result, we evaluated the TAM program IPR&D asset for potential impairment due to the change in projected development and regulatory timelines related to the program and recorded a non-cash partial impairment charge of $14.5 million for the fourth quarter of 2020. During the third quarter of 2021, we evaluated our out-licensing progress since December 31, 2020 and the status and expectation for the TAM program. Despite our efforts to out-license, there was a lack of interest in the program from third parties. Therefore, we evaluated the TAM program IPR&D asset for potential impairment using a discounted cash flow fair value model and concluded that the TAM IPR&D asset was fully impaired. A non-cash impairment charge of $3.5 million was recorded during the third quarter of 2021. As a result of the discontinuation of the CDX- 3379 program in the second quarter of 2020, we concluded that the CDX-3379 IPR&D asset was fully impaired, and a non-cash impairment charge of $3.5 million was recorded in the second quarter of 2020. We performed an annual impairment test of the remaining IPR&D assets during the fourth quarter of 2021 and concluded that the IPR&D assets were not impaired.

Research and Development Expenses

Research and development costs, including internal and contract research costs, are expensed as incurred. Research and development expenses consist mainly of clinical trial costs, manufacturing of clinical material, toxicology and other preclinical studies, personnel costs, depreciation, license fees and funding of outside contracted research.

Clinical trial expenses include expenses associated with clinical research organization, or CRO, services. Contract manufacturing expenses include expenses associated with contract manufacturing organization, or CMO, services. The invoicing from CROs and CMOs for services rendered can lag several months. We accrue the cost of services rendered in connection with CRO and CMO activities based on our estimate of costs incurred. We maintain regular communication with our CROs and CMOs to assess the reasonableness of our estimates. Differences between actual expenses and estimated expenses recorded have not been material and are adjusted for in the period in which they become known.

Stock-Based Compensation Expense

We record stock-based compensation expense for all stock-based awards made to employees, consultants and non-employee directors based on the estimated fair values of the stock-based awards expected to vest at the grant date and adjust, if necessary, to reflect actual forfeitures. Our estimates of employee, consultant, and non-employ director stock option values rely on estimates of future uncertain events. Significant assumptions include the use of historical volatility to estimate the expected stock price volatility. We also estimate expected term based on historical exercise patterns. For consultant and non-employee director grants, we may elect to use the contractual term as the expected term in the option-pricing model. Actual volatility and lives of options may be significantly different from our estimates. Compensation expense for all stock-based awards is recognized using the straight-line method over the term of vesting or performance.

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RESULTS OF OPERATIONS

Year Ended December 31, 2021 compared with Year Ended December 31, 2020

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Net Loss

The $10.7 million increase in net loss for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily the result of an increase in research and development and general and administrative expenses, a decrease in the gain on fair value remeasurement of contingent consideration and revenue, partially offset by a decrease in non-cash intangible asset impairment expense.

Revenue

The Company’s agreement with Rockefeller University, as amended, (the “Rockefeller Agreement”) provides for the Company to perform manufacturing and development services for Rockefeller University for their portfolio of antibodies against HIV. This portfolio was licensed to Gilead Sciences in January 2020 from Rockefeller University (“Rockefeller Transaction”). The $2.3 million decrease in revenue from product development and licensing agreements for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to the $1.8 million received from the Rockefeller Transaction in the first quarter of 2020. The $0.5 million decrease in revenue from contracts and grants for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily related to a decrease in services performed under our contract manufacturing and research and development agreements with Rockefeller University and Gilead Sciences. We expect revenue to decrease over the next twelve months as a result of a decrease in revenue from contracts and grants.

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Research and Development Expense

Research and development expenses consist primarily of (i) personnel expenses, (ii) laboratory supply expenses relating to the development of our technology, (iii) facility expenses and (iv) product development expenses associated with our drug candidates as follows:

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Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $4.5 million increase in personnel expenses for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to higher stock-based compensation expense and an increase in employee headcount. We expect personnel expenses to increase over the next twelve months as a result of additional headcount to support the expanded development of CDX-0159, although there may be fluctuations on a quarterly basis.

Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. The $1.6 million increase in laboratory supply expenses for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to higher laboratory materials and supplies purchases. We expect laboratory supplies expenses to remain relatively consistent over the next twelve months, although there may be fluctuations on a quarterly basis.

Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. The $1.6 million decrease in facility expenses for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to lower rent as a result of the consolidation of our Massachusetts lab and manufacturing facilities in the second quarter of 2020 and lower depreciation expenses. We expect facility expenses to remain relatively consistent over the next twelve months, although there may be fluctuations on a quarterly basis.

Product development expenses include clinical investigator site fees, external trial monitoring costs, data accumulation costs, contracted research and outside clinical drug product manufacturing. The $6.0 million increase in product development expenses for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to an increase in CDX-0159 clinical trial and contract research expenses. We expect product development expenses to increase over the next twelve months as a result of further increases in CDX-0159 clinical trial, contract manufacturing and contract research expenses, although there may be fluctuations on a quarterly basis.

General and Administrative Expense

The $6.0 million increase in general and administrative expenses for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to higher stock-based compensation and legal expenses. We expect general and administrative expenses to increase over the next twelve months primarily due to increased commercial planning efforts for CDX-0159, although there may be fluctuations on a quarterly basis.

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Intangible Asset Impairment

We evaluated the TAM program IPR&D asset for potential impairment in the fourth quarter of 2020 as a result of our decision to focus our efforts on out-licensing opportunities for the program, which caused changes in projected development and regulatory timelines related to the program. We concluded that the TAM program IPR&D asset was partially impaired, and a non-cash impairment charge of $14.5 million was recorded in the fourth quarter of 2020. During the third quarter of 2021, we evaluated the TAM program IPR&D asset for potential impairment as a result of a lack of interest in the program from third parties. We concluded that the TAM program IPR&D asset was fully impaired, and a non-cash impairment charge of $3.5 million was recorded in the third quarter of 2021. We evaluated the CDX-3379 IPR&D asset for potential impairment as a result of the discontinuation of the CDX-3379 program in the second quarter of 2020. We concluded that the CDX-3379 IPR&D asset was fully impaired, and a non-cash impairment charge of $3.5 million was recorded in the second quarter of 2020.

Gain on Fair Value Remeasurement of Contingent Consideration

The $1.4 million gain on fair value remeasurement of contingent consideration for the year ended December 31, 2021 was primarily due to updated assumptions for the TAM program, partially offset by losses related to changes in discount rates and the passage of time.

Investment and Other Income, Net

The $1.9 million decrease in investment and other income, net for the year ended December 31, 2021, as compared to the year ended December 31, 2020, was primarily due to lower other income related to our sale of New Jersey tax benefits. We expect investment and other income to increase over the next twelve months due to higher levels of cash as a result of our July 2021 underwritten public offering, although there may be fluctuations on a quarterly basis.

Income Tax Benefit

A $0.2 million non-cash income tax benefit was recorded for the year ended December 31, 2021 related to the impairment of the TAM program IPR&D asset in the third quarter of 2021.

Year Ended December 31, 2020 compared with Year Ended December 31, 2019

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Net Loss

The $8.9 million increase in net loss for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily the result of an increase in non-cash intangible asset impairment expense, partially offset by an increase in revenue and an increase in the gain on fair value remeasurement of contingent consideration.

Revenue

The $1.8 million increase in product development and licensing agreements revenue for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to the $1.8 million received from the Rockefeller Transaction. The $2.0 million increase in contracts and grants revenue for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily related to an increase in services performed under our contract manufacturing and research and development agreements with Rockefeller University and Gilead Sciences, partially offset by a decrease in services performed under our manufacturing and research and development agreement with Duke University.

Research and Development Expense

Research and development expenses consist primarily of (i) personnel expenses, (ii) laboratory supply expenses relating to the development of our technology, (iii) facility expenses and (iv) product development expenses associated with our drug candidates as follows:

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Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $0.4 million increase in personnel expenses for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to an increase in bonus expense.

Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. The $0.1 million increase in laboratory supply expenses for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to higher laboratory materials and supplies purchases.

Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. The $0.4 million decrease in facility expenses for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to lower rent and depreciation expense.

Product development expenses include clinical investigator site fees, external trial monitoring costs, data accumulation costs, contracted research and outside clinical drug product manufacturing. The $0.1 million increase in product development expenses for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to an increase in clinical trial and contract manufacturing expenses of $1.2 million, partially offset by a decrease in contract research expenses of $1.0 million.

General and Administrative Expense

The $1.0 million decrease in general and administrative expenses for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due lower stock-based compensation expense and lower facility expenses as a result of the consolidation our Massachusetts lab and manufacturing facilities in the second quarter of 2020.

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Intangible Asset Impairment

We evaluated the TAM program IPR&D asset for potential impairment as a result of changes in projected development and regulatory timelines related to the program in the fourth quarter of 2020. We concluded that the TAM program IPR&D asset was partially impaired, and a non-cash impairment charge of $14.5 million was recorded in the fourth quarter of 2020. We evaluated the CDX-3379 IPR&D asset for potential impairment as a result of the discontinuation of the CDX-3379 program in the second quarter of 2020. We concluded that the CDX-3379 IPR&D asset was fully impaired, and a non-cash impairment charge of $3.5 million was recorded in the second quarter of 2020.

Other Asset Impairment

We concluded that the Company’s investment in an undisclosed private company was impaired as a result of a deterioration in the private company’s financial condition and recorded a non-cash impairment charge of $1.8 million during the first quarter of 2019.

Gain on Fair Value Remeasurement of Contingent Consideration

The $4.2 million gain on fair value remeasurement of contingent consideration for the year ended December 31, 2020 was primarily due to updated assumptions for CDX-3379 related milestones due to the discontinuation of the CDX-3379 program partially offset by changes in discount rates and the passage of time.

Investment and Other Income, Net

The $1.7 million decrease in investment and other income, net for the year ended December 31, 2020, as compared to the year ended December 31, 2019, was primarily due to lower interest rates on fixed income investments and lower other income related to our sale of New Jersey tax benefits.

Income Tax Benefit

A $1.2 million non-cash income tax benefit was recorded for the year ended December 31, 2020 related to the partial impairment of the TAM program IPR&D asset in the fourth quarter of 2020 and the full impairment of the CDX-3379 IPR&D asset in the second quarter of 2020.

LIQUIDITY AND CAPITAL RESOURCES

Our cash equivalents are highly liquid investments with a maturity of three months or less at the date of purchase and consist primarily of investments in money market mutual funds with commercial banks and financial institutions. We maintain cash balances with financial institutions in excess of insured limits. We do not anticipate any losses with respect to such cash balances. We invest our excess cash balances in marketable securities, including municipal bond securities, U.S. government agency securities and high- grade corporate bonds that meet high credit quality standards, as specified in our investment policy. Our investment policy seeks to manage these assets to achieve our goals of preserving principal and maintaining adequate liquidity.

The use of our cash flows for operations has primarily consisted of salaries and wages for our employees; facility and facility-related costs for our offices, laboratories and manufacturing facility; fees paid in connection with preclinical studies, clinical studies, contract manufacturing, laboratory supplies and services; and consulting, legal and other professional fees. We anticipate that our cash flows from operations will continue to be focused in these areas as we progress our current drug candidates through the clinical trial process and develop additional drug candidates. To date, the primary sources of cash flows from operations have been payments received from our collaborative partners and from government entities and payments received for contract manufacturing and research and development services provided by us. The timing of any new contract manufacturing and research and development agreements, collaboration agreements, government contracts or grants and any payments under these agreements, contracts or grants cannot be easily predicted and may vary significantly from quarter to quarter.

At December 31, 2021, our principal sources of liquidity consisted of cash, cash equivalents and marketable securities of $408.3 million. We have had recurring losses and incurred a loss of $70.5 million for the year ended December 31, 2021. Net cash used in operations for the year ended December 31, 2021 was $60.9 million. We believe that the cash, cash equivalents and marketable

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securities at December 31, 2021 are sufficient to meet estimated working capital requirements and fund planned operations through 2025. This could be impacted if we elected to pay Kolltan contingent milestones, if any, in cash.

During the next twelve months, we may take further steps to raise additional capital to meet our long-term liquidity needs including, but not limited to, one or more of the following: the licensing of drug candidates with existing or new collaborative partners, possible business combinations, issuance of debt, or the issuance of common stock or other securities via private placements or public offerings. Although we have been successful in raising capital in the past, there can be no assurance that additional financing will be available on acceptable terms, if at all, and our negotiating position in capital raising efforts may worsen as existing resources are used. There is also no assurance that we will be able to enter into further collaborative relationships. Additional equity financings may be dilutive to our stockholders; debt financing, if available, may involve significant cash payment obligations and covenants that restrict our ability to operate as a business; and licensing or strategic collaborations may result in royalties or other terms which reduce our economic potential from products under development. Our ability to continue funding our planned operations into and beyond twelve months from the issuance date is also dependent on the timing and manner of payment of future contingent milestones from the Kolltan acquisition, in the event that we achieve the drug candidate milestones related to those payments. We may decide to pay those milestone payments in cash, shares of our common stock or a combination thereof. If we are unable to raise the funds necessary to meet our long-term liquidity needs, we may have to delay or discontinue the development of one or more programs, discontinue or delay ongoing or anticipated clinical trials, license out programs earlier than expected, raise funds at a significant discount or on other unfavorable terms, if at all, or sell all or a part of our business.

Operating Activities

Net cash used in operating activities was $60.9 million for the year ended December 31, 2021 compared to $40.4 million for the year ended December 31, 2020. The increase in net cash used in operating activities was primarily due to increases in research and development and general and administrative expenses and a decrease in revenue. We expect that cash used in operating activities will increase over the next twelve months as a result of the expanded development of CDX-0159, although there may be fluctuations on a quarterly basis.

Net cash used in operating activities was $40.4 million for the year ended December 31, 2020 compared to $46.4 million for the year ended December 31, 2019. The decrease in net cash used in operating activities was primarily due to an increase in revenue and decreases in both general and administrative and research and development expenses.

We have incurred and will continue to incur significant costs in the area of research and development, including preclinical and clinical trials and clinical drug product manufacturing as our drug candidates are developed. We plan to spend significant amounts to progress our current drug candidates through the clinical trial processes as well as to develop additional drug candidates. As our drug candidates progress through the clinical trial process, we may be obligated to make significant milestone payments, pursuant to our existing arrangements and arrangements we may enter in the future.

Investing Activities

Net cash used in investing activities was $216.2 million for the year ended December 31, 2021 compared to $98.2 million for the year ended December 31, 2020. The increase in net cash used in investing activities was primarily due to net purchases of marketable securities for the year ended December 31, 2021 of $214.9 million as compared to $96.7 million for the year ended December 31, 2020. We expect that cash provided by investing activities will increase over the next twelve months as we fund our operations through the combination of net proceeds from the sales and maturities of marketable securities, cash provided by financing activities and/or new partnerships, although there may be significant fluctuations on a quarterly basis based on the amount of cash provided by financing activities and/or new partnerships.

Net cash used in investing activities was $98.2 million for the year ended December 31, 2020 compared to net cash provided by investing activities of $17.1 million for the year ended December 31, 2019. The increase in net cash used in investing activities was primarily due to net purchases of marketable securities for the year ended December 31, 2020 of $96.7 million as compared to net sales and maturities of marketable securities of $17.8 million for the year ended December 31, 2019.

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Financing Activities

Net cash provided by financing activities was $272.4 million for the year ended December 31, 2021 compared to $171.2 million for the year ended December 31, 2020. Net proceeds from stock issuances, including stock issued pursuant to employee benefit plans, were $272.4 million during the year ended December 31, 2021 compared to $171.2 million for the year ended December 31, 2020.

Net cash provided by financing activities was $171.2 million for the year ended December 31, 2020 compared to $16.3 million for the year ended December 31, 2019. Net proceeds from stock issuances, including stock issued pursuant to employee benefit plans, were $171.2 million during the year ended December 31, 2020 compared to $16.3 million for the year ended December 31, 2019.

Equity Offerings

In November 2020, we filed an automatic shelf registration statement with the Securities and Exchange Commission to register for sale any combination of the types of securities described in the shelf registration statement.

In May 2016, we entered into a controlled equity offering sales agreement with Cantor Fitzgerald & Co. (“Cantor”) to allow us to issue and sell shares of our common stock from time to time through Cantor, acting as agent. During the years ended December 31, 2020 and 2019, we issued 7.1 million and 5.0 million shares of common stock, respectively, under the agreement with Cantor resulting in net proceeds of $29.4 million and $16.2 million, respectively, after deducting commission and offering expenses. No shares of common stock were sold under the Cantor Agreement during the year ended December 31, 2021. At December 31, 2021, we had $50.0 million remaining in aggregate gross offering price available under our November 2020 prospectus supplement.

During the second quarter of 2020, the Company issued 15,384,614 shares of its common stock in an underwritten public offering resulting in net proceeds to the Company of $141.4 million, after deducting underwriting fees and offering expenses.

During the third quarter of 2021, we issued 6,845,238 shares of common stock in an underwritten public offering resulting in net proceeds of $269.9 million, after deducting underwriting fees and offering expenses.