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FRONTIER-3: a randomised phase 2a study to investigate tozorakimab, an anti-interleukin-33 monoclonal antibody, in early-onset asthma

Year: 2025

Type: article

Abstract: Background Interleukin (IL)-33 is implicated in the initiation and progression of asthma. FRONTIER-3 ( NCT04570657 ) was a phase 2a study to investigate tozorakimab, an anti-IL-33 monoclonal antibody, in adults with moderate-to-severe early-onset asthma receiving standard of care. Methods Patients were randomised 1:1:1 to tozorakimab 600 mg, tozorakimab 300 mg or placebo, once every 4 weeks subcutaneously. The primary end-point was change from baseline to week 16 in pre-bronchodilator (pre-BD) forced expiratory volume in 1 s (FEV 1 ) measured in clinic. Secondary and exploratory end-points included home pre-BD FEV 1 , home peak expiratory flow (PEF), rescue medication use, CompEx, pharmacokinetics, immunogenicity and safety. Results The intent-to-treat (ITT) population included 235 patients with a median disease duration of >30 years; a majority had a baseline blood eosinophil count (BEC) <300 cells·μL −1 . At week 16, tozorakimab did not show a statistically significant improvement in change from baseline in clinic pre-BD FEV 1 versus placebo (least-squares mean difference (LSMD) (80% CI), 600 mg: 4 mL (−71–79), p=0.473; 300 mg: 36 mL (−38–111), p=0.267). Compared with the ITT population, a pre-specified subgroup of patients with ≥2 prior exacerbations showed greater improvements in clinic pre-BD FEV 1 at week 16 with tozorakimab versus placebo (LSMD (80% CI), 600 mg: 212 mL (102–322), p=0.007; 300 mg: 77 mL (−34–187), p=0.186). Tozorakimab also showed greater improvements in home FEV 1 and home PEF versus placebo at week 16 in patients with ≥2 prior exacerbations than in the ITT population. Tozorakimab was well tolerated. Conclusions Although FRONTIER-3 did not meet the primary study end-point, tozorakimab treatment showed encouraging efficacy signals in patients with early-onset asthma and a history of exacerbations.

Source: ERJ Open Research

DOI: 10.1183/23120541.00183-2025