Biotech Values

[NP1986]

but the real point of that article seemed to me to be an indictment of "response rates" as an endpoint for clinical trials.

No, I don't see that as the main point of the article. In fact, the conclusion in the abstract provides an apt summary of what the main point of the article is, i.e:

Promising results from phase II studies frequently do not translate into “positive” phase III
studies. Response rates in most phase III studies are lower than those in preceding phase
II studies.

While the authors do discuss some possible reasons why this may be the case, those aren't the real findings of the study.

I would also wager that if a similar analysis was done with trials using PFS or OS as an endpoint, the conclusions would be analagous.