Chiesi has announced the advance of its transition to next-generation, lower-carbon pressurised metered-dose inhalers (pMDIs), with European regulatory submissions for reformulated versions of Fostair (beclometasone/formoterol) and Trimbow (beclometasone/formoterol/glycopyrronium) now validated and under assessment.
The formulations replace the existing HFA-134a propellant with HFA-152a, a next-generation hydrofluoroalkane propellant with a substantially lower global warming potential (GWP).
Chiesi estimates that the transition could reduce the carbon footprint of its pMDIs by up to 90%.
For the triple-therapy Trimbow, the application has been submitted through the European Medicines Agency (EMA) centralised procedure.
The Fostair application is being handled through a coordinated multi-country procedure, with Germany’s Federal Institute for Drugs and Medical Devices (BfArM) acting as Reference Member State.
The UK's MHRA is expected to validate the procedures once completed, with Chiesi saying it anticipates UK regulatory approval during the first half of next year.
The European submissions follow a significant UK milestone in July, when the MHRA approved new versions of Chiesi’s Clenil Modulite beclometasone inhalers formulated with HFA-152a.
The approval represented the world’s first authorisation of a pMDI using the next-generation propellant.
Chiesi has been developing its carbon-minimal inhaler platform since 2019, when it committed €350m to developing pMDIs using HFA-152a.
The company completed its Phase III TRECOS study in 2025, with more than 820 adults with asthma enrolled across 140 sites in 15 countries.
The study compared an HFA-152a formulation with an HFA-134a formulation and supported the new propellant's longer-term safety and tolerability.
Recent independent clinical research has also added to the evidence base for HFA-152a. A 2025 study reported that HFA-152a and HFA-134a had similar effects on mucociliary clearance, with neither propellant inducing bronchoconstriction in the Phase I studies.
Why this matters
Inhaler propellants can account for a substantial share of respiratory medicines’ lifecycle emissions.
NHS England estimates that inhalers account for around three per cent of the NHS carbon footprint, with propellant from metered-dose inhalers responsible for most inhaler-related emissions.
For Chiesi, replacing HFA-134a with HFA-152a is therefore central to its ambition to achieve Net Zero greenhouse gas emissions across its entire value chain by 2035.
The company has previously identified inhaler propellants as its single largest source of greenhouse gas emissions.
The firm says the approach aims to reduce the environmental impact of pMDIs while keeping the device format as an option for patients who need it, rather than relying solely on switching patients to alternative inhaler technologies such as dry powder inhalers.
