The study investigated SNG001 in patients representing mild-moderate through to severe asthmatics, who caught a cold, and was well tolerated.
The difficult to treat asthma patient catergory were approximately half of the patients in the trial.
The trial findings in the difficult to treat asthma patient catergory demonstrated clinically important and statistically significant differences in favour of SNG001 as compared to placebo across recognised measures of asthma symptom severity and lung function.
Synairgen founder Stephen Holgate said: "This is the first clinical study which appears to demonstrate that, by boosting the antiviral defences of the lungs of asthmatics rather than trying to inhibit rapidly evolving viruses, we can limit the adverse effects of viral infection significantly to prevent worsening of asthma symptoms in a high risk group of patients."