BARCELONA--AstraZeneca said its new drug for chronic obstructive pulmonary disease showed benefits across a broad patient population in late-stage clinical trials, boosting a medicine the company expects to generate multibillion-dollar sales.

The drug, tozorakimab, achieved reductions in moderate and severe COPD exacerbations--or lung attacks--by around 30% compared with the standard therapy in two late-stage studies, the U.K. pharmaceutical company said Tuesday.

The company said the drug worked across patient subgroups, with a 43% reduction for those with the highest level of disease exacerbations, and a 23% decline for those with milder forms.

In addition to reducing exacerbations, the drug also reduced mucus plugging in lungs, AstraZeneca said. Tozorakimab was generally well tolerated, it added.

"What we have seen in the data is what we classify as a scientific breakthrough," AstraZeneca's biopharmaceuticals unit president, Ruud Dobber, said in an interview.

The trial results, published in the New England Journal of Medicine and presented at the European Respiratory Society Congress in Barcelona, could help AstraZeneca turn a page on a challenging few weeks. The failure of a heart-disease trial and takeover speculation hit its stock. The company declined to comment on the takeover reports.

AstraZeneca recently upgraded its annual peak sales estimate for tozorakimab to more than $5 billion and said the medicine is set to be its largest respiratory product.

The COPD treatment market generated $11.6 billion in sales for the pharma industry last year and is expected to grow to $14.8 billion in 2033, according to data provider Evaluate. Tozorakimab is forecast to become the No. 3 COPD drug globally by sales in the early 2030s, according to Evaluate data.

Analysts at Berenberg said before the study results were published that a 30% reduction in COPD exacerbations would be considered highly positive and ahead of expectations.

Trial setbacks for rival treatments from Roche Holding and Sanofi, the overall size of the COPD market and potential uses of the drug in other diseases led AstraZeneca to dial up its sales expectations, Dobber said.

The company is running studies for tozorakimab in asthma and viral respiratory diseases, and is considering whether to launch more for conditions like bronchiectasis, he added.

The U.S. Food and Drug Administration has granted priority review to AstraZeneca's application for tozorakimab, with a target decision date set for the first quarter of 2027, the company said.

If approved, AstraZeneca would commercialize the drug under the framework of a U.S. policy known as "most favored nation," or MFN, which ties U.S. prices of newly launched drugs to those of other wealthy countries.

Dobber said negotiations with governments in Europe, Japan and Canada are set to take place over the next six to 12 months.

"We are constructive. Time will tell whether the other side of the table will be as constructive as well, and then we will see what we do," Dobber said.