A phase 2a trial of the IL-33 monoclonal antibody tozorakimab in patients with COPD: FRONTIER-4

Background Interleukin-33 may have a role in COPD pathobiology. FRONTIER-4 ( NCT04631016 ) investigated tozorakimab (an anti-interleukin-33 monoclonal antibody) in patients with moderate-to-severe COPD with chronic bronchitis receiving dual or triple inhaled therapy. Methods FRONTIER-4 was a phase 2a, randomised, double-blind, placebo-controlled study. Patients received tozorakimab 600 mg or placebo subcutaneously every 4 weeks for 24 weeks. The primary end‑point was change in pre-bronchodilator forced expiratory volume in 1 s (FEV 1 ) from baseline to week 12. Secondary outcomes included post-bronchodilator FEV 1 , time-to-first COPD composite exacerbation event and safety. Results The intent-to-treat population included 135 patients (tozorakimab, n=67; placebo, n=68). At week 12 in the intent-to-treat population, tozorakimab showed a greater increase, although nonsignificant, from baseline in pre-bronchodilator FEV 1 (least-squares mean difference (LSMD) 24 mL, 80% confidence interval (CI) −15–63 mL, p=0.216) and a significantly greater increase in post-bronchodilator FEV 1 (LSMD 67 mL, 80% CI 17–116 mL, p=0.044) when compared with placebo. At week 12 in a prespecified subgroup of patients with at least two prior exacerbations, tozorakimab also showed improvements versus placebo in change from baseline in pre-bronchodilator FEV 1 (LSMD 69 mL, 80% CI 9–130 mL, p=0.072) and post-bronchodilator FEV 1 (LSMD 124 mL, 80% CI 47–201 mL, p=0.020). Tozorakimab did not significantly reduce the risk of COPD composite exacerbation events (hazard ratio 0.79, 80% CI 0.57–1.11, p=0.186) in the intent-to-treat population, although there were greater effects in patients with at least two prior exacerbations (hazard ratio 0.61, 80% CI 0.37–1.00). Results were similar in former and current smokers. Tozorakimab was well tolerated. Conclusion Although the primary end-point was not met in the intent-to-treat population, tozorakimab showed positive efficacy signals versus placebo in a subgroup of patients with COPD with a high risk of exacerbations.