Post Hoc Analysis Suggests Benefits of SNG001 for Hospitalized COVID-19 Patients

Though it failed to meet its primary study endpoints, post hoc analysis of SNG001 showed the inhalable reduced the risk of severe COVID-19 disease and death in high-risk patients.

COVID-19 suppresses the production of IFN-beta, a naturally occurring protein that enables the body’s antiviral defenses. Today, Synairgen announced the first presentation of data from its phase 3 trial, evaluating the safety and efficacy of SNG001 for hospitalized COVID-19 patients.

In vitro, SNG001 has demonstrated antiviral activity against the Alpha, Beta, Gamma, Delta, and Omicron COVID-19 variants. Now, Synairgen says that post hoc analyses showed SNG001 could have important clinical implications for patient groups at increased risk of severe or fatal COVID-19 disease.

The phase 3 SPRINTER trial (SG018; NCT04732949) was a global, randomized, placebo-controlled, double-blind clinical study. The trial evaluated inhaled SNG001 to treat adults hospitalized with COVID-19 who required supplemental oxygen. SPRINTER included 624 participants, randomly assigned to either SNG001 (n = 309) or placebo (n = 314) in addition to standard of care.

In February 2022, Synairgen announced that SPRINTER did not meet its primary endpoints of hospital discharge and illness recovery. However, there was a signal in reduction in the relative risk of progression to severe disease or death within 35 days. Synairgen noted there was a 25.7% reduction in the intention-to-treat population and a 36.3% reduction in the per protocol population.

Investigators performed post hoc analyses on groups of patients recognized to be at greater risk of developing severe disease in the hospital. Identified patients were 65 years and older and had comorbidities associated with worse COVID-19 disease outcomes. Patients included in the post hoc analysis also had clinical signs of weakened respiratory function at baseline (oxygen saturation of ≤ 92% or respiratory rate ≥ 21 breaths/min), despite receiving low flow oxygen.

There were stronger effects of SNG001 in this subgroup of high-risk patients, with the greatest benefit observed in those with compromised respiratory function. These patients comprised about a third of the overall SPRINTER trial population, and SNG001 reduced their risk of severe disease and death by 70%.

SNG001 is a pH-neutral investigational formulation for inhalation, containing the broad-spectrum antiviral protein interferon beta. SNG001 is delivered directly to the lungs with a mesh nebulizer. SNG001 may be broadly applicable for respiratory infection symptoms caused by influenza, para-influenza, and Respiratory Syncytial Virus (RSV).

SNG001 was reportedly well tolerated, with treatment-emergent adverse events of 22.6% for SNG001 and 25.4% for placebo. The rate of severe adverse events was 12.6% for SMG001 and 18.1% for placebo.

Synairgen is presenting data from the SPRINTER trial today at the Clinical Trials Symposium of the American Thoracic Society 2022 International Conference in San Francisco, California.