update #2 - Regeneron to appeal

Of mice and mAbs: EPO revokes Regeneron patent after Kymab and Novo appeal

By Gareth Macdonald

- Last updated on GMT

Babraham Research Campus in Cambridge, UK. Home to Kymab
Babraham Research Campus in Cambridge, UK. Home to Kymab

Related tags Regeneron Novo nordisk Monoclonal antibodies

European authorities have revoked a Regeneron patent covering a genetic modification technique used to generate mouse monoclonal antibody (mAb) production platforms after an appeal by several European firms.

The patent​ – which remains in force to allow Regeneron to appeal – covers techniques used to replace genes encoding mouse antibody variable regions with human variable regions in animals used to generate candidate mAbs by drug developers. 

The European Patent Office (EPO) revoked the patent because it lacked the inventive step needed under article 56 of the European patent convention​ in a decision cautiously welcomed by Christian Grøndahl, CEO of UK-based antibody platform developer Kymab.

Whilst the revocation by the EPO Opposition Division is a clear public signal judging Regeneron’s mouse invention to be unpatentable, we do acknowledge that this can and likely will be appealed​,” he told BioPharma-Reporter.com.

This was confirmed by the EPO which told us Regeneron can challenge the ruling by filing an appeal within three months of the decision being published.

He explained that if Regeneron do appeal “the case will go to a Technical Board of Appeal who will review the ruling of the OD in the light of objections made by Regeneron in their writ provided they are taking their case further, which we don’t know at this stage.

The patent stays valid as granted until the Board of Appeal has reached its decision, which is a final one. However, should there be no appeal, the decision reached by the OD would enter into force with the publication of the decision of the OD​.”

Industry impact

If any Regeneron appeal is unsuccessful the implications for Kymab, its fellow appellants Novo Nordisk A/S and Merus BV, and the wider European mAb development sector are significant according to Grøndahl.

Total loss of the patent at that stage would indeed be a very significant development for third parties operating transgenic human-mouse antibody platforms in Europe​” he said.

A spokesman for Novo nordisk echoed the importance of a potential total loss, explaining that: "Kymab and Merus initiated the opposition proceedings against Regeneron’s patent in June 2013".

He added that: "Novo Nordisk joined the opposition in April, after Regeneron sued NNAS in the UK based on this patent in January. We believe that the patent is invalid​."

Mouse, mAb melee 

Developers of mouse mAb production platforms have been jockeying for position for the past few years​, with Sanofi, Regeneron and Kymab's Babraham Institute neighbour Crescendo Biologics​ being among the leading players.

Kymab’s own “extensive” collection of mouse modification patents do not expire until 2034 Grøndahl said, adding that: “freedom-to-operate for players in this field would need to navigate that [portfolio] still​.”

The firm’s key product is the Kymouse platform, which is used in its own mAb development programmes and by Novo Nordisk under a licence agreement signed in 2013.

Grøndahl also predicted that revocation of the patent would be good for Kymab, explaining that: “This unanimous ruling of the EPO is an important reading of Regeneron’s European patent that provides a significant and independent signal to our current and potential business partners, investors and scientific collaborators going forwards​.”


A Regeneron spokesman told us "Regeneron will appeal the decision. Pending the appeal, Regeneron will continue its lawsuits against Kymab and Novo Nordisk in the UK and against Merus in the Netherlands based on the national patents in those countries.​"

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