November 8, 2000
Abstracted from AP, CNN, and Reuters News Stories

Pfizer Patent on Viagra Ruled
Invalid in United Kingdom

---LONDON, November 8, 2000. A British court ruled today that a patent of Pfizer Inc---one covering the anti-impotence drug Viagra---was invalid, paving the way for other pharmaceutical companies in Britain to develop drugs that act in the same way.

Patents Court Justice Hugh Laddie upheld a challenge by U.S.-based Lilly Icos which had claimed that Pfizer's monopoly right was stifling the development of competitive products. Justice Laddie’s ruling is available online here. At USRF, this ruling is of great interest because of implications for future development of related products. USRF has been involved with Viagra trials since 1994 and published the first independent trial of the new drug.

The patent dispute, only applying to Britain, centered on how Viagra works in inhibiting a chemical known as PDE-5 in the treatment of impotence. Pfizer's patent for the process expires in 2013. The mechanism of Viagra is explained here.

The court ruled that Pfizer cannot prevent competitors from developing compounds other than Viagra's active ingredient that also inhibit PDE-5. Pfizer said it was "disappointed" and was considering an appeal.

The ruling said the 1993 patent was "invalid for obviousness" because the scientific knowledge on which it was based was already in the public domain. In the light of that, Viagra was not an "unexpected discovery," Laddie said.

Lilly Icos, a joint venture of Indianapolis-based Eli Lilly & Co. and Icos Corp. [NasdaqNM:ICOS - news] of Bothell, Wash., was in the process of producing its own anti-impotence drug that works by inhibiting PD5. Lily Icos, whose financial backers include Microsoft (NasdaqNM:MSFT - news) chairman Bill Gates, feared the patent would stand in its way. Meanwhile, the early research work with the new ICOS drug, known as Cialis, was presented at this year’s national urology meeting.

In the third quarter, Pfizer reported worldwide sales of Viagra were up 36 percent to $332 million, including a 53 percent rise in sales outside the United States to $133 million.