(Reuters) – British drugmaker GlaxoSmithKline Plc said on Thursday that its three-in-one drug Trelegy met the main goal of a late-stage asthma study, signalling a possible boost to its lung medicines division that has been hit by generic competition.

The company, along with co-developer Innoviva Inc, said the once-daily inhaler improved lung function in patients with uncontrolled asthma, compared to its other medicine Relvar/Breo Ellipta.

However, GSK said Trelegy Ellipta did not meet its secondary goal of showing a reduction in the rate of exacerbations.

“We plan to submit these data for regulatory review after the full dataset is available,” said GSK’s Chief Scientific Officer Hal Barron.

The results come at a time when GSK is hit by generic competition for its blockbuster asthma treatment Advair and it looks to newer respiratory drugs to make up for declines in older medicines.

Trelegy Ellipta is already approved for treatment of chronic obstructive pulmonary disease (COPD), a condition that limits airflow to the lungs.

The drug became the first once-daily triple medicine for COPD when U.S. regulators gave it the green light in late 2017, putting GSK ahead of rivals such as AstraZeneca and Novartis.

More than 30 percent of asthma patients cannot fully restore their lung functions with two-drug inhalable combinations such as GSK’s Breo, creating a market opportunity for a more powerful combination therapy.

Trelegy, delivered through GSK’s inhaler Ellipta, generated 156 million pounds ($203 million) in sales last year, from its use against chronic obstructive pulmonary disease (COPD), or smokers’ lung.

Analysts at HSBC project 1.4 billion pounds in Trelegy revenue by 2023, also helped by future use against asthma, though COPD will likely remain the larger commercial opportunity.

(Reporting by Pushkala Aripaka in Bengaluru and Ludwig Burger in Frankfurt; Editing by Maju Samuel and Elaine Hardcastle)