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The Supreme Court of Canada has taken the Viagra patent away from Pfizer
Last reviewed: 01.07.2025
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From now on, the American pharmaceutical giant Pfizer will have to compete with other companies in the production of the famous potency-improving drug in Canada.
Israeli pharmaceutical company Teva Pharmaceutical Industries Ltd. has won a lawsuit against Pfizer, having its monopoly patent overturned. The Israeli company's lawyers managed to prove that the patented drug was not described accurately enough in the document, which is contrary to Canadian law.
A seven-judge panel unanimously ruled that Pfizer's patent on Viagra was invalid.
"Pfizer benefited from the patent's exclusive monopoly rights, but the patent did not disclose the information required by law," one of the judges explained.
“The law does not allow such ‘games’ with patents, therefore this patent was declared invalid.”
Pfizer had previously successfully defended its patents against Teva in the United States, Spain, Norway and New Zealand, but the company ran into trouble with Canadian law.
"Pfizer's Viagra will soon face generic competition in Canada. The company is disappointed with the court's decision," the losing side commented.
Pfizer patented Viagra in 1998, and that patent covered 260 quintillion different chemical compounds. But only one of those compounds, sildenafil, is active, and it's the one the patent doesn't cover enough.
"Pfizer had the necessary information about the active ingredient in the drug, but chose not to disclose it," the court ruling explains.
"Even if Pfizer knew at the time it filed its patent application that the active compound was sildenafil, it chose to describe the drug in a way that does not clearly indicate that the drug is truly a new invention."
Teva was able to prove the validity of its claim in the Supreme Court of Canada, while two previous instances of the Canadian court system sided with Pfizer.