I mean a controlled study showing that EPO enhances athletic performance. From the very beginning, it was assumed that an oxygen vector would enhance performance—which is why I said HBOCs should do so—but the kind of statement made by Schumacher about HBOCs could have been made about EPO for many years (in fact, wasn’t it only a year or two ago that some scientist claimed—obviously incorrectly, but with a lot of publicity—that there was no compelling evidence that EPO enhanced performance?). When was the first study determining the effect of EPO on FTP carried out? I’m not sure, but the most convincing study was published less than ten years ago, and even then, it necessarily involved non-elite athletes.
You don’t need a scientific study to rationalize taking a PED. If you ride a TT significantly faster than you ever have before with EPO, you know it enhances performance, but that one observation would not suffice for a scientific study.
In the case of HBOCs, the safety problems, as Archibald notes, make even pilot studies difficult. EPO is an approved drug, so it's possible to get approval to run studies on its effect on performance. HBOCs are not approved in most countries, including the U.S., so such studies would not be possible. I assume the studies Schumacher is referring to occurred during an early Phase I or possibly II trial, since if the drug was considered unsafe, it would never get beyond that stage. But drugs that never get beyond that stage would not ordinarily be tested for athletic performance benefits, since the purpose of the drug is for medical benefits.