AstraZeneca’s experimental drug tozorakimab has delivered a major breakthrough in the fight against chronic obstructive pulmonary disease (COPD), with late-stage trials showing it can significantly cut dangerous flare-ups in patients who have long had limited treatment options.

 

High-level results from the Phase III OBERON and TITANIA trials revealed that the first-in-class monoclonal antibody reduced the annual rate of moderate-to-severe COPD exacerbations compared with placebo. 

 

The benefit was seen not only in former smokers—the primary study group—but across a broad patient population that included current smokers, all blood eosinophil levels, and every stage of lung function severity. The drug was also generally well tolerated, with a favourable safety profile.

 

Tozorakimab works by targeting interleukin-33 (IL-33), a key driver of inflammation. Unlike existing biologics, it blocks both the reduced and oxidised forms of IL-33, offering a dual approach—dampening inflammation while disrupting the cycle of mucus dysfunction that worsens the disease.

 

The trials focused on patients who continued to suffer exacerbations despite standard inhaled therapies, a persistent challenge in COPD care. Participants received either 300mg of tozorakimab or a placebo every four weeks alongside their usual treatment.

 

The stakes are high: nearly 400 million people worldwide are living with COPD, the third leading cause of death globally. Even with current standard treatments, more than half of patients still experience exacerbations, raising their risk of hospitalisation, cardiopulmonary complications, and death.

 

“These trial results suggest that targeting the IL-33 pathway with tozorakimab delivers meaningful clinical benefit in a trial representing a broad COPD population, independent of smoking status and eosinophilic levels. 

 

"COPD has long been a difficult-to-treat disease with inherent heterogeneity and significant unmet need, with up to half of patients worldwide at risk of exacerbations, hospitalisations, cardiopulmonary events, and death — underscoring the importance of these results for advancing COPD science,” said Frank Sciurba, Professor of Pulmonary and Critical Care Medicine, University of Pittsburgh, Chief Investigator of LUNA programme.

 

“Today’s tozorakimab results deliver the first two confirmatory Phase III trials for an IL-33 biologic, which is a major scientific advancement in COPD, the world’s third leading cause of death. 

 

"Tozorakimab works in a fundamentally different way from other biologics, inhibiting the signalling of the reduced and oxidised forms of IL-33 to both decrease inflammation and disrupt the cycle of mucus dysfunction that are key disease drivers in COPD,” said Sharon Barr, Executive Vice President, BioPharmaceuticals R&D, AstraZeneca.