Executives from Celldex Therapeutics (NASDAQ:CLDX) outlined a busy year of clinical and development milestones at the TD Cowen Healthcare Conference, highlighting completed enrollments in two Phase 3 chronic spontaneous urticaria (CSU) trials, the launch of a Phase 3 study in chronic inducible urticaria (CIndU), and multiple upcoming data readouts across dermatology and immunology programs.
CSU Phase 3 EMBARQ program: enrollment completed ahead of schedule
Celldex said both Phase 3 trials in its CSU EMBARQ program completed enrollment around six months ahead of prior guidance, which management attributed to global enthusiasm for the investigational drug barzolvolimab and engagement from principal investigators. The company noted that the rapid accrual occurred despite a shifting competitive landscape that now includes recent approvals for other therapies in the category.
Celldex stated the Phase 3 studies are 90% powered to detect a 10-point difference in mean change from baseline in Urticaria Activity Score 7 (UAS7) versus placebo. The company emphasized that the trials are powered to show this effect both in the overall population and in a subgroup of patients refractory to omalizumab.
Discussing prior results, executives referenced Phase 2 follow-up data indicating a deepening response over time, including a complete response rate cited at 41% at 76 weeks after follow-up, with earlier timepoints described as higher while on treatment. They also discussed the lack of an approved therapy that has demonstrated statistically significant efficacy in omalizumab-refractory CSU, positioning that population as a key unmet need.
Dosing, durability, and commercialization considerations
Celldex said it did not specifically power the Phase 3 CSU program to detect differences between two dosing regimens. The company discussed the possibility that regulators may ultimately approve more than one dose, allowing physician flexibility.
Executives also addressed durability observed after discontinuation in earlier studies, noting that tryptase levels suggested mast cells returned to normal levels during an off-treatment period discussed as up to several months. The team said it expects symptoms to recur in many patients over time, but described the return as potentially slow and still under investigation mechanistically.
On potential post-approval studies, management said Phase 4 work could explore alternative dosing strategies, though they also noted that physicians often adapt dosing in real-world practice once a product is available.
On administration, Celldex said barzolvolimab dosing in the CSU trials is subcutaneous and administered in-office. Commercially, the company said it plans to launch with a pre-filled syringe for in-office use, with a goal of introducing a self-injected auto-injector about a year later. The company indicated that additional work would be required to support at-home use with the pre-filled syringe.
Regarding pricing, management said the company is still doing the work but is considering a premium to therapies such as Dupixent, Olumiant, and Rinvoq, without providing specifics.
Safety monitoring topics: neutropenia, hypersensitivity, and a male fertility study
Celldex said neutropenia events observed to date have been mostly mild, reversible while patients remain on therapy, and not associated with infections. Based on this, the company indicated it does not currently believe routine monitoring would be beneficial for that issue. Hypersensitivity surveillance in trials is being handled through standard adverse event reporting at study visits.
The company also discussed an ongoing study evaluating effects on sperm in healthy male volunteers. Celldex expects the study to read out in time for a planned biologics license application (BLA) filing. Management described the study as assessing sperm count and broader parameters such as hormone levels, and reiterated that systemic KIT inhibition is known to impact sperm maturation and is expected to be reversible.
CIndU Phase 3: single-dose strategy to support feasibility
Celldex said it has started a Phase 3 study in CIndU (including ColdU and symptomatic dermographism) with approximately 240 patients randomized 1:1. The company selected a single active regimen—citing the rarity of CIndU relative to CSU and a desire to keep accrual manageable—while noting that two dose levels were active and statistically significant in Phase 2. Management said the chosen approach incorporates a loading dose to support faster onset, consistent with the CSU program.
The company described CIndU as under-recognized and under-treated, similar to CSU, and suggested that increased therapeutic activity in the category could improve diagnosis and treatment rates over time.
Dermatology readouts and CDX-622 next steps
Celldex said enrollment is complete for two Phase 2 dermatology studies of barzolvolimab:
- Prurigo nodularis (PN): a randomized, placebo-controlled Phase 2 study with two dose arms versus placebo. The company said it planned for 120 patients but enrolled 140, and expects a data readout later this year. The study includes a 24-week placebo-controlled period with a primary endpoint at 12 weeks. Celldex said it chose a higher dosing strategy in PN than in CSU to avoid underdosing, based on earlier signals suggesting more complete tryptase suppression at higher exposure.
- Atopic dermatitis (AD): a randomized, placebo-controlled study with similar dosing to the PN trial. Celldex said enrollment finished at 131 patients and that data are expected later in the year. The primary endpoint is the percent decrease in peak pruritus score at 16 weeks, with skin endpoints as secondary measures. Management said the itch-focused endpoint was selected based on confidence informed by PN data, and described a potential positioning in patients who fail IL-4/IL-13-targeting agents but before use of JAK inhibitors.
Separately, Celldex provided an update on CDX-622, its stem cell factor/TSLP bispecific program. Management referenced single ascending dose data showing an approximately 18-day half-life, no immunogenicity, and a clean safety profile. The company said it is now in Part 2 with multiple ascending dose IV dosing and is also evaluating a subcutaneous formulation in the same trial, with data expected this summer. Celldex added that it has initiated a proof-of-mechanism study in asthma to gather pharmacodynamic data, including lung-related biomarkers using induced sputum sampling, to inform broader development decisions. Potential future opportunities mentioned included pulmonary indications and food allergy, though the company said it has not provided timing guidance for asthma study data.
About Celldex Therapeutics (NASDAQ:CLDX)
Celldex Therapeutics, Inc is a clinical-stage biopharmaceutical company focused on the discovery and development of targeted immunotherapies for cancer and other serious diseases. The company’s research platforms leverage novel antibody and vaccine technologies designed to engage the patient’s immune system, with a particular emphasis on oncology and neurologic indications. Celldex’s pipeline includes both monoclonal antibodies and biologic agents that seek to modulate immune responses or deliver targeted cytotoxic activity.
Among Celldex’s lead product candidates is glembatumumab vedotin, an antibody–drug conjugate directed against the glycoprotein NMB (gpNMB) for the treatment of certain breast and skin cancers.
