Celldex Therapeutics, Inc.

Previous wording

We are a biopharmaceutical company dedicated to exploring the science of mast cell biology and developing therapeutic antibodies which have the ability to engage the human immune system and/or directly affect critical pathways to improve the lives of patients with severe inflammatory, allergic, autoimmune and other devastating diseases. Our drug candidates include monoclonal and bispecific antibodies designed to address mast cell mediated diseases for which available treatments are inadequate.

Current wording

We are a biopharmaceutical company dedicated to developing novel antibody-based treatments that engage the human immune system and directly affect critical pathways to improve the lives of patients with allergic, inflammatory and autoimmune disorders. Our drug candidates include monoclonal and bispecific antibodies designed to address mast cell mediated diseases for which available treatments are inadequate.

Previous wording

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.

Current wording

Our strategy 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.

Previous wording

During the past five years through December 31, 2024, we incurred an aggregate of $459.7 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 nine months ended September 30, 2025 and 2024. 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 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.

Previous wording

Barzolvolimab was initially studied in chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), diseases where mast cell degranulation plays a central role in the onset and progression of the disease. In July 2024, we initiated two Phase 3 studies in CSU. In July 2023, we announced that enrollment was complete in the ongoing Phase 2 CSU study. In November 2023, we reported that barzolvolimab achieved the primary efficacy endpoint in this study, with a statistically significant mean change from baseline to Week 12 of UAS7 (weekly urticaria activity score) compared to placebo and was well tolerated. In September 2024, we presented 52 week treatment data from the CSU study, demonstrating sustained and deepening disease efficacy and a well tolerated long term safety profile. In June 2025, we presented follow up data from this study through Week 76, 7 months after the completion of dosing with barzolvolimab, demonstrating ongoing profound, sustained complete response and improved quality of life. The study is complete. In April 2024, we announced enrollment was complete in the ongoing Phase 2 CIndU study. In July 2024, we announced that our Phase 2 study in CIndU achieved the primary efficacy endpoint, (statistically significant difference between the percent of patients with a negative provocation test compared to placebo at Week 12) and was well tolerated. 12 week data from the CIndU study were presented in October of 2024 and all secondary endpoints across the study were also met and were highly statistically significant and clinically meaningful. Patients on study continued to receive barzolvolimab for 20 weeks of treatment and were then followed for up to 24 additional weeks without treatment. In November 2025, data from the 20 week placebo controlled treatment period were presented, demonstrating sustained efficacy and a favorable safety profile. Patients with returning or continuing symptoms were eligible to enroll into an open label extension (OLE). The study was recently completed and data from the OLE are expected to be presented in the first quarter of 2026.

Current wording

Barzolvolimab was initially studied in chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), diseases where mast cell degranulation plays a central role in the onset and progression of the disease.

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), atopic dermatitis (AD) and eosinophilic esophagitis (EOE; further development discontinued). 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 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.

Previous wording

Chronic Spontaneous Urticaria (CSU) Summary of Phase 1 and Phase 2 Data Presented to Date

Current wording

Chronic Spontaneous Urticaria (CSU) Summary of Phase 1 and Phase 2 Data

Previous wording

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. It is one of the most frequent dermatologic diseases with a prevalence of 0.5-1.0% of the total population or up to approximately 1 to 3 million patients in the United States (Weller et al. 2010. Hautarzt. 61(8), Bartlett et al. 2018. DermNet.Org). Approximately 50% of patients with CSU achieve symptomatic control with antihistamines. Omalizumab, an IgE inhibitor, provides relief for roughly half of the remaining antihistamine refractory patients. Consequently, there is a need for additional therapies.

Current wording

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. It is one of the most frequent dermatologic diseases with a prevalence of 0.5-1.0% of the total population or up to approximately 1 to 3 million patients in the United States (Weller et al. 2010. Hautarzt. 61(8), Bartlett et al. 2018. DermNet.Org). Approximately 50% of patients with CSU achieve symptomatic control with antihistamines. Currently approved advanced therapies address downstream mediators/mechanisms in CSU and do not provide symptom free complete control (absence of itch and hives, UAS7=0) in a majority of patients. Consequently, there is a need for additional therapies.

Previous wording

In June of 2025, 52 week data on angioedema activity and additional measures of angioedema control were presented at the EAACI 2025 Congress. Barzolvolimab continued to demonstrate robust, durable and deepening improvements in angioedema symptoms over the treatment period. At Week 52, an 86% mean reduction from baseline was reported for 150 mg Q4W arm and an 82% reduction was reported for the 300 mg Q8W. Up to 77% of patients treated with barzolvolimab who had angioedema at baseline were angioedema free (AAS7=0) at Week 52. Patients treated with barzolvolimab were angioedema free up to 72% of the time over the 52 week treatment period. Up to 87% of patients reported clinically meaningful improvement (>8 point) in AAS7 at Week 52.

Current wording

In June of 2025, 52 week data on angioedema activity and additional measures of angioedema control were presented at the EAACI 2025 Congress. Barzolvolimab continued to demonstrate robust, durable and deepening improvements in angioedema symptoms over the treatment period.

Previous wording

In June of 2025, long term follow up data from the Phase 2 CSU study were presented at the EAACI 2025 Congress. At Week 76, seven months after completion of dosing, patients continue to experience profound clinical benefit on study. Key highlights included:

Current wording

In June of 2025, long term follow up data from the Phase 2 CSU study were presented at the EAACI 2025 Congress. At Week 76, seven months after receiving their final dose of barzolvolimab, patients continued to experience profound clinical benefit on study. Key highlights included:

Previous wording

In September at EADV 2025, data were presented demonstrating rapid and strong efficacy regardless of baseline immunoglobulin E (IgE) levels and in November 2025 at the American College of Allergy, Asthma & Immunology’s Annual Scientific (ACAAI) Meeting, data were presented demonstrating that barzolvolimab leads to rapid and profound improvements in UCT7 scores with sustained disease control off treatment.

Current wording

In September at EADV 2025, data were presented demonstrating rapid and strong efficacy regardless of baseline immunoglobulin E (IgE) levels. In November 2025, at the American College of Allergy, Asthma & Immunology’s Annual Scientific (ACAAI) Meeting, data were presented demonstrating that barzolvolimab leads to rapid and profound improvements in UCT7 scores with sustained disease control off treatment.

Previous wording

We believe these results strongly support the further development of barzolvolimab in CSU. In July 2024, we initiated two Phase 3 studies of barzolvolimab in CSU. The studies, EMBARQ-CSU1 and EMBARQ-CSU2, are designed to establish the efficacy and safety of barzolvolimab in adult patients with CSU who remain symptomatic despite H1 antihistamine treatment. Both Phase 3 trials are randomized, double-blind, placebo-controlled, parallel group, global studies (approximately 40 countries; 250 sites per study) where approximately 915 patients per trial will be randomized evenly to barzolvolimab 150 mg every 4 weeks (following 300 mg loading dose), barzolvolimab 300 mg every 8 weeks (following 450 mg loading dose) or placebo for 52 weeks. At 24 weeks, patients on placebo will be re-randomized to active treatment across both dosing groups. After completion of the 52 week treatment period, patients on study will continue to be followed for 16 weeks. The primary endpoint of the studies will evaluate the clinical effect of barzolvolimab in reducing urticaria activity (weekly urticaria activity score; UAS7) at Week 12. The studies are designed to detect a clinically meaningful difference between each of the active arms versus placebo in the overall population as well as in the subpopulation of omalizumab refractory participants. Enrollment continues as planned and is expected to be completed in the summer of 2026.

Current wording

In July 2024, we initiated two Phase 3 studies of barzolvolimab in CSU. The studies, EMBARQ-CSU1 and EMBARQ-CSU2, are designed to establish the efficacy and safety of barzolvolimab in adult patients with CSU who remain symptomatic despite H1 antihistamine treatment. 1,939 patients were enrolled—the largest program conducted in antihistamine refractory CSU, including patients with advanced therapy experienced/refractory CSU. The studies included 43 countries and over 500 sites. Both Phase 3 trials are randomized, double-blind, placebo-controlled, parallel group, global studies where patients have been randomized evenly per trial to barzolvolimab 150 mg every 4 weeks (following 300 mg loading dose), barzolvolimab 300 mg every 8 weeks (following 450 mg loading dose) or placebo for 52 weeks. At 24 weeks, patients on placebo are re-randomized to active treatment across both dosing groups. After completion of the 52 week treatment period, patients on study are followed for 16 weeks. The primary endpoint of the studies will evaluate the clinical effect of barzolvolimab in reducing urticaria activity (weekly urticaria activity score; UAS7) at Week 12. The studies are designed to detect a clinically meaningful difference between each of the active arms versus placebo in the overall population as well as in the subpopulation of omalizumab refractory participants. The primary endpoint analysis will be performed when all patients have completed the placebo controlled portion of the study at 24 weeks. Enrollment to the studies was completed in February 2026 and topline data will be available in Q4 2026. Assuming positive Phase 3 data, the Company plans to file a BLA in 2027.

Previous wording

Chronic Inducible Urticaria (CIndU) Summary of Phase 1 and Phase 2 Data Presented to Date

Current wording

Chronic Inducible Urticaria (CIndU) Summary of Phase 1 and Phase 2 Data

Previous wording

We recently completed a Phase 2 study in patients with CIndU who remain symptomatic despite antihistamine therapy. The study was conducted at approximately 85 sites across approximately 12 countries. The randomized, double-blind, placebo-controlled, parallel group Phase 2 study evaluated the efficacy and safety profile of multiple dose regimens of barzolvolimab in patients with CIndU to determine the optimal dosing strategy. 196 patients in 2 cohorts (differentiated by CIndU subtype) including 97 patients with cold urticaria and 99 patients with symptomatic dermographism were randomly assigned on a 1:1:1 ratio to receive subcutaneous injections of barzolvolimab at 150 mg every 4 weeks, 300 mg every 8 weeks or placebo during a 20-week treatment phase. Patients then entered a follow-up phase for an additional 24 weeks. In addition, the study included the option for patients who had symptoms following the treatment phase, including patients who were on placebo, to enroll in an open label extension where all patients received 300 mg of barzolvolimab every 8 weeks. The primary endpoint of the study was the percentage of patients with a negative provocation test at Week 12. Secondary endpoints included safety and other assessments of clinical activity including CTT (Critical Temperature Threshold), CFT (Critical Friction Threshold) and WI-NRS (Worst itch numeric rating scale).

Current wording

We completed a Phase 2 study in patients with CIndU who remain symptomatic despite antihistamine therapy. The study was conducted at approximately 85 sites across approximately 12 countries. The randomized, double-blind, placebo-controlled, parallel group Phase 2 study evaluated the efficacy and safety profile of multiple dose regimens of barzolvolimab in patients with CIndU to determine the optimal dosing strategy. 196 patients in 2 cohorts (differentiated by CIndU subtype) including 97 patients with cold urticaria and 99 patients with symptomatic dermographism were randomly assigned on a 1:1:1 ratio to receive subcutaneous injections of barzolvolimab at 150 mg every 4 weeks, 300 mg every 8 weeks or placebo during a 20-week treatment phase. Patients then entered a follow-up phase for an additional 24 weeks. In addition, the study included the option for patients who had symptoms following the treatment phase, including patients who were on placebo, to enroll in an open label extension where all patients received 300 mg of barzolvolimab every 8 weeks. The primary endpoint of the study was the percentage of patients with a negative provocation test at Week 12. Secondary endpoints included safety and other assessments of clinical activity including CTT (Critical Temperature Threshold), CFT (Critical Friction Threshold) and WI-NRS (Worst itch numeric rating scale).

Previous wording

We believe these results strongly support the further development of barzolvolimab in CIndU and Celldex plans to initiate a global Phase 3 study in ColdU and SD in December 2025.

Current wording

We believe these results strongly support the further development of barzolvolimab in ColdU and SD.

Previous wording

We have completed a Phase 1b multi-center, randomized, double-blind, placebo-controlled intravenous study in PN. Data from the study, including 24 weeks of follow-up, were presented at the 12th World Congress on Itch (WCI) held in November 2023. 24 adults (evaluable: n=23 safety; n=22 efficacy) with moderate to severe PN were randomized across three arms: (1) barzolvolimab 3.0 mg/kg (n=9), barzolvolimab 1.5 mg/kg (n=7) and placebo (n=8). The primary endpoint of the study was safety; key secondary endpoints include changes from baseline in Worst Itch-Numerical Rating Scale (WI-NRS) & Investigator Global Assessment (IGA). The primary timepoint for evaluation of clinical activity was 8 weeks; patients were followed for safety and efficacy endpoints to 24 weeks. Patients on study generally had moderate to severe disease with mean baselines scores across all arms of 8.6 for WI-NRS and 3.3 for IGA.

Current wording

We have completed a Phase 1b multi-center, randomized, double-blind, placebo-controlled intravenous study in PN. Data from the study, including 24 weeks of follow-up, were presented at the 12th World Congress on Itch (WCI) held in November 2023. 24 adults (evaluable: n=23 safety; n=22 efficacy) with moderate to severe PN were randomized across three arms: (1) barzolvolimab 3.0 mg/kg (n=9), barzolvolimab 1.5 mg/kg (n=7) and placebo (n=8). The primary endpoint of the study was safety; key secondary endpoints include changes from baseline in Worst Itch-Numerical Rating Scale (WI-NRS) & Investigator Global Assessment (IGA). The primary timepoint for evaluation of clinical activity was 8 weeks; patients were followed for safety and efficacy endpoints to 24 weeks. Patients on study generally had moderate to severe disease with mean baseline scores across all arms of 8.6 for WI-NRS and 3.3 for IGA.

Previous wording

In April 2024, we initiated a Phase 2 subcutaneous study in PN. This randomized, double-blind, placebo-controlled, parallel group study is evaluating the efficacy and safety profile of 2 dose levels of barzolvolimab compared to placebo in approximately 120 patients with moderate to severe PN who had inadequate response to prescription topical medications, or for whom topical medications are medically inadvisable (such as concerns for safety). Patients are randomly assigned on a 1:1:1 ratio to receive barzolvolimab injections of 150 mg Q4W after an initial loading dose of 450 mg, 300 mg Q4W after an initial loading dose of 450 mg, or placebo during a 24‑week Treatment Phase. Participants then enter a follow-up phase with no study treatment for an additional 16 weeks through Week 40. The primary objective of this study is to evaluate the clinical effect of barzolvolimab, compared to placebo, on itch response as measured by the proportion of participants with ≥ 4-point improvement in the worst intensity itch per a numeric rating scale (WI-NRS). Secondary objectives include but are not limited to additional measures of itch response from baseline compared to different timepoints, the assessment of skin lesions as measured by the Investigator Global Assessment (IGA), QoL outcomes and safety. The study includes approximately 75 clinical trial centers worldwide, including the United States. Enrollment is ongoing. Initial data from this study are expected to be presented in the second half of 2026.

Current wording

In April 2024, we initiated a Phase 2 subcutaneous study in PN. This randomized, double-blind, placebo-controlled, parallel group study is evaluating the efficacy and safety profile of 2 dose levels of barzolvolimab compared to placebo in patients with moderate to severe PN who had inadequate response to prescription topical medications, or for whom topical medications are medically inadvisable (such as concerns for safety). 140 patients were randomly assigned on a 1:1:1 ratio to receive barzolvolimab injections of 150 mg Q4W after an initial loading dose of 450 mg, 300 mg Q4W after an initial loading dose of 450 mg, or placebo during a 24‑week Treatment Phase. Participants then entered a follow-up phase with no study treatment for an additional 16 weeks through Week 40. The primary objective of this study is to evaluate the clinical effect of barzolvolimab, compared to placebo, on itch response as measured by the proportion of participants with ≥ 4-point improvement in the worst intensity itch per a numeric rating scale (WI-NRS). Secondary objectives include but are not limited to additional measures of itch response from baseline compared to different timepoints, the assessment of skin lesions as measured by the Investigator Global Assessment (IGA), QoL outcomes and safety. In addition, the study included the option for patients who had symptoms following the treatment phase, including patients who were on placebo, to enroll in an open label extension where all patients received 300 mg of barzolvolimab every 4 weeks following a loading dose of barzolvolimab 450 mg. The study included the United States and 5 additional countries and approximately 75 clinical trial centers. Enrollment was completed in December 2025. Topline data from the study is expected in summer 2026.

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. Approximately 120 patients will be 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 will be re-randomized at Week 16 into 1 of the 2 active treatment arms. Patients then enter 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. When all clinical trial sites are open, the study includes approximately 40 clinical trial centers in the United States. Enrollment is ongoing. Initial data from this study are expected to be presented in the second half of 2026.

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,

Previous wording

In 2023, we completed the transfer of our current barzolvolimab manufacturing process to a CDMO and successfully scaled up the drug substance manufacturing process to produce larger cGMP batches in support of late-stage trials and to prepare for potential commercialization. Drug product manufacturing into 1 mL pre-filled syringes has been completed and are actively being used in the ongoing Phase 3 CSU trials. In the third quarter of 2025, we initiated the Process Performance Qualification (PPQ) manufacturing runs for drug substance and are currently planning for the drug product PPQ activities in 2026.

Current wording

The barzolvolimab manufacturing process has been successfully transferred and scaled up to produce larger cGMP batches at both Drug Substance (DS) and Drug Product (DP) commercial Contract Development and Manufacturing Organizations in support of late-stage trials and to prepare for potential commercialization. Drug product manufacturing into 1 mL pre-filled syringes has been completed and pre-filled syringes are actively being used in Phase 3 trials. In 2025, we initiated the Process Performance Qualification (PPQ) manufacturing runs for DS and anticipate the completion of those activities in 2026. We are currently preparing for the DP PPQ activities and expect to complete these activities in 2026.

Previous wording

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 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.

Previous wording

In November 2024, we initiated a Phase 1 study of CDX-622 in healthy volunteers. 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 single ascending doses (Part 1), multiple ascending doses (Part 2) and single ascending doses administered subcutaneously (Part 3) of CDX-622 in up to 80 healthy participants. A single dose of CDX-622 or placebo was administered intravenously once during Part 1. In Part 2, CDX-622 or placebo is administered every 2 weeks (Q2W) for up to 6 weeks following the first dose, for a total of 3 doses. A single dose of CDX-622 or placebo will be administered subcutaneously once during Part 3. Participants will be 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. A subcutaneous formulation is currently being manufactured and will be added to this study in 2025.

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

Previous wording

We presented positive data from the 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. Enrollment is ongoing to the multiple ascending doses portion of the study (Part 2).

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. 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.

Previous wording

The $24.9 million increase in net loss for the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, was primarily due to an increase in research and development expenses related to barzolvolimab and decreases in revenue and investment and other income, net.

Current 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.

Previous wording

Revenue from product development and licensing agreements for the three months ended September 30, 2025 was relatively consistent with the three months ended September 30, 2024. The $3.2 million decrease in contracts and grants revenue for the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, was primarily due to a decrease in revenue from our contract manufacturing and research and development agreements with Rockefeller University. We expect revenue to remain relatively consistent over the next twelve months, although there may be fluctuations on a quarterly basis.

Current 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

Previous wording

Personnel expenses primarily include salary, benefits, stock-based compensation and payroll taxes. The $0.6 million increase in personnel expenses for the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, 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 $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.

Previous wording

Laboratory supplies expenses include laboratory materials and supplies, services, and other related expenses incurred in the development of our technology. The $0.8 million increase in laboratory supply expenses for the nine months ended September 30, 2025, as compared to the nine months ended September 30, 2024, was primarily due to higher laboratory materials and supplies purchases.

Current 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.

Previous wording

Facility expenses include depreciation, amortization, utilities, rent, maintenance and other related expenses incurred at our facilities. Facility expenses for the three months ended September 30, 2025 were relatively consistent with the three months ended September 30, 2024. In September 2025, we signed a new lease in New Haven, CT that we will relocate our existing New Haven operations to in 2026. 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 $0.5 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.

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 $15.8 million increase in product development expenses for the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, was primarily due to an increase in barzolvolimab clinical trial and contract manufacturing expenses. We expect product development expenses to increase over the next twelve months as a result of the expanded development of barzolvolimab, including manufacturing PPQ activities planned for the fourth quarter of 2025 and throughout 2026, 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 $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.

Previous wording

The $3.4 million decrease in investment and other income, net for the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, was primarily due to lower levels of cash and investment balances. We expect investment and other income to decrease over the next twelve months due to lower levels of cash and investment balances, although there may be fluctuations on a quarterly basis.

Current 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.

Previous wording

At September 30, 2025, our principal sources of liquidity consisted of cash, cash equivalents and marketable securities of $583.2 million. We have had recurring losses and incurred a loss of $177.4 million for the nine months ended September 30, 2025. Net cash used in operations for the nine months ended September 30, 2025 was $147.0 million. We believe that the cash, cash equivalents and marketable securities at September 30, 2025 are sufficient to meet estimated working capital requirements and fund current planned operations through 2027. 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 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.

Previous wording

Net cash used in operating activities was $147.0 million for the nine months ended September 30, 2025 as compared to $125.3 million for the nine months ended September 30, 2024. The increase in net cash used in operating activities was primarily due to increases in research and development and general and administrative expenses, partially offset by a decrease in advance payments to clinical research and contract manufacturing organizations. 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 $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.

Previous wording

Net cash provided by investing activities was $153.6 million for the nine months ended September 30, 2025 compared to net cash used in investing activities of $314.2 million for the nine months ended September 30, 2024. The increase in net cash provided by investing activities was primarily due to net sales and maturities of marketable securities of $155.1 million for the nine months ended September 30, 2025 as compared to net purchases of marketable securities of $313.0 million for the nine months ended September 30, 2024.

Current 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.

Previous wording

Net cash provided by financing activities was $1.0 million for the nine months ended September 30, 2025 as compared to $441.1 million for the nine months ended September 30, 2024. The decrease in net cash provided by financing activities was primarily due to a decrease in net proceeds from stock issuances.

Current 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.

Previous wording

In March 2024, we issued 9,798,000 shares of common stock in an underwritten public offering, resulting in net proceeds of $432.3 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 approximately $323.9 million, after deducting underwriting fees and offering expenses.