Cat dander is one of the most common triggers of allergies worldwide. A new approach to these respiratory allergies could represent a breakthrough in allergy therapy in general. In addition to therapy to suppress symptoms, the only treatment option available to physicians to date is allergen-specific immunotherapy against the triggering allergen. Now, however, a new treatment seems to be promising: it relies on direct therapy with artificially produced allergen-specific IgG antibodies (immune globulin G) against the allergen.
Allergic rhinitis, conjunctivitis and especially allergic asthma: If you want to avoid such symptoms, the first recommendation for cat allergy sufferers in Germany is to avoid the allergen. If the symptoms are already present, they can be treated with antihistamines, cortisone nasal spray, or even asthma medications. Allergen-specific immunotherapy, commonly referred to as hyposensitization, is currently the only treatment option that can, in principle, create an insensitivity of the immune system to a specific allergen. However, the onset of efficacy is delayed until several months after the start of therapy. In this process, the administration of the allergen stimulates the immune system to produce immunoglobulins involved in the immune response.
Since allergen-specific immunotherapy involves administering the disease-causing allergens, in rare cases the treatment can trigger serious side effects, especially in cat allergy sufferers with asthma. In Germany, allergen-specific immunotherapy with cat allergen is therefore only recommended to a very limited extent and is only performed in a few patients. An effective, simple allergy therapy with few side effects is therefore sought. “Such a treatment option may now be in sight” says Prof. Dr. Randolf Brehler, Head of Allergology, Occupational Dermatology and Environmental Medicine at the UKM Dermatology Clinic, who is conducting research on the project on behalf of the Medical Faculty of the WWU Münster. “A new research approach relies on patients no longer being injected with the allergen itself, but rather with specific IgG antibodies directed against the allergen, which can be produced artificially. Phase 2 studies have been highly successful, with a single injection of these antibodies literally switching off the allergy for several weeks. Skin tests also showed that patients hardly reacted allergically to cat allergen anymore,” says Brehler.
The larger Phase 3 study in more than a thousand patients is now imminent worldwide. “If the effectiveness of the method is confirmed in the study, it will be a major breakthrough for allergy therapy overall,” Brehler said. “The therapy trial with the artificially produced immunoglobulins directly interferes with the mechanisms of the allergy cascade. However, we cannot yet say anything about the long-term effect, i.e. a lifelong suppression of the allergic reaction, if possible, the allergist added. A possible combination of immunoglobulin therapy with allergen-specific immunotherapy is also conceivable. Then symptoms would be suppressed by immunoglobulin therapy, and long-term sustained effects could be achieved by allergen-specific immunotherapy.
The new therapeutic principle is not only being tested for cat allergy. Studies are also being conducted with IgG antibodies directed against a birch pollen allergen.
Source: Münster University Hospital
