AstraZeneca reported that its experimental drug tozorakimab became the first biologic to significantly reduce “mucus plugs” in chronic obstructive pulmonary disease (COPD), according to data presented at the European Respiratory Society (ERS) 2026 congress.
What are mucus plugs — and why they matter
In COPD, thick mucus can physically clog the small airways (bronchi), blocking airflow segment by segment. These mucus plugs are linked to faster disease progression and more exacerbations (flare-ups). The company said tozorakimab achieved “a significant reduction in the number of lung segments with mucus plugs in a broad population” — the first time a biologic has shown this effect.
The drug
Tozorakimab is an IL-33 inhibitor. IL-33 is an “alarmin” — an early-warning signal that kicks off airway inflammation — so blocking it aims to calm the inflammatory cascade upstream. COPD is a leading cause of death worldwide with limited biologic options, so a mechanism that targets mucus obstruction directly is notable.
The caveat
This is a conference readout, and some specifics — trial name, phase, enrollment and other endpoints like exacerbation and lung-function changes — were part of analyst commentary not fully detailed publicly. The mucus-plug result is encouraging and differentiating, but the full picture depends on the complete trial data. Not medical advice.