Pfizer’s pregabalin litigation: the latest twist
On February 1 2023, the Court of Appeal of England and Wales handed down its decision in the latest instalment of the ongoing litigation concerning Pfizer’s product Lyrica (pregabalin), which first emerged back in 2014.
This decision leaves NHS Scotland open to continue to push for damages from Pfizer, although most NHS trusts have now settled their claims.
The background
Pfizer and Warner-Lambert (the patentee and a subsidiary of Pfizer) brought infringement proceedings against many generics companies, including Actavis, Dr Reddys, Sandoz, Teva and Mylan, for infringement of the patent relating to use of pregabalin for pain treatment.
The situation was complicated because pregabalin was authorised for treatment of neuropathic pain (which fell within the claims of the patent), but also for epilepsy and generalised anxiety disorder, for which the use would be off-patent.
Pfizer and Warner-Lambert lost the litigation at every instance up to and including the Supreme Court because the asserted claims were found invalid.
However, other claims relating to treatment of inflammatory pain were not invalidated.
An interim injunction
Back in February 2015, to try to ensure that so far as possible generic pregabalin was not used for the treatment of neuropathic pain while the infringement proceedings were ongoing, Pfizer was granted an interim injunction. This mandated that the NHS issue guidance that where pregabalin was prescribed for pain, it should be prescribed by the Pfizer brand name Lyrica.
In order to obtain this injunction, Pfizer had to give an undertaking to compensate for any losses caused by the injunction should it turn out to have been wrongly granted. As Pfizer’s infringement case failed due to the invalidity finding, the injunction had been wrongly granted, so those who had suffered financial loss were entitled to make a claim.
“A large number of entities—NHS bodies and generics companies— made claims either due to the injunction or because of the groundless threats, or both.”
Additional claims were also possible because certain letters sent by Pfizer were held to have been groundless threats of infringement (groundless again because the relevant claims of the patent were found to be invalid).
A large number of entities—NHS bodies and generics companies—made claims either due to the injunction or because of the groundless threats, or both.
But then Pfizer sought to introduce a new argument that in fact some of the pregabalin would have been used for inflammatory pain (notwithstanding that this was not an authorised indication so such use would be off label), and argued that it should not have to compensate for sales that would have fallen within the scope of claims of their patent that had not been found invalid.
The judge, Justice Anthony Zacaroli, decided that Pfizer could not introduce this argument, for various reasons related to the fact that they had never previously alleged infringement of the inflammatory pain claims.
Pfizer appealed, and in this latest judgment, the Court of Appeal affirmed the decision of Justice Zacaroli that Pfizer cannot introduce this new argument so late in proceedings.
Lord Justice Richard Arnold delivered the main judgment (and as he was the High Court judge who had decided the original infringement and validity litigation at first instance, was extremely familiar with the complicated background of the case).
Lord Justice Arnold upheld the first instance judgment, holding that the amendments to the case that Pfizer sought to make should be refused because they had no realistic prospect of success, or they could present an abuse of process. He declined to make a finding on a third possible ground based on general case management powers.
Rejected arguments
In one of its arguments, Pfizer relied on a theory that a patent would provide a right beyond that defined by actual infringement, and that this could be relied on to support its argument that it should not have to compensate for lost sales for indications covered by the valid claims, even if there was no actual infringement.
It would therefore be inequitable for Pfizer to have to compensate for those lost sales, the pharma company argued.
However, this contention was held to be wrong in law. In another argument, Pfizer suggested that the inflammatory pain claims might be considered (in the counterfactual situation) infringed by pharmacists, and so compensation should not be made on that basis.
The introduction of this argument was mainly rejected on abuse of process grounds, although Lord Justice Arnold also saw severe difficulties with the idea that a pharmacist’s acts might be considered infringing in those circumstances.
Lord Justice Stephen Males delivered a concurring judgment.
Meanwhile, Pfizer has settled with most of the claimants, and only NHS Scotland and Dr Reddy’s are still actively litigating the case.
There is scheduled a trial in November 2023 to determine the remaining issues and to calculate what damages Pfizer must pay to these two entities.
Darren Smyth is a partner at EIP. He can be reached at: dsmyth@eip.com
