Michael Tappin QC, James Whyte and William Duncan appeared at the trial of this claim by Regeneron for infringement of its patent by Kymab’s antibody-producing transgenic mice. The subject-matter was described by the judge, Henry Carr J, as being of great technical complexity. In essence, the patent related to transgenic mice in which variable regions of the endogenous immunoglobulin gene loci had been subject to “in situ replacement” by human variable region gene loci, but in which the murine constant regions were retained, so that hybrid antibodies were produced.
Henry Carr J held that Kymab’s mice would have infringed the patent, had it been valid, but that it was invalid for insufficiency. He held that the central aspect of the patent’s disclosure, namely the replacement of the whole of the murine variable region gene loci with human variable region gene loci, could not have been performed at the priority date without undue burden and invention.
Michael Tappin QC and James Whyte appeared for Kymab, instructed by Powell Gilbert LLP
William Duncan appeared as junior counsel for Regeneron, instructed by Allen & Overy LLP