Regeneron patent law case comes before UK Supreme Court

The case before the court involves life sciences companies Regeneron and Kymab. The companies are in dispute over the validity of patents owned by Regeneron. In any event the Supreme Court determines the patents are valid, the Court of Appeal has held that Kymab has infringed Regeneron's patent rights.

The hearings before the Supreme Court, scheduled for 11 and 12 February, are concerned with the concept of 'sufficiency' under UK patent law.

The concept is derived from section 72(1)(c) of the Patents Act 1977, which states that a patent is liable to be revoked if "the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art". The relevant date for assessing a patent's sufficiency is the time the patent application was filed.

Courts in the UK have previously considered the concept of sufficiency, with judges outlining three types of insufficiency – classical insufficiency; ambiguity, and excessive claim breadth.

'Classical insufficiency' is where the specification of the patent does not enable a person skilled in the art to perform the claimed invention without undue burden.

'Ambiguity' is where, after performing the invention in line with the specification, you cannot tell whether it has worked or not.

'Excessive claim breadth', also referred to as "Biogen insufficiency", is where performing the specification leads to the claimed invention working across some but not all of the scope of the claims made in the patent.

However, in a previous case, the Court of Appeal said the question of whether the requirements of sufficiency are met really boils down to whether the skilled person can readily perform the invention over the whole area claimed without undue burden and without needing inventive skill.

The Supreme Court is likely to look at whether the law of sufficiency requires patent claims to work as stated in the specification or whether it is enough that the specification will lead the skilled person to do what is claimed in another way.

The court is also expected to consider whether the requirements of sufficiency can be said to be met if a skilled person were to use common general knowledge to effectively fix deficiencies in the patent specification and thereby perform the patent claims in instances where performing the claim based on the specification alone does not work.

The patents at issue in the Regeneron and Kymab case concern the production of human antibodies using transgenic mice. The two patents describe a technique for making such antibodies for treating human disease. Regeneron has claimed that the various strains of transgenic mice produced by Kymab infringe its patents. Kymab has denied infringement and has counterclaimed for revocation of Regeneron's patents.

Regeneron lost the first round of the legal battle before the High Court in London in 2016. The court held that Regeneron's patents were invalid, with Mr Justice Carr determining that all of the claims of the patents failed to meet the requirements for sufficiency "on the basis that, at the priority date, the skilled person would not have been able to perform the invention over the whole area claimed without undue burden and without needing inventive skill". The judge said, though, that had the patents been valid, Kymab would have liable for patent infringement.

Both companies raised appeals against the High Court's ruling, and hearings took place before the Court of Appeal in October 2017. In March 2018, the Court of Appeal overturned the High Court's findings that Regeneron's patents were invalid.

"We are satisfied that the specifications of the patents do disclose the claimed inventions clearly enough and completely enough for them to be performed by a person skilled in the art," the Court of Appeal judgment said.

The Court of Appeal dismissed Kymab's challenge against the High Court's findings of infringement.

Kymab won the right to appeal the Court of Appeal's sufficiency findings before the Supreme Court, which will now consider the case.