Determination of the efficacy rate and time-to-efficacy of subcutaneous immunotherapy in dogs with atopic dermatitis

Background Allergen-specific immunotherapy (ASIT) is reported to have a success rate of 50-70% when given for up to 12 months to dogs with atopic dermatitis (AD). How soon ASIT is clinically effective is unclear. Objectives To compare the efficacy rate (ER) and time-to-efficacy (TTE) of various types of subcutaneous immunotherapy (SCIT) administered using conventional dosing regimens using the methodology of a critically appraised topic. Methods and materials Three databases were searched to extract information on the ER and TTE of SCIT in dogs with AD. Herein, "efficacy" was defined as a >= 50% reduction in pruritus and/or skin lesions, and the TTE as the time needed to achieve such a reduction. Results We selected 12 publications including 194 dogs. The ER was significantly higher with the polymerised allergoids coupled with nonoxidized mannan than for the "classic" aqueous and alum-precipitated SCIT types. A TTE of three months or shorter was seen in a significantly higher proportion of dogs receiving mannan-couple allergoids, pullulan-conjugated Der f 2 or tyrosine-adjuvanted than aqueous or alum-precipitated SCIT; with the latter two formulations, the TTE might be nine months or longer in <= 20% of atopic dogs. Conclusions and clinical relevance In spite of the low number of articles available for review and small number of enrolled dogs, novel SCIT regimens appear to have a faster - and possibly higher - efficacy than the currently available aqueous or alum-precipitated formulations. A standardisation of outcome measures for ASIT clearly is needed to allow a more meaningful comparison between SCIT types.