AstraZeneca COPD Drug Cuts Exacerbation Risk by Up to 34% in Late-Stage Trials

AstraZeneca on Tuesday published complete results from two late-stage trials of its experimental chronic obstructive pulmonary disease (COPD) drug, tozorakimab. The drug, administered every four weeks, reduced COPD exacerbation events across a broad patient population.

In the primary study population of former smokers, tozorakimab cut moderate and severe exacerbations by 29% and 34%, respectively, compared with a control group receiving current inhaled standard-of-care plus placebo. In the larger population that included both current and former smokers, the drug reduced moderate and severe exacerbations by 30% and 29%, respectively. Subgroup analyses showed a 23% reduction in patients with blood eosinophil counts below 150, a 34% reduction in those with counts of 150 or higher, and a 43% reduction in patients with counts of 300 or above.

COPD is a progressive lung disease that obstructs airflow and causes breathing difficulty. According to data provided by AstraZeneca, an estimated 16 million to 26 million people in the United States have COPD, including diagnosed and undiagnosed cases, making it the fifth-leading cause of death in the country. Currently, the only biologics approved for COPD are Dupixent and Nucala, both restricted to patients with elevated eosinophil levels. Dupixent, developed by Regeneron and Sanofi, is among the world's best-selling drugs, while GSK's Nucala entered the COPD market in 2025. No biologic is available for patients with blood eosinophil counts below 150.

AstraZeneca's two trials enrolled both former and current smokers, covering all eosinophil count levels and severities of lung function impairment. The drug works by blocking IL-33, a key protein driving inflammation and mucus secretion, both underlying mechanisms of COPD. Several other companies have previously attempted to develop IL-33 therapies without significant success.

AstraZeneca recently raised its peak annual sales forecast for the drug to more than $5 billion, a revision that supports the company's goal of reaching $80 billion in total revenue by 2030. The drug is currently under regulatory review for COPD in major markets including the European Union and China, and is also being studied in a Phase II trial for severe asthma and a Phase III study for severe viral lower respiratory tract disease.