its good to see that you're reasoning your way through this, and starting to put the assays into a more detailed perspective.
I say assays, but of course the release assays put forward by MSB to the FDA were in the form of an assay matrix - which can sound like a singular assay, when in fact its a plurality. Steve Bauer acknowledged & agreed with the propriety of doing so at teh ODAC hearing. The assay elements may be biological or non-biological analytical i.e. 'analytical', as the FDA refer to them. They may even be some combination of these elements. Confusing, I know.
But when Dr Eric Rose talks about "the assay" (in response to a dumb question from a stock analyst without notice), I think you should keep this in mind.
Separately you suggested:
" If all that was necessary to validate a potency assay was to show that batches of remestemcel-L (whether they are samples set aside from lots that went into patients or whether they are inventory from lots that have not gone anywhere yet except into the inventory) have anti-T cell activity in vitro then sure - but I don't think that that is enough to validate a potency assay.
I think to validate a potency assay you have to show that some associated activity also carries over into the in vivo environment - which means the new potency assay's associated and consequential activity has to itself be carried over to get tested in vivo (in the body - of patients) environment. "
What's actually required, as I understand the FDA's requirements, is set largely out in this page 8 extract from the FDA's own guidance:
So, there is a huge degree of flexiibility available to MSB in meeting these requirements IMO. Also, please review the excellent posts by @ImaScientist in April 2022 on this point. I believe you were corresponding with him then. Hope this assists.
Have a great day all.
MSB Price at posting:
80.5¢ Sentiment: Buy Disclosure: Held
(20min delay)