Celldex Therapeutics, Inc.

Previous wording

During the past five years through December 31, 2025, we incurred an aggregate of $662.2 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 three months ended March 31, 2026 and 2025. The amounts disclosed in the following table reflect direct research and development costs and an allocation of indirect research and development costs to each program.

Current wording

During the past five years through December 31, 2025, we incurred an aggregate of $662.2 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 six months ended June 30, 2026 and 2025. The amounts disclosed in the following table reflect direct research and development costs and an allocation of indirect research and development costs to each program.

Previous wording

Based on the positive results reported in urticaria, we expanded development of barzolvolimab into additional indications where mast cells are believed to play an important role. We are conducting ongoing Phase 2 studies in prurigo nodularis (PN) and atopic dermatitis (AD). We continue to assess potential opportunities for barzolvolimab in other diseases where mast cells play an important role, such as dermatologic, respiratory, allergic, gastrointestinal and ophthalmic conditions.

Current wording

Based on the positive results reported in urticaria, we expanded development of barzolvolimab into additional indications where mast cells are believed to play an important role. We are conducting an ongoing Phase 2 study in atopic dermatitis (AD) and continue to assess potential opportunities for barzolvolimab in other diseases where mast cells play an important role, such as dermatologic, respiratory, allergic, gastrointestinal and ophthalmic conditions.

Previous wording

We have completed a Phase 2 study in patients with CSU who remained symptomatic despite antihistamine therapy. The study was conducted at approximately 75 sites across 9 countries. The study was a randomized, double-blind, placebo-controlled, parallel group Phase 2 study that evaluated the efficacy and safety profile of multiple dose regimens of barzolvolimab to determine the optimal dosing strategy. 208 patients were randomly assigned on a 1:1:1:1 ratio to receive subcutaneous injections of barzolvolimab at 75 mg every 4 weeks, 150 mg every 4 weeks, 300 mg every 8 weeks or placebo during a 16-week placebo-controlled treatment phase. After 16 weeks, patients then entered a 36-week active treatment period, in which patients receiving placebo or the 75 mg dose were randomized to receive barzolvolimab 150 mg every 4 weeks or 300 mg every 8 weeks; patients already randomized to the 150 mg and 300 mg treatment arms remained on the same regimen as during the placebo-controlled treatment period. After 52 weeks, patients then entered a follow-up period for an additional 24 weeks. The primary endpoint of the study was mean change in baseline to Week 12 in UAS7 (weekly urticaria activity score). Secondary endpoints included safety and other assessments of clinical activity including ISS7 (weekly itch severity score), HSS7 (weekly hive severity score) and AAS7 (weekly angioedema activity score).

Current wording

We have completed a Phase 2 study in patients with CSU who remained symptomatic despite antihistamine therapy. The study was conducted at approximately 75 clinical trial sites across 9 countries. The study was a randomized, double-blind, placebo-controlled, parallel group Phase 2 study that evaluated the efficacy and safety profile of multiple dose regimens of barzolvolimab to determine the optimal dosing strategy. 208 patients were randomly assigned on a 1:1:1:1 ratio to receive subcutaneous injections of barzolvolimab at 75 mg every 4 weeks, 150 mg every 4 weeks, 300 mg every 8 weeks or placebo during a 16-week placebo-controlled treatment phase. After 16 weeks, patients then entered a 36-week active treatment period, in which patients receiving placebo or the 75 mg dose were randomized to receive barzolvolimab 150 mg every 4 weeks or 300 mg every 8 weeks; patients already randomized to the 150 mg and 300 mg treatment arms remained on the same regimen as during the placebo-controlled treatment period. After 52 weeks, patients then entered a follow-up period for an additional 24 weeks. The primary endpoint of the study was mean change in baseline to Week 12 in UAS7 (weekly urticaria activity score). Secondary endpoints included safety and other assessments of clinical activity including ISS7 (weekly itch severity score), HSS7 (weekly hive severity score) and AAS7 (weekly angioedema activity score).

Previous wording

We have expanded clinical development of barzolvolimab 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 is currently only one FDA approved therapy 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.

Current wording

In July 2026, we announced topline results from a Phase 2 study in prurigo nodularis (PN), 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. We designed the Phase 2 study to determine if barzolvolimab could deplete mast cells and, in turn, improve clinical outcomes in PN. Topline results demonstrated that the trial did not meet primary or key secondary endpoints at Week 12 at either dose level evaluated. Barzolvolimab was well-tolerated and demonstrated a favorable safety profile consistent with prior studies. Rapid and profound suppression of circulating tryptase, indicative of systemic mast cell depletion was observed. These data indicate that mast cells may not be the key pathogenic driver in PN. Based on these results, we are discontinuing the Phase 2 PN study.

Previous wording

The randomized, double-blind, placebo-controlled, parallel group Phase 2 study is evaluating the efficacy and safety profile of subcutaneous barzolvolimab in patients with moderate to severe AD. 131 patients were randomly assigned on a 1:1:1 ratio to receive subcutaneous injections of barzolvolimab at either 150 or 300 mg or placebo every 4 weeks after an initial loading dose of 450 mg or placebo during a 16-week placebo-controlled treatment phase. Participants randomized into the placebo arm were re-randomized at Week 16 into 1 of the 2 active treatment arms. Patients then entered a 16-week active treatment phase, in which all patients will receive barzolvolimab every 4 weeks. The primary endpoint of the study is to evaluate the clinical efficacy of the two dose levels compared to placebo using the Peak Pruritus Numerical Rating Scale (PP-NRS) at Week 16, a well‐defined, reliable,

Current wording

The randomized, double-blind, placebo-controlled, parallel group Phase 2 study is evaluating the efficacy and safety profile of subcutaneous barzolvolimab in patients with moderate to severe AD. 131 patients were randomly assigned on a 1:1:1 ratio to receive subcutaneous injections of barzolvolimab at either 150 or 300 mg or placebo every 4 weeks after an initial loading dose of 450 mg or placebo during a 16-week placebo-controlled treatment phase. Participants randomized into the placebo arm were re-randomized at Week 16 into 1 of the 2 active treatment arms. Patients then entered a 16-week active treatment phase, in which all patients will receive barzolvolimab every 4 weeks. The primary endpoint of the study is to evaluate the clinical efficacy of the two dose levels compared to placebo using the Peak Pruritus Numerical Rating Scale (PP-NRS) at Week 16, a well‐defined, reliable, sensitive and valid scale for evaluating worst itch intensity in adults with moderate‐to‐severe AD. Secondary endpoints include the evaluation of the clinical efficacy of barzolvolimab, compared to placebo across multiple patient-reported outcomes, including assessing impressions of disease change and severity and improvements in quality of life. The study included approximately 40 clinical trial centers in the United States. Enrollment was completed in January 2026. Topline data from the study is expected in late 2026.

Previous wording

Our next generation bispecific antibody platform is supporting the expansion of our pipeline with additional candidates for inflammatory diseases. Targets are being selected based on new science as well as their compatibility to be used in bispecific antibody formats with our existing antibody programs. Development is focused on emerging, important pathways controlling inflammatory diseases.

Current wording

Our next generation bispecific antibody platform is supporting the expansion of our pipeline with additional candidates for inflammatory diseases. Targets are being selected based on new science as well as their compatibility to be used in bispecific antibody formats with our existing antibody programs. Development is focused on emerging, important pathways controlling inflammatory diseases. In June 2026 we presented first-in-human data that demonstrated neutralizing soluble SCF can selectively inhibit KIT signaling in mast cells. This approach provides a validated anchor mechanism that enables the development of diverse bispecific candidates where a dual mechanism approach may overcome the heterogeneity inherent in the pathophysiology of many inflammatory disorders.

Previous wording

CDX-622 is a bispecific antibody that targets two complementary pathways that drive chronic inflammation, potently neutralizing the alarmin thymic stromal lymphopoietin (TSLP) and depleting mast cells via stem cell factor (SCF) starvation. TSLP has been directly implicated in several respiratory and dermatological disorders, such as asthma, chronic obstructive pulmonary disease (COPD), eosinophilic esophagitis, atopic dermatitis and chronic spontaneous urticaria, and in fibrotic diseases such as systemic sclerosis and idiopathic pulmonary fibrosis. In these disorders, TSLP is often upregulated and associated with disease severity. Similarly, mast cells drive or contribute to the pathophysiology of allergic, inflammatory, autoimmune and fibrotic disorders and CDX-622 contains a unique SCF neutralizing function that is expected to inhibit and deplete mast cells. Combined neutralization of SCF and TSLP with CDX-622 is expected to simultaneously reduce tissue mast cells and inhibit Type 2 inflammatory responses to potentially offer enhanced therapeutic benefit in inflammatory and fibrotic disorders. CDX-622 has been engineered to disable effector function (AQQ) and reduce clearance (YTE). In preclinical studies, CDX-622 inhibits TSLP and SCF with similar potency to both its respective parental mAbs and comparator mAbsin vitro and preferentially inhibits the soluble over the membrane form of SCF, which may lead to differential impact on KIT-dependent processes. CDX-622 was well tolerated in a multi-dose 8 week toxicology study in non-human primates and led to a profound mast cell depletion in several tissues. The No Adverse Event Level (NOAEL) was established to be 75 mg/kg, the highest dose level tested.

Current wording

CDX-622 is our first bispecific antibody based on this science and targets two complementary pathways that drive chronic inflammation, potently neutralizing the alarmin thymic stromal lymphopoietin (TSLP) and depleting mast cells via stem cell factor (SCF) starvation. We believe CDX-622 has significant potential across indications where both TSLP and mast cells play a pathogenic role. Combined neutralization of SCF and TSLP with CDX-622 is expected to simultaneously reduce tissue mast cells and inhibit Type 2 inflammatory responses to potentially offer enhanced therapeutic benefit in inflammatory and fibrotic disorders. CDX-622 has been engineered to disable effector function (AQQ) and reduce clearance (YTE). Prioritized indications include severe asthma, allergic rhinitis, and food allergy.

Previous wording

In November 2024, we initiated a multi-part Phase 1 study of CDX-622 in healthy volunteers and enrollment was completed across all parts in January 2026. The Phase 1a clinical trial is a three-part, randomized, double-blind, placebo-controlled, dose escalation study designed to assess the safety, pharmacokinetics, and pharmacodynamics of CDX-622 in up to 80 healthy participants. A single dose of CDX-622 or placebo was administered intravenously (IV) once during Part 1. In Part 2, CDX-622 or placebo was administered IV every 2 weeks (Q2W) for up to 6 weeks following the first dose, for a total of 4 doses. In Part 3, a single dose of CDX-622 or placebo was administered subcutaneously once. Participants are followed for 12 weeks in all Parts following the last dose

Current wording

In November 2024, we initiated a multi-part Phase 1 study of CDX-622 in healthy volunteers and enrollment was completed across all parts in January 2026. The Phase 1a clinical trial is a three-part, randomized, double-blind, placebo-controlled, dose escalation study designed to assess the safety, pharmacokinetics, and pharmacodynamics of CDX-622 in up to 80 healthy participants. A single dose of CDX-622 or placebo was administered intravenously (IV) once during Part 1. In Part 2, CDX-622 or placebo was administered IV every 2 weeks (Q2W) for up to 6 weeks following the first dose, for a total of 4 doses. In Part 3, a single dose of CDX-622 or placebo was administered subcutaneously once. Participants are followed for 12 weeks in all Parts following the last dose of study drug. The pharmacodynamic biomarkers from blood and skin will be highly informative on the ability of CDX-622 to engage and neutralize SCF and TSLP.

Previous wording

We presented positive data from the Phase 1 single ascending dose portion of the study (Part 1) at the CIA (Collegium Internationale Allergologicum) Biennial Symposium in October 2025. CDX-622 was well tolerated with no dose limiting toxicities and no emergent events related to systemic KIT inhibition. CDX-622 exhibited a good pharmacokinetic profile and induced rapid and sustained dose dependent reductions in serum tryptase, indicative of mast cell inhibition and depletion. Data from the multiple ascending doses portion of the study (Part 2) and subcutaneous administration (Part 3) are expected in the third quarter of 2026.

Current wording

We presented positive data from the Phase 1 single ascending dose portion of the study (Part 1) at the CIA (Collegium Internationale Allergologicum) Biennial Symposium in October 2025. CDX-622 was well tolerated with no dose limiting toxicities and no emergent events related to systemic KIT inhibition. CDX-622 exhibited a good pharmacokinetic profile and induced rapid and sustained dose dependent reductions in serum tryptase, indicative of mast cell inhibition and depletion. Complete results from the Phase 1, first-in-human trial were presented at the European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress in June 2026.

Previous wording

In January 2026, we initiated an open-label, single-dose Phase 1 proof of mechanism study to assess the safety, pharmacodynamics, and pharmacokinetics of CDX-622 in adults with mild to moderate asthma. Participants will receive a single IV infusion of CDX-622 and be followed for 12 weeks. PD effects of CDX-622 on fractional exhaled nitric oxide (FeNO), absolute eosinophil count (AEC) and serum biomarkers, including TSLP- and SCF-related biomarkers, will be evaluated.

Current wording

In January 2026, we initiated an open-label, single-dose Phase 1 proof of mechanism study to assess the safety, pharmacodynamics, and pharmacokinetics of CDX-622 in adults with mild to moderate asthma to assess the impact of dual neutralization of SCF and TSLP. Participants receive a single IV infusion of CDX-622 and are followed for 12 weeks. PD effects of CDX-622 on fractional exhaled nitric oxide (FeNO), absolute eosinophil count (AEC) and serum biomarkers, including TSLP- and SCF-related biomarkers, will be evaluated.

Previous wording

The $24.9 million increase in net loss for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to an increase in research and development expenses related to barzolvolimab and a decrease in investment and other income, net.

Current wording

The $16.9 million increase in net loss for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, was primarily due to an increase in research and development expenses related to barzolvolimab.

Previous wording

Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $2.0 million increase in personnel expenses for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to 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 barzolvolimab.

Current wording

Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $1.8 million increase in personnel expenses for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, was primarily due to 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 development of barzolvolimab.

Previous wording

Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. The $0.7 million decrease in laboratory supply expenses for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to lower 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.

Current wording

Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. The $1.0 million increase in laboratory supply expenses for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, 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.

Previous wording

Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. The $0.5 million decrease in facility expenses for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to lower expense related to our leased facilities. In 2025, we signed a new lease in New Haven, Connecticut to which we will relocate our existing New Haven operations to in 2026. As a result, we expect facility expenses to increase over the next twelve months, although there may be fluctuations on a quarterly basis.

Current wording

Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. The $0.2 million decrease in facility expenses for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, was primarily due to lower expense related to our leased facilities. In 2025, we signed a new lease in New Haven, Connecticut and we are in process of relocating our existing New Haven operations to that facility. In addition, we expanded our leased space in Hampton, New Jersey in June 2026. As a result, we expect facility expenses to increase over the next twelve months, although there may be fluctuations on a quarterly basis.

Previous wording

Product development expenses include clinical investigator site fees, external trial monitoring costs, data accumulation costs, contracted research and outside clinical drug product manufacturing. The $18.0 million increase in product development expenses for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to an increase in barzolvolimab clinical trial and contract manufacturing expenses. We expect product development expenses to remain relatively consistent over the next twelve months, although there may be fluctuations on a quarterly basis.

Current wording

Product development expenses include clinical investigator site fees, external trial monitoring costs, data accumulation costs, contracted research and outside clinical drug product manufacturing. The $8.2 million increase in product development expenses for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, was primarily due to an increase in barzolvolimab clinical trial expenses. We expect product development expenses to increase over the next twelve months primarily due to increased costs associated with the development of barzolvolimab, although there may be fluctuations on a quarterly basis.

Previous wording

The $0.6 million increase in general and administrative expenses for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to higher commercial planning expenses. We expect general and administrative expenses to increase over the next twelve months as a result of the expanded development of barzolvolimab and an increase in commercial planning efforts, although there may be fluctuations on a quarterly basis.

Current wording

The $2.7 million increase in general and administrative expenses for the three months ended June 30, 2026, as compared to the three months ended June 30, 2025, was primarily due to higher commercial planning expenses and an increase in employee headcount. We expect general and administrative expenses to increase over the next twelve months primarily due to increased costs to support commercial planning efforts and the continued growth of our organization in preparation for potential commercialization of barzolvolimab, although there may be fluctuations on a quarterly basis.

Previous wording

The $0.6 million decrease in contracts and grants revenue for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to a decrease in revenue from our contract manufacturing and research and development agreements with Rockefeller University. We expect revenue to increase over the next twelve months as a result of an

Current wording

The $1.3 million decrease in contracts and grants revenue for the six months ended June 30, 2026, as compared to the six months ended June 30, 2025, was primarily due to a decrease in revenue from our contract manufacturing and research and development agreements with Rockefeller University.

Previous wording

The $3.2 million decrease in investment and other income, net for the three months ended March 31, 2026, as compared to the three months ended March 31, 2025, was primarily due to lower levels of cash and investment balances. We expect investment and other income to increase over the next twelve months due to higher levels of cash and investment balances as a result of our April 2026 underwritten public offering, although there may be fluctuations on a quarterly basis.

Current wording

The $3.3 million decrease in investment and other income, net for the six months ended June 30, 2026, as compared to the six months ended June 30, 2025, was primarily due to lower cash and investment balances prior to the April 2026 underwritten public offering and lower yields on fixed income investments.

Previous wording

At March 31, 2026, our principal sources of liquidity consisted of cash, cash equivalents and marketable securities of $451.5 million. We have had recurring losses and incurred a loss of $78.7 million for the three months ended March 31, 2026. Net cash used in operations for the three months ended March 31, 2026 was $65.6 million. We believe that the cash, cash equivalents and marketable securities at March 31, 2026, along with the approximately $323.9 million in net proceeds from our April 2026 underwritten public offering, are sufficient to meet estimated working capital requirements and fund current planned operations through 2028. This could be impacted if we elect to pay the future milestone under the Settlement Agreement with SRS in cash, in the event that we achieve the milestone related to that payment.

Current wording

At June 30, 2026, our principal sources of liquidity consisted of cash, cash equivalents and marketable securities of $717.6 million. We have had recurring losses and incurred a loss of $152.2 million for the six months ended June 30, 2026. Net cash used in operations for the six months ended June 30, 2026 was $123.0 million. We believe that the cash, cash equivalents and marketable securities at June 30, 2026 are sufficient to meet estimated working capital requirements and fund current planned operations through 2028. This could be impacted if we elect to pay the future milestone under the Settlement Agreement with SRS in cash, in the event that we achieve the milestone related to that payment.

Previous wording

Net cash used in operating activities was $65.6 million for the three months ended March 31, 2026 as compared to $54.4 million for the three months ended March 31, 2025. The increase in net cash used in operating activities was primarily due to an increase in research and development expenses related to barzolvolimab. We expect that cash used in operating activities will increase over the next twelve months as a result of the expanded development of barzolvolimab.

Current wording

Net cash used in operating activities was $123.0 million for the six months ended June 30, 2026 as compared to $98.4 million for the six months ended June 30, 2025. The increase in net cash used in operating activities was primarily due to an increase in research and development expenses related to barzolvolimab, partially offset by an increase in accounts payable during the six months ended June 30, 2026. We expect that cash used in operating activities will increase over the next twelve months as a result of the expanded development of barzolvolimab.

Previous wording

Net cash provided by investing activities was $72.1 million for the three months ended March 31, 2026 compared to $43.0 million for the three months ended March 31, 2025. The increase in net cash provided by investing activities was primarily due to net sales and maturities of marketable securities of $73.8 million for the three months ended March 31, 2026 as compared to $43.2 million for the three months ended March 31, 2025.

Current wording

Net cash used in investing activities was $183.4 million for the six months ended June 30, 2026 compared to net cash provided by investing activities of $92.8 million for the six months ended June 30, 2025. The increase in net cash used in investing activities was primarily due to net purchases of marketable securities of $178.6 million for the six months ended June 30, 2026 as compared to net sales and maturities of marketable securities of $93.8 million for the six months ended June 30, 2025.

Previous wording

Net cash provided by financing activities was $0.3 million for the three months ended March 31, 2026 as compared to $0.2 million for the three months ended March 31, 2025. The increase in net cash provided by financing activities was primarily due to an increase in proceeds from issuance of stock from employee benefit plans.

Current wording

Net cash provided by financing activities was $325.0 million for the six months ended June 30, 2026 as compared to $0.3 million for the six months ended June 30, 2025. The increase in net cash provided by financing activities was primarily due to an increase in proceeds from stock issuances.

Previous wording

In April 2026, we issued 11,896,750 shares of common stock in an underwritten public offering resulting in net proceeds of approximately $323.9 million, after deducting underwriting fees and offering expenses.

Current wording

In April 2026, we issued 11,896,750 shares of common stock in an underwritten public offering resulting in net proceeds of $323.8 million, after deducting underwriting fees and offering expenses.