The prevalence of Allergic rhinitis (AR) is reached 49.2% in 2019. In particular, the prevalence of Japanese cedar (JC) pollinosis is 38.8%, and the onset age of pollinosis is becoming younger. AR is known to be a risk factor for the development of allergic asthma, a potentially life-threatening condition. Allergy immunotherapy (AIT) is a well-documented, safe, effective treatment option for respiratory allergic disease. It has been demonstrated that AIT can provide relief from clinical symptoms and that AIT has the potential to provide long-term post-treatment effect. Unlike pharmacotherapy, AIT addresses the basic immunological mechanisms that are responsible for the development and persistence of allergic conditions. Currently two main routes of AIT administration are commonly available, subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT).
In Japan, house dust mite (HDM) SLIT tablets have been available since 2015, and JC SLIT tablet is approved by 2018 without any age limitation. The randomized DBPC trials that included pediatric patients have been conducted in Japan. In phase II/III trail with JC SLIT tablets, treatment effect-size (improvement of clinical symptoms compared to placebo) was 46.3% after three years treatment. In addition, AR was improved in 45.3% (1 year) and 34.0% (2 years) after discontinuation of SLIT. Adverse reactions in the first season were 50.3%, mostly modulate to mild reactions such as oral edema and pharyngeal irritation.
In April 2023, several future government initiatives against cedar pollen allergies were announced as follows; (1) Measures to control the source of cedar pollen, (2) Improvement in the accuracy of pollen dispersal forecasts, and (3) Measures to prevent the onset and exposure to cedar pollen including the AIT. This presentation will be covering the findings to date, including immunotherapy not only for JC pollinosis but also for HDM induced perennial AR.