Talking about the Patent Protection of Medicament in China from “Remdesivir”

Wang Fang-Borsam IP
【Background】The epidemic of new coronavirus pneumonia has received continuous attention. On February 4th, Wuhan Institute of Virology, Chinese Academy of Sciences announced on its official website that its research results based on the screening of new coronavirus drugs had been filed for patent for Remdesivir's use against 2019 new coronavirus on January 21. However, Remdesivir is an antiretroviral drug developed by US company, Gilead Sciences, Inc., and Gilead has many related patents or patent applications in China. As soon as the news came out, it aroused widespread concern and heated discussion in society. This article simply introduces the patent protection of medicament in China by “Remdesivir” and focuses on the issue of patents for medical-use.
【Key Words】Remdesivir; medicament patent; medical-use invention
1. What are the types of medicament patents
1.1 Type overview
The patents that can be filed for medicament can be roughly divided into product patent and process patent, which can be summarized as follows:

Specific to Remdesivir, its product claims relate to the general formula, isomers, crystals and salts of the compounds, or medicament compositions; its process claims include the preparation process, medical-use of Remdesivir and disease treatment method using it as active compound, etc.
1.2 What is a medical-use invention patent?
Major economies other than the United States exclude the diagnosis and treatment of diseases from patentable matters, so the claim to "use a medicine to treat a disease" cannot be granted a patent. In order to solve this problem, someone has invented a novel claim: use of compound A for manufacturing a medicament for the treatment of disease B. This form of claim was originally accepted in Switzerland and is therefore called a "Swiss-type claim" or "Swiss-type use claim". The corresponding patent is also referred to herein as the medical-use invention patent.
China's Guidelines for Patent Examination specifically regulates the use invention of the product. Part II, Chapter 4, Section 4.5 states: “An invention of new use of known product refers to the invention of using a known product for a new purpose.” In addition, Part II, Chapter 10, Section 4.5.1 states: "The invention relating to the use of a chemical product is made on the basis of discovery of a new property of the product and the use of such property. Regardless of a new or known product, its property is inherent in the product per se. The essence of the use invention does not lie in the product per se, but in the application of its property. Hence, a use invention is an invention of process, and its claim is a process claim. "
It can be seen that the medical-use invention emphasizes the new use of medicine, which can be new use of new medicine, or new use of known medicine.
The subject of the patent application of Wuhan Institute of Virology is the use of Remdesivir against new coronavirus in 2019, which belongs to the new use of known medicine (that is, the second medical use) and is a typical medical-use invention patent.
2. Requirements for medicament patent to be granted?
2.1 General requirements
Medicament patent application, like ordinary patent applications, needs to meet the requirements of the Patent Law. The main conditions involved are as follows:
(1) The subject matter shall be patentable;
(2) Sufficiently disclosure, i.e. those skilled in the art can implement it;
(3) Three characteristics: novelty, inventive step, and practical applicability.
2.2 What kind of medical-use invention patents can be granted?
Specific to the medical-use invention patent, the judgment about the above conditions is as follows:
2.2.1. Whether the subject matter is patentable?
The Guidelines for Patent Examination provides: “An application relating to the medical use of a substance shall not be granted if its claim is drafted in the wording “use of substance X for the treatment of diseases”, “use of substance X for diagnosis of diseases” or “use of substance X as a medicament”, because such claim is one for “method for the diagnosis or for the treatment of diseases” as referred to in Article 25. 1(3). However, since a medicament and a method for the manufacture thereof are patentable according to the Patent Law, it shall not be contrary to Article 25. 1(3) if an application for the medical use of a substance adopts pharmaceutical claim or use claim in the form of method for preparing a pharmaceutical, such as “use of substance X for the manufacturing of a medicament”, “use of substance X for the manufacturing of a medicament for the treatment of a disease” and so on.
The above-mentioned use claim in the form of method for manufacturing a medicament may be drafted as “use of compound X for manufacturing a medicament for the treatment of disease Y” or the like.”
2.2.2 Whether the specification sufficiently disclosed the invention?
According to the relevant provisions of Patent Law and Guidelines for Patent Examination, the specifications for new-use invention patent for known medicament must have relevant medicinal effect test data in order to meet the requirements for sufficiently disclosure of the specification. The medicinal effect test may be a clinical test, an animal test, or a cell test.
2.2.3 Whether it has novelty, inventive step and practical applicability?
(i) Whether it has novelty?
The Guidelines for Patent Examination provides: “As for a medical-use invention relating to a chemical product, the following aspects shall be taken into consideration when the examination of novelty is carried out.
(a) Whether or not 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 of them is the same.
(b) Whether or not 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.
(c) Whether or not the new use belongs to generic (upper level) term of the known use. The known use defined by specific (lower level) term may destroy the novelty of the use defined by generic (upper level) term.
(d) Whether or not the features relating to use, such as the object, mode, route, usage amount, interval of administration can define the procedure of manufacture of a pharmaceutical. The distinguishing features merely present in the course of administration do not enable the use to possess novelty.”
(ii) Whether it has inventive step?
The provisions of the Guidelines for Patent Examination for inventive step of use invention of chemical product are as follows:
“(a) Inventive step of use invention of new product
A use invention of a new chemical product is regarded as involving an inventive step if the use cannot be expected from the known product having a similar structure or composition.
(b) Inventive step of use invention of known product
A use invention of a known product is regarded as involving an inventive step if the new use cannot be derived or expected from the structure, composition, molecular weight, known physical/chemical property and existent use of the product, but utilizes a newly discovered property of the product, and produces unexpected technical effect.”
In general, the criterion for judging whether a new use of a known drug is obvious to its existing use is: if the new use can be obtained through simple, non-creative experiments based on the inspiration of the existing use, then the new use will be considered obvious; on the contrary, if not only experiments are needed, but also some creative factors that are not known to those skilled in the art, such as finding new targets and adopting new pharmacology , then it may be considered that the new use has novelty and inventive step.
(iii) Whether it has practical applicability?
The Patent Law provides: “Practical applicability means that the subject matter of a patent application for invention or utility model must be one which can be made or used in an industry and can produce effective results.”
Regarding the current patent application of Wuhan Institute of Virology, it can be seen from the available information that it can meet the requirements of novelty and practical applicability, but whether it can meet the requirements of inventive step depends on whether the specification of the patent application has valid comparative experimental data to prove that new uses can bring unexpected technical effects.
3. Protection of medicament patent
3.1 Different types of medicament patents have different levels of patent protection
Different types of medicament patents have different levels of patent protection after being granted. In general, product patents are stronger than process patents.
General speaking, after the compound is granted for a patent, the patentee's permission is required to use, promise to sell, sell, and import the compound for any purpose. With regard to medical-use invention patent, all persons, including patentees of medicament compounds, shall not implement the patent for the use patent of the medicament without the authorization of the patentee for the medical-use invention patent. However, in fact, since the medical-use invention patent does not prohibit doctors from using medicament for patented uses, it merely prohibits other medicament companies from labeling the medicament for patented uses, and its actual exclusive effect is quite limited.
In addition, during the duration of patent protection of a compound, if the other patentee only obtains a license for a medical-use of the compound, then even if the latter wants to implement the right of the medical-use, he should obtain the license from the patentee of the compound. Of course, conversely, when a patentee of a compound patent wants to implement a right of a medical use, he also needs to obtain the license from the patentee of the medical-use.
3.2 Duration of protection
China has not specifically stipulated duration of protection for medicament patent. In China, except for the possible design patent application for medicament packaging, other patents involving medicament are generally invention patents. The duration of patent right for inventions shall be 20 years from the filing date.
Regarding the patent term extension system, on April 12, 2018, the Premier of the State Council announced at an executive meeting of the State Council that “The data exclusivity period for innovative chemical medicines is 6 years at maximum, and medicines of the same species will not be authorized to commercialize within this period. In addition, a maximum of 5 years’ compensation of patent term will be offered for innovative new medicines which are applied for commercialization on domestic and oversea markets simultaneously.”
At present, China is still exploring and improving the protection of intellectual property rights of medicament. The patent term extension system for medicament patent is expected to be in line with international standards.
【Summary】The research on new medicament is costly and risky. The research and development results for medicament should be comprehensively protected from multiple aspects such as compound structure, use, and preparation. The development of new uses of known medicament is often cheaper and the risk of research and development is lower than the development of new medicament, enterprises should also pay attention to the corresponding patent protection and layout work.
1. Guidelines for Patent Examination of China,2019
2. Qingkui ZHANG, Filing and Examination of medicament patent