Inside IP: No Interim Injunction Following Obviousness Ruling On Tadalafil Dosage Patent

In a rare intervention in relation to inventive step, the Court of Appeal has overturned a High Court decision of Mr Justice Birss in relation to ICOS/Lilly's tadalafil 5mg dosage regimen patent. Tadalafil is the generic name of the drug sold under the brand 'Cialis' for the treatment of male erectile dysfunction (ED).

The inventive concept of the patent was stated to be a smaller 5mg dosage of tadalafil, which remained effective but was combined with minimal side effects. However, the appeal court found that there was no invention in a dose that was discovered by virtue of the dose ranging studies carried out as part of routine Phase IIb clinical studies. The patent (EP (UK) 1,173,181) was therefore invalid, and with the Supplementary Protection Certificate for tadalafil also expiring in November, the way became clear for Actavis, Teva and Mylan to launch generic products to compete with Cialis.

Having applied for permission to appeal to the Supreme Court, Lilly made an urgent application in the Patents Court for an interim injunction to stop generic products entering the market, pending any possible appeal. An appeal to the Supreme Court can take some time to resolve (around one to two years from filing the petition to judgment) - if the interim injunction had been granted, this would have meant generic manufacturers would potentially have to factor in the likely timing of an appeal to the Supreme Court when taking steps to clear the way before launch.

In the event, such policy arguments did not impact on the Patents Court's decision refusing to grant an interim injunction. The judge, Mr Justice Henry Carr, concluded that Lilly did not have a realistic prospect of success in a further appeal, as the Court of Appeal had applied the facts, as found by the High Court, to existing and settled principles of law. Further, he would also have been against Lilly on the question of unquantifiable loss (not least as, following the accepted downward price spiral, the patent would expire not long after a period of restored monopoly). In contrast, he accepted that the generic companies would all lose their 'first mover' advantage, outweighing any unquantifiable losses to Lilly.

Whether or not a distinct dosage regime of a known compound can be inventive is an important policy question underlying this litigation. Whilst the Court of Appeal's decision does not rule this out, it did not consider there to be an invention on the facts of this case. The...