I'm not familiar with the company running this trial, but I can basically guarantee you they have found a way to patent this. Their intention is to come to market in 5 to 10 years, and there's no way they're bearing the expense of phase 3 trials just to become a generic manufacturer. Psilocybin isn't hard enough to manufacture (as opposed to say, propofol) to provide any sort of moat. They'll probably try to patent either an extended-release form or a particular administration device (e.g., inhaler).

E.g., the company that did the major trials for ketamine actually studied the s-enantiomer of ketamine using a nasal spray, which is quite distinct from the years of data we've accumulated on racemic ketamine with prolonged IV infusion. But this let them get a patentable version of ketamine on the market.

They can’t get a “composition of matter” patent, since psilocybin is already known.

They could get a “method of use” patent that describes treating a co diction with psilocybin.

Even without either of those, the FDA will give them 3 years of market exclusivity (no other drugs will be approved).