In addition to good science, astute strategy has helped Pfizer (NYSE:PFE), a Motley Fool Inside Value recommendation, get where it is today. The company's prowess in this department is evident in its acquisitions, which have brought lucrative medicines under its control. Pfizer's purchase of Warner-Lambert, through which it acquired the blockbuster cholesterol medicine Lipitor, is a shining example of smart planning. Pfizer is again demonstrating its sense of strategy, this time in protecting its Lipitor investment. However, the firm's course of action is not popular with everyone.

The company is currently running late-stage trials on torcetrapib, a compound that is designed to raise levels of HDL, or "good" cholesterol. But Pfizer's development program has a twist -- the firm is evaluating torcetrapib in combination with its existing medication Lipitor, which lowers LDL, or "bad" cholesterol. The idea is that the two compounds together will pack an especially potent punch in lowering cardiovascular risk.

Beyond its health value, Pfizer's plan for torcetrapib also looks to maximize existing assets. Lipitor's patent runs out in 2010. Pfizer is hoping, though, that it can transition Lipitor users to the Lipitor-torcetrapib combination before Lipitor becomes available in generic form. Thus the combination will extend the value of Lipitor well beyond its patent expiration.

Pfizer's strategy is not entirely unique. Vytorin, for example, also consists of two cholesterol medications, Merck's (NYSE:MRK) Zocor and Zetia, which was jointly developed by Schering-Plough (NYSE:SGP) and Merck. However, the difference is that torcetrapib will not be available on a stand-alone basis, while Zocor and Zetia both are sold as individual medicines.

This difference has caused some to criticize Pfizer's plan. The latest complaint comes in an article in the New England Journal of Medicine by Harvard researcher Jerry Avorn. Avorn argues that in linking torcetrapib with Lipitor, Pfizer is limiting choice. Patients should have the option of taking torcetrapib alone or in combination with another statin, Avorn claims.

For its part, Pfizer is plowing ahead with trials for the combination medicine. It's important to note that the program has the blessing of the Food and Drug Administration, a fact that suggests regulatory authorities see value in pairing the two compounds. However, investors should be aware that Avorn probably won't be the last to argue that torcetrapib should be sold separately. If the pressure gets intense enough, Pfizer will have a tough time maintaining the combination strategy.

Merck is a Motley Fool Income Investor recommendation.

Fool contributor Brian Gorman is a freelance writer in Chicago. He does not own shares of any companies mentioned in this article.