Celldex Announces Multiple Upcoming Presentations from Leading Mast Cell Targeting Pipeline at the Upcoming 2026 European Academy of Allergy and Clinical Immunology Annual Congress

-- Flash talks on barzolvolimab clinical program in CSU and Cold Urticaria -- -- Late-breaking poster presentation on CDX-622 --

HAMPTON, N.J., June 10, 2026 (GLOBE NEWSWIRE) -- Celldex (NASDAQ:CLDX) announced today that three presentations from the barzolvolimab and CDX-622 programs will be shared at the upcoming European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress being held in Istanbul, Türkiye, on June 12-15, 2026.

Results supporting Celldex’s leadership and barzolvolimab’s first-in-class, best-in-disease profile in chronic spontaneous urticaria (CSU) and cold urticaria (ColdU) will be presented in two flash talks.

New, first-in-human results from the Phase 1 trial of the novel bispecific CDX-622 in healthy volunteers will be presented in a late-breaking poster session, highlighting the potential for bispecific targeting of soluble stem cell factor (SCF) and thymic stromal lymphopoietin (TSLP) to inhibit KIT signaling in mast cells.

All presentations will be posted on the Celldex website at the dates and times listed below.

Presentation details are as follows:

Presentation: Phase 1 Study of CDX-622, a Bispecific Antibody Targeting TSLP and Mast Cells via Stem Cell Factor Session Date/Time: Sunday, June 14, 12:15-1:15 pm local time (5:15 am-6:15 am ET) Title: TPS68- Asthma 12 Type: Thematic Poster Session Poster Number: D3.165 Location: Poster Zone

Presentation: Long-term Barzolvolimab Treatment Results in Sustained Off-treatment Improvement in Angioedema in Patients with CSU Refractory to Antihistamines Session Date/Time: Sunday, June 14, 5:21 pm local time (10:21 am ET) Title: FT23- Urticaria contact dermatitis Type: Flash Talks Presentation Number: 000816 Location: Athens room

Presentation: ​Psychometric Validation of the Worst Itch Numeric Rating Scale (WI-NRS) as a Patient-Reported Outcome (PRO) in Cold Urticaria: Data from a Clinical Trial of Barzolvolimab Session Date/Time: Sunday, June 14, 5:35 pm local time (10:35 am ET) Title: FT23- Urticaria contact dermatitis Type: Flash Talks Presentation Number: 000825 Location: Athens room

About Barzolvolimab Barzolvolimab is a humanized monoclonal antibody with a novel mechanism of action that targets mast cells by binding with high specificity to a unique part of the KIT receptor and potently inhibiting its activity. The KIT receptor is abundantly expressed by mast cells and critical for their function and survival. Mast cells are drivers of inflammatory responses such as hypersensitivity and allergic reactions and, in certain inflammatory diseases, such as chronic urticarias, mast cell activation plays a central role in the onset and progression of the disease. Based on data from robust, randomized, placebo-controlled Phase 2 studies, barzolvolimab has significant potential as a first-in-class and best-in-disease treatment option for patients with chronic spontaneous urticaria (CSU), cold urticaria (ColdU), and symptomatic dermographism (SD). Barzolvolimab is currently being studied in Phase 3 studies in CSU and ColdU/SD, and Phase 2 studies in prurigo nodularis (PN) and atopic dermatitis (AD), with additional indications planned for the future.

About CDX-622 CDX-622 is a bispecific antibody that targets two complementary, clinically validated pathways that drive chronic inflammation, potently neutralizing the alarmin thymic stromal lymphopoietin (TSLP) and depleting mast cells via stem cell factor (SCF) starvation. SCF activation of the KIT receptor is required for mast cell survival and plays a key role in their activation, maturation and tissue recruitment. 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.

About Celldex Celldex is pioneering new horizons in immunology to deliver life-changing therapies. We are relentless in our pursuit of 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. Visit www.celldex.com .

Forward Looking Statement This release contains "forward-looking statements" made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements are typically preceded by words such as "believes," "expects," "anticipates," "intends," "will," "may," "should," or similar expressions. These forward-looking statements reflect management's current knowledge, assumptions, judgment and expectations regarding future performance or events. Although management believes that the expectations reflected in such statements are reasonable, they give no assurance that such expectations will prove to be correct or that those goals will be achieved, and you should be aware that actual results could differ materially from those contained in the forward-looking statements. Forward-looking statements are subject to a number of risks and uncertainties, including, but not limited to, our ability to successfully complete research and further development and commercialization of Company drug candidates, including barzolvolimab (also referred to as CDX-0159) and CDX-622, in current or future indications; the uncertainties inherent in clinical testing and accruing patients for clinical trials; our limited experience in bringing programs through Phase 3 clinical trials; our ability to manage and successfully complete multiple clinical trials and the research and development efforts for our multiple products at varying stages of development; the availability, cost, delivery and quality of clinical materials produced by our own manufacturing facility or supplied by contract manufacturers, who may be our sole source of supply; the timing, cost and uncertainty of obtaining regulatory approvals; the failure of the market for the Company's programs to continue to develop; our ability to protect the Company's intellectual property; the loss of any executive officers or key personnel or consultants; competition; changes in the regulatory landscape or the imposition of regulations that affect the Company's products; our ability to continue to obtain capital to meet our long-term liquidity needs on acceptable terms, or at all, including the additional capital which will be necessary to complete the clinical trials that we have initiated or plan to initiate; and other factors listed under "Risk Factors" in our annual report on Form 10-K and quarterly reports on Form 10-Q.

All forward-looking statements are expressly qualified in their entirety by this cautionary notice. You are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date of this release. We have no obligation, and expressly disclaim any obligation, to update, revise or correct any of the forward-looking statements, whether as a result of new information, future events or otherwise.

Company Contacts Sarah Cavanaugh Senior Vice President, Corporate Affairs & Administration (508) 864-8337 [email protected]

Elizabeth Higgins Executive Director, Investor Relations & Corporate Communications (857) 404-2088 [email protected]