Human subjects enrolled in a clinical trial often pay for the
routine care associated with their treatment.  Either the individual
or their insurance company pays for it.  Sometimes US companies will
ask that a hospital-university submit bills to their third party payor
to see whether they'll cover any study costs.  I don't know if asking
study participants to pay for their participation breaks any law, but it
doesn't feel right to me. I wonder if the company will share any profits
with the human subjects if the drug makes it big!