A Study to Compare Safety of 4 Weeks Exposure to Propellants Hydrofluoroalkane 1,1-difluoroethane (HFA-152a) and HFA-1,1,1,2-tetrafluoroethane (134a)

To join this study, you need to be at least 18 years old.

You should have been diagnosed with asthma for at least 6 months and your asthma should be stable, meaning no serious flare-ups in the last three months. Also, you should be managing your asthma with regular treatment, which could be an inhaler used when needed, or daily preventer inhalers, or even more advanced treatments. If you use a special device to measure your breathing, your result (called FEV1) should be at least 50% of what's expected for someone your age and height. Your asthma control, measured by a short questionnaire (ACQ-6), should also be good (score less than 1.5).

It's important that you haven't smoked or used any vaping products in the last year, and your total smoking history isn't more than 10 'pack-years' (a way to measure how much someone has smoked over their lifetime). Also, using marijuana even with a prescription would mean you can't join this study.

If you decide to take part, you'll be given an asthma inhaler containing either the new propellant (HFA-152a) or the standard one (HFA-134a). You'll use this inhaler as part of your usual asthma treatment for about four weeks. The study will involve regular check-ups with the research team. These appointments will likely include discussions about how you're feeling, checking your breathing, and possibly some blood or urine tests to monitor your health and safety. You might also be asked to complete questionnaires about your asthma symptoms. After the four-week period, there will be a final check-up to make sure everything is okay. The total time you'd be involved in the study, including all visits and follow-ups, would be relatively short, focusing mainly on that four-week treatment period.