Potent Canadian Court Ruling Strips Pfizer of Viagra Patent

Lisa Shuchman

Corporate Counsel

11-09-2012

Pharmaceutical giant Pfizer Inc. has lost a patent battle in Canada over its top-selling drug Viagra.

The Supreme Court of Canada upheld an appeal by Israel-based Teva Pharmaceutical  Industries that Pfizer’s original patent application was incomplete, rendering the patent on the drug used to treat erectile dysfunction invalid. 

The ruling clears the way for generic drug manufacturers such as Teva to start producing their own versions of the popular drug in Canada. 

In a unanimous 7-0 decision, the court said Pfizer had purposely withheld disclosure of information about the drug, and in a sharp rebuke of the company wrote that, “patentees cannot be allowed to ‘game’ the system in this way.”

In a statement, Pfizer said it is “disappointed” with the court’s ruling and expects to face generic competition in Canada soon. The Viagra patent in Canada was not scheduled to expire until 2014.

Teva had alleged in its lawsuit that the patent on Viagra was invalid because Pfizer named a long list of chemical compounds in the patent but did not sufficiently disclose the exact compound—sildenafil—that is effective in treating erectile dysfunction. Canada’s lower courts had ruled in favor of Pfizer, but the Supreme Court agreed with Teva. 

The Supreme Court ruling will not fundamentally change the Canadian patent system, said Robert Gold, a professor at McGill University School of Law in Montreal who specializes in patent law. “But it clarifies how far you can push the boundaries on disclosure,” he told CorpCounsel.com. 

When it applied for the patent many years ago, Pfizer may have intentionally withheld information about the active ingredient used to treat erectile dysfunction so it could get into the market ahead of competitors. But it went too far for Canada, Gold said.

"Pfizer gained a benefit from the [Patent] Act—exclusive monopoly rights—while withholding disclosure in spite of its disclosure obligations under the Act," Justice Louis LeBel wrote on behalf of the court.

Teva hailed the ruling, saying a new generic version of Viagra will mean consumers can save millions. Teva Canada’s president and chief executive officer, Barry Fishman, said availability of a generic version will also make the medication accessible to people who otherwise might not have been able to afford it. Teva’s generic version is expected to sell at a significantly lower price than Viagra. 

Pfizer has previously defended Teva’s challenges to its Viagra patent in other countries, including the U.S., Spain, and New Zealand. In those countries, Pfizer prevailed.

Viagra was first introduced in 1998 and has since been used by millions of men worldwide. In the U.S., no other company will be allowed to make, use, or sell a competitive generic version of Viagra until April 2020, Pfizer said. In the U.S., the drug is actually covered by two patents—the “method of use” patent, which covers the erectile dysfunction indication for which Viagra is used, and the “composition of matter” patent for Viagra’s active ingredient, sildenafil. 

Also, in February, sildenafil was granted an additional six months of U.S. patent protection because it is being tested in studies on children with pulmonary arterial hypertension. Federal law provides for such extensions of exclusivity as an incentive for drug makers to test products that may be helpful to children. 

In several European counties, the patent on Viagra is due to expire soon. Like many global pharmaceutical companies, Pfizer is facing a “patent cliff”—many of its patents are set to expire, and new drugs in the pipeline are not yet approved for market.