Synairgen has said its inhalable therapy failed an international late-stage trial testing the treatment in patients hospitalised with Covid--19, in a blow to the development of the British drugmaker's key product.

SNG001, an inhalable formulation containing the broad-spectrum antiviral protein interferon beta, is also being tested in a late-stage Covid-19 trial sponsored by the US National Institutes of Health. Results from that trial are yet to be announced.

“While we are disappointed by the overall outcome, SNG001 has been administered to hospitalised patients on top of standard of care which changed substantially between our Phase 2 and Phase 3 trials,” Chief Executive Officer Richard Marsden said.