CLDX Stock Down 10% After-Hours — What’s Driving The Selloff?

• The trial failed to meet its main goal: a meaningful reduction in worst daily itch at week 12 compared with placebo.
• Celldex said it is discontinuing further development of barzolvolimab in prurigo nodularis.
• The company will continue advancing barzolvolimab in late-stage trials for chronic spontaneous urticaria.

Shares of Celldex Therapeutics (CLDX) dropped as much as 10% in after-hours trading on Tuesday after the company reported that its experimental drug barzolvolimab missed key goals in a mid-stage study for prurigo nodularis, a chronic itchy skin condition.

Trial Details

The randomized, placebo-controlled study enrolled 140 adults with moderate to severe prurigo nodularis who had not responded well to topical treatments. Patients received either of two doses of barzolvolimab or a placebo for 24 weeks. The drug works by targeting mast cells, which were thought to play a role in driving itch and inflammation.

The trial failed to meet its main goal: a meaningful reduction in worst daily itch at week 12 compared with placebo. Secondary measures, including doctor assessments of skin lesions and itch relief at later time points, also showed no clear advantage for the drug. Even though treatment continued through week 24, results remained similar to placebo, the company said.

Barzolvolimab did produce strong, sustained depletion of mast cells, as shown by sharp drops in a key blood marker. However, this biological effect did not translate into symptom improvement for patients. The drug was generally well tolerated, with a safety profile consistent with earlier studies.

Steps Ahead

Celldex said it is discontinuing further development of barzolvolimab in prurigo nodularis. CEO Anthony Marucci called the outcome disappointing, noting the drug had shown strong results in other mast-cell-driven conditions such as chronic hives. The company will continue advancing barzolvolimab in late-stage trials for chronic spontaneous urticaria, with data expected this fall. Earlier mid-stage data showed strong efficacy, including sustained off-treatment benefits in the condition.

Barzolvolimab is Celldex’s lead asset. The company is also studying the drug in cold urticaria and atopic dermatitis. None of Celldex’s candidates have received FDA approval or marketing authorization anywhere.

How Did CLDX Retail Traders React?

On Stocktwits, retail sentiment around CLDX stock stayed within the ‘neutral’ territory over the past 24 hours, while message volume stayed at ‘high’ levels.

A Stocktwits user stated that Celldex’s asset can rival Dupixent, developed and commercialized by Sanofi and Regeneron Pharmaceuticals. The drug, used to treat moderate-to-severe inflammatory conditions like eczema, generated $17.8 billion in 2025.

CLDX stock has gained 31% year-to-date. 

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