May 22 (Reuters) - The U.S. Food and Drug Administration

has approved British drugmaker GSK's asthma drug to

treat some patients with a chronic lung disease commonly known

as "smoker's lung", the company said on Thursday.

The approval expands the use of the drug, Nucala, as an

add-on treatment for patients with a type of chronic obstructive

pulmonary disease.

Sanofi and Regeneron's blockbuster drug

Dupixent and Verona Pharma's inhaled therapy Ohtuvayre

are also approved for the condition, which affects the lungs,

causing restricted airflow and breathing problems.

GSK's Nucala is a monoclonal antibody that inhibits

interleukin-5, which helps regulate eosinophils, a type of white

blood cell that causes inflammation in the lungs when

overproduced.

The regulator had set a target action date of May 7 for its

decision on the drug. The approval, however, came two weeks

later.

This is the latest instance where the drug regulator has

missed its deadline after mass layoffs as part of a major

overhaul of federal health agencies under Secretary of Health

and Human Services Robert F. Kennedy Jr.

The approval was based on a late-stage trial, in which

patients treated with Nucala and an inhaled maintenance therapy

for up to 104 weeks had significantly reduced exacerbations by

21% compared to placebo.

"There's a very high burden when you have severe

exacerbations and end up being hospitalized. The aim is to keep

patients out of the hospital, keep them stable, and keep them at

home," GSK's Chief Commercial Officer Luke Miels said ahead of

the approval.

Nucala recorded 1.78 billion pounds ($2.38 billion) in total

sales last year.

The disease commonly affects cigarette smokers but can also

be caused by air pollution and related occupational hazards. It

is the fourth leading cause of death worldwide, according to the

World Health Organization.