What is the relationship between drug R&D and patent?

Patented drugs are innovative drugs that are patented and within the patent period.

Patented drugs are innovative drugs that are patented and within the patent period. Innovative drugs include patented drugs and innovative drugs that are not patented after research and development.

Drug research and development is a promising career, because there are many diseases in clinical medicine that depend on drug treatment, and there are many incurable diseases.