The data currently available indicate that a 3-year duration of SIT results in a sustained efficacy for at least an equivalent period of time following discontinuation of treatment. There is a need for studies evaluating the long-term efficacy of SCIT and SLIT for more extended periods of observation after stopping to properly assess the influence of immunotherapy on the natural history of respiratory allergy and, in particular, on the capacity to achieve complete control of the disease. Another important aspect is the identification of the different clinical phenotypes of allergic patients to be treated with SIT. For example, patients with more severe forms of disease are of particular interest. A recent post-hoc analysis of published studies using the grass-pollen tablet showed that the higher clinical efficacy of SLIT is observed in patients with more severe allergic rhinitis. This phenotype is frequently resistant to drug treatment but is responsive to SIT and deserves specific investigations on the appropriate length of treatment to attain durable clinical effects and consequently to give a significant benefit to the quality of life and the economic burden of the disease, which are both of particular concern owing to the high number of missed work days and high consumption of drugs.
Immunotherapy. 2013;5(2):131-133. © 2013 Future Medicine Ltd.