Do you need to commit to a pre-use post-sterilization integrity test (PUPSIT) strategy? Is it a control needed for your product? If so, what is the best way to implement it?

These are questions that have been challenging operations and their filtration experts since the inclusion of PUSPIT in Annex 1. Finding the correct answers has become increasingly significant with the ongoing debate about the wording and interpretation in the current Annex 1 redraft.

More specifically, you will need to be able to answer the following questions:

• How could a sterile filter and its system fail through its lifecycle from manufacture to post-use testing? What are the levels of these risks and how are they controlled by your suppliers? How should you control potential failure modes in-use?
• What operating conditions might cause your biological products to blind a fault and cause a final filter integrity test to pass in error?
• What tests or data could you use to understand if your drug products could cause bridging that might lead to blinding in normal operating conditions?
• What risks must be considered if you add a PUPSIT control strategy, and how can these be mitigated in the design of equipment and operational protocols?

The lack of availability of science-based, documented answers to these questions has become an uncomfortable problem for industry.

In 2017, BioPhorum and the PDA formed the Sterile Filtration, Quality Risk Management Consortium. The goal has been to fill these knowledge gaps with studies and guidance that provide professionals and license holders with the best science and widest consensus available and help them make informed decisions about risk management strategies. Now, 18 months later, the output of the collaboration is close to being published in a series of papers. Due to their interdependence, and to avoid any misinterpretation of results, these will be published simultaneously in Q4 2019 or Q1 2020.

There will be four papers:

• Paper 1 – Data mining to determine the influence of fluid properties on integrity test values
• Paper 2 – Filter masking studies and results, Part 1 (Part 2 to follow)
• Paper 3 – Risk assessment and management from filter production to end-use
• Paper 4 – Points to consider in the best practice use of PUPSIT

To update our respective members on progress with these efforts, the team published an article in the PDA Letter in August 2019. This gives a detailed progress report on the collaboration workstreams and the four proposed papers.

Over time, we are sure that further studies, new technologies and techniques will deepen our mastery of these topics, but for now we believe these studies describe state-of-the-art sterile filtration quality risk management. We hope the PDA Letter update will be useful to all BioPhorum members awaiting these papers.

For more information, contact the facilitator Jannika Kremer on jannika@biophorum.com