Regeneron's Allergen-Blocking Antibodies Show Promise in Phase 3 Trials

Regeneron Pharmaceuticals has reported positive results from two phase 3 clinical trials evaluating novel allergen-blocking antibodies for cat and birch pollen allergies. The studies demonstrate significant reductions in allergy symptoms, potentially offering a new approach to allergy treatment that could replace traditional immunotherapy methods.

Cat Allergy Trial Results

In a phase 3 study involving 64 patients with cat allergies, Regeneron's combination of two FelD1-blocking antibodies, REGN1908 and REGN1909, showed impressive efficacy. The trial met its primary endpoint, reducing itchy eyes by 52% compared to placebo one week after treatment. Secondary endpoints were also achieved, with conjunctival redness and skin prick reactivity decreased by 39% and 44%, respectively.

Birch Pollen Allergy Trial Outcomes

A separate phase 3 trial enrolled 54 patients with birch pollen allergies, testing a combination of REGN5713 and REGN5715, monoclonal antibodies targeting the BetV1 protein. This study also met its primary endpoint, with a 51% reduction in itchy eyes compared to placebo. Secondary endpoints showed similar success, with conjunctival redness reduced by 46% and skin prick reactivity decreased by 44%.

Novel Approach to Allergy Treatment

Both treatments were administered as single subcutaneous doses, with allergen challenges conducted eight days post-treatment. Regeneron CEO George Yancopoulos, M.D., Ph.D., highlighted the potential of this approach to provide rapid and durable allergy relief after a single treatment, contrasting it with traditional allergy desensitization shots that can require years of frequent administration.

The antibodies were developed using Regeneron's VelocImmune technology, which has previously been employed in creating successful drugs like Dupixent and Libtayo. Both treatments were reported to be well-tolerated, with no serious treatment-related adverse events observed.

Regeneron plans to advance the birch pollen treatment to further phase 3 development later this year, while the cat allergy program is slated for progression in the first half of 2026. These developments represent a potentially significant advance in allergy treatment, offering hope for more effective and convenient options for millions of allergy sufferers worldwide.