• To incentivize the pharma companies to keep innovating and investing money, regulators across the country offer them protection on their inventions.
  • If they create a breakthrough drug - like a drug to battle AIDS, cancer, etc - they are granted a patent for 20 years.
  • During those 20 years, they have exclusive rights to manufacture and sell the drug - no other company can create the same drug with the same formulation.

After 20 years - entry of generics

  • After 20 years, other companies can step in can create their own versions of the drug. These versions are called generics.
  • Due to the competition of multiple players in the market, the price of the drug spirals down and becomes affordable.

Sources