Research and Development

Has cost requirements of Research and Development and patent protection affected the structure of the pharma industry? Ideally, the presentation notes would focus on judging patent law/ evergreening strategy using maybe one big pharma company as an example – I was thinking about Pfeizer (?). I would need couple of statistics or graphic examples ( I mean I could include them on my own had I known the source that will be used )  from a source or two and maybe summary: ethical aspect via profitability? Thank you!