OBJECTIVES: Allergic rhinitis (AR) is recognized as a major risk factor for developing allergic asthma (AA). Previous research show childhood AR increases the risk of new-onset asthma two- to seven-fold. Having both AR and AA in childhood increases the risk of asthma persisting into adulthood.

This study estimates costs and effectiveness for early initiation of 75,000 SQ-T grass SLIT-tablet, by quantifying the risk-reduction of new-onset of AA in children with moderate/severe AR.

METHODS: We developed a Markov model to capture the interrelation between AR and AA. Age-specific risk of developing asthma and treatment-specific transition matrices for movements between mild and moderate/severe AR were estimated and extrapolated for grass SLIT-tablet and symptom-relieving medication using the GRAZAX^® Asthma Prevention (GAP) placebo-controlled trial in children aged 5–12 years. Together with the treatment effect of grass SLIT-tablet compared to symptom-relieving medication and placebo these constituted the key model parameters. Costs were estimated using previously published data from the IBM MarketScan database.

RESULTS: Modelling a cohort of 1,000 children diagnosed with moderate/severe seasonal AR, initiating grass SLIT-tablet at age five compared to age nine prevents 71 incidences of AA, equal to a number needed to treat of 14, as well as 1,220 patient years with AA in the 20 years following AR diagnosis. In the same period costs were reduced by 4,179 USD. Comparing grass SLIT-tablet initiation at age five to six also showed positive results (26 avoided AA incidences, 492 patient years, reduced costs by 1,518 USD).

CONCLUSIONS: Results suggest initiating 75,000 SQ-T grass SLIT-tablet at age five compared to initiation later in childhood is associated with a clinically meaningful reduction in new AA cases. Moreover, early initiation of 75,000 SQ-T grass SLIT-tablet is a dominant treatment (better efficacy and cost-saving) strategy compared to both later initiation and treatment with symptom-relieving medication alone.