Allowability of Patent Claim Amendments After Trial


Following the earlier decision of Arnold J to find European Patent (UK) No. 0934061 patent invalid in Generics (UK) Limited v Warner-Lambert ([2015] EWHC 2548), Warner Lambert made a conditional application to amend the patent.  This decision considered whether such an application should be allowed.

Both Mylan and Actavis on the one hand and Warner-Lambert on the other were given permission to appeal the decisions of the earlier judgment in relation to insufficiency. In the meantime, Warner-Lambert made a conditional application to amend the patent.

Some proposed amendments amounted to the deletion of claims found invalid. These amendments were uncontroversial. However, Warner-Lambert also sought to amend claim 3 as granted, which was directed to the use of pregabalin for treating neuropathic pain, by adding “caused by injury or infection of the peripheral sensory nerves.

Mylan and Actavis both opposed this amendment. Mylan and Actavis both contended that the application amounted to an abuse of process and if the application was allowed to proceed, it would not be allowable on the grounds that it lacked clarity, added subject matter and did not cure the invalidity of claim 3.

This judgment is in relation to the issue of whether the application amounted to an abuse of process.

Arnold J summarised the issue of abuse of process in general and its specific application to patent cases, referring in particular to Nokia v IPCom [2011] EWCA Civ 6. Warner-Lambert made specific reference to Article 138 of the European Patent Convention as well as decision of both the Supreme Court of the Netherlands and the Bordeaux Cour d’Appel. The judge found that none of these were relevant in relation to this case.

Both sides relied on the procedural history prior to the first instance hearing. However, Arnold J noted that the parties’ interpretations of that history differed. Accordingly, the judge set out the procedural history in detail.

Mylan and Actavis contended that the application to amend claim 3 was an abuse of process because not only could the application have been made before trial, it should have been made before trial, and now a second trial would be required if the application to amend was allowed to proceed. Warner-Lambert disputed that a second trial was required, contending that the application could be decided on the basis of the findings of the previous judgment. Although Warner-Lambert accepted that a second hearing would be necessary to determine the issues raised by Mylan and Actavis, as no expert evidence or cross-examination would be required, it would not amount to a second trial.

In addition, Warner-Lambert argued that, in any event, the application did not represent an abuse of process because it was the victim of procedural unfairness as Mylan and Actavis had not raised the point about central neuropathic pain, namely that central neuropathic pain differed from peripheral neuropathic pain and did not relate to central sensitisation, until late in the proceedings.

Arnold J first considered whether a second trial would be required. He concluded that the insufficiency objection could not be fairly determined without giving Mylan and Actavis the opportunity to adduce evidence as to whether the claim was plausible just for peripheral neuropathic pain rather than any neuropathic pain. However, he considered that the amendment application would not necessarily necessitate a second trial on infringement.

The judge then moved on to consider whether Warner-Lambert had been the victim of procedural unfairness. The judge noted a number of points during the proceedings where Warner-Lambert should have been aware before the trial of the need to make a conditional application to amend claim 3. Therefore, he did not accept Warner-Lambert’s submission on this point.

Arnold J also considered that the risk that the amendment application could delay the overall resolution and also the risk to wider public interest of allowing the application were minor additional factors in favour of refusal of the application.

Therefore, the judge concluded that, on balance, the application to amend claim 3 was an abuse of process because it could and should have been made prior to trial. Therefore, he struck out the application for amendment of claim 3 by Warner-Lambert.

[2015] EWHC 3370 (Pat)

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