There has been increasing criticism in recent years of a perceived problem with the European Patent Convention and the British Patents Act. The perception was that, while it was perfectly proper for the Patent Office to refuse the grant of a patent with claims that were overly broad based on the description, there seems to be no provision in the convention or the statute for revocation of a patent after grant on this ground. This was contrasted with provisions in previous acts that had permitted revocation of a patent if the claims were not "fairly based" on the description given in the specification.

The Court of Appeal has now challenged this perception in the case of Biogen v. Medeva. The defendants had challenged the scope of the claims alleging that the specification did not sufficiently describe the invention. However, at first instance it was held that as long as there was sufficient disclosure of a single embodiment falling within the scope of the claim the specification was to be regarded as being "sufficient." The Court of Appeal disagreed and held that disclosure must be commensurate with the scope of the claim in order for it to be "sufficient." Hence, it appears that the Court of Appeal is in fact construing the sufficiency requirement of the European Patent Convention and the 1978 Patent Law to add to it the "fair basis" requirement of previous U.K. Patent Laws in addition to the requirements traditionally required in order to meet the sufficiency test under U.K. Law.

In another reversal of previous case law, the Court of Appeal held that the relevant date for determining this sufficiency of the specification was not, as had previously been held, the date of publication but the date on which the application was filed.

In addition to finding against the patentee on the sufficiency issues, the Court of Appeal also found that the invention claimed was obvious. The claims were for recombinant DNA molecules coding for certain proteins effective as hepatitis B antigens. The claims were drafted in a similar form to those considered in the Genentech case (see our Information Letters N.S. 170 and 174). The court essentially reached the same conclusion as in Genentech, namely, that where one uses known techniques to produce a product that was expected to be a worthwhile target then, in the absence of unexpected difficulties in reaching that target, claims directed to that target molecule would be found to be invalid on the basis of obviousness. This was so even though an EPO Appeal Board had held the claims not to be obvious on the ground that one skilled in the art at the filing date would have had no reasonable expectation of being able to reach the stated target.