PhotoCure v Queens University: Implications for Patent Law

by Clare Cunliffe

A recent Federal Court decision by Justice Merkel, in relation to the validity and alleged infringement of Queens University's patent for the treatment of skin cancer and other skin lesions by photodynamic therapy, has implications for Australian patent law.

Factual Background

Queens University at Kingston (Queen's University) held a patent for an invention for the treatment of skin cancer and other skin lesions by photodynamic therapy(the Patent), using a compound (ALA) which could be topically applied and had a selective effect. ALA induces production of a photosensitiser (PpIX) in cells to be treated. The creation of PpIX enables the detection/ destruction of abnormal cells. Both ALA and PpIX occur naturally in human cells as one step in a series of reactions leading to the creation of heme (the pathway to heme). Queens University assigned the Patent to DUSA Pharmaceuticals, Inc (DUSA).

PhotoCure ASA (PhotoCure) applied for the revocation of the Patent. PhotoCure claimed that the Patent was invalid on a variety of grounds including lack of novelty and not involving an inventive step.

DUSA cross claimed against PhotoCure and PhotoCure's exclusive licensee. DUSA alleged that the exploitation and supply of PhotoCure's product Metvix in Australia and the use of Metvix in Metvix Photodynamic Therapy (Metvix PDT) infringed the Patent.

Metvix PDT is a method of treating basal cell carcinoma and actinic keratoses. The method requires the topical application of Metvix, which contains methyl-ALA, the methyl ester of ALA. Like ALA, Methyl-ALA induces the production of PpIX. Unlike ALA, however, methyl-ALA does not occur naturally in the pathway to heme.

Validity

Justice Merkel concluded that the patent was valid. In reaching this conclusion, Justice Merkel made some comments which are of interest to patentees and patent lawyers.

Lack of Inventive Step
  • The Court's determination of who is the skilled addressee to whom the patent is addressed is vitally important in considering expert evidence. Unless the Court accepts that an expert's knowledge coincides with that of the skilled addressee, the expert evidence may not be taken into account.

  • Justice Merkel found that the state of common general knowledge in Australia did not differ materially to the level of common general knowledge internationally. It may therefore be appropriate to use overseas based expert witnesses where the relevant field is an international one.
Lack of Novelty

Justice Merkel's findings on novelty emphasise that:
  • the Court will construe claims from the perspective of the skilled addressee, even if this requires the Court to find additional integers of the invention are implied;

  • a prior art disclosure which teaches away from the invention will not amount to an anticipation; and

  • prior art which discloses an invention in terms so broad as to be unclear and imprecise will not amount to an anticipation.
Lack of Sufficiency
  • Sufficiency

    Where a patent gives sufficient information to work the invention without the need to make new inventions, additions or prolonged study, the disclosure in the patent will be sufficient, notwithstanding that standard testing might be required to finetune the invention and that some of the claimed embodiments might not work.


  • Best method

    To succeed on this basis, an applicant for revocation must demonstrate that the patentee was aware of but did not disclose the best method of performing the invention.

  • Lack of Definition

    Invalidity on this basis will only arise if the claims of a patent are incapable of resolution by a skilled addressee by the application of common sense and common knowledge.

    Lack of Fair Basis

    Patent claims may be fairly based on the description notwithstanding the fact that the examples in the patent do not disclose the subject matter claimed, as long as the specification as a whole describes the claimed invention in at least as much detail as the claims. A claim may be fairly based notwithstanding that there is no express disclosure in the specification, provided that there is an 'oblique' disclosure.

    Infringement

    Justice Merkel concluded that the patent was not infringed by Metvix. In reaching this conclusion, Justice Merkel made the following interesting observations.

    Commercial Use

    Justice Merkel's judgment indicates that pre-commercial activity might constitute an infringement where 'there can be little doubt that commercial exploitation is intended as soon as all of the necessary regulatory approvals have been obtained.'

    Tests of infringement

    Justice Merkel considered whether:
    • Metvix and Metvix PDT fell within the literal meaning of the Patent; and

    • Metvix and Metvix PDT fell within the substance of the Patent.
    Literal Test

    Justice Merkel's judgment applied well established principles of patent construction:
    • patents will be construed from the position of the notional skilled addressee;

    • terms used must be given their technical meaning if such meaning exists, or else their ordinary meaning;

    • expert evidence may be used to assist in ascertaining a term's meaning, although ultimately issues of construction are for the Court; and

    • terminology is construed in the light of the manner in which the terminology is used in the specification.
    On the basis of his application of these principles, Justice Merkel concluded that the use of Met-ALA in Metvix PDT did not literally infringe the patent, which related to ALA.

    Infringement in Substance

    Justice Merkel resolved a long standing debate as to the rules that should be applied in determining whether a product or method infringes a Patent in substance. Justice Merkel held that the three limb test set out in the English decision of Improver Corporation v Remington Consumer Products Limited [1990] FSR 181 (Improver) applies in Australia, albeit as a helpful guideline rather than a rule of construction. The test is as follows:
    • does the variant have a material effect on the way the invention works? If yes, the variant is outside the claim. If no -

    • would the fact that the variant had no material effect have been apparent to a skilled reader at the publication date of the patent? If no, the variant it outside the patent. If yes -

    • would the reader skilled in the art would have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning of the claim was an essential requirement of the invention?

    • Applying this test, Justice Merkel concluded that DUSA failed to make out a case of substantive infringement.


    • Conclusion

      By way of summary, Justice Merkel's judgment in PhotoCure stands as a timely clarification of the following patent law issues:
      • parties to patent litigation should take care in constructing expert evidence to ensure the profile of the expert is consistent with that of the skilled addressee;

      • it may be appropriate to use overseas expert witnesses where the relevant field is an international one;

      • disclosures which suggest an invention will be ineffective will not amount to an anticipation;

      • the Court will use well known rules of construction when determining literal infringement; and

      • the three limb test set out in the Improver decision may be applied in Australia to determine infringement in substance.



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