A report in The Lancet Respiratory Medicine journal reveals that a trial of the drug Fevipiprant helped reduce inflammation in the airways of asthma patients.
The trial was conducted by scientists at the University of Leicester.
The pill is being evaluated by patients with severe asthma and Dr Samantha Walker from Asthma UK, said the research showed "massive promise".
She said: "The possibility of taking a pill instead of using an inhaler will be very welcome among the 5.4 million people in the UK with asthma, particularly as this study focused on people who develop the condition in later life, some of whom we know can struggle with the dexterity required to use an inhaler.
"More research is needed and we're a long way off seeing a pill for asthma being made available over the counter, but it's an exciting development and one which, in the long term, could offer a real alternative to current treatments."
Prof Stephen Durham, Professor of Allergy and Respiratory Medicine at Imperial College London, said researchers "provide compelling evidence" that Fevipiprant taken twice daily and on top of usual medication "has the ability to reduce asthmatic inflammation, increase lung function and improve asthma control in this severe group".
Asthma affects more than 300 million people worldwide and most asthma deaths could be prevented if patients received better care, according to a hard-hitting report published in July by medical experts.
According to the first National Review of Asthma Deaths, half the cases examined were being treated for mild or moderate disease, suggesting patients and doctors underestimated how serious their condition was.