The U.S. Food and Drug Administration has approved Sanofi and Regeneron's blockbuster drug Dupixent for patients with a chronic lung disease, commonly known as "smoker's lung," the companies said on Friday.

The approval is expected to add billions of dollars in sales for the treatment, which is one of the top-selling drugs for both the companies.

Sanofi recorded 10.72 billion euros ($11.94 billion) in sales for Dupixent in 2023, which includes Regeneron's share.

Analysts on average expect Dupixent, by far Sanofi's best-selling drug, to generate more than 21 billion euros in sales in 2030, according to LSEG data.

Chronic obstructive pulmonary disease (COPD) damages the lungs progressively and causes restricted airflow. It is a lifelong condition that commonly affects cigarette smokers but can also be caused by air pollution and related occupational hazards.