Regeneron Says Experimental Therapy Reduced Symptoms Of Cat, Birch Allergies In Late-Stage Trials

Regeneron Pharmaceuticals, Inc. (REGN) said on Monday that its experimental therapy significantly reduced symptoms of cat and birch allergies in late-stage trials, successfully meeting their key endpoints.

In the trials, patients with moderate to severe cat or birch allergies received direct instillation of either cat dander or birch pollen into the eyes, followed by a single subcutaneous administration of the allergen-blocking antibodies. The antibody blockers “significantly reduced” allergy symptoms compared to placebo, the company said.

The company stated that the data from the studies will be presented at an upcoming medical conference and used to inform confirmatory late-stage trials. Both the cat and birch allergy programs are part of a broader allergy pipeline, which includes an ongoing study in adults with severe food allergy. Initial results from the food allergy trial have been encouraging, the company said on Monday.

Regeneron Chief Scientific Officer George D. Yancopoulos stated on Monday that the company anticipates significant relief at the earliest assessment time point, which is expected to last over three months, in both our cat and birch allergy programs.

On Stocktwits, retail sentiment around REGN stock fell from ‘bullish’ to ‘neutral’ territory over the past 24 hours, while message volume stayed at ‘low’ levels. Shares of the company traded 1% higher in the pre-market session at the time of writing.

Yancopoulos said that while millions suffer from the effects of allergies, most undergo allergy desensitization shots, often with disappointing results.

“The purpose of these burdensome allergy shots is to try to build up allergen-blocking antibodies in the body. We wondered whether we could instead manufacture and directly provide allergen-blocking antibodies,” he said. “These recent Phase 3 allergen challenge trials, together with our earlier Phase 2 trials, provide compelling evidence that our first-in-class approach can have the potential to provide profound allergy relief – rapidly and durably after a single treatment – decreasing ocular, nasal and even asthma measures.”

Regeneron noted that Birch pollen is one of the most common seasonal allergens in the U.S., affecting more than 10 million people, while cat allergy affects more than 20 million people. In the trials, patients received a combination of two antibody blockers or a placebo. Those who received the combination had fewer allergy symptoms, such as conjunctival redness.

While additional late-stage trials in cat allergy are planned to begin in the first half of 2026, further late-stage development in birch allergy is expected to commence by the end of the year.

REGN stock is down by 20% this year and by about 50% over the past 12 months.

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