BIRCH trial: Birch subcutaneous immunotherapy for soy milk pollen-food allergy syndrome in children

Randomised, open-label trial of birch pollen extract in Pollen Food Allergy Syndrome (PFAS), birch pollen allergy and alder pollen allergy (2 arms), sponsored by Japanese Society of Allergology. Primary endpoint: Tolerance acquisition to 50 ml of soy milk after 12 months. Started Jun 2026; status: active, not recruiting.