AbstractBackgroundThe allergists´ tool box in cat allergy management is limited. Clinical studies have shown that holo beta‐lactoglobulin (holoBLG) can restore micronutritional deficits in atopic immune cells and alleviate allergic symptoms in a completely allergen‐nonspecific manner. With this study, we aimed to provide proof of principle in cat allergy.MethodsA novel challenge protocol for cat allergy in a standardized ECARF allergen exposure chamber (AEC) was developed. In an open pilot study (NCT05455749), patients with clinically relevant cat allergy were provoked with cat allergen for 120 min in the AEC before and after a 3‐month intervention phase (holoBLG lozenge 2x daily). Nasal, conjunctival, bronchial, and pruritus symptoms were scored every 10 min– constituting the total symptom score (TSS). Peak nasal inspiratory flow (PNIF) was measured every 30 min. In addition, a titrated nasal provocation test (NPT) was performed before and after the intervention. Primary endpoint was change in TSS at the end of final exposure compared to baseline. Secondary endpoints included changes in PNIF, NPT, and occurrence of late reactions up to 24 h after exposure.Results35 patients (mean age: 40 years) completed the study. Compared to baseline, holoBLG supplementation resulted in significant improvement in median TSS of 50% (p< 0.001), as well as in median nasal flow by 20 L/min (p= 0.0035). 20% of patients reported late reactions after baseline exposure, but 0% after the final exposure.ConclusionsCat allergic patients profited from targeted micronutrition with the holoBLG lozenge. As previously seen in other allergies, holoBLG supplementation also induced immune resilience in cat allergies, resulting in significant symptom amelioration.