We caught up with Audrey Turley ahead of her educational discussions for MD&M Minneapolis to ask about her take on biological evaluation plans and ISO 10993-1. Turley is the Senior Senior Biocompatibility Expert at Nelson Labs and is giving two presentations.
The first presentation is Biocompatibility Standard Changes 2010-2019 and the second is on Managing Biocompatibility Risk: Applying the New ISO 10993 Standards.
Q&A With Audrey Turley, Sr. Biocompatibility Expert At Nelson Labs
Is there a pattern you’ve seen emerge in organizations‘ Biological Evaluation Plans or is each plan unique?
Audrey Turley: Overall, every plan is unique however, we do work to keep consistent with ISO 10993-1 in what is included. One trend we notice that has been a surprise to our clients is that the lower class devices (low risk) are far more complex in the initial analysis. This is due to the difficulty in assessing the specific patient contact of certain materials (i.e. intact skin). Some of these low-risk device materials are not very compatible with some of the test systems and can show unexpected results (i.e. foams, spandex materials).
Also, the level of detail regarding the materials, suppliers, and processes consumes much of the BEP as this is the first requirement of ISO 10993-1 – gathering physical and /or chemical information. Another important discussion in the BEP is the specific patient contact. Giving as many specifics and even pictures that show the exact location of patient contact and specific contact time.
Using general categories of contact based on Table A.1 in ISO 10993-1 like “less than 24 hours” with “tissue/bone” does not provide enough information to the reviewer to indicate that the risk assessment fully addresses the use of the device. A device with 5 minutes contact sterile tissue (i.e. scalpel) will need a different consideration than a device with 12 hours contact with brain tissue.
What potential conflicts exist, if any, between the FDA and ISO ISO 10993-1:2018 as organizations design for patient outcomes?
Audrey Turley: The US FDA is quite aligned with the current revision of ISO 10993-1, however, there are some minor differences which can be identified with a careful comparison of the 2018 revision of ISO 10993-1 and the US FDA guidance on ISO 10993-1 (2016).
The FDA has combined the consideration of subacute/subchronic testing, so where subacute toxicity needs to be addressed, subchronic toxicity will also need to be addressed. Whereas in ISO 10993-1:2018, these two endpoints are separated in consideration based on the contact duration of the medical device. The main differences between the US FDA and ISO 10993 lie in test specifics, like incubation duration for cytotoxicity testing of implants should be 72 hours, according to the US FDA.
Also, bacterial endotoxin testing is mentioned for certain devices, a test typically only discussed during sterilization validation however, is important from a biocompatibility standpoint as endotoxins are another source of pyrogens.
Are you finding organizations battling recent standards changes, as they change product materials to alternatives that can’t maintain functionality?
Audrey Turley: Any engineer will tell you that a design is never finished! The pursuit of additional suppliers, lower costs, and better functionality drive constant change in any medical device. The challenge I see most is tracking and addressing the changes in an efficient manner where the impact of the change can truly be assessed to ensure patient safety.
We write Biological Risk Assessments to address device changes, however, these are lengthy documents and do not lend themselves to minimal changes. I often recommend that companies have a robust change control program where there is a step required to assess if the change will impact biocompatibility.
If the answer is yes, and the conversation is more complex where perhaps more testing is needed, then it is appropriate to step into a separate and detailed risk assessment. However, many of the changes that I discuss can be addressed with a risk assessment approach that is well documented in the change control system which will make the conversation much simpler for the company to track and for the reviewer to follow.
Sign Up For Audrey Turley’s Sessions
MD&M Minneapolis is October 23-24th in the Minneapolis Convention Center. Audrey Turley has two sessions taking place. You can learn more information about her talk by clicking here. You can learn more about Audrey Turley and Nelson Labs by clicking here.
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