Monday, September 14, 2015
International Consensus on Allergy Immunotherapy
Allergen immunotherapy (AIT), or the administration of an allergen with the intent of decreasing a patient’s sensitivity to it, remains underused. Numerous clinical trials show it is effective in the treatment of those with allergic rhinitis (AR), but it is estimated to be used in treatment of fewer than 10% of these patients worldwide. AIT can stop the progression of AR to asthma and it can be used to treat controlled allergic asthma. Safer and more effective AIT strategies are being developed, but ongoing barriers to its use include questions on cost-effectiveness, the need for an improved safety profile, a lack of standardization of AIT products between companies, and the lack of high quality studies regarding optimal dosing and disease-modifying potential.
The subject calls for a consensus on the best AIT practice, because AIT is the only treatment that can potentially alter the progression of allergic disease and induce allergen-specific immune tolerance. To this end, the International Collaboration in Asthma, Allergy, and Immunology (iCAALL) has issued an International Consensus (ICON) on AIT. Jutel et al review the pertinent literature and summarize the key statements (J Allergy Clin Immunol 2015; 136(3): 556-568).
Historically AIT has been given via subcutaneous injection (SCIT) or allergy shots, and in the past 25 years there has been an increase in the use of sublingual immunotherapy (SLIT). Epicutaneous and intra-lymphatic administration are under current investigation. The duration of AIT is generally three to five years. There are a number of clinical scenarios in which AIT proves an effective therapy. Prospective studies have demonstrated SLIT with house dust mite extract resulted in remission of AR symptoms for seven to eight years after therapy ended. It can be used to treat mild and moderate asthma that is controlled via pharmacotherapy, and there is an expected benefit of the reduced need for steroids as a result. AIT may also be used for patients with respiratory allergic diseases associated with atopic dermatitis. Its use for food allergy is an important area of research, and it is not at this time recommended for clinical practice.
While AIT was introduced over a century ago, work must be done to address the reasons it remains under-used. There is a lack of non-specialist provider awareness and limited access to specialist care. There are concerns about reimbursement policies, safety, and effectiveness. The authors call for better definition of homologous allergen groups, large multi-center studies evaluating the optimal age of treatment initiation in young children, and biomarkers to select study responders and allow for objective evaluation of efficacy.