Synairgen upbeat on latest data from SNG001 trials

Respiratory drug discovery and development company Synairgen announced positive data from the interim analysis of its exploratory phase 2 clinical trial of inhaled ‘SNG001’ on Tuesday, in chronic obstructive pulmonary disease (COPD) patients with a confirmed respiratory viral infection.

The AIM-traded firm said SNG001 was well-tolerated during the treatment period in a study population that was elderly and suffering from reduced respiratory function, as measured by forced expiratory volume in one second.

It said the percentage of on-treatment adverse events was similar in the placebo and SNG001 treatment groups, with treatment-related adverse events being more frequent in the placebo group compared to the SNG001 group.

That safety data was added to the safety database for SNG001, supporting the company’s interactions with regulatory agencies in respect of Covid-19, where older age and poor lung function were risk factors, the board said in its statement.

Over the treatment period, the firm said lung antiviral responses to viral infection were “significantly enhanced” in patients receiving SNG001 compared to those on placebo, as assessed by measuring increases in the gene expression of interferon beta-dependent antiviral biomarkers MX1 and OAS1 in lung cells.

Analysis of blood biomarkers was said to be ongoing.

The board said the impact of viral infections on COPD patients in the trial was most evident on peak expiratory flow rate - a measure of lung function - and patient-reported symptoms assessed using the ‘Breathlessness Cough and Sputum Score’ (BCSS), and was said to be particularly apparent in exacerbating patients.

Exacerbating patients who received SNG001 had “significantly better” lung function during the treatment period.

Although there was no significant difference in total BCSS in that group over the treatment period, there was a trend for the breathlessness component of the score, suggesting that patients may have recovered more rapidly if they received SNG001 rather than placebo.

Viral infections had less impact on non-exacerbating patients, Synairgen said, and there were no significant treatment effects.

Looking at virology, the company said a range of common respiratory viruses including rhinovirus, influenza, adenovirus, respiratory syncytial virus (RSV), human metapneumovirus (HMPV), parainfluenza and cold-causing coronavirus were identified in nasopharyngeal and sputum samples from the COPD patients in the trial.#

It said that was relevant because Covid-19 patients could be coinfected with other respiratory viruses such as influenza.

SNG001 demonstrated antiviral activity against multiple viruses in cell-based assays, the firm said, with further virology work being conducted.

COPD exacerbations are the second most common cause of unplanned hospital admission in England, and occur most frequently in the winter virus season, the board said.

The data from the trial, coupled with the data from the Covid-19 trial in hospitalised patients, provide a strong rationale for assessing SNG001 in COPD patients admitted to hospital with exacerbations from confirmed viral lung infections.

Synairgen said it was also in discussions with a number of regulatory agencies worldwide to establish the regulatory route to the approval of SNG001 as a treatment for Covid-19.

It said it was also working closely with its manufacturing partners on scale-up activity.

“COPD exacerbations are the second most common cause of unplanned hospitalisation in England, behind cardiovascular disease,” said chief executive officer Richard Marsden.

“These interim data from our first trial of SNG001 in COPD show that SNG001 could be a valuable novel therapeutic for exacerbating COPD patients.

“Overall, SNG001 has now been shown to raise the body's natural viral defences when challenged by a wide variety of respiratory viruses, indicating that it could be an important treatment in the coming virus season, where there may be coinfection with influenza and other viruses alongside Covid-19.”

Marsden said the company’s immediate priority was to progress SNG001 as a therapeutic for Covid-19 and, as such, its COPD programme would remain paused.

“We are, nevertheless, pleased to provide further evidence that supports SNG001 as a potential treatment for Covid-19 through the safety, biomarker, and efficacy data generated from patients in this interim review of the COPD trial.”

At 1514 BST, shares in Synairgen were up 0.74% at 197.45p.