Answer:
The investigator should discuss the pros and cons of both the investigational drugs and the drugs that are commercially available drug and then allow the subject so that he can decide whether to withdraw form the ongoing research to take the new drug.
Step-by-step explanation:
When the 46-year man enrolled in the Phase III study of the drug. When the research was going on a new drug became available in the market in that case the investigators should discuss the benefits and the drawbacks of the investigational drug and the other drug that is commercially available then let the subject decide whether to keep on the research or not.