His Honour Judge Hacon (sitting in the Patents Court) has handed down judgment in Celltrion Inc. v. Genentech Inc. and Novartis AG [2025] EWHC 174 (Pat). Tom Mitcheson KC and Stuart Baran acted for the successful co-patentees, Novartis and Genentech. The action concerned the validity and infringement of their patent, to a particular formulation of the antibody omalizumab which is the basis of the product Xolair®, a highly successful biologic asthma treatment.

A copy of the judgment is available here. Novartis and Genentech successfully resisted allegations of anticipation, obviousness, lack of technical contribution and added matter. Celltrion’s anticipation case included an allegation of anticipation of an equivalent – i.e. that even if the (novelty-only) prior art citation did not anticipate the claimed invention of the Patent, it anticipated something equivalent to it. The judge found that such an attack was not available in law.

Pursuant to §5A of the Patents Court Guide, and the recent guidance of the Lady Chief Justice, on both sides the junior barristers took an active role in the trial: on each side, leading and junior counsel cross-examined one expert each.

Tom Mitcheson KC and Stuart Baran worked on this case with a team from Bristows LLP, led by partner Rachel Mumby.

(Image created using ChatGPT by OpenAI)