1. Medical Inventions in Europe are Protected by ‘Medical Use Claims’ with the following formats:
EPC2000 purpose limited product claim:
[Substance X] for use in a method of treating [Indication Y]
Swiss style purpose limited use claim:
Use of [Substance X] in the manufacture of a medicament for treating [Indication Y]
These claims are legal fictions, but are the only way to cover inventions that relate to methods of treatment.
2. Any invention relating to a method of treatment that cannot be defined as an acceptable medical use claim potentially cannot be protected in Europe. These claims can only relate to ‘substances’, and so cannot relate to devices, electrical impulses, X-rays or particle beams, for example. They can relate to substances delivered by devices.
3. Medical use claims are suitable for protecting many improvements for a known therapy, for example if the invention lies in the choice of administration schedule, treating a specific patient group or co-administration with other substance. It is usually straightforward to protect such inventions if all components can be ‘structurally’ and ‘completely’ defined without any steps that require obtaining of information. Problems can occur in defining features functionally, particularly substances or indications.
4. For medical inventions where there are ‘information gathering’ steps it can be problematic to protect them with medical use claims. If the step requires identifying the presence of a feature in the patient or somehow choosing the therapy then it might only be possible to claim these using normal method claims:
A possible method claim:
‘A method of selecting the dosage of [Substance X] to administer to treat an individual with [Indication Y] comprising identifying the level of biomarkers A+B present in the individual and [based on this] determining the dosage that should be administered’
The medical use claim:
[Substance X] for use in a method of treating [Indication Y], wherein the dosage is determined by the level of biomarkers A+B present in the individual.
The medical use claim is preferred because it should cover the manufacturer of [Substance X] as a direct infringer and that is likely to be the highest value infringer.
5. EPO case law has decided that the EPC2000 medical use claim is of broader scope than the Swiss style claim for the purpose of post-grant amendment (T250/05) and double patenting (T1780/12), though the two formats seem to have the same scope for validity.
6. The determination of validity for medical use claims is relatively straightforward, simply assessing whether the relevant features are disclosed in the prior art. The reference to ‘manufacture’ of a medicament in the Swiss style claim is not relevant to validity. It cannot be used as a limiting feature when assessing validity.
7. Determination of infringement will depend on the national law of the relevant territory. It seems that it may well be easier to show infringement for a first medical use than a second one. In the ongoing UK case Warner Lambert v Actavis determination of infringement of a claim covering a second medical use is proving complex. At this time the Court is requiring that the manufacturer must ‘foresee’ use of the drug for the patented indication and that there has to be actual intent to do so by a user, that is either the doctor, pharmacist or patient. So far in this case so user has been shown to have the required intent!
8. The novelty of patient groups is presently a lenient test. Early case law (T233/96) decided there could be no overlap. This was contradicted by T1399/04 which allowed more than 50% overlap. The present position is reflected by T734/12 which allowed overlap. It is not immediately clear what sort of novelty test this is. It does not seem to be a ‘selection invention’ or ‘prior use’ test.
9. Plausibility of successful therapy seems to be emerging as an important requirement in assessing medical use inventions. It has been considered in several recent UK biotech court cases as a sufficiency requirement. Where it is used to assess the contents of a prior art document a lack of plausibility can negate the effects of potentially novelty destroying disclosure.
10. Plausibility is going to be important in attacking medical use claims post-grant as there is usually no data relating to therapy in humans in specifications. Plausibility can be considered in terms of whether therapy is shown to be achievable and whether it will be achievable across the breadth of the claim. That means that when attacking consideration will in particular need to be given to how the data in the specification supports the breadth of the patient group and the conditions to be treated. Importantly post-filing data cannot be used to fix plausibility issues.