A novel treatment helped patients with mild asthma from developing an allergic reaction after challenge to a major cat allergen, according to recent research presented at the virtual American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting.

REGN1908-1909, a monoclonal antibody cocktail developed by Regeneron, blocked Fel d 1, a major allergen present in cat dander, in patients enrolled in a phase 2 trial, according to researchers at the meeting.

“Cat allergy is one of the most common allergic respiratory diseases, impacting millions of people who must alter their lives by withdrawing from certain social situations, occupations and relationships. For those with co-existing asthma, cat allergies can trigger exacerbations that, although rare, can lead to hospitalization,” Frederic J. de Blay, MD, professor of pulmonology and allergist at Strasbourg University, stated in a press release. “These encouraging trial results showed that a single dose of REGN1908-1909 prevented early asthma reactions in cat-allergic patients with mild asthma rapidly and durably – as early as one week after treatment and up to three months.”

In a proof-of-concept trial, 56 patients with mild asthma and a cat allergy were randomized to receive subcutaneous REGN1908-1909 (600 mg) or placebo and then followed for 12 weeks. At 1 week, 4 weeks, 8 weeks, and 12 weeks, patients underwent an allergen challenge in an environmental exposure unit and researchers compared their results with how the patients reacted when exposed to the cat allergen for 2 hours in the week before receiving REGN1908-1909 or placebo.

The results showed the patients had an improved early asthma reaction for the 3-month duration of the trial. Specifically, there was a significant extension of median reaction time, as measured by forced expiratory volume in 1 second (FEV1), before an early asthma reaction during challenge at 1 week for patients who received REGN1908-1909 (> 4 hours) compared with placebo (51 minutes) group (P = .0083). Patients who received REGN1908-1909 also had 68% of their lung function decline prevented after being exposed at 1 week compared with 23% in the placebo group, with “similar benefit” seen in the 3-month post-treatment period. In addition, patients who received REGN1908-1909 tolerated 60 nanograms of allergen compared with the placebo group, which tolerated 20 nanograms of allergen (P = .003).

There was a similar rate of adverse events between the group that received REGN1908-1909 and placebo (76% vs. 78%), with injection-site reactions as the most common event (7% vs. 4%).

“These data add further evidence supporting a completely new way to combat common allergies,” George D. Yancopoulos, MD, PhD, president and chief scientific officer at Regeneron, stated in the release. “Under this new approach pioneered by Regeneron, patients are given antibodies that provide immediate and durable protection against offending allergens, a type of passive immunity. We have developed and are currently studying several allergen-specific antibodies, including REGN1908-1909 for cat allergy and a phase 3 trial investigating REGN5713-5715 in patients with birch allergy.”