See Bruce's blog for some interesting research: blog

Research direct link.

Looks very promising to me.

Does anyone have insight into FDA approval for the microRNA process? Is there an umbrella approval for the virus and its payload? Or?

Any microRNA based treatment that has been approved already?

Hi Bob,
As far as I know, there is not any miRNA-based therapy approved yet. I don't know one in the clinical phase. There are still a lot of questions to answer first.
However, in August 2018, FDA approved the first-ever siRNA-based therapy, patisiran. siRNAs resemble miRNAs, as both interferes with RNAs. This product treats a rare genetic neurological disorder, not KD (https://www.alzforum.org/news/research-news/fda-approves-first-rnai-therapy).
Unfortunately, it costs a fortune, $450,000, yearly.
There is another RNA-targeting therapy against SMA (spinal muscular atrophy - not KD), nusinersen, approved. Quite the same price.
Best regards,
István Reinhardt