Desperate times call for desperate measures.

Over the past couple of years, Pfizer (NYSE:PFE) has been getting a small preview of what it's going to feel like when Lipitor, which fights high cholesterol, goes off patent in November 2011. Sales in the U.S. have been sinking since Merck's (NYSE:MRK) Zocor, a similar statin, lost patent protection in the middle of 2006 and generics flooded the market.

 

2006

2007

2008 through September

Lipitor U.S. sales (millions)

$7,849

$7,195

$4,717

Year-over-year increase (decrease)

6%

(8%)

(12%)*

Source: Company earnings releases.
* Compared with the same period of 2007.

To try to get some of those sales to cheaper generics back, the company ran a study comparing Lipitor with generic versions of Zocor.

But this wasn't a controlled head-to-head clinical trial -- no, that would cost way too much. Instead, the company used data collected by WellPoint's (NYSE:WLP) health outcomes research subsidiary to observe whether patients who took the drugs had differences in their chances of having a cardiac event, such as a heart attack, a stroke, or needing a bypass. 

Lo and behold, the group that took Lipitor had a 13% reduction in the relative risk of a cardiac event.

The only problem -- and it's a biggie -- is that these observational studies aren't very controlled. The scientists compiling the data try to factor the differences in, but it's somewhat out of their control. For instance, the patients taking Lipitor were on the drug for nine months on average, compared with just seven months for the patients taking generic Zocor. Pfizer even warns us that the study isn't testing a hypothesis, but rather generating one. How could anyone take the conclusions seriously?

And yet, I'm not sure that Pfizer wasted investors' money. The study probably wasn't all that expensive to compile, and enough doctors won't bother to read the fine print, so it might help gain a few sales that would have gone to generic Merck or perhaps even AstraZeneca's (NYSE:AZN) Crestor or Merck and Schering-Plough's (NYSE:SGP) Vytorin.

Investors should think of this study as an elaborate advertisement. It won't create a windfall, but it might slow the slide toward the cliff a little.

More Foolishness:

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Pfizer is also a Motley Fool Income Investor pick, and the Fool owns shares of it. The Fool has a disclosure policy.