The European Union has approved Sanofi's blockbuster drug Dupixent for the treatment of chronic obstructive pulmonary disease (COPD), the French pharmaceutical giant said on Wednesday.

The debilitating disease, sometimes called "smoker's lungs", is the third-leading cause of death worldwide, according to the World Health Organization.

"Dupixent is the first new treatment approach for COPD in more than a decade and a new option for approximately 220,000 adults in the EU," Sanofi said in a statement.

The EU's European Medicines Agency "is the first regulatory authority in the world to approve Dupixent for COPD patients," it added.

The drug, which has now been approved for six different illnesses in the EU, is also being reviewed by the United States, Japan and China for COPD patients.

The illness causes irreversible airflow blockage and breathing problems that limit people's daily lives.

It is usually treated with inhalers that widen the airways of patients, sometimes combined with corticosteroids to reduce inflammation.

Flare-ups called exacerbations mostly caused by infections can make the disease much worse.

The European Commission approved injections of the monoclonal antibody Dupixent for patients already on inhalers.

According to phase 3 trials, the drug reduced the rate of exacerbations by more than 30 percent in patients with type two inflammation over 52 weeks.

The trials also found improvements in lung function for patients on Dupixent beginning as early as week two.

Heavy smoking causes more than 70 percent of COPD cases in wealthy countries, while air pollution is also a driver of the disease, according to the WHO.

A bad cough, shortness of breath and other chronic symptoms can make it difficult for COPD patients to climb stairs or tie their shoelaces.

Dupixent, which accounts for a quarter of Sanofi's sales, had already been approved to treat five other illnesses in the EU: eczema, asthma, nasal polyps, skin disorder prurigo nodularis and eosinophilic esophagitis.