23 October 2020

Regeneron v Kymab: Transgenic mice claims found insufficient

In this article, which was published in Volume 12, Issue 13 of the International Pharmaceutical Industry (IPI) Journal, Mathys & Squire Partner Martin MacLean demonstrates how, following the case of Regeneron v Kymab, transgenic mice claims have been found insufficient by the Court of Appeal.

The Supreme Court judgment (24 June 2020) sends a clear “no” Brexit message to any big pharma contemplating corporate muscle-flexing of excessively broad patent claims. This ruling overturned the position held by the Court of Appeal that, for patents relating to “a principle of general application”, there was no requirement to teach how to make the full range of claimed products. In this regard, the Court of Appeal held that Regeneron’s contribution to the field extended beyond the products (transgenic mice) that could be made back in 2001, and instead related to the general principle of providing ‘better’ mice (thereby overcoming a prior art immuno-sickness problem inherent to mice transfected with human DNA). With hindsight, the Court of Appeal allowed too much weight to be given to the relative contribution the ‘better’ mice aspect provided in producing a(ny) mouse having commercial utility. In sum, the Supreme Court considered the Court of Appeal had incorrectly watered down the “sufficiency of disclosure” requirement of patent law and, in doing so, this judgment maintains a sensible balance between patent law enforceability and invalidity and provides guidance on what might constitute a ‘principle of general application’ for which broad claim scope might be held valid.

Click here to read the article in full. This provides an update to the original version, which was published in June 2020.