On 2 June 2006, the Beijing No. 1 Intermediate People Court made the ruling in Pfizer v. the Patent Reexamination Board (PRB) of the State Intellectual Property Office, a case involving the invalidation of the patent for Viagra, and Pfizer is the winner. The China Patent Agent (H.K.) Ltd., representing Pfizer, has participated in the case all the way through the proceedings of application for, and invalidation of the patent in suit to the administrative lawsuit.

The patent for Viagra is the Chinese patent CN94192386.X. After amendments were made to the patent application during the substantive examination proceedings, the claims of the patent, the grant of which was published on 19 September 2001, related to a compound used as medicine orally taken for the treatment and prevention of erectile deficiency (or ED) of male animals, including man.

On the very day on which the grant of the patent was published, Pan Huaping and 12 Chinese pharmaceutical manufacturers and dealers respectively filed a request of their own with the PRB for invalidation of the patent in suit.

On 5 July 2004, the PRB, after examination of the invalidation requests together, made the Invalidation Request Examination Decision No. 6228, declaring the patent invalid on the ground of insufficient disclosure.

Dissatisfied with the Decision, Pfizer brought the administrative action before the Beijing No. 1 Intermediate People Court within the statutory time limit. On 2 June 2006, the collegial panel rendered the ruling of first instance that the facts were wrongly ascertained, and the law erroneously applied in the PRB’s Decision No. 6228; hence the Decision should be cancelled. In the Ruling, the PRB is also required to make another invalidation request examination decision in respect of the invalidation grounds which have not been examined or reviewed.