Allergies to cat dander and birch pollen affect millions, often causing persistent ocular, nasal, and respiratory symptoms despite standard treatments like antihistamines, nasal sprays or immunotherapy.
On September 8, 2025, Regeneron announced positive Phase 3 results from two ocular allergen challenge trials testing first-in-class allergen-blocking antibodies—a single subcutaneous dose provided rapid, significant relief.
Cat Allergy (REGN1908 + REGN1909 targeting Fel d 1):
Ocular itch reduced by 52% vs. placebo (primary endpoint, p<0.0001).
Conjunctival redness down 39%, skin prick reactivity 44% (both p<0.0001).
Benefits started as early as day 8 and lasted at least 3 months in prior studies.
Birch Pollen Allergy (REGN5713 + REGN5715 targeting Bet v 1):
Ocular itch reduced by 51% vs. placebo (p<0.0001).
Conjunctival redness down 46%, skin prick reactivity 44% (both p<0.0001).
Similar rapid onset and 3-month durability seen in earlier nasal/environmental challenge trials.
Both treatments were well-tolerated, with no serious treatment-related adverse events or discontinuations.
Unlike traditional allergy shots that slowly build immunity over years, these direct antibody blockers offer potential for fast, profound, and convenient relief from one dose.
These investigational therapies remain unapproved, pending additional evaluation. If successful, they could transform care for refractory cat and birch allergies, addressing a major unmet need.
Treatment Options for
Allergic Rhinitis (AR) (click to enlarge the image).
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