Use-limited product claims in Europe

A use-limited product claim is a claim format often used in Europe as an alternative to method of treatment claims. However, it is a claim format in its own right, and an understanding of its uses and limitations may be useful when drafting patent applications which are destined to be prosecuted before the European Patent Office (EPO).

Use-limited product claims allow a known compound to be protected for a first medical use (where its use as a medicament was previously unknown), or for a further medical use (where the compound was previously known as a medicament). They are essentially a product claim in which the product is limited by its use, and the basic formats for drafting such claims are provided below:

• Compound x for use as a medicament. (First medical use)
• Compound x for use in the treatment of disease y. (Further medical use)

This is a deviation from normal claim interpretation in Europe, in which defining that a product is for a particular use is merely interpreted as meaning that the product is “suitable for” that use (see F-IV, 4.13.1 of the EPO Guidelines).

As with all claims, in order to be allowable, it must be novel and inventive, and be supported by the description. As the compound is known, this means that the new medical use must be novel and inventive. There must also be sufficient evidence provided in the description to make the claimed use credible.

The main limitations on use-limited product claims are, firstly, that the use must be a medical use. Use-limited product claims cannot be used to protect, for example, the new use of a known compound as a pesticide.

Secondly, a use-limited product claim must relate to a specific disease or group of diseases.  Where a use-limited product claim is directed to a group of diseases the group must be clearly defined and cannot be directed only to a mechanism of action. Some examples are provided below:

• Compound x for use in the treatment of any condition susceptible of being improved or prevented by selective occupation of receptor x. This claim is acceptable as it defines a group of illnesses in functional terms, provided that the patent application details experimental tests or testable criteria to allow the skilled person to recognise conditions that fall within this definition, or that such tests are common general knowledge in the art, and some examples of treatable conditions are provided.
• Compound x for use in the downregulation of gene y. This claim would not be acceptable, as it relates to a mechanism of action and not to a defined disease or group of diseases.
• Compound x for use as an antibacterial agent. This claim would not be acceptable as it does not define a specific medical use but encompasses non-medical uses (the use of antibacterial agents in non-medical settings).

A use-limited product claim may also be directed to other aspects of medical treatment, including a new dosage regime, administration mode or the treatment of a novel set of patients for a specific disease, even where the general use of the relevant compound for the treatment of that disease was previously known. Sufficient data must be provided in the specification to demonstrate that the claimed use is not an arbitrary selection from what has gone before, but has some unexpected or beneficial effect over the prior art.

Thirdly, a use-limited product claim must relate to a substance or composition. Use-limited product claims cannot be used to protect, for example, a known medical device for a new medical use.

Where a method of treatment claim is to be rewritten as a use-limited product claim, this is typically rewritten as a second or further medical use claim.  For example:

A method of treating breast cancer by administration of a pharmaceutically effective amount of a compound according to Formula (I).

may be rewritten in the use-limited product format as:

A compound according to formula (I) for use in the treatment of breast cancer.

Dependent claims are then formulated to make clear their dependency on the use limitation of the independent claim, for example compound x for use according to Claim 1...