GSK (GSK) said Monday that China's National Medical Products Administration has approved Nucala, or mepolizumab, as an add-on maintenance treatment of a certain chronic obstructive pulmonary disease in adult patients.

The approval was based on data from two phase III trials in which mepolizumab showed a "clinically meaningful and statistically significant" reduction in the annualized rate of exacerbations in patients, compared with placebo plus standard of care, the company said.

GSK shares were down 1% in recent premarket activity.