An inhaled coronavirus treatment has been described as a “game changer” after preliminary trial results showed it significantly reduced the number of hospitalised patients needing intensive care.

Patients who received the drug, known as SNG001, had a 79 per cent lower risk of developing severe disease and were more than twice as likely to recover from Covid-19 as those on the placebo.

Synairgen, the pharmaceutical company behind the drug, said it “could signal a major breakthrough in the treatment of hospitalised Covid-19 patients.”

So how exactly does it work?

The treatment uses a protein called interferon beta 1a (IFN-beta), which the body naturally produces when faced with a viral infection.

Interferons – a group of signalling proteins – are released by white blood cells to heighten the anti-viral defences of nearby cells and alter the immune system’s response to infections.

Specifically, beta interferon, which is released at the end of an immune attack, helps to reduce inflammation and the body’s immune reaction.

However, SARS-CoV-2, the virus responsible for Covid-19, appears to suppress the production of this crucial protein, resulting in an overreactive immune response that can cause serious damage to the body.

The SNG001 drug developed by Synairgen is a special formulation of interferon beta, delivered as an aerosol directly to the airways via a nebuliser.

The early results suggest that the drug, when inhaled, is capable of restoring the lungs’ anti-viral response, enhancing protection, accelerating recovery and countering the impact of Sars-CoV-2 virus.

Is the drug safe?

Previous studies involving asthmatic patients have shown that SNG001 is well tolerated, enhances the lungs’ anti-viral defences and improves lung function during cold or flu infection.

Interferon beta is also commonly used in the treatment of multiple sclerosis (MS). It has been claimed that interferons can produce an 18-38 per cent reduction in the rate of MS relapses.

How have the experts reacted?

Steve Goodacre, professor of emergency medicine at the University of Sheffield, said: “These results are not interpretable. We need the full details and, perhaps more importantly, the trial protocol. The trial should have been registered and a protocol made available before any analysis was undertaken. I am concerned they have not done this.

Naveed Sattar, professor of metabolic medicine at the University of Glasgow, said: “The results seem very impressive, and although accepted that the trial is small with just over 100 participants, a 79 per cent reduction in disease severity could be a game changer.

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“It would be good to see the full results once presented and peer-reviewed to make sure they are robust and the trial conduct was rigorous. Also, with small numbers comes less certainty on the true level of benefit, or whether benefits vary between people with differing risk characteristics. Such work would require a larger trial but, even so, these results are very exciting.”

Stephen Evans, a professor of pharmacoepidemiology at London School of Hygiene & Tropical Medicine (LSTHM), said: “It is clear that this seems to be a promising treatment for the early stages of Covid-19 but should definitely be regarded as preliminary.

“It is a phase II study, though it has some aspects of a phase III trial in that it considers clinical outcomes and is randomised with a placebo control. From this point of view the study has definite strengths.”