IP Cases & Articles

Post-Published Evidence - Generics v Yeda and Teva

Back in July 2013, the Court of Appeal handed down its decision in Generics [UK] Limited v Yeda Research & Development Co Ltd & Teva Pharmaceuticals Industries Ltd [2013] EWCA Civ 925. This was an important decision for the admissibility of evidence published after the priority date of the patent (post-published evidence).

The decision concerned Yeda’s patent (EP(UK) 0762888) for an improved composition of a synthetic copolymer known as copolymer-1. Copolymer-1 is a mixture of polypeptides composed of alanine, glutamic acid, lysine and tyrosine in a molar ratio of approximately 6:2:5:1, and is marketed by Teva as exclusive licensee of Yeda’s patent, for the treatment of relapsing-remitting multiple sclerosis. Claim 1 of the patent concerns:

A copolymer-1 fraction, wherein said fraction contains less than 5% of species of copolymer-1 having a molecular weight over 40 kilodaltons and wherein over 75% of said fraction is within a molecular weight range from 2 kilodaltons to 20 kilodaltons.

According to the examples of the patent, the claimed lower molecular weight copolymer-1 material is better than the known copolymer-1 in terms of toxicity and allergy or hypersensitivity reactions.

At first instance, the judge (Arnold J) refused the requests of Generics (who trade as Mylan) for revocation and a declaration of non-infringement in respect of their product. On appeal, Mylan argued that Yeda’s patent was invalid for obviousness on the basis of a lack of technical contribution. They alleged that the specification did not make it ‘plausible’ that the described technical problem was solved by the products falling within the claims.

Although there is nothing in the statute (the European Patents Convention or the UK Patents Act 1977) which dictates that ‘lack of technical contribution’ is a ground for invalidity, the European Patent Office’s (EPO’s) problem and solution assessment for inventive step necessarily isolates a technical contribution or effect from the claimed invention.

The patent is compared to the closest prior art and any technical effect associated with the difference(s) is determined, ie, a technical contribution is identified. This technical contribution is then used to formulate the objective technical problem solved by the claimed invention over the closest prior art. It is also established EPO case law that the technical contribution must be shared by everything falling within the claim (see T939/92 – the AgrEvo case [1996] EPOR 171).

After reviewing the EPO’s problem and solution approach and T939/92, Arnold J concluded that post-published evidence may be relied on to confirm that:

  • the disclosure in the patent does or does not make it plausible that the invention solves the technical problem;

But that such evidence may not be relied upon to:

  • establish a technical effect which is not made plausible by the specification; or
  • to contradict a technical effect which is made plausible.

Arnold J therefore held that if the patent made a technical effect ‘plausible‘ it was not open to Mylan to mount a challenge to the existence of that effect by the use of post-published evidence.

The Court of Appeal disagreed.

The Court of Appeal ruled that post-published evidence showing that the claimed invention does not in fact result in a particular technical effect will be admissible, provided that one of the issues to be decided for inventive step is whether the technical contribution has been made.

A party may therefore challenge the existence of a technical effect relied on by the patentee with post-published evidence.

This decision was primarily based on the principle that the extent of the patent monopoly should correspond to and be justified by the technical contribution to the art. The Court of Appeal noted that the problem and solution approach to obviousness requires the court to judge inventiveness by reference to what it is that the invention brings with it.

The technical contribution of the claimed invention in Yeda's patent was defined as “the proposition that copolymer-1 as claimed caused less irritation at the injection site and/or a reduced incidence of systemic side effects.”

Although the examples did not strictly support the molecular weight ranges cited in claim 1, Arnold J held that the general trend shown made it ‘plausible‘ that the claimed copolymer-1 was superior to copolymer-1 falling outside the claim, and hence that the invention provided a technical contribution.

The Court of Appeal agreed with this conclusion and upheld Arnold J’s refusal of Mylan’s request for revocation and a declaration of non-infringement.

Thus whilst the Court of Appeal’s divergence over the admissibility of post-published evidence did not affect the overall decision, it highlights an important point of law which has a general application to all patents.

Furthermore, the court’s consideration of the EPO’s problem and solution approach and T939/92 shows how the requirement for a patent to have a ‘plausible technical contribution‘ is a development in line with European practice.

Useful links

The full decision (Generics v Yeda and Teva)

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