My reasoning behind the vote to close is the following.
There is a Nature article, which makes a nebulous statement with an evident link for more information.
The top 10 prescription drugs in sales have a cumulative clinical response rate of less than 20%
Note that both I and the author agree that it's not clear what is meant by "cumulative clinical response".
The link goes to another article with a much clearer explanation of what is meant. The original claim is better specified there.
The top ten highest-grossing drugs in the United States help between 1 in 25 and 1 in 4 of the people who take them
The article also contains a list of the drugs in question.
What is the actual claim which the OP meant to ask about?
If it's the first and not the second, then the question is non notable, because it's about a specific bit of wording, not about the more precise claim on specific effectivenesses.
If it's both, then the question needs major editing and rewording. However the OP seemed to mind even a one-word edit, therefore I am not going to touch it.
No matter what the OP meant, however, the version of the question which I closed appeared to be referring to the first claim, as in 1., which is why I voted as such.
While the linked article might not be the best evidence on the medical statistics, it is certainly the best evidence on what claim in the article meant. If someone wants to know more, they only need to follow that link, answering that here has no value.
I'd be quite happy to reopen, as always, if the question was properly fixed, not about confusing wordings but about facts.