Synairgen's shares jump on study results of inhaled interferon beta for COVID-19

Synairgen's shares jumped more than 40% on Friday after data from a Phase II study of its inhaled formulation of interferon beta, dubbed SNG001, in hospitalised COVID-19 patients were published in The Lancet Respiratory Medicine. Positive top-line results from the SG016 trial were first disclosed in July showing that SNG001 significantly reduced the chance of developing severe disease or dying by 79% compared to placebo.

The study randomised 101 hospitalised COVID-19 patients to receive either SNG001 or placebo by inhalation via a mouthpiece once daily for 14 days. The trial's primary endpoint was the change in clinical condition using the WHO Ordinal Scale for Clinical Improvement (OSCI) during the dosing period in the intention-to-treat population.

More likely to recover

The latest findings showed that the odds ratio of SNG001-treated patients achieving improvement on the OSCI scale was 2.32, and they were also more likely to recover to "no limitation of activity" during treatment, with a hazard ratio of 2.19. Specifically, during the two weeks of treatment, 44% of patients in the SNG001 group recovered compared with 22% on placebo, while on day 28, 58% in the treatment group had recovered, versus 35% on placebo.

SNG001 was well tolerated in the trial, with the most frequently reported treatment-emergent adverse event being headache in 15% of patients in the SNG001 group, versus 10% in the placebo arm. Meanwhile, there were three deaths in the placebo group and none in patients given SNG001. In addition, 22% of patients in the placebo group developed severe disease or died by day 16 compared with 13% in the SNG001 arm.

Lead author Tom Wilkinson remarked "the results confirm our belief that interferon beta…may have the potential as an inhaled drug to restore the lung's immune response and accelerate recovery from COVID-19." Wilkinson added that as SNG001 "boosts lung defences rather than targeting specific viral mechanisms…this might carry additional advantages of treating COVID-19 when it occurs alongside infection by another respiratory virus such as influenza or respiratory syncytial virus that may well be encountered in the winter months."

No impact on discharge rates, mortality

However, results also showed that there was no significant difference between treatment groups in the odds of hospital discharge by day 28, with 81% of subjects in the SNG001 group discharged within this time period, compared to 75% in the placebo group. In an accompanying commentary, Nathan Peiffer-Smadja and Yazdan Yazdanpanah further noted that the data "showed no impact of the evaluated treatment on…mortality, although the study was not adequately powered to analyse mortality outcomes."

Peiffer-Smadja and Yazdanpanah highlighted that "the number of patients enrolled in the present study was small," adding that "larger randomised clinical trials are therefore needed to further investigate the effectiveness of nebulised interferon beta-1a therapy in this setting."

Study expanded to home environment

In September, Synairgen said that it expanded the SG016 trial to include a further 120 patients with confirmed COVID-19 to be dosed in the home environment, with the objective of initiating dosing earlier in the infection cycle of COVID-19, and before severe lower respiratory tract symptoms have developed. The study is recruiting patients who are either aged 65 or over, or are aged 50 or over with a high-risk comorbidity.

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