Patent practice in China – diagnosis or treatment?

A substance can have a medical use for the diagnosis or treatment of a disease. However, an invention involving methods of diagnosis and treatment will not be granted a patent right under Article 25.1(3) of the Patent Law. Taking into consideration the Patent Law’s regulations and the Guidelines for Examination issued by the China National Intellectual Property Administration (CNIPA), it is vital to pay close attention to the drafting of a patent application when seeking to obtain a patent right in China.

Methods for diagnosis and treatment

Diagnostic methods refer to the processes of identifying, studying and determining the cause or focus of disease in living human or animal bodies. Where a method involving the diagnosis of a disease complies with the following two requirements, it is a diagnostic method and cannot be granted a patent right:

• it is practised on a living human or animal body; and
• its immediate purpose is to obtain the diagnostic result of a disease or health condition.

If an invention, as viewed from its description, is used on samples in vitro, but its immediate purpose is to obtain the diagnostic result of a disease or health condition for the same subject, it will not be granted a patent right.

Patent rights will not be granted for the following diagnostic methods, among others:

• evaluating the risk of suffering in disease;
• predicting the therapeutic efficacy for disease; and
• gene screening diagnostic methods.

Methods of treatment for disease refer to the processes of intercepting, relieving or eliminating the cause or focus of diseases so that the living human or animal bodies may recover, gain health or be relieved of pain.

Methods of treatment for diseases include the various methods that serve a treatment purpose or have a treatment nature. Prophylactic and immunisation methods are regarded as methods of treatment for disease.

Regulations: methods of diagnosis and treatment

A patent right will not be granted for a method that serves both a diagnostic/treatment purpose and a non-diagnostic/treatment purpose, unless it is clearly stated that the method serves a non-diagnostic/treatment purpose. If the invention focuses on the non-diagnostic/treatment purpose, it should be clearly stated in the claim.

An application relating to the medical use of a substance will not be granted if its claim is drafted as:

• use of substance X for the treatment of disease;
• use of substance X for the diagnosis of disease; or
• use of substance X as a medicament.

This is because such a claim relates to the “method for the diagnosis or for the treatment of diseases” as referred to in Article 25.1(3). However, since a medicament and the method for its manufacture are patentable according to the Patent Law, it is not contrary to Article 25.1(3) if an application for the medical use of a substance adopts a pharmaceutical claim or uses the claim in the form of a method for preparing a pharmaceutical (ie, a Swiss-type use claim, such as ‘use of substance X for the manufacture of a medicament’ and ‘use of substance X for the manufacturing of a medicament for the treatment of a disease’, among others). As for a second medical use, there are different formats in different jurisdictions; for example, it is drafted as ‘Substance X, for the treatment of disease Y’ in Europe. However, this kind of claim is deemed a product claim per se in China, which would result in a patentability issue if the substance is known in the prior art since the product should be characterised by its structure (eg, structure formula or constituent). The feature ‘treatment of disease Y’ is a use feature substantively and cannot be used to distinguish it from the known substance. Second medical use can be drafted as a Swiss-type use claim, which is patentable in China.

For novelty of a medical-use invention relating to a substance, the following aspects should be considered:

• whether the new use is different in substance from the known use – the use invention does not possess novelty when the difference between the new use and the known use lies merely in the form of expression, but the substance is the same;
• whether the new use is revealed directly by the mechanism of action or pharmacological action of the known use – the use does not possess novelty if it is directly equivalent to the mechanism of action or pharmacological action of the known use;
• whether the new use belongs to the generic (upper-level) term of the known use – the known use defined by the specific (lower-level) term may destroy the novelty of the use defined by the generic (upper-level) term; and
• whether the features relating to use (eg, object, mode, route, usage amount and interval of administration) can define the procedure of manufacture of a pharmaceutical – the distinguishing features may present themselves in the course of administration but do not enable the use to possess novelty.

Another concern regarding medical-use claims is the issue of support in China. In general, experiments that are performed in vivo or in vitro are necessary to prove that the substance can be used to treat the mentioned diseases. Sometimes the owner of the invention intends to protect the solution involving the specific disease or diseases to be treated by a substance; however, only the action mechanism of the substance to treat the specific disease is proved in the examples. Under these circumstances, the relationship between the action mechanism of the substance and the treatment of the specific disease should be established by evidence from the prior art, otherwise it is difficult to institute legal proceedings against the solution involving the specific disease in China. It is also difficult for a party to initiate proceedings against an invention involving the mechanism action under China’s current patent practice.

Case study: diagnosis and treatment

In some cases, an invention will focus on the combined use of two or more substances to treat a particular disease. There are two ways to prosecute these types of invention:

• First, if two or more substances are present in the form of a mixture, the claim may be drafted as ‘Use of substance … and substance X for the manufacture of a medicament or pharmaceutical composition for treating disease Y’.
• Second, if two or more substances are present separately, regardless of whether they are used simultaneously or sequentially, the claim may be drafted as ‘Use of substance X … and substance X for the manufacture of a kit for treating disease’.

But how can a party institute legal proceedings against an invention involving dosage regimen in a Swiss-type use claim? According to the regulations of the Guidelines for Examination in China, distinguishing features that are merely present in the course of administration do not enable the use to possess novelty. However, the applicant may obtain inspiration from the following cases.

Case I

Case I involves the solution “use of substance A for the manufacture of a medicament for oral administration to treat disease B, wherein the medicament comprises [0.04 to 5 milligrams (mg)] of substance A”.

Case I was granted during the substantive examination but invalidated during the invalidation procedure since the panel of the Re-examination Board holds that dosage is a feature involved in the administration of a medicament and is not involved during its preparation. The ‘oral administration’ feature does not carry the gist of the invention over the prior art, although it does imply that the adjuvant contained in the medicament is suitable for oral administration and could thereby be deemed a distinguishing feature. The judge of the Beijing Intermediate People’s Court agreed with the Re-examination Board regarding dosage. However, the judge held that a medical-use invention is, in essence, a method for using a medicine, and the technical features regarding how to use it (ie, the ‘administration features’ such as dosage form and dose) will be considered. In addition, the preparation of a medicament should cover all production processes prior to packaging, including administration features such as dosage form and dose. Under these circumstances, the dosage feature of 0.04mg to 5mg constitutes a distinguishing feature over the prior art.

Case II

Case II involves the solution “use of substance A in preparation of a medicament for treating infection without skeletal muscle toxicity, wherein the dosage of treatment is [4 to 7 milligrams per kilogram (mg/kg)] substance A, and the dosage is repeated with an interval of 24 or 48 hours”.

The panel of the Re-examination Board held that “the use dosage feature of a medicine has no limiting effect on a Swiss-type use claim, the administration interval feature also belongs to an administration feature and cannot limit the manufacture process of a medicine, and the feature ‘without skeletal muscle toxicity’ cannot distinguish the claimed use from the use of substance for treating infection known in the art, thereby the claim is not novel over the prior art”. The judges in both the Beijing Higher People’s Court and the Supreme Court held the same view regarding the dosage feature (ie, if a medical-use invention differs from the prior art only in the administration amount or administration interval that is related to the use of the medicine but not to the procedure of manufacture of the medicine, then the medical use is not novel).

But why are there different conclusions for cases involving a dosage feature? The key point when considering a dosage feature lies in whether it is definite or whether it is involved in the doctor’s treatment behaviour. The doctor’s treatment behaviour involves only the use of the medicament rather than its preparation and, therefore, is not involved in the patent infringement regarding the medicament’s preparation. If the dosage feature is involved in the medicament’s preparation, it may be considered during the judgment of novelty.

In Case I, the dosage of a substance contained in the medicament is 0.04mg to 5mg, which is ‘definite’ and could be performed during the medicament’s preparation. However, in Case II, the dosage of a substance is 4mg/kg to 78mg/kg, which is ‘variable’ depending on the weight of the subject and cannot be performed during the preparation of the medicament. In addition, the feature “the dosage is repeated with an interval of 24 or 48 hours” is part of the doctor’s treatment behaviour. Under these circumstances, different conclusions have been reached, although both cases involve the dosage feature.

Case III

Case III involves the solution “use of substance A for the preparation of a medicament for the prevention or treatment of disease B, wherein said medicament is administered according to a dosing regimen having a dosing periodicity ranging from about twice a day to about once every other day”.

Under the patent practice regarding dosage regimen in China, the feature “a dosing regimen having a dosing periodicity ranging from about twice a day to about once every other day” is not considered in a Swiss-type use claim. The gist of this invention also focuses on the dose of substance A: “a pharmaceutical composition, characterised in comprising 1mg to 500mg of substance A” or “an individual dosage unit, characterised in comprising 1mg to 500mg of substance A”, wherein the term ‘individual dosage unit’ refers to the individual pharmaceutical formulation (eg, a tablet containing substance A to be administered to a patient at that time of the dosage regimen based on the disclosure of the description). The subject matter ‘individual dosage unit’ focuses on the pharmaceutical formulation differing from the subject matter ‘pharmaceutical composition’.

Suggestions for applicants

The claim format (ie, a Swiss-type use claim) is suggested by the CNIPA if the patent application focuses on methods for diagnosis or treatment of disease. However, some information involved in the Swiss-type use claim (eg, the subject matter ‘kit’) should be recorded in the document as originally filed to avoid the possible rejection for introducing new matter. It is a challenge for the inventor to grant the solution involving dosage regimen in China. However, the Guidelines for Examination may be revised dynamically every year and the practice regarding dosage regimen will hopefully be changed in the near future as it is a requirement for both innovative and public entities.