Winsantor, the company trialing pirenzepine, is in phase two trials right now for DPN. Phase one was safety, phase two is efficacy. Phase two is scheduled to be done in December 2019.

They did a reddit AMA (ask me anything) in May that's useful to read: https://twitter.com/WinSanTor/status/1125539822313934848?s=20

Interestingly, they could find no big pharma company interested in funding them. So they crowd funded and got government funding.

They have a patent which describes what they've found. Pirenzipene reversed PN in mice whether given orally, topically or by injection. They sound quite excited if you read the patent. https://patents.google.com/patent/CA2804797C/en

The great thing is that pirenzepine has an excellent safety profile having been used in Europe and elsewhere for years. Side effects seem very small and the drug is unable to cross the blood/brain barrier.

I've also found cases of people self trialing this on themselves (the drug can be found for sale overseas through google searching). Someone posted that they had reversed their systems in the Neuropathy group on reddit. (https://www.reddit.com/r/smallfiberneuropathy/comments/attfxc/i_reversed_most_of_my_sfn/)