SPCs, drug costs, evidence and proof: can you help?

The SPC Blog has received a request for information from David Verbeeten, PhD (Cantab). David, a Research Associate, Health Innovation, Policy and Evaluation, The Conference Board of Canada, Ottawa, wonders whether any of those kind souls who contribute to this weblog are aware of evidence as to the effects of SPCs effects on European drug prices since their implementation in the early 1990s. He also asks:

"Have drug costs gone up as a result of this mechanism? Is there any definitive proof? Are there studies that have looked into this question?"

This blogger isn't immediately aware of such statistics, but he finds it difficult to imagine that an industry sector as closely monitored and regulated as the pharmaceutical sector, and as closely scrutinised by the competition authorities, could have gone from the early 1990s until now without there being quantities of evidence, both from the two sides of industry and from third parties, to which David might profitably be pointed. If you have a handy reference or weblink to any helpful data, please post it as a comment beneath this blog post -- together with any pertinent comments you may have as to their currency, veracity or objectivity.