특허명세서 용이실시(enablement) 요건 : 캐나다 대법원 비아그라 사건

The patent specification must enable a skilled person to utilize the claimed invention. In determining whether a specification complies with the enablement requirement, the court normally first specifies the invention and then second decides whether the invention can be easily carried out by a skilled person. In the relevant Canadian patent, which claims a new use of sildenafil for erectile dysfunction, whose commercial version being Pfizer’s “Viagra”, the specification discloses many other compositions, one of which is sildenafil. Traditionally, in determining compliance of enablement requirement of a specification, the determination starts from the invention. Under such an approach, claim 7, which claims sildenafil is being enabled by the specification. However, because of many other compositions disclosed in the specification and claimed in claims 1 to 6, it could require extra experimentations to recognize the only effective composition, sildenafil. The Canadian Supreme Court, disregarding the traditional approach, pointed the quid pro quo of patent system, under which an applicant discloses his invention and then in return he receives patent right, and interpreted that Pfizer’s specification is hiding only one real invention behind many non-inventions. To penalize this kind of gaming, the Court revoked the patent as a whole, relying on the enablement requirement. This case highlights the necessity to delete unnecessary items from the specification, and to set claim scope in compliance with the invention itself.