The effective allergenic reactivity of house dust mite sublingual immunotherapy tablets is determined by tablet formulation

Abstract

House dust mite (HDM) sublingual immunotherapy (SLIT) in the form of SLIT-tablets is now an established treatment option for HDM allergy and HDM-induced allergic asthma. In SLIT-tablet immunotherapy allergen extracts are formulated as dry tablets and administered under the tongue where it must be solubilized in saliva in order to be able to interact with the immune system of the sublingual mucosa. Solubilization of the extract must occur within a short time span of about one minute after administration, determined by the sublingual holding time recommended by the manufacturer. Currently, two types of HDM SLITtablets are available. Both tablet types contain natural HDM extracts from two common HDM species as the active ingredient, but differ with regard to formulation as one tablet type is based on a freeze-dried tablet formulation while the other is based on a compressed formulation. HDM extracts contain a number of major and minor allergens, which in combination provide the allergenic activity that drives the immunological response and in turn the clinical efficacy of the tablets. Here, a biologically relevant human immunoglobulin E (IgE)-based assay is used to compare the ability of the two HDM SLIT-tablet types to deliver HDM allergenic reactivity from the dry tablet into soluble form. The experiments demonstrate that the freeze-dried formulation delivers HDM allergenic activity into solution faster and more efficiently than the compressed formulation.