The article was first published in EPLAW Patent Blog, December 2015

Generics (UK) Limited trading as Mylan v Warner-Lambert Company LLC, High Court of England and Wales (Arnold J), London, UK, 25 November 2015, Neutral Citation Number: [2015] EWHC 3370 (Pat)

Arnold J has struck out Warner-Lambert’s conditional application to amend a patent held invalid at first instance, and which was subject to ongoing appeal proceedings. This is because the application amounted to an abuse of process. Arnold J held that if the amendment application had been allowed to proceed, the validity of the amended claim could not have been determined without a second trial. Warner-Lambert could and should have made the conditional application before the first instance trial. Bringing the application after the event amounted to unjust harassment of the counterparties, Mylan and Actavis.

Background

In an earlier judgment handed down on 10 September 2015, Arnold J found Warner-Lambert’s patent for the use of pregabalin in the treatment of inter alia neuropathic pain partly invalid for insufficiency, and in any event not infringed. Central to Arnold J’s decision was the rejection of Warner-Lambert’s narrow construction of “neuropathic pain” as being limited to peripheral neuropathic pain. Having held that “neuropathic pain” covered both peripheral and central neuropathic pain, Arnold J held that while the patent disclosed pregabalin as a plausible treatment for the former, there was not enough data credibly to support the claim to the latter. As such, the claim directed to neuropathic pain as a whole was insufficient.

Both Actavis and Mylan on the one hand, and Warner-Lambert on the other, were granted permission to appeal. Warner-Lambert subsequently made a conditional application to amend the patent (i.e. Warner-Lambert still contend that the granted claims are valid, but applied for the amendment to be made only in the event that the granted claims are held to be invalid on appeal). It is the application to amend that is the subject of this latest judgment of Arnold J.

The application to amend

The proposed amendments included the deletion of those claims found to be invalid and the rewriting of the claim to neuropathic pain such that it was limited to peripheral neuropathic pain. Mylan and Actavis both opposed the “rewriting” amendment. They argued that it was an abuse of process. They also contended that if the amendment application was allowed to proceed, the amendment would not be allowable on the grounds that it lacked clarity, added subject matter and does not cure the invalidity of the relevant claim.

As Arnold J sets out in his judgment, the abuse of process allegation relies on a line of case law preventing re-litigation in cases which do not amount to strict res judicata. This can be traced back to the High Court decision in Henderson v Henderson in 1843. In short, as Jacob LJ summised in Nikken v Pioneer and Nokia v IPCom, “a party should not normally be allowed to advance in a second proceeding matter he could have advanced in the first”.

Arnold J first dealt with Warner-Lambert’s argument that EPC 2000 provided a basis on which the amendment application should be allowed to proceed. Firstly, Arnold J rejected Warner-Lambert’s attempts to rely on Article 138, which concerns the amendment of European Patents during proceedings. He noted that the purpose of the provision was simply to ensure that all EPC contracting states permitted post-grant amendment; Article 138 did not have any impact on UK law concerning procedural fairness in litigation. Similarly, Arnold J rejected Warner-Lambert’s argument in relation to central limitation: the fact that it would not amount to an abuse of the process of the EPO for Warner-Lambert to apply centrally to limit its European Patent pursuant to Articles 105a-105c EPC 2000, did not mean that seeking to rely on the centrally limited claims would not amount to an abuse of process before the English Courts. The case law of other contracting states was held not to assist Warner-Lambert on the grounds that EPC contracting states differ in their procedural rules and philosophies.

On the question of whether the application amounted to an abuse of process, Mylan and Actavis argued that allowing the amendment application to proceed would engender the need for a second trial vis-a-vis its objections concerning the validity of the amended claim. Warner-Lambert argued that a decision on validity could be reached based on the findings and conclusions of the 10 September judgment, i.e. without the need for further expert evidence or cross-examination. Warner-Lambert also agreed not to bring a further claim for infringement based on the same facts. Arnold J agreed with Warner-Lambert insofar as the application concerned added matter; the requisite findings concerning the common general knowledge to allow for the construction and comparison of the application as filed and the amended claims had been made.

However, although clarity would typically be determined by Patent Offices without the need for evidence, it would not be fair to deprive Mylan and Actavis the opportunity to adduce further evidence in this case. Similarly, at first instance, “the sub-class of peripheral neuropathic pain was not a target which Mylan and Actavis had to hit”. As such, the insufficiency objection could not be fairly determined without giving the opportunity to adduce further evidence. Accordingly, Arnold J held that a second trial would be required to determine the validity of the patent.

Warner-Lambert further argued that it had been a victim of procedural unfairness as a result of Mylan and Actavis having failed to raise the point about central neuropathic pain earlier than they did. Arnold J also rejected this argument; at all material times Warner-Lambert was, or ought to have been, aware that there was a distinction between these two types of neuropathic pain and should have appreciated that there was a dispute concerning whether the relevant claim would be adjudged to cover both.

Having found that a second trial would be required if the amendment was permitted, there were two minor additional factors in Mylan and Actavis’ favour. Firstly, although it could not be assumed that the second trial would necessarily delay the overall resolution of the dispute, there was clearly a risk that it would do so i.e. because the appeal of the 10 September judgment would be delayed to allow for the second trial. Secondly, the public interest associated with the principle of finality in litigation in this case outweighed the public interest associated with incentivising research in the pharmaceutical field.

Accordingly, Warner-Lambert’s application to amend was struck out and held to have amounted to an abuse of process. The appeal of the 10 September judgment continues.

Read the entire decision (in English) here.

Steven Willis