Study of Cat Allergy Using Controlled Methodology—A Review of the Literature and a Call to Action

Abstract

The prevalence of cat allergen-induced AR is increasing worldwide, prompting its study using controlled methodology. Three general categories of allergen exposure models currently exist for the study of cat allergen-induced AR: natural exposure cat rooms, allergen exposure chambers (AEC), and nasal allergen challenges (NAC). We evaluated existing literature surrounding the use of these models to study cat allergen induced AR using online research databases, including OVID Medline, Embase, and Web of Science. We report that natural exposure cat rooms have been important in establishing the foundation for our understanding of cat allergen-induced AR. Major limitations, including variable allergen ranges and differing study designs highlight the need for a more standardized protocol. In comparison, AECs are an exceptional model to mimic real-world allergen exposure and study long-term implications of AR with large sample sizes. Existing AECs are limited by heterogeneous facility designs, differing methods of cat allergen distribution, and issues surrounding cost and accessibility. Conversely, NACs allow for smaller participant cohorts for easier biological sampling and are ideal for phase I, phase 2 or proof-of-concept studies. NACs generally have a standardized protocol and are less expensive compared to AECs. Nevertheless, NACs solely capture acute allergen exposure and have the further limitation of using allergen extracts rather than natural allergen. As the use of combined controlled methodologies is sparse, we recommend concurrent use of AECs and NACs to study short- and long-term effects of AR, thereby providing a more holistic representation of cat allergen-induced AR.

The holo beta‐lactoglobulin lozenge reduces symptoms in cat allergy—Evaluation in an allergen exposure chamber and by titrated nasal allergen challenge

“…However, they are not yet accepted by regulatory bodies for pivotal (Phase III) trials, 48 even though it was previously used to document the efficacy of immunotherapeutic strategies in cat allergy. 47 In the present study, we established a protocol for cat allergen exposure in the highly standardized AEC 48 and applied both sub- A limitation of this pilot study is that it was conducted without a placebo control. The high reproducibility of the provocation conditions in the exposure chamber may reduce the risk of influencing the results, but it cannot be completely excluded.…”

“…However, the AEC is the highest standardized tool to mimic natural allergen exposure and is accepted by the European Medicines Agency as a valuable tool in clinical studies phase II (dose‐range‐finding or proof‐of‐concept) trials on AIT products. However, they are not yet accepted by regulatory bodies for pivotal (Phase III) trials, 48 even though it was previously used to document the efficacy of immunotherapeutic strategies in cat allergy 47 …”

“…Typically, symptom improvement is subjectively evaluated by the patient (VAS, online diaries, asthma/rhinitis quality of life), and objectively through allergen provocation at various sites of the body (skin, nasal, conjunctival, bronchial provocation tests). To mimic natural cat allergen exposure, natural “cat rooms” have previously been established in AIT studies, where cats were held 44 , 45 or cat blankets were shaken out ( 45 , 46 reviewed in 47 ). However, the AEC is the highest standardized tool to mimic natural allergen exposure and is accepted by the European Medicines Agency as a valuable tool in clinical studies phase II (dose‐range‐finding or proof‐of‐concept) trials on AIT products.…”

“…However, they are not yet accepted by regulatory bodies for pivotal (Phase III) trials, 48 even though it was previously used to document the efficacy of immunotherapeutic strategies in cat allergy. 47 …”

Diagnostics of Allergy to Furry Animals—Possibilities in 2024

“…Directly during the provocation, cats are either kept in cages inside the room or they move freely around the room. Unfortunately, cat rooms are characterised by various allergen exposures depending on the design of the facility, and the allergen range in the same room within the course of the experiment is variable, which may considerably affect the results obtained [ 62 , 63 , 64 ].…”