P4.029: The HDM SLIT-Tablet Improves QoL and Reduces Clinical Symptoms in Children (5-11 Years) With House Dust Mite Allergic Rhinitis/Rhinoconjunctivitis – Results from a Global Phase III Clinical Trial

Background: House dust mite (HDM)-driven allergic rhinitis/rhinoconjunctivitis (HDM AR/C) has a negative impact on quality of life (QoL) and sleep in children. A recent phase III trial with the HDM SLIT-tablet in children (5-11 years) with HDM AR/C met the primary efficacy endpoint of total combined rhinitis score (22% reduction vs placebo, p< 0.0001) and all key secondary efficacy endpoints. Here, we present the trial outcomes on symptom reduction and QoL improvement.

Methods: MT-12/MATIC (NCT04145219) was a double-blind, placebo-controlled phase III trial including 1458 subjects (5-11 years) randomized and treated (1:1) with the HDM SLIT-tablet (12 SQ-HDM) or placebo for approximately 1 year. The primary efficacy assessment period was the last 8 weeks of treatment when daily rhinitis symptoms and medication use were recorded (using an e-diary). Additional endpoints included the pediatric rhinoconjunctivitis quality of life questionnaire (PRQLQ), individual average rhinitis daily symptoms, rhinitis symptom-free days, rhinitis mild days, and rhinitis exacerbation days. Safety was assessed rigorously by adverse event reporting throughout the trial.

Results: The HDM SLIT-tablet demonstrated a statistically significant treatment effect across all endpoints vs. placebo. PRQLQ score after 1 year of treatment was improved by 16.6% [95%CI 8.8;24.0, p< 0.0001] over placebo. QoL improvement was consistent and statistically significant across all 5 PRQLQ domains vs. placebo (nose, eye, other symptoms, activity limitation, practical problems). Rhinitis daily symptom score was significantly reduced vs. placebo (-22.2%, p< 0.0001), and consistent reductions were observed across all individual rhinitis symptoms (nasal congestion, nasal pruritus, running nose, sneezing) (range from -22.2% to -28.3%, all p< 0.0001 vs. placebo). Odds ratio for rhinitis symptom-free days, rhinitis mild days and rhinitis exacerbation days were all statistically significant in favor of the HDM SLIT-tablet.
The HDM SLIT-tablet was well tolerated. Few subjects discontinued due to treatment-related adverse events (TRAEs) (HDM SLIT-tablet: 1.8%; Placebo: 1.0%). The most common TRAEs were local reactions, with onset within the first days and gradually disappearing within the first weeks of treatment.

Conclusion: The HDM SLIT-tablet demonstrated a significant and clinically relevant treatment effect by improving QoL and reducing clinical symptoms. It was safe and well tolerated in children with HDM AR/C.