immunosuppresant drugs

Gold is an atomic snob. It has nothing but disdain for almost all chemicals that might want to bond with it. With few exceptions, gold – a noble metal (1) – is quite pleased with itself; it doesn't want to change.
"Clinical trial" is just a nice-sounding term for "human experiment." We don't like to use that term because it carries a lot of baggage, like the torturous and murderous "experiments" conducted by Nazi doctor Josef Mengele.