Biogen Inc v. Medeva Plc

The House of Lords dismissed Biogen's appeal and held that the earlier UK patent application ("Biogen 1") did not support the broad claims of the European patent. The central legal principles were:

• For priority under section 5(2)(a) Patents Act 1977 an earlier application must contain an enabling disclosure capable of performing the claimed invention.
• Sufficiency/enablement is a common concept underlying section 5(2)(a), section 14(3) and the ground for revocation in section 72(1)(c).
• Claims must not be broader than the technical contribution disclosed; a patentee cannot claim all possible ways of achieving a result when the specification teaches only one method and other methods exist which do not rely on that teaching.
• The proper date for testing sufficiency in revocation is the date of filing (not later developments), so subsequent advances in the art cannot cure an originally insufficient or non-enabling disclosure.

Applying these principles, the House accepted the trial judge's findings that Professor Murray had made HBV antigens using recombinant DNA methods but held that Biogen 1 taught only a particular approach (working with unsequenced genomic fragments and certain restriction-enzyme choices). That teaching did not support a claim to every recombinant method of producing the antigens, so Biogen was not entitled to the earlier priority date; the patent was therefore obvious at the later filing date and invalid.

Background and parties: Biogen Inc. (appellants) sued Medeva plc (respondents) for infringement of a European patent claiming recombinant DNA molecules and polypeptides that display hepatitis B virus (HBV) antigen specificity. The patent traced priority to an earlier UK application filed 22 December 1978 ("Biogen 1"). Medeva counterclaimed for revocation, alleging lack of inventive step, lack of entitlement to the priority date, absence of an "invention" and insufficiency.

Procedural history: At first instance Aldous J. held the patent valid, entitled to the priority of Biogen 1 and infringed. The Court of Appeal allowed Medeva's appeal and held Biogen 1 did not support the claimed invention and that the invention was obvious at the earlier date. Biogen appealed to the House of Lords.

Nature of the claim and issues: The principal claim was to a recombinant DNA molecule characterised by a DNA sequence coding for a polypeptide (or fragment) displaying HBV antigen specificity, operatively linked to an expression control sequence and expressed in a suitable host. Key issues were:(i) whether Biogen 1 provided an enabling disclosure supporting those claims for priority under section 5(2)(a); (ii) whether the claimed subject-matter involved an inventive step as at the priority date; and (iii) whether the specification was sufficient under section 72(1)(c), including the correct date for testing sufficiency.

Court's reasoning:

• The Lords analysed the state of the art in 1978 on HBV genetics and recombinant DNA techniques. They accepted Aldous J.'s finding that Professor Murray had succeeded in expressing HBV antigens in bacterial cells by working with large genomic fragments and pBR322 vectors, and accepted that this was not obviously achievable to all skilled persons at that date.
• However, Biogen 1 disclosed and enabled a particular method for achieving the result (expressing unsequenced eukaryotic DNA in a prokaryotic host by choosing restriction enzymes to produce large fragments and ligating into plasmid vectors). The patent, by contrast, claimed any recombinant DNA molecule or any method of producing the antigens.
• The House applied established principles about enabling disclosure and claim scope: where a specification teaches only a particular route, it cannot support monopoly claims covering other routes that owe nothing to the disclosed teaching. Biogen's technical contribution did not establish a general principle that compelled later workers to use the same method.
• Accordingly, Biogen 1 did not "support" the broad claims of the European patent for priority purposes. Without the earlier priority the claimed invention was obvious at the European filing date and therefore invalid. The Lords further held that the proper date for testing sufficiency under section 72(1)(c) is the date of filing, so later advances cannot cure an insufficient filing.

Wider context: The decision emphasises limits on claim breadth where the patentee's contribution is a single method rather than a general principle and clarifies the relationship between priority/support, enablement under section 14 and revocation under section 72(1)(c).

Appeal dismissed. The House held that Biogen 1 did not contain an enabling disclosure supporting the breadth of the European patent claims (so Biogen could not rely on the earlier priority date). Without that priority the claimed invention was obvious at the filing date and invalid. The Court also held that sufficiency for revocation must be tested as at the date of filing and that claims cannot monopolise all methods of achieving a result when the specification teaches only one method.

First instance: Aldous J. held the patent valid, Biogen entitled to priority from Biogen 1 and patent infringed. European Patent granted 11 July 1990; EPO opposition proceedings dismissed on appeal 28 July 1994. Court of Appeal allowed Medeva's appeal (3 November 1994) reversing Aldous J. and holding Biogen 1 did not support the claimed invention and that the invention was obvious at the earlier date. House of Lords appeal dismissed (31 October 1996).