There's still many opportunities to patent, they just aren't as "easy" as novel target drugs. E.g. MDMA is known to have some serotonergic toxicity at higher en

There's still many opportunities to patent, they just aren't as "easy" as novel target drugs. E.g. MDMA is known to have some serotonergic toxicity at higher ends of the therapeutic window, so there are opportunities to patent a delivery system which controls the peak plasma concentration, or a co-drug to block some of that toxicity.