Abstract
BACKGROUND: Subcutaneous immunotherapy (SCIT) has been proven as an effective therapy against some allergens for seasonal allergic rhinitis (SAR) patients unresponsive to intranasal corticosteroids and/or antihistamines but carries risk of systemic allergic reactions. Dupilumab blocks the shared receptor component for interleukin-4 and interleukin-13, key and central drivers of type 2 inflammation in multiple diseases. OBJECTIVE: To evaluate the efficacy and safety of SCIT+dupilumab vs SCIT alone. METHODS: This phase 2a, multicenter, double-blind, placebo-controlled parallel-group study conducted in 103 adults with grass pollen-induced SAR (NCT03558997) randomized patients 1:1:1:1 to SCIT, dupilumab (300 mg every 2 weeks), SCIT+dupilumab, or placebo. SCIT was administered using an 8-week cluster protocol followed by 8 weeks of maintenance injections. Primary endpoint was change from pre-treatment baseline in area under the curve (AUC) in total nasal symptom score (TNSS) 0-1 h following nasal allergen challenge (NAC) with timothy grass extract at Week 17. RESULTS: Although 16 weeks of treatment with SCIT+dupilumab did not significantly improve TNSS AUC (0-1 h) following NAC at Week 17 vs SCIT (least squares mean -56.76% vs -52.03%), a higher proportion of SCIT+dupilumab-treated patients (61.5%) achieved SCIT maintenance dose vs SCIT (46.2%). A lower proportion of SCIT+dupilumab-treated patients (7.7%) required epinephrine rescue treatment vs SCIT (19.2%). There were significantly fewer withdrawals in the SCIT+dupilumab group than in the SCIT group (n = 2 [7.7%] vs n = 8 [30.8%]; P = 0.0216); the majority of SCIT group withdrawals were due to SCIT-related intolerability, compared with no discontinuations from the SCIT+dupilumab group. CONCLUSION: In SAR patients, 16 weeks of SCIT+dupilumab may improve SCIT tolerability but did not incrementally reduce post-allergen challenge nasal symptoms compared with SCIT alone. CLINICAL STUDY NUMBER: NCT03558997.