The European Patent Convention states in Article 52(4) that:

Methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practiced on the human or animal body shall not be regarded as inventions.

The position is complicated, however, by a proviso in Article 54 (5) that states that this prohibition shall not exclude patentability for any "substance or composition for use in [such] a method" even if previously known for some other purpose as long as that purpose was not a method of treatment or diagnosis practiced on a human or animal body. The use of compound-limited use claims and the so-called "Swiss form" second medical use claim to provide some means of alleviating the problems caused by this wording in seeking to protect inventions relating to new medical uses of known compounds are by now well known.[1]

The exact meaning of the Swiss form claim in the infringement context is still not fully resolved. However, a South African court when confronted with such a claim (the present South African law is largely modeled on the European Patent Convention) held that production of a transdermal nicotine patch was an infringement of a claim of this type.[2]

Such "Swiss form" claims are, however only acceptable in the case of new uses of a medicament. Thus in Second Surgical Use/Codman they were not allowed for other types of medical treatment such as a new use of a known laser surgery system.[3] The board opined that " a surgical use of an instrument is not analogous to a therapeutic use...since the former is not consumed in the application and could be used repeatedly for the same or even other purposes as well...Medicaments, on the other hand, are expended in the process of use and have only a once for all utility. Any new use is exactly correlated with a corresponding expansion of the manufacture of the entity for the purpose." [4]

Similarly laser removal of portions of a lenticule that had already been implanted in an eye and attached to the cornea was held to be an unpatentable medical treatment.[5] Furthermore the Flow measurement decision noted in footnote 4 was distinguished in Cardiac pacing/Teletronics[6] where it was held that in order to avoid the prohibition on claims to methods of medical treatment it was necessary that if the claim contained a method step (even if the claim was ostensibly directed to an apparatus - in casu a cardiac pacer characterized by certain method steps) it was essential that none

of the method steps should be a method for treatment of a human or animal body by way of therapy surgery or diagnosis. In the present case certain signals interpreted by the device controlled the output of the pacer which was applied to the human body to obtain a therapeutic effect. This contrasted with the Flow measurement case where there was no functional link between the value that was measured and the therapeutic treatment applied.

However, in Blood flow/See-shell[7] a claim involving measurement of blood flow to specific tissue in an animal was allowed because the claim involved subsequent sacrificing of the animal, so that although a surgical operation had been carried out on a live animal, it was clear that therapy was not the over-all objective.

In Trigonelline/MAI[8] second medical use claim was held to be appropriate for the use of an encapsulated extract from fenugreek seed for treatment of hair loss even though the prior art showed that topical compositions had been used for the same purpose. This was the first time that an encapsulated product had been used for this purpose. Hence there was an invention. Similarly in HCG/Serono[9] the following claim was held to be patentable:

Use of HCG for the manufacture of a non-depot medicament for use in the treatment by subcutaneous administration of infertility or male sexual disorders.

This holding was despite the fact that HCG (human chorionic gonadotrophin) had been used previously for some of the stated conditions. However, the prior route for administration had been by intramuscular injection. Subcutaneous injection provided a number of advantages, including the fact that no visit to a physician was required to make the injection but the prior art showed prejudice against subcutaneous injections for products of this type since resorption of the drug is slower since subcutaneous tissue is poorly vascularized and comprised of a lipid layer.[10]

Similarly, a second medical use type claim has been held to be the only permissible type of claim for an invention relating to including lanthanum in oral-care preparations for the purpose of removing plaque or staining, the body of the specification making reference to the medical as well as cosmetic advantages of such plaque removal.[11] In this case the prior art had shown the use of lanthanum in toothpaste and similar compositions to inhibit erosion of tooth enamel. Thus, the present invention represented a new medical effect. Since this was of a prophylactic nature, it was inherent in any cosmetic effect achieved, thus precluding the allowability of a claim limited to the cosmetic effects as had been allowed in Appetite Suppressant/DuPont noted in footnote 3 above.

It has also been held that a therapeutic treatment of animals did not lose its therapeutic character simply because it had the side effect of increasing meat production from the treated animals.[12] Nor should a treatment be considered as being other than therapeutic simply because it was ancillary to a treatment for a different purpose (contraception).[13]

A different approach to the question of contraception was followed in Contraceptive method/British Technology Group.[14] In this case the claim was a use claim to the use of a specified compound as a contraceptive by application to the cervix of a female. After agreeing that contraception is not a method of therapy for which patent protection is barred, the Board nevertheless maintained the rejection of the claim on the ground that the acts specified in the claim were of a private nature and so the invention as claimed was incapable of industrial application. The fact that acts of contributory infringement would clearly be of industrial applicability was felt to be irrelevant; some act of direct infringement had to be industrially applicable for patentability.