Alzheimer's drugmakers Novartis (NYSE: NVS), Johnson & Johnson (NYSE: JNJ), and Pfizer (NYSE: PFE) can breathe a little sigh of relief. The insanely good data that newcomer EPIX Pharmaceuticals (Nasdaq: EPIX) released last month turned out to be insanely wrong.

EPIX blamed the contract research organization (CRO) that helped it run the trial.

The revised data doesn't look that bad, but isn't nearly as stellar as the previous data. The highest dose of EPIX's experimental drug, PRX-03140, really scored a mean improvement of 3.6 points on the Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog), compared with the 5.7-point improvement that had been reported.

Alzheimer's drugs usually demonstrate a three- to four-point improvement after a full 12 to 24 weeks in clinical studies. This was just a two-week trial, so the data is still a reason for hope -- both for patients and for shareholders.

The ironic thing is that when EPIX presented the original data on a conference call, it included Alzheimer's doctor Paul Solomon, who was basically flabbergasted at the data and hadn't seen anything like it. He still hasn't seen anything like it.

All kidding aside, the trial was still successful in its goal as a proof of concept. Only a longer trial with more patients, which EPIX and marketing partner GlaxoSmithKline (NYSE: GSK) are still planning on running in the first half of this year, will tell us how well the drug really works.

The funny thing is that I like EPIX better now that it's approaching a $100 million market cap than I did at a $150 million market cap with the old stellar data. Because it was a small, short clinical trial, the patients' responses could turn out to be an anomaly that disappears in a larger trial. The lower share price gives investors a little more margin for error.

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Fool contributor Brian Orelli, Ph.D., just took a bath on his EPIX pick in Motley Fool CAPS, but doesn't own shares of any company mentioned in this article. Glaxo and Johnson & Johnson are Income Investor recommendations. Pfizer is a pick of the Inside Value newsletter. The Fool has a disclosure policy.