I would be surprised if it did contribute to new innovation. There are problems with having these patents and with having a monopoly.
Some of the issues that have been brought up by other experts in terms of looking at these government protective monopolies are excessive marketing expenses. It leads to that, as firms seek to pursue the monopoly profits associated with patent protection. Data from the industry suggests that marketing costs are currently comparable to the amount of money spent on research. It's not really clear that that's such an advantage.
There's also wasted research spending on duplicating drugs. Industry data indicates that roughly two-thirds of research spending goes into developing duplicative drugs rather than drugs that actually represent a qualitative breakthrough over existing drugs.
There's also a neglect of research that is not likely to lead to drugs that can be patented. There can be research done that could be valuable and should be in the public domain so that people know what the research is leading to, but if it doesn't lead immediately to a drug patent, then the research just gets abandoned.