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Re: Conference call at 45.30 minutes Mamtami and 46 minutes stan answersI spent 4 years developing vaccine potency assays for one of the big vaccine makers and have a few thoughts. Since this is a recombinant protein vaccine, I would be surprised if they aren’t using an ELISA for their potency assay. Especially because I would assume that the antibody toolkit for spike protein detection is extensive and has been for a while. (For what it’s worth, ELISAs were used for most, if not all, of the potency assays for the protein vaccines in the clinic and in commercial production) A couple of ideas about what might be causing the delay in the potency assay (if I’m correct that it’s an ELISA): 1. Availability of finished product from a sufficient number of lots from the final manufacturing process - If I remember correctly, robustness studies require use of material from separately manufactured lots. All of the vaccines I worked on had only 1 or 2 production sites only in the US so this wasn’t an issue. However, with their complex manufacturing setup, this might not be trivial. But this is a completely guess bc I never was involved in something this complex. 2. Reagent problems - antibody, reference standard, or positive control (I.e. any “critical reagents”) - Seems trivial but reagent problems were often the culprit when we had issues where I worked and we were a well-capitalized and very experienced organization. Could be a hundred things that fall in this category that could cause a delay. For instance, if they identified that the reference standard being used wasn’t derived from a process equivalent to the final manufacturing process they’d have to repeat qualification/validation studies with a new, appropriate reference standard. This is often neglected even at bigger companies. 3. Unidentified source of assay variability between sites - another complete guess, but another non-trivial challenge. There are many sources of assay variability including liquid handlers, plate readers/washers, technician experience etc. Ideally, you want to have as few testing sites as possible to minimize whatever instrument or technician-specific bias is introduced. Because these are bespoke tests, it’s a lot harder than you might think to make this happen. The fact that novavax has so many production sites compounds the difficult of this significantly. This is all speculation especially since I don’t even know if they’re using an ELISA. But either way, potency assay development and validation is far from trivial and the fact that they have delays is not surprising based on my experience at one of the leading vaccine makers. mRNA is FAR simpler to characterize and assess potency than a protein subunit vaccine, so it’s not really a fair comparison. If they’ve actually locked the assay/reagents then completing validation should just be a matter of time. |
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Msg # | Subject | Author | Recs | Date Posted |
127844 | Re: Conference call at 45.30 minutes Mamtami and 46 minutes stan answers | 12roundsdeepwater | 0 | 5/12/2021 3:20:13 PM |
127845 | Re: Conference call at 45.30 minutes Mamtami and 46 minutes stan answers | luckijack | 3 | 5/12/2021 3:22:16 PM |
127853 | Re: Conference call at 45.30 minutes Mamtami and 46 minutes stan answers | redplate | 3 | 5/12/2021 4:00:37 PM |