Ann: Appendix 4C - Quarterly - 31 March 2022, page-10

This perhaps points to the problems in the engineering run
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During the quarter, Patrys has worked closely with its CDMO to develop an improved, large-scale purification process. On the back of this, Patrys’ CDMO will undertake a second engineering run of PAT-DX1 which is expected to complete during the current quarter.
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assuming that the work Patrys has been doing with the CDMO is about correcting the problems of the engineering run, then at some stage of the process impurities in the flow have contaminated the end product or reduced the volume available. Remember, the engineering run was not a failure per se, it merely failed to produce sufficient volume to support the trials required in this next stage. In other words, we got product from the run, there just wasn't enough of it.
So, this gives rise to a couple of workarounds.
1. increase the scale of the engineering run to give the output required. (perhaps filtration is the answer)
2. improve the quality of the flow to improve the yield. (perhaps filtration is the answer)

Naturally this is all speculation. However if I was doing the engineering run, i'd want to avoid a whole bunch of questions/suggestions/advice from people who are smart enough to comment, but lack the 20 years of experience in production of pharmaceutical grade cell lines that would make any of that feedback worthwhile.
That's just an invitation to visit crazy town. (with zombies)

For me, I'm happy to wait for the company to operate at its own schedule, and to do the work required.