LONDON - Last week the UK Court of Appeal delivered its much-awaited judgement in the UK round of the multi-jurisdictional patent dispute between Amgen and Transkaryotic Therapeutics/Hoechst Marrion Roussel.
Broadly, the decision confirms that the UK Courts will uphold meritorious patents for DNA sequences, permitting broad claims where the invention is one of general application.
However, new technologies that did not exist at the time a patent has been filed, and that would not have been expected to work at that date, will not be covered by the earlier patent.
It is expected that Amgen may seek leave to appeal the decision on infringement to the UK's highest court, the House of Lords.
In the meantime the parallel US litigation between Amgen and TKT continues. The case was recently argued on appeal and the decision is awaited with interest.
Validity-insufficiency
At first instance in the UK High Court, TKT and Roche were found to infringe the Amgen erythropoietin gene patent. Roche and Amgen settled their differences after the High Court decision. TKT appealed the finding of infringement and validity of the Amgen patent. Although TKT was not found to infringe the patent, holders of gene-sequence patents will revel in the Court of Appeal's finding that the patent was valid.
As with may challenges to gene-sequence patents, the main ground of attack was that the patent was insufficient in that it did not enable the invention to be worked across the scope of its claims. The patent was not challenged on the ground of obviousness, or a lack of inventive steps. As a result it made it easier for the UK courts, at first instance and on appeal, to hold that the patent had in fact related to a principle of general application that accordingly deserved broad claims. The main rulings of the Court of Appeal in relation to insufficiency were:
--A patent will not be insufficient merely because it covers inventive improvements;
--Amgen's epo patent disclosed a principle capable of general application and therefore was entitled to claims in correspondingly broad terms;
--The fact that the claims covered a large number of analogues, some of which might not "work," will only lead to insufficiency if there is evidence to prove that specific examples do not, in fact, work. TKT did not submit such evidence;
--Sufficiency must be judged at the date of the application for the patent, any functional parameters to the claims must be tested using the methods available at that date. If those parameters can be tested in a number of ways, one of which will not work, will not prove fatal because the court will look at practicalities rather than "puzzles at the edge of the claims" dreamt up by lawyers; and
--Lack of clarity of the claims is not a valid objection in patent-revocation proceedings, even if "dressed-up" as an insufficiency allegation.
Infringement
TKT uses a method of gene activation in which a cell's endogenous DNA encoding epo is switched on. The methods claimed by the Amgen patent were held to be limited to exogenous, or isolated, DNA sequences. So:
--The TKT technology involves the use of endogenous DNA that does not literally infringe claims limited to the isolated DNA sequence for epo (a claim to endogenous DNA would not be patentable since it would not be novel over the native gene for epo).
--On the issue of non-literal, or purposive, infringement, the Court of Appeal found that the TKT technology had a material effect on the way in which the invention worked and therefore was not an infringing "equivalent." Following that finding, Amgen could not succeed with its argument of purposive infringement. Nevertheless, the court still went on to consider the further limbs of the so called "Protocol questions" that are applied by the courts in relation to purposive infringement.
The second element of the test asks: 'If the variant does not work in a different way from the claimed invention, would that fact have been obvious to a person skilled in the art at the priority date?' The question sought to know whether the person skilled in the art should be deemed to have been told that the variant does in fact work. The answer was no. It is now clear that if the skilled person would have expected that the variant would not work--for example because it was developed after the priority date--the second element of the protocol questions test should be answered in the negative with the consequence that the patent will not be infringed.
Penny Gilbert is a partner and Alex Wilson is a senior assistant in the BioPharma Group of the UK law firm Bristows.
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