Brief History of Viagra and Pfizer's Involvement

Pfizer, a global pharmaceutical corporation, played a pivotal role in the development and distribution of Viagra. Sildenafil, the active ingredient in Viagra, was patented in 1996. The patent application filed by Pfizer was a quick process in comparison to other drugs. In only two years, by 1998, it received FDA approval for use in treating erectile dysfunction, a clinical term for impotence.

The Original Patent: Pfizer's 1994 Patent Application for Sildenafil as Viagra

The groundwork for Pfizer's patent began with the invention of sildenafil, believed to be the work of Peter Dunn and Albert Wood. Pfizer filed a patent for the use of sildenafil, under the brand name Viagra, to treat erectile dysfunction. This groundbreaking development was a significant stride in Pfizer's history, marking their venture into a novel medical solution for a globally prevalent condition.

Viagra's Market Presence: Publication of the Patent and its Duration (2002-2019)

After its patent was approved, Pfizer held exclusive rights to sell Viagra, creating a monopoly in the market for erectile dysfunction treatment. The patented Viagra proved to be a lucrative venture for Pfizer, generating substantial revenues annually. However, as per US patent law, Pfizer's exclusive rights to sell Viagra were valid until 2019.

The Patent Beyond the US: Expiry of Pfizer's Patents on Viagra Outside the US in 2012

While the US market remained under Pfizer's control, the scenario was different outside the US.

Pfizer's patents on Viagra expired in Europe, Japan, and Australia in 2012.

This expiration hinted at what Pfizer would later face in the United States.The end of Pfizer's patent protection led to a decrease in annual revenues from Viagra sales in these regions, from US$472 million to US$146 million between 2012 and 2015.

Generic Drugs Enter the US Market: Pfizer's Settlements with Mylan and Teva in 2017

As the end of the patent's term approached, Pfizer faced litigation from other pharmaceutical companies, eager to introduce their generic versions of sildenafil. Notably, Pfizer settled litigation with Mylan and Teva, allowing them to introduce their generics in the US market on 11 December 2017. Under the settlement, Teva was obligated to pay royalties to Pfizer until 2020.

Patent Battles: Pfizer's 2011 Infringement Case Against Teva Pharmaceutical Industries Ltd in the US

Legal battles were a significant part of Pfizer's journey with Viagra. In 2011, Pfizer won a patent infringement case against the US unit of Teva Pharmaceutical Industries Ltd, preventing Teva from selling a generic version of Viagra in the US. This ruling ensured that Pfizer could maintain its exclusivity in the US market for a few more years.

Legal Challenges in Canada: The 2012 Supreme Court of Canada Ruling and Teva's Appeal

Meanwhile, Pfizer faced challenges in Canada. In 2012, the Supreme Court of Canada upheld an appeal by Israel's Teva Pharmaceutical, ruling that Pfizer's original patent application was incomplete. This ruling allowed Teva to sell a generic version of Viagra in Canada, breaching Pfizer's erstwhile monopoly.

Ongoing Litigations: Pfizer's 2013 Litigation Against Teva Pharmaceuticals, USA Inc.

In addition to previous litigation, Pfizer also faced ongoing legal proceedings. In 2013, Pfizer announced that it had settled its litigation against Teva Pharmaceuticals, USA Inc., in relation to the Viagra patent. This settlement was part of Pfizer's consistent efforts to protect its patent covering the use of Viagra.

Patent Expiration in the UK: End of Pfizer's Patent Protection in 2013 and Emergence of Generic Versions

The UK saw a similar progression with Pfizer's patent for Viagra. By 21 June 2013, Pfizer's patent protection in the UK had expired, permitting rival companies to sell generic versions of the drug under its chemical name, sildenafil. This development marked another region where Pfizer's exclusive control over Viagra had ended.

Final Rulings on the Patent: The 2020 US Court Decision Upholding Pfizer's Patent Until 2019

Despite various legal battles, Pfizer was able to maintain its patent in the US until 2019. A US court ruling in 2020 confirmed that Pfizer's patent for Viagra was valid until 2019, effectively halting any other companies from manufacturing unbranded versions of the drug until after this date.

The Current Status of Viagra's Patent and its Impact on the Pharmaceutical Market

The journey of Viagra's patent was characterized by significant market control by Pfizer, followed by a wave of generic versions after patent expirations. While Pfizer managed to extend its exclusive rights until 2020 through various settlements and legal battles, the market for erectile dysfunction treatment has since become more diverse. The patent journey of Viagra has had profound implications for the pharmaceutical market and the treatment of erectile dysfunction worldwide.