Tozorakimab Reduced COPD Exacerbations in Two Phase 3 Trials

Tozorakimab (AstraZeneca) reduced annualized rates of moderate or severe exacerbations compared with placebo in two replicate phase 3 trials of adults with symptomatic chronic obstructive pulmonary disease (COPD), the company reported. The human monoclonal antibody binds interleukin-33 (IL-33) and is designed to inhibit signaling by reduced and oxidized forms of IL-33.

The double-blind, placebo-controlled OBERON and TITANIA trials randomized 2,306 patients who had experienced at least two moderate or one severe COPD exacerbation during the previous year. Participants included current and former smokers across blood eosinophil counts and lung-function severity. They received tozorakimab 300mg every 4 weeks or placebo for 52 weeks in addition to inhaled therapy. Before enrollment, they had received standard-of-care inhaled maintenance therapy for at least 3 months. The primary endpoint was the annualized rate of moderate-to-severe exacerbations among former smokers; a key secondary endpoint assessed this outcome in current and former smokers combined.

Among former smokers, tozorakimab reduced annualized exacerbation rates by 29% in OBERON (RR, 0.71; 95% CI, 0.57-0.88) and 34% in TITANIA (RR, 0.66; 95% CI, 0.55-0.80). In the overall populations, reductions were 30% in OBERON (RR, 0.70; 95% CI, 0.58-0.85) and 29% in TITANIA (RR, 0.71; 95% CI, 0.59-0.84).

In pooled prespecified analyses, exacerbation rates were 23% lower among patients with baseline eosinophil counts below 150 cells/µL and 43% lower among those with counts of 300 cells/µL or higher. AstraZeneca reported that tozorakimab was generally well tolerated and that injection-site reaction was the only adverse drug reaction identified.

AstraZeneca said the FDA accepted its Biologics License Application for Priority Review of tozorakimab 300mg every 4 weeks as add-on maintenance treatment for adults with COPD. The company anticipates a Prescription Drug User Fee Act date in the first quarter of 2027. Tozorakimab remains under regulatory review.

Source: AstraZeneca. Tozorakimab demonstrated statistically significant and highly clinically meaningful reduction in COPD exacerbations in OBERON and TITANIA phase III trials. Press release. AstraZeneca; September 8, 2026. Accessed September 9, 2026.