Bielski noted that the FDA began publishing PSGs in 2013 using the weight-of-evidence approach; the first PSG including an alternative approach to BE was published in 2019, with all PSGs including option-based alternative approaches by 2025. The agency’s goal now, she says is to focus on key studies and to provide more clarity on recommendations for BE studies.
Regarding the effort to focus on key studies, she presented data comparing data from plume geometry and spray pattern testing to realistic aerosol particle size distribution testing, finding strong correlations between the two for some solution MDIs. As a result, she said, the agency has concluded that rAPSD can provide sufficient data for determining BE without needing additional spray pattern and plume geometry tests.
She also discussed evaluation of data from single actuation content testing alone versus SAC plus priming studies, with the agency concluding that separate priming / repriming data is not necessary.
Eliminating that study leaves a total of four tests for determining BE: SAC, APSD, rAPSD, and dissolution. Shortly after the conclusion of RDD 2026, the FDA announced the availability of updated PSGs for many MDIs to reflect the new recommendations. Bielski and other FDA speakers also encouraged delegates to participate in the upcoming CRCG workshop on Advancing Bioequivalence Frameworks for Inhalation and Nasal Drug Products.
The LGWP propellant transition
In the Building a Sustainable Future session, Lucas Silva of Nanopharm provided updates on LGWP propellant studies performed under a 2023 FDA contract with parent company Aptar Pharma, work that was also cited in FDA presentations in the same session. Markham Luke and Bryan Newman presented the FDA’s current think on “An Evolving Regulatory Landscape: U.S. FDA’s Evidence Based Perspectives on Next Generation Propellant Product Transitions.,” also updating their RDD 2024 presentation.
