Several years ago I was doing advertising websites, one of our customers was (Pfizer? Bayer? both were customers) they had developed a drug against Dupuytren's contracture[1] and apparently found it effective enough against Peyronie's that we were asked to create a website describing this (possibly off label) use of that drug.

Honestly I have no idea if it was effective or not, nor do I know anything about the side effects, but just in case you were unaware of that particular option I want to put it out there.

From what I can find, doing an online search along that path it might have been Xiaflex/Xiapex by Pfizer.

(Not paid by anyone in this particular business anymore, just remembered it when I read your comment).

[1]https://en.wikipedia.org/wiki/Dupuytren%27s_contracture