30 August 2017
Case law: Supreme Court reforms the test to determine protection given by a patent
Owners of patents looking out for infringers should review their patent claims to check whether the wording is intended to protect an invention literally as defined in the patent claim, or whether the patent is intended to protect an inventive concept beyond the literal interpretation of the wording used, following a landmark Supreme Court ruling.
Traditionally, when deciding whether a patent has been infringed, the courts have applied a 'purposive' construction to the language used by the owner of the patent in their claim, so that what is protected by the patent is 'what the person skilled in the art would have understood the patentee to be claiming'.
In a landmark ruling, the Supreme Court has now moved away from this approach. It ruled that when considering whether a 'variant' of an invention infringes the patent on that invention, the questions to be answered, from the perspective of a person skilled in the relevant art, are:
- Does the variant infringe any of the claim, as a matter of normal interpretation of the words used in that claim?
- If not, does the variant infringe the patent because it differs from the invention only in an immaterial way (or ways), so that the scope of the protection given by the patent extends beyond the ordinary meaning of its words?
If the answer to either is 'yes', the variant infringes the patent.
The first issue is a matter of interpretation (applying the usual rules of interpretation). The second issue usually depends on the facts and expert evidence, whereas the purposive test conflated the two issues.
When considering whether a variation is immaterial, the Court said that asking the following questions could be a helpful guideline:
- Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, ie it infringes the inventive concept revealed by the patent?
- Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
- Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?
There would be an infringement if the answer to the first two questions was 'yes', and the answer to the third was 'no.
In this case, one side had filed a patent claim in relation to a product, referring to a specific pemetrexed salt used in it. The other side had made a product which contained a similar pemetrexed salt. The patent owner argued that the patent protected against use of any pemetrexed salt by the other side (not just the one specified in the claim), so the other side had infringed its patent. It was the use of a pemetrexed salt generally which was the essence of its patent.
The Court found that 'as a matter of ordinary language' the claim did not extend to the variant. Therefore, on a literal reading of the patent claim, the variant did not infringe the patent. However, the Court found that the variant did achieve substantially the same result as the invention and that it would have been obvious to a person skilled in the art, who had read the patent, that it did so in the same way as the invention covered by the patent.
It also found that a person skilled in the art would not have concluded that the patentee intended that compliance with the literal meaning of the claim was essential to the protection of the invention.
The Supreme Court therefore ruled that the patent had been infringed.
- Owners of patents looking out for infringers should review their patent claims to check whether their wording is intended to protect an invention as specifically defined in the patent claim, or whether the patent is intended to protect an inventive concept, beyond the literal interpretation of the wording used
Case ref: Actavis UK Limited & Ors v Eli Lilly and Company  UKSC 48