Celldex Therapeutics Teases Key Barzolvolimab Phase 3 Updates, New Data at Guggenheim Summit

Key Points

• Phase 3 momentum and timing: Celldex is advancing multiple barzolvolimab Phase 3 programs — CSU trials across >500 centers (≈1,830 patients) with accrual expected to finish in summer 2026 and a guidance update due soon, plus a 240‑patient ColdU/SD program and AD/PN Phase 2 readouts planned in H2 2026 to inform Phase 3 starts.
• Strong CSU efficacy with manageable safety: Physician‑reported CSU results show rapid symptom relief with complete response rates reported “up to 70%” and 41% of patients still responding seven months after last dose, while the safety profile has been consistent and investigators describe KIT‑mediated side effects (neutropenia, hair/skin changes) as generally mild and reversible.
• Early bispecific promise and funding outlook: CDX‑622 (anti‑SCF/TSLP) has shown no safety signals and significant sustained tryptase reductions with MAD and subcutaneous data expected around summer, and Celldex reported $583M cash at Q3-end—projected to fund operations through 2027 but additional capital will be needed for a launch.

Celldex Therapeutics NASDAQ: CLDX executives used a presentation at the Guggenheim Emerging Outlook Biotech Summit 2026 to outline upcoming clinical milestones for barzolvolimab across multiple allergic and inflammatory indications, provide an update on long-term chronic spontaneous urticaria (CSU) data that has been discussed with physicians, and review early progress for its bispecific program CDX-622.

Pipeline execution and upcoming milestones

President and CEO Anthony Marucci said 2025 was a “really busy year” for the company on execution and development. Celldex initiated a second Phase 3 study in chronic inducible urticaria (CIndU) subtypes—cold urticaria (ColdU) and symptomatic dermographism (SD)—in December 2025. The company also completed Phase 2 studies in prurigo nodularis (PN) and atopic dermatitis (AD) around December 2025 and January 2026.

In CSU, Celldex has two ongoing Phase 3 trials. Marucci said the company has guided since beginning the Phase 3 program in 2024 that it would finish accrual in summer 2026, and added that the company plans to update that guidance in its earnings release “at the end of this month.” He said the CSU trials are being conducted at more than 500 centers across 43 countries, with at least 1,830 patients expected across the two studies combined.

For the Phase 3 ColdU and SD program, Marucci described a 240-patient set of studies, with 120 patients in each arm. He said the company’s timing guidance for those studies is around 18 months.

Celldex guided that AD and PN Phase 2 data are expected in the second half of 2026. Marucci said the company would use those data to inform the start of Phase 3 studies in those programs. He also noted the company is evaluating additional potential indications, including food allergy, allergic rhinitis, and chronic pruritic itch of unknown origin, with possible development timing later in 2026 or in 2027.

Physician feedback on CSU durability and safety

Chief Medical Officer Diane Young said physicians have been “very excited” about the company’s CSU data, which she described as “unprecedented.” She highlighted rapid symptom responses on UAS7 and said complete response rates have been reported “up to 70%,” with durability that includes 41% of patients still responding seven months after the last dose. Young also pointed to improvements in quality of life and angioedema endpoints that have been presented alongside symptom scores.

In discussing safety perceptions, Young said the safety profile has been consistent across the data shown so far and that investigators are “very, very comfortable” with it. She said the most common side effects are mediated by KIT, occur in a subset of patients, are mild, and have been shown to be reversible. The conversation referenced neutropenia, hair color changes, and skin pigmentation as areas of interest to investors.

Upcoming conference presentations and trial design details

Young said Celldex would have three presentations at AAAAI. She described one as additional long-term response data following a subset of patients who were well controlled at 52 weeks, tracking symptoms over the seven months after therapy. She said those data show the majority maintained a complete response and that recurrences tended to be milder.

The other two posters are related to the Phase 2 CIndU study: one focused on 20-week placebo-controlled period data on quality of life and the urticaria control test, and another late-breaking poster on retreatment. Young said patients whose symptoms recurred after the placebo-controlled period could be retreated with barzolvolimab, and the company has shown it can successfully retreat patients.

On the CSU Phase 3 design, Young said the trial was intended to be kept as close as possible to Phase 2 with respect to inclusion and exclusion criteria, with the main difference being the addition of a loading dose to each dose level. Although the primary endpoint is change from baseline in UAS7 at 12 weeks, Young said the placebo-controlled period is 24 weeks and the company will conduct its first analysis after all patients have completed the 24-week period, allowing for a fuller six-month safety dataset alongside the efficacy endpoint. She also said the “primary completion” date visible on ClinicalTrials.gov was more reflective of enrollment completion than a data readout date.

Commercial positioning and market considerations

Marucci discussed a competitive landscape that now includes Novartis, Sanofi, and Roche, and said their activity could expand the overall market. He reiterated Celldex’s view that the market includes roughly 750,000 “biologically eligible” patients, while noting Novartis appears to view the market as larger.

He said Celldex’s “entry point” is expected to be after Xolair in allergist treatment pathways, and also behind “Remi or Dupixent,” describing the opportunity as participation in a growing second-line biologic market over the next five to 10 years. On pricing, he said remibrutinib could be a proxy for Dupixent pricing, and added that Celldex believes its data “requires a premium price,” while emphasizing that pricing would depend on Phase 3 outcomes and the commercial process.

CDX-622: bispecific program progress and next data

Chief Scientific Officer Tibor Keler described Celldex’s bispecific program as an effort to build on learnings from mast cell targeting while combining mast cell inhibition with another validated pathway. CDX-622 neutralizes stem cell factor (SCF), the ligand for KIT, and also targets TSLP.

Keler said the company initiated a healthy volunteer study earlier last year and reported single ascending dose data in the fall. He cited a half-life of more than 24 days at the highest dose, said the company has seen “absolutely no” safety signals so far, and highlighted significant and sustained reductions in tryptase as evidence of mast cell impact. He said multiple ascending dose (MAD) testing—four doses given every other week—is underway, with data expected “around this summer.” He added that a subcutaneous formulation has been developed and added to the healthy volunteer study, with subcutaneous dosing data also planned for disclosure.

Keler also said Celldex has initiated a proof-of-mechanism study in mild to moderate asthma patients to validate both ends of the molecule, including biomarker effects expected from TSLP blockade. He said the asthma study uses a single IV dose at the highest dose level and includes sputum sampling to assess lung mast cells and other inflammatory biomarkers.

In response to a question on immunogenicity, Keler said the single ascending dose results showed good pharmacokinetics without measurable immunogenicity, adding that the company hopes to maintain that profile as development continues.

On financial position, Marucci said Celldex had $583 million at the end of the third quarter and has guided that its cash is sufficient to fund operations through 2027. He noted the company would “need more capital for a launch and other development.”

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.

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