A 2016 editorial in the BMJ makes the following claim:
The top 10 prescription drugs in sales have a cumulative clinical response rate of less than 20%.
The claim is not the central theme of the article, which is an argument for doing clinical trials differently.
The author references this claim with a link to a Nature Comment piece. But it is unclear whether the claim is a fair summary of the argument from Nature or the consensus view of the literature.
Hence the question: do the most prescribed drugs have a cumulative clinical response rate of less than 20%? What does the claim itself mean in layman's terms and is it a fair summary of scientific opinion on the effectiveness of prescription pharmaceuticals?