Britain's biggest drugmaker believes the results confirm the potential of the once-daily single inhaler, Trelegy Ellipta, a product it hopes will offset the impact of generic competition to the older lung drug Advair.

Trelegy won approval based on clinical tests showing it improved lung function and exacerbations more than AstraZeneca's long-established two-drug inhaler Symbicort, which works in a similar way to Advair.

The latest clinical trial, however, compares Trelegy to two more modern two-drug combinations and was seen as a more critical test for doctors wanting to know if the new product really delivers an added benefit.

The IMPACT study, which involved 10,355 patients, showed Trelegy delivered statistically significant reductions in the rate of annual exacerbations, or attacks, compared with both Breo and Anoro, two other relatively new GSK medicines.

GSK and its partner Innoviva plan to submit the latest data from the so-called IMPACT trial to regulatory authorities from the second quarter of 2018, with the aim of expanding the indicated patient population for Trelegy.

(Reporting by Ben Hirschler; editing by Jason Neely)

Stocks treated in this article : GlaxoSmithKline, Innoviva Inc