Should Sick People Be Paid to Risk Their Lives?

This article talks about the idea of paying patients to become a test subject for a new drug. It talks about the justifications about paying money for patients to risk using a new drug. It talks about the paradox that if a effective drug is already available, patients will have little reason to volunteer for tests of drugs that could be better. A good example they use is HIV. If there is a medicine that can make people live on for decades, why should they experiment with a new drug?

Question: Why would a doctor pay someone money to try a new drug, if there is already a good drug that can cure them already?

Neo Kim