Ant Venom Immunotherapy: Improving method and maintenance.

The objectives of this study are to improve the delivery of venom immunotherapy (VIT) by assessing the efficacy and safety of different approaches to venom immunotherapy, namely ultra-rush (ultra-rapid initiation over 2 days) versus semi-rush (initiation over 10 weeks) and half-dose (50 microgram) versus standard dose (100 microgram) maintenance treatment. Specific hypotheses are that: (i) ultra-rush initiation will be equivalent to outpatient semi-rush initiation in terms of allergic reaction rates to immunotherapy; (ii) A maintenance dose of 50 mcg will be as efficacious as a 100 mcg maintenance dose, and; (iii) VIT with both initiation methods and maintenance doses will have a sustained positive impact (reduced reaction risk) after cessation of VIT. The study will have important implications. If the different approaches are equivalent, we will be able to significantly reduce the amount of venom extract used and thus increase the number of patients that we can treat, given that our venom supplies are expensive and limited. Because it will be impossible to conceal treatment allocations, the different initiation methods will be unblinded. Maintenance doses will be single blinded (known to the treating doctor but not the patient) because of the significant day-to-day dose adjustments required during immunotherapy would make double-blinding difficult and potentially dangerous. The main outcome measures will be (1) the occurence of systemic allergic reactions to immunotherapy (safety of treatment) and (2) systemic allergic reactions to deliberate sting challenges and accidental stings (effectiveness of treatment)