The High Court has held that claims of a second medical use patent, although not obvious, were invalid for insufficiency and, even if valid, were not infringed.
Second medical use claims in the Swiss form use are as follows: use of substance X for the preparation of a medicament, or pharmaceutical composition, for treating indication Y (a purpose-limited process claim). Article 54(5) of the European Patent Convention (EPC) now enables the grant of these claims in the form: product X for treating indication Y (a purpose-limited product claim).
A patent for an invention is infringed by a person who keeps, disposes of, or offers to dispose of, any product obtained directly by means of the claimed process (section 60(1)(c), Patents Act 1977) (1977 Act) (section 60(1)(c)) (direct infringement).
Indirect infringement 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 (section 60(2), 1977 Act) (section 60(2)). Section 60(2) therefore requires a double mental element: that of the supplier and that of the person to whom the product is supplied or possibly an end user.
W marketed a prescription-only drug for three different indications under a single registered trade mark. Patent protection for the drug itself had expired but W owned a second medical use patent for pain relief, which was one of the three authorised indications.
A applied for a marketing authorisation for a generic version of the drug limited to the other two indications (a so-called "skinny label"). W was concerned that, despite this, the generic drug would be dispensed for pain relief because most prescriptions are written generically. As very few prescriptions state the indication for which the drug has been prescribed, the dispensing pharmacist will generally not know this. W also argued that, because the generic drug is usually cheaper than the patentee’s product, pharmacists would have a strong commercial incentive to dispense the generic version of the drug unless positive steps were taken to prevent this.
W sued for patent infringement and sought an interim injunction requiring A to take specific actions to prevent its generic version of the drug being dispensed for patients who had been prescribed the drug for the patented indication, pain relief. The High Court refused to grant an interim injunction and struck out the claim of indirect infringement, but dismissed A’s application to strike out the claim entirely.
The Court of Appeal dismissed W's appeal in relation to the interim injunction but allowed its appeal against the order striking out the indirect infringement claim. The word "for" in the context of a Swiss claim is construed as meaning suitable and intended for, but the meaning of “intended” in this context is unclear. In the Court of Appeal's opinion, '"for" does not imply subjective intent. In relation to direct infringement under section 60(1)(c), the Court of Appeal’s view, arguably obiter, was that a manufacturer that knows or could reasonably foresee that some of its drug would intentionally be used for pain relief is making use of the patentee’s inventive contribution in the same way as a manufacturer that actively desired that result.
The case proceeded to full trial by the High Court.
The court held that none of the claims of the patent was obvious over the cited prior art, but certain claims that were directed to the treatment of pain other than inflammatory pain were invalid on the ground of insufficiency. However, even if valid, A had not infringed any claims under section 60(1)(c) or section 60(2).
The Court of Appeal’s judgment on the mental element was not binding but was highly persuasive. The court had doubts as to the correctness of the Court of Appeal's interpretation, but it was not clearly wrong and so should be followed. Such interpretation requires a double mental element, i.e. that of both the manufacturer and the person to who it is supplied. As a result the intention of the doctor and the pharmacist is relevant to direct infringement, as it is when considering indirect infringement. In relation to direct infringement under section 60(1)(c), the High Court held that:
- The intention of the doctor is highly relevant because it is the prescribing doctor who intends to produce the new therapeutic effect (treating pain). However, it is not sufficient that the prescribing doctor intends the drug from any source to be administered for the treatment of pain. Infringement depends on what the manufacturer could foresee happening with the drug it manufactured, not the drug made by others.
- The intention of the pharmacist is also likely relevant. In general, the pharmacist simply intends to dispense the drug to treat whatever indication the doctor has prescribed that drug for, and would not know what that indication was. In those circumstances, the pharmacist's intention adds nothing to that of the doctor. But if the pharmacist knows that the doctor prescribed the generic drug for treating pain and dispenses the generic manufacturer's product, it seems that the result is intentional administration of the generic manufacturer's product to treat pain.
- The patient's intention is not relevant. In general, the patient intends to take whatever drug the doctor prescribes for whatever condition the doctor prescribed it for. The patient relies on the pharmacist to dispense the correct drug, and usually has no choice as to the source of that drug.
A had not directly infringed the patent under section 60(1)(c). For product manufactured in the period before steps were taken to notify prescribers and dispensers of the requirement only to provide A's drug if it was prescribed for pain, it was not foreseeable to A that the generic drug would be intentionally administered for the treatment of pain save in a small number of exceptional cases, which it was proper to regard as de minimis. For product manufactured at later dates when guidance had been issued and then later when other generic products came on the market, it was not foreseeable that more than a de minimis proportion of the product would be intentionally prescribed or dispensed for pain.
A had also not indirectly infringed the patent under section 60(2). The claims were directed to an act of manufacture, not a method of treatment, and there was no act of manufacture by any party downstream from A. Although the generic drug's active ingredient was a means, relating to an essential element of the invention, for putting the invention into effect, the drug was not suitable for putting, or intended to put, the invention into effect. Either the invention had already been put into effect by the time that it left A's hands or it was not put into effect at all.
The decision highlights the difficulties inherent in proving infringement of Swiss-form claims. In future, the situation will be different as second medical use claims granted under Article 54(5) of the EPC are purpose-limited product claims, as opposed to Swiss-form purpose-limited process claims.
In relation to the key question of whether the Court of Appeal's interpretation of "for" was correct, the High Court pointed out that the construction adopted was not one that was contended for by either party in the Court of Appeal. Given the difficulties in applying this interpretation in circumstances where the ultimate use of the product is outside the manufacturer's control, the Court of Appeal may be persuaded to look at it again.
The case raised a subsidiary issue as to whether common general knowledge has a territorial dimension. It was common general knowledge in the US, but not in the UK, that a closely related drug was being used off-label by clinicians for the treatment of neuropathic pain. The court held that it had to be shown that the matter in question was common general knowledge in the UK because, whether dealing with the validity of a European (UK) or UK patent, one was concerned with a right in respect of the UK. While the prior art might have been published anywhere in the world, that did not alter the need for the skilled team to consider that art as if they were located in the UK.
Case: Generics (UK) Ltd (trading as Mylan) and others v Warner-Lambert Company LLC, intervenor Secretary of State for Health  EWHC 2548 (Pat).
First published in the November 2015 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.