(Reuters) -British drugmaker GSK said on Friday that its asthma drug, Nucala, met the main goal of a late-stage study in treating patients with chronic obstructive pulmonary disease (COPD), or smoker's lungs.

Patients treated with Nucala and an inhaled maintenance therapy for up to 104 weeks had a lower annualised rate of moderate or severe exacerbations than those given a placebo, GSK said.

COPD causes restricted airflow and breathing problems and is also known as 'smoker's lungs' because in Western countries, it primarily affects cigarette smokers.

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.

GSK said COPD affects more than 300 million people, with up to 40% of patients exhibiting type 2 inflammation characterised by raised blood eosinophil count.

Nucala, known also as mepolizumab, was first approved in 2015 for a type of severe asthma in the United States. Its sales grew 18% to 1.7 billion pounds in 2023. It contributed nearly 6% to GSK sales last year.

(Reporting by Yadarisa Shabong in Bengaluru; Editing by Savio D'Souza)