REGN1908/1909 prevented cat allergen-induced early asthmatic responses in an environmental exposure unit.

Background: The dominant allergen in cat dander, Felis domesticus allergen 1 (Fel d 1), is a persistent trigger for allergic rhinitis and asthma symptoms.

Objective: We evaluated the efficacy of Fel d 1 monoclonal antibodies (REGN1908/1909) in preventing cat allergen-induced early asthmatic responses (EARs) in cat-allergic patients with mild asthma.

Methods: Patients were randomized to single-dose REGN1908/1909 600 mg (n = 29) or placebo (n = 27).

Cat allergen exposure in a naturalistic exposure chamber: A prospective observational study in cat-allergic subjects.

Background: To determine the proportion and reproducibility of cat-allergic mild asthmatics with early asthmatic response (EAR) during cat allergen exposure in a naturalistic exposure chamber (NEC).

Methods: This was a prospective, observational study in 30 cat-allergic mild asthmatics who received two 180-min cat-allergen (Felis domesticus allergen 1 [Fel d 1]) challenges 27 days apart in an NEC.

Results: An EAR (≥20% reduction from baseline in forced expiratory volume in 1 s [FEV1]) was observed in 67% and 52% of subjects at first and second NEC exposure, respectively, with similar median time to EAR; 44% of subjects had an EAR on days 1 and 28.