Pfizer Gets Extension on Viagra Patent Until 2019

If you live in the United States and you have been waiting for generic Viagra to hit the market it looks like you will be waiting quite a while yet. Pfizer, the makers of Viagra, just had a crucial patent validated in a federal court of law.

It all started when the Israeli medical giant Teva received a tentative approval by the FDA for a pill using sildenafil, the active ingredient in Viagra. Teva were intending to start selling the pill in March 2012 when Pfizer's sildenafil patent runs out.

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Pfizer responded by suing Teva for patent infringement, based on a second patent. This patent runs until 2019 and is a so called method-of-treatment patent, meaning that even though sildenafil comes up for grabs in 2012 it would be until 2019 before anyone but Pfizer could market it as an impotence drug.

Patent Should Have Run Out in 2012

During a twelve day trial, between June 15 and July 13, Teva's lawyers argued that the 2019 was invalid and that method of treatment should be inferred in Pfizer's 2012 patent. Under US law a patent cannot be registered if that patent is obvious, meaning that the patent refers to something about an invention which was previously well-known or which is not the result of any new activity. That sildenafil could be used to treat erectile dysfunction, Teva argued , was known and could not warrant a second patent. They also contended that Pfizer "breached their duties of candor and good faith to the [Patent and Trademark Office] with deceptive intent to obtain broad claims to which they knew they were not entitled" by failing to turn over certain documents.

In Pfizer's defence, several of the company's scientists testified to the accidental nature of the discovery of sildenafil's effects on erectile health. The company was studying its use for treating high blood pressure and hypertension at the time.

In the ruling, Judge Rebecca Beach Smith concluded that the patent was not obvious and that "Teva has overstated the level of knowledge concerning erectile function during the relevant time period." She also said that "Teva has not shown by clear and convincing evidence that the patent is invalid."

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"We are pleased," said Pfizer Executive Vice President Amy Shulman, "that the court recognized the validity and enforceability of our Viagra patent for the treatment of erectile dysfunction. Protecting the intellectual property rights of our innovative core is critical, and Friday's court decision acknowledges Teva's clear violation of our patent rights." read more at business wire

Although generic Viagra is already available in New Zealand, where the method of treatment patent expired in June, it looks like most of the world will have to wait eight more years before legal Viagra generics become available.