The only real R&D Big Pharma does is patent extension. Patents have a life so companies will make minor changes to the molecule or the delivery mechanism to reset that patent protection period.
What makes Big Pharma particularly evil is it's one of those industries that profits from inelastic demand (ie people will die without some product) and buying the government to build a moat and make themselves a monopoly. The prices US consumers pay for pharmaceuticals is absolutely criminal.
This is capitalism working as intended: taking a captive market (eg diabetics that cannot live without insulin) and extracting wealth from them to the hands of a very few.