Two European pharmaceutical companies are headed to the U.S. to go to court. Danish Novo Nordisk (NYSE:NVO) is suing French Sanofi-Aventis (NYSE:SNY), claiming that Sanofi's SoloStar insulin pen infringes on its patent for the dose management system in its NovoPen 4. Since the patent covers the U.S., the two companies will need to fight it out in U.S. courts.

Novo Nordisk is the world's leading supplier of insulin. In 2006, diabetes care accounted for about 70% of Novo Nordisk's sales, so it's understandable that it would like to squash the competition.

Sanofi gained marketing approval for SoloStar in April and plans to begin selling the disposable insulin pens in the U.S. by the end of the summer. The device is already being sold in Germany and France, and Sanofi plans to roll out the product in the rest of Europe over the next year. SoloStar has been successful enough that Sanofi has established a dedicated manufacturing site for the product that will be capable of churning out 1 million units per day when it reaches maximum capacity.

This isn't the first time that the companies have sparred over patents on insulin pens. Novo Nordisk sued Sanofi in 2005, claiming that Sanofi's OptiClick infringed on patents used in Novo's FlexPen device. The dispute never made it to court, since Novo Nordisk voluntarily dismissed the lawsuits.

There was expectation that inhaled insulin would steal market share from the injectable variety like a phlebotomist steals blood from a patient -- quickly, and yet still quite painfully -- but that hasn't really come to fruition. Sales of Pfizer (NYSE:PFE) and Nektar's (NASDAQ:NKTR) Exubera have been less than stellar, suggesting that diabetics are either sadomasochists or they just get used to poking themselves once a day.

While it's nice to invest in companies that have a clean bill of legal health, I don't think the lawsuit is a reason to stay away from Sanofi. While it's possible that a judge would stop SoloStar's U.S. rollout, I think it's more likely that the presiding judge will allow it to begin sales, since the patent dispute case will likely take years to resolve. Even if Sanofi loses the case, it will likely only cost it a royalty fee for sales of the device in the U.S., which should be mostly inconsequential to a global company as large as Sanofi.

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Fool contributor Brian Orelli, Ph.D., winces when his kids get a shot. He doesn't own shares of any company mentioned in this article.  The Fool's disclosure policy is rock-solid.