The Canadian Supreme Court dealt Pfizer a minor setback this week after informing the pharmaceutical giant that special patent protection awarded to Viagra will not be renewed when it expires in 2014. The court unanimously decided to support an appeal filed by Teva Pharmaceuticals, the world's largest generic drug manufacturer, which asserted that Pfizer's original application was too vague.

At the heart of the matter is a unique legislative provision regarding invention disclosure practices. As CTV News pointed out, Canadian law awards companies a 16-year monopoly on products if they can prove the novelty of their invention and provide developmental details that could be of use to competitors.

Although Pfizer was originally awarded such protection in 1998, the appeals process called into question the transparency and functionality of proprietary details supplied by the manufacturer at the time.

"Pfizer gained a benefit from the [legislation] - exclusive monopoly rights - while withholding disclosure in spite of its disclosure obligations under the [law]," Justice Louis LeBel wrote in the court opinion. "As a matter of policy and sound interpretation, patentees cannot be allowed to 'game' the system in this way."

According to Reuters, the court identified a "willful intent" by Pfizer to obscure the effects of the drug's active ingredient when details were made publicly available during the initial patent approval process.