Knowledge & News

Supreme Court Decision: Regeneron v Kymab

29 June 2020

The Supreme Court has handed down judgment in Regeneron v Kymab, the latest instalment in a long-running global patent dispute between US biotechnology behemoth Regeneron, and the UK-based (and Gates Foundation, Wellcome Trust, and LifeArc-backed) company Kymab.
The dispute concerns patents to transgenic mice that have been genetically engineered to produce human, rather than mouse, antibodies. These transgenic animals can be used to develop new and improved antibody therapeutics that do not provoke adverse immune responses when administered to humans.
The UK arm of the dispute concerns two Regeneron patents to mice containing human antibody genes which have been inserted into the murine genome in a particular way (referred to as a “reverse chimeric locus”). Use of a reverse chimeric locus is said by Regeneron to improve the level of the mouse’s antibody response as compared to transgenic mice that had previously been used in the field. However, at the time Regeneron’s patents were applied for, only a tiny subset of the full repertoire of human antibody genes could successfully be introduced into a reverse chimeric locus, meaning that Regeneron’s mice could produce some, but not all, human antibodies. Regeneron alleged that transgenic mice developed by Kymab infringed its patents, notwithstanding that Kymab’s mice could only be produced as a result of improvements in biotechnological methods that post-dated the Regeneron patents and which enabled the full repertoire of human antibody genes to be inserted into the mice.
In 2016 the High Court had held that Regeneron’s patents were invalid as they sought to monopolise more than they contributed to the field – it was only later technological developments that allowed mice like Kymab’s to be produced. In 2018 the Court of Appeal reversed that decision, holding that the reverse chimeric locus was a “principle of general application” and that Kymab’s mice (which did contain a reverse chimeric locus) therefore infringed the patents, even though they contained far more human genetic material than could be transferred using the technology disclosed by Regeneron.
The Supreme Court has now reversed the Court of Appeal decision and upheld the original finding that the patents are invalid, re-affirming the central tenet of the patent system that a patentee isn’t entitled to monopolise more than it has contributed to the field. This is a very important decision for Kymab, whose business is founded upon the allegedly infringing mice, and also for those companies with which it has partnered with to produce new candidate drugs which might otherwise have been said to also infringe the patents. However, the Supreme Court’s reasoning that, in order to be sufficient, a product claim which covers a range of variants (where the variable significantly affects the value or utility of the product in achieving its purpose) must enable all such variants to be made, has potentially significant consequences for the patent system as a whole. Patents commonly claim products that are improved in one particular aspect, but which may also utilise other, later, inventions that contribute in a meaningful way to the product’s utility. If the courts now apply the Supreme Court’s reasoning so as to render earlier claims invalid on the basis of such ‘inventive infringements’ it will represent a significant departure from the previously settled position.
See the full judgment here.


Trevor Crosse

Trevor Crosse Partner London (UK) Solicitor (UK)

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