Safety and tolerability of the low global warming potential propellant HFA-152a in patients with asthma receiving beclometasone dipropionate/formoterol fumarate/glycopyrronium: The TRECOS study

Background Propellants currently used in pressurised metered-dose inhalers (e.g., HFA-134a) are being replaced by low global warming potential alternatives, including HFA-152a. This study aimed to assess the bronchoconstriction potential and the safety and tolerability of triple combination beclometasone dipropionate/formoterol fumarate/glycopyrronium (BDP/FF/G) HFA-152a pMDI compared to BDP/FF/G HFA-134a pMDI. Methods Adults with moderate-to-severe controlled asthma received BDP/FF/G HFA-134a pMDI for a two-week run-in, then were randomised 1:2 to either continue the HFA-134a pMDI formulation or switch to the HFA-152a pMDI formulation, both for 12 weeks. The primary objective was to compare the bronchoconstriction potential of BDP/FF/G HFA-152a vs HFA-134a in terms of the relative change from pre-dose in forced expiratory volume in 1 s (FEV 1 ) at 10 min post-dose on Day 1. Safety and tolerability assessments included adverse event occurrence. Results Of 553 patients randomised to treatment, 539 (97.5%) completed the study (356/368 [96.7%] and 183/185 [98.9%] with the HFA-152a and HFA-134a formulations, respectively). There was no difference between the two groups for the primary endpoint, with an adjusted mean (95% confidence interval) HFA-152a vs HFA-134a difference of −1.143% (−2.769%, 0.483%). A total of 19.3% patients experienced adverse events with the HFA-152a formulation (71/368) compared to 27.6% with the HFA-134a formulation (51/185); most events with both formulations were mild or moderate in severity. Conclusions Overall, transitioning to the low global warming potential HFA-152a formulation had no impact on the safety and tolerability of BDP/FF/G, with the positive effect on lung function comparable to the original HFA-134a formulation.