The Court of Appeal has held that a patent with claims in Swiss form directed to a second medical use was invalid for insufficiency and also commented on direct and indirect infringement of such second medical use patents.


A patent application must disclose the invention sufficiently, clearly and completely for it to be carried out by a person skilled in the art, and the claims must be supported by the description (section 14, Patents Act 1977) (1977 Act). A patent may be revoked if the specification does not disclose the invention in a manner which is sufficient (section 72(1)(c), 1977 Act).

The Court of Appeal has set out the principles for determining sufficiency:

  • If it is possible to make a reasonable prediction, or the invention will work with substantially everything falling within the scope of the claim, it cannot be said the claim is insufficient simply because the patentee has not demonstrated the invention works in every case.
  • If it is not possible to make such a prediction or if it is shown the prediction is wrong and the invention does not work with substantially all the products or methods falling within the scope of the claim, then the scope of the monopoly will exceed the technical contribution the patentee has made to the art and the claim will be insufficient (Regeneron Pharmaceuticals Inc and another v Genentech Inc).

A patent for an invention to a process is infringed, inter alia, by a person who keeps, disposes of, or offers to dispose of, any product obtained directly by means of the claimed process (direct infringement) (section 60(1)(c), 1977 Act) (section 60(1)(c)).

Infringement also occurs where an infringing invention is not put into effect by the defendant, but by someone who was supplied with means relating to an essential element of the invention for putting the invention into effect when he knows or it is obvious to a reasonable person in the circumstances that the means are suitable for putting and intended to put the invention into effect (indirect infringement) (section 60(2), 1977 Act) (section 60(2)).


W marketed a prescription-only drug for three different indications (neuropathic pain relief, GAD and epilepsy) under a single registered trade mark. Patent protection for the drug itself had expired but W owned a second medical use patent directed at the use of the drug for pain relief, which covered one of the three authorised indications (neuropathic pain relief).

A applied for a marketing authorisation for a generic version of the drug limited to the other two indications (GAD and epilepsy). W was concerned that it was still likely that the generic drug would be dispensed for neuropathic pain relief because very few prescriptions state the indication for which the drug has been prescribed, and that pharmacists would have a strong commercial incentive to dispense the cheaper, generic version of the drug.

W sued for patent infringement and made a conditional application to amend the patent by deleting claims found invalid and by rewriting an existing claim to exclude use for central neuropathic pain.

The High Court held that (1) certain claims that were directed to the treatment of pain or neuropathic pain were invalid on the ground of insufficiency; and (2) that even if valid, A had not infringed any claims under section 60(1)(c) or section 60(2). It also refused W's conditional application to amend the patent on the basis that this would be an abuse of process. A and W appealed.


The court dismissed the appeals.

Claim 1 (use of the drug for treating pain) and 3 (use of the drug for treating neuropathic pain) were invalid as not being plausible across their breadth. The basis for these findings was the lack of data in the patent to support a claim to the use of the drug to treat central neuropathic claim.

The court rejected the argument that the patent did not make plausible a claim that the drug was effective to treat peripheral neuropathic pain. The test for plausibility represents a low threshold and rejected the argument that the test for plausibility should be aligned with that sometimes used for obviousness namely that the reader of a patent needs to be encouraged to try the invention with a reasonable expectation of success.

The court also held that W’s conditional application to amend claim 3 would amount to an abuse of process. W had had the opportunity before the commencement of the trial to amend its patent in the event that it was found invalid for insufficiency.

Given the finding of patent invalidity, W's infringement claim failed. However, the court commented on the construction of second medical use claims in Swiss form. It commented that an objective approach to the issue of intention was necessary. One would normally regard a person to intend what he knows or can reasonably foresee as the consequences of his actions. IF the test of knowledge or foresight was satisfied the court should then consider whether the manufacturer has taken all reasonable steps within his power to prevent the consequences occurring.

The High Court had been wrong to dissect the requirement for intentional treatment of pain by considering the position of the doctor, the pharmacist and patient; the requirement was simply whether the manufacturer knows or is able to foresee that there will be intentional use of the drug for the new medical indication. The test was whether the manufacturer of the generic drug knew or could foresee that at least some of the prescriptions written generically for the drug to treat pain would in fact be fulfilled with its generic product.

In relation to indirect infringement, as the invention was understood to be the use of the drug in the preparation of a pharmaceutical composition for treating pain, the Court commented that the process would not necessarily be completed when the drug had been formulated into a pharmaceutical composition by a manufacturer. The process of preparing the composition could continue through any packaging step performed by the manufacturer and also include a labelling step performed by a pharmacist. The High Court was not therefore correct in assuming that there could be no relevant act of preparation by a pharmacist and therefore at least a prospect of downstream manufacture.

The most controversial aspect of this decision is the discussion of infringement of second medical use patents. The court’s interpretation places the burden on the generic manufacturer to show that it took all reasonable precautions to prevent the product being used for the patented purpose. There are different views in the various European jurisdictions as to what is required for the generic manufacturer to avoid infringement. This complex area of law will be considered by the Supreme Court in other proceedings (Actavis v Eli Lilly) in early 2017.

Case: Warner-Lambert Company LLC v Generics (UK) Ltd (t/a Mylan) and others [2016] EWCA Civ 1006.

First published in the December 2016 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.