Lost in yesterday's hubbub about Merck (NYSE: MRK) and Schering-Plough's (NYSE: SGP) Enhance trial was a post-marketing clinical trial from Schering that yielded better results for the company, although not without some controversy.

Schering's clinical trial -- dubbed IDEAL, an acronym invented by some guy with too much time on his hands -- was a post-marketing requirement from the FDA. It mandated testing for two doses of hepatitis C virus treatment Pegintron, to see if the lower dose worked as well with fewer side effects. Since it was going to have to spend all that time and money running the trial, Schering threw Pegintron's competitor, Roche's Pegasys, into the mix as well.

Around 40% of patients taking the two Pegintron doses -- as well as those taking Pegasys -- showed a sustained virologic response. That is, they didn't have detectable levels of the virus after treatment. For Schering, that's a win, since Pegintron isn't selling as well as Pegasys.

The better news for Schering was that fewer Pegintron patients relapsed compared to the Pegasys patients. Schering didn't give any statistics for the trial, so one has to wonder if the difference is due to chance alone.

Roche, however, is crying foul. The drugmaker claims that, by using different doses of ribavirin -- a drug used in combination with both of the drugs -- for Pegintron and Pegasys, Schering set up Pegasys for failure. Schering seems to have seen this argument coming, and noted that it used the "recommended doses in accordance with their approved U.S. labeling"; it even presented the data for just those taking comparable doses of ribavirin.

With so many potential new hepatitis C drugs in the clinic, now is the time for the two companies to try and establish dominance. Not only do these drugs have potential competitors in the works, but some of the new drugs, such as Vertex Pharmaceuticals' (Nasdaq: VRTX) phase 2 candidate, telaprevir, are being tested in combination with the proven therapies. Since the standard of care that gets used in a combination clinical trial is more likely to be used by doctors once it's approved, this trial may have been designed as much to encourage up-and-coming competitors like InterMune (Nasdaq: ITMN) to use Pegintron in their trials as it was to persuade doctors to prescribe Pegintron now. Considering the way Roche is fighting back, I'd say that Schering's spin machine is working.

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Fool contributor Brian Orelli, Ph.D., loves it when companies name their trials something that's easy to pun. He doesn't own shares of any company mentioned in this article. The Fool's disclosure policy doesn't like to be called DP, but we do it anyway.