Give AstraZeneca (NYSE: AZN) credit for attempting to differentiate Crestor as the cholesterol drug market is about to get flooded with generic versions of Pfizer's (NYSE: PFE) top-selling Lipitor. Too bad it blew up in its face.

Don't believe me? Try this quote from the drugmaker: "Conclusions on the efficacy of Crestor should not be based on the Saturn study alone."

Saturn, the head-to-head trial comparing Crestor to Lipitor, showed Crestor's small advantage in treating atherosclerosis was not statistically significant. Crestor fared better in the secondary endpoint, measuring total atheroma volume, but that's really just a "thanks for playing" consolation prize. Had the results been different, you can bet AstraZeneca spokespeople would be touting this study as definitive proof of Crestor's superior efficacy.

AstraZeneca was counting on good results. When Lipitor goes generic, it will hurt more than just Pfizer. The drug accounts for more than $5 billion of annual sales in a $21 billion domestic market, and the ripple effects will be massive when the cost per pill goes from $3 a day to less than $1. Doctors will prescribe generic Lipitor and, more importantly, insurance companies like WellPoint (NYSE: WLP) and UnitedHealth (NYSE: UNH) may only pay for the generic in an effort to cut costs. Crestor needed superiority to justify its soon-to-be-premium pricing and hold onto its 12% of the U.S. market.

The generics are almost upon us. Sanofi (NYSE: SNY) just signed an exclusive deal with Pfizer to supply generic Lipitor in France during the second quarter of next year. Watson Pharmaceuticals (NYSE: WPI) and Ranbaxy also have agreements with Pfizer, while Teva (Nasdaq: TEVA) and Mylan are also chomping at the bit.

Pfizer has its work cut out for it in a post-protected-Lipitor world, but so does AstraZeneca. Defending Crestor's branded premium was valiant, but I can't help wondering if risking the perception that Crestor was more effective on a Hail Mary was a great idea.

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Fool contributor David Williamson owns shares of Pfizer, but he holds no other position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Teva Pharmaceutical and UnitedHealth Group. Motley Fool newsletter services have recommended buying shares of UnitedHealth Group, Pfizer, WellPoint, and Teva Pharmaceutical, as well as creating a diagonal call position in UnitedHealth Group. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.