"Yet the patenting of a small change in how an existing drug is made or taken by patients is part of a tried-and-true pharmaceutical industry strategy of enveloping products with a series of protective patents.
Drug companies typically have less than 10 years of exclusive rights once a drug hits the marketplace. They can extend their monopolies by layering in secondary patents, using tactics critics call “evergreening” or “product hopping.”
Lisa Larrimore Ouellette, a patent law expert at Stanford University, said the pharmaceutical industry gets a greater financial return from its patent strategy than any other industry does."
