Sublingual immunotherapy tablet for the treatment of house dust mite allergic rhinitis in Canada: an alternative to minimize treatment costs?

A cost-minimization analysis (CMA) was performed to estimate the economic impact of introducing the SQ house dust mite sublingual immunotherapy (SQ HDM SLIT)-tablet marketed as ACARIZAX™ (regulatory approval May 2017) for the treatment of HDM-induced allergic rhinitis in Canada (Ontario and Quebec), where house dust mite subcutaneous immunotherapy (HDM SCIT) is already an available treatment option. A CMA was deemed appropriate and was based on the assumption that the SQ HDM SLIT-tablet has comparable efficacy to HDM SCIT. A societal perspective was adopted in the model, including relevant costs of medications, health care services and productivity loss. A 3 year time horizon was used corresponding to a recommended treatment course of allergy immunotherapy. Resource use and costs were based on published sources, where possible, and validated and complemented by a Canadian specialist clinician (allergist) in active practice in Ontario and in Quebec, respectively, where applicable. A discount rate of 1.5% was applied in accordance with the Canadian Agency for Drugs and Technologies in Health (CADTH) guidelines. To assess the robustness of the results, sensitivity analyses were performed by testing alternative assumptions for selected parameters, to understand their impact on the results of the analysis. The direct treatment costs for a 3-year treatment with SQ HDM SLIT-tablets were higher than for HDM SCIT for both provinces, Ontario and Quebec ($4732.12 and $4829.03 vs. $3434.51 and $2987.74). However, when adding the indirect costs to the model, total savings for the treatment with SQ HDM SLIT-tablets of $1833.00 for Ontario and $769.03 for Quebec were observed. Sensitivity analyses with varying HDM SCIT resource use, discount rates, titration and maintenance injections, nurse time, and number of injections per vial resulted in savings of SQ HDM SLIT-tablets over HDM SCIT in all scenarios analysed. The CMA indicates that SQ HDM SLIT-tablets are a cost-minimizing alternative to HDM SCIT when considered from a societal perspective in Ontario and Quebec.