Synairgen is a University spin-off and public limited company (plc) ^[2][1][3] working in drug discovery and biotechnology. It was founded in 2003 by University of Southampton professors Stephen Holgate,^[4] Donna E. Davies and Ratko Djukanovic [Wikidata]. The company is developing an inhaled formulation of interferon-beta for severe viral respiratory diseases including COVID-19.^{[5][6][7][8][9]}

Richard Marsden was appointed chief executive officer in September 2009.^[10]

Synairgen has developed and is testing an inhaled formulation of interferon beta, a naturally occurring protein which orchestrates the body's antiviral responses. Viruses, including coronaviruses, have evolved mechanisms which suppress natural IFN-β production, thereby helping the virus evade the immune system.^[11]

Richard Marsden, the company's chief executive, said one of the main ways viruses evaded the immune system was “to suppress the production of interferon beta”, which plays a significant role in activating the wider immune response and preventing a virus from replicating. “All we’re doing is putting . . . this protein, that everyone makes, back into the battleground, and the battleground that matters is in the lungs,” Marsden said.^[12]

In March 2020,^[13] Synairgen initiated a placebo-controlled Phase 2 trial of SNG001, an inhaled form of interferon beta, in COVID-19 patients in the UK.

In July 2020, Synairgen announced SNG001 lowered the risk of severe COVID-19 in infected patients in a small clinical trial. The details of the study were published in Lancet in November 2020.^[14]

The Phase 3 SPRINTER trial (SG018), a randomised, double-blind, placebo-controlled study evaluating SNG001 for the treatment of hospitalised COVID-19 patients, was initiated in January 2021.^[15] It completed enrolment of 610 patients in November 2021^[16] across 17 countries.  

SNG001 is also being investigated independently as part of the US National Institute of Health's ACTIV-2 (Accelerating COVID-19 Therapeutic Interventions and Vaccines) programme ^[17] to accelerate the development of the most promising COVID-19 treatments.  

The ACTIV-2 study, sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and led by the NIAID-funded AIDS Clinical Trials Group (ACTG), is testing agents in outpatient adults with documented positive SARS-CoV-2 infection and symptoms of COVID-19.  Synairgen's SNG001 was advanced into Phase 3 in October 2021.^[18]