I am aware of some work such as
O'Donoghue (1998): "A Patentability Requirement for Sequential Innovation", RAND Journal of Economics
that discuss cases in which offering better protection for intellectual property (in these cases, by lowering patentability requirements) might reduce the incentive for firms to innovate.
Very roughly, the basic mechanism in these papers is that lowering the threshold for patentability means that an incumbent with a patent expects to be superseded by someone else with a better patent very quickly. Since the advantage to a patent does not last long, the incentives to invest in innovation to acquire such a patent are reduced.
I am curious whether people can suggest other mechanisms by which strengthening intellectual property protection (including moving from no protection to a positive degree of protection) can reduce innovation, and provide relevant references.