Abstract: Induced pluripotent stem cell is of great research interest at present in the cellular biology and molecular biology field, thus the amount of patent applications of inventions in China involving induced pluripotent stem cells is increasing. However, due to that there is a certain limit on the patentable subject according to Chinese Patent Law, before filing a patent application for a technical solution related to induced pluripotent stem cells, it needs to be considered whether the technical solution belongs to the allowable subject matters according to Chinese Patent Law; simultaneously, it also especially needs to be noted whether the technical solution has industrial applicability. In this paper, the patentability of several subject matters involving induced pluripotent stem cells is primarily discussed. Furthermore, the author tried to provide some references for determining whether to file a Chinese patent application or not and the manner in which the the application is filed for an applicant.

I. Outline of induced pluripotent stem cells

    Induced pluripotent stem cells (iPS) are embryonic stem cell (ES) like pluripotent cells obtained by introducing some transcription factors into somatic cells of animals or humans through gene transfection techniques and then directly reconstructing these somatic cells. Induced pluripotent stem cells not only are very similar to embryonic stem cells in terms of cell morphology, growth properties and stem cell marker expression etc., but also almost the same as embryonic stem cells in terms of DNA methylation patterns, gene expression profiles and chromatin state etc.

    Initially, induced pluripotent stem cells are obtained by Japanese scientist Shinya Yamanaka through using a viral vector to transfer a combination of four transcription factors (Oct4, Sox2, Klf4 and c-Myc) into differentiated somatic cells and then reprogram these somatic cells in 2006. After this, scientists gradually found that it also can produce this kind of cells by other methods.

    Although induced pluripotent stem cell technique is established no more than 10 years, it is greatly concerned and extensively studied, and now it becomes the focus of study and discussion in life science field and brings unprecedented hope for basic study and clinical disease treatment.

    In practical applications, the method for obtaining induced pluripotent stem cells is relatively simple and stable, and it does not need to use oocytes or embryos, so it has more advantages than other methods in terms of techniques and ethics. The establishment of induced pluripotent stem cells further shortens the distance between stem cells and clinical disease treatment, and it has a large potential value in terms of alternative cell therapy, pathogenic mechanism study and new drug screening. Furthermore, the effects of induced pluripotent stem cells in nervous system diseases and cardiovascular diseases have been gradually found, and induced pluripotent stem cells have been successfully differentiated into neuron cells, neurogliocytes, cardiovascular cells and primitive germ cells etc. in vitro.

    Although people know that induced pluripotent stem cells have a large application value in clinical disease treatment, in fact, before being used in clinical, induced pluripotent stem cells have many problems, such as: ① the potential risk of retrovirus and lentivirus vectors causing tumorigenesis need to be effectively prevented; ② it is needed to deeply study and compare induced pluripotent stem cells and human embryonic stem cells in terms of cell biological characteristics and directional differentiation mechanism to determine that whether they have significant differences; ③ it is needed to establish a new method to avoid the potential risk of gene transfection or gene transduction, such as in the manner of some chemical drugs or factors activating above-mentioned transcription factors which are inherent in somatic cells to replace the manner of exogenous gene transfection, or using transient expression of some factors to replace permanent introduction; ④ it is needed to improve the efficiency of preparing induced pluripotent stem cells.

Therefore, the study on induced pluripotent stem cells is just started, and there still are many technical problems to be solved and overcome. The solution of these problems and the improvement of techniques need to be protected by patent right, therefore, the patent prospect of technical solutions related to induced pluripotent stem cells is particularly important.

II.  Whether a technical solution related to induced pluripotent stem cells belongs to the allowable subject matters and has industrial applicability in China

    Due to that there is a certain limit on the patentable subject according to Chinese Patent Law, some technical subject matters related to induced pluripotent stem cells may not be protected by patent right. Therefore, before filing a Chinese patent application for a technical innovation regarding induced pluripotent stem cells, it needs to be considered whether the technique belongs to the allowable subject matters according to Chinese Patent Law, the problems such as whether the technique has industrial applicability etc also need to be considered.

    Techniques related to induced pluripotent stem cells mainly comprise following stages: (1) Collecting somatic cells from living animal or human bodies; (2) preparing induced pluripotent stem cells from somatic cells; (3) inducing induced pluripotent stem cells to differentiate; (4) separating and purifying induced pluripotent stem cells which have been induced to differentiate; (5) transplanting a transplant containing induced pluripotent stem cells, which have been induced to differentiate, into a human body or animal body.

    Therefore, techniques related to induced pluripotent stem cells may relate to the following subject matters:
    - a method for collecting somatic cells from living animal or human bodies;
    - a method for preparing induced pluripotent stem cells from somatic cells;
    - an induced pluripotent stem cell product;
    - a method for inducing induced pluripotent stem cells to differentiate;
    - a method for separating and purifying induced pluripotent stem cells which have been induced to differentiate;
    - a transplant product containing induced pluripotent stem cells which have been induced to differentiate;
    - a method for transplanting transplant into human body or animal body.
The author will in particular discuss whether above-mentioned subject matters belong to the allowable subject matters and have industrial applicability in the following text.

1. Method for collecting somatic cells from living animal or human bodies

    Before discussing whether "method for collecting somatic cells from living animal or human bodies" may be granted patent right, we need to understand the relevant provisions in "Guidelines for Patent Examination (2010)" for methods of surgery.

    According to the provisions of section 4.3.2.3, chapter 1, part II in "Guidelines for Patent Examination (2010)", methods of surgery refer to the methods of traumatic or invasive treatment such as incision, resection, stitching, and tattooing practiced on living human or animal bodies with the aid of instrument. Such methods of surgery cannot be granted patent rights.

    In particular, methods of surgery are divided into one category for the purpose of treatment and the other category for the purpose of non-treatment. A method of surgery for the purpose of treatment belongs to methods of treatment, for which no patent right shall be granted in accordance with the provisions of Article 25.1 (3) in Chinese Patent Law; and method of surgery for non-treatment purposes does not have practical applicability because these methods are practiced on the living human or animal body and cannot be used industrially, they also cannot be granted patent rights according to the provisions of section 3.2.4, chapter 5, part II in "Guidelines for Patent Examination (2010)".

    Therefore, the focus to be discussed herein is whether "method for collecting somatic cells from living animal or human bodies" belongs to methods of surgery in the sense of the Patent Law. If "method for collecting somatic cells from living animal or human bodies" belongs to methods of surgery, then it cannot be granted patent right regardless of whether its purpose is treatment or not.

    Although "Guidelines for Patent Examination (2010)" defines methods of surgery (i.e. the methods of traumatic or invasive treatment such as incision, resection, stitching, and tattooing practiced on living human or animal bodies with the aid of instruments), it does not define the methods of traumatic or invasive treatment. In fact, the methods of traumatic or invasive treatment in the sense of the Patent Law differ from the methods of traumatic or invasive treatment in the common sense.

    Following conclusions can be obtained from general approach of substantive patent examination practice at present[1]: In the sense of the Patent Law, the methods of traumatic treatment not only comprise opened methods of treatment which need an operation to expose focus, but also comprise closed methods of treatment which do not need an operation and minimal invasive surgery but will cause damages of cells or tissues in the body; the methods of invasive treatment not only comprise the methods which do not need an operation to expose focus and only need to perform minimal invasive treatment on blood vessels and skin, but also comprise method of performing non-traumatic treatment through original pipelines in a human body.

    According to above-mentioned viewpoints, method for collecting somatic cells from living animal or human bodies, no matter what its particular operating steps are, it must causes damages of cells in the body, therefore, it belongs to the methods of traumatic treatment, and belongs to methods of surgery in the sense of the Patent Law.

    By this, a conclusion can be obtained: "method for collecting somatic cells from living animal or human bodies" belongs to methods of surgery in the sense of the Patent Law, it cannot be granted patent right.

    Furthermore, the author considers that collecting somatic cells does not mean that induced pluripotent stem cells prepared from these somatic cells must be used for treating animals or humans, so when judging whether method for collecting somatic cells belongs to the patentable subject, we should not extend it to the subsequent stage of treating a patient using induced pluripotent stem cells. Therefore, method for collecting somatic cells from living animal or human bodies generally should not be considered for the purpose of treatment, in contrast, the method is most likely considered as it belongs to methods of surgery for the purpose of non-treatment, it cannot be granted patent right due to lacking practical applicability.

2. Method for preparing induced pluripotent stem cells from somatic cells

    After obtaining somatic cells, transferring pluripotent marker genes into somatic cells, inducing somatic cells to be reprogrammed into pluripotent stem cells, this is a general method for preparing induced pluripotent stem cells. This method generally is completed in vitro, and therefore, it does not belong to the category of methods for treating diseases.

    However, it needs to be noted that when judging whether this method can be granted patent right, we should consider that whether the involved somatic cells are obtained from living animal or human bodies. Till now, somatic cells of animals or humans have been commercialized, for example, skin fibroblasts can be purchased from the market. Therefore, it is generally considered that the somatic cells used as the raw material in such a method are commercially available somatic cells; however, if the description of a patent application definitely describes the method of obtaining the somatic cells is directly collecting somatic cells from living animal or human bodies, then the method for preparing induced pluripotent stem cells using the somatic cells may be considered to relate to surgery for the purpose of non-treatment, it cannot be granted patent right due to lacking practical applicability.

3. Induced pluripotent stem cell product

    Induced pluripotent stem cells, as a product, they will not be considered to belong to a method for diagnosing and treating a disease; and if their raw material for preparation, i.e. somatic cells do not derive from living animal or human bodies, then they generally will not be considered to be lacking practical applicability.

    Here, which needs to be especially discussed is: Whether "induced pluripotent stem cell product" belongs to animal variety in the sense of the Patent Law.

    According to the provisions of section 9.1.2.3, chapter 10, part II in "Guidelines for Patent Examination (2010)", an embryonic stem cell of an animal, an animal individual and an animal at the various stages of its formation and development, such as a germ cell, an oosperm, an embryo and so on belong to the category of the "animal variety" of Article 25. 1(4) in the Patent Law, they cannot be granted patent rights. A somatic cell of an animal and a tissue and an organ of an animal (except an embryo) are not in conformity with the definition of "animal", therefore they do not belong to the category according to the provisions of Article 25.1 (4) in the Patent Law.

    Induced pluripotent stem cells have their specific characteristic: On the one hand, they derive from somatic cells which do not belong to the category of the "animal variety"; on the other hand, they have performances similar to embryonic stem cells which belong to the category of the "animal variety". Therefore, whether induced pluripotent stem cells belong to animal variety, it needs to be carefully analyzed.

    According to Chinese patent practice, a totipotent stem cell formed from a somatic cell through reprogramming can develop into an animal body, so the totipotent stem cell belongs to the category of the animal variety. Here, it needs to be emphasized that a stem cell like cell formed by dedifferentiation of a somatic cell belongs to the category of the animal variety only when it has totipotency. As known to a person skilled in the biological field, a stem cell derived from a somatic cell generally does not have totipotency, it can be granted patent right. However, if the description definitely describes or even uses detailed data to demonstrate that an induced pluripotent stem cell has totipotency and can develop into an animal body, then although the cell derives from a somatic cell, it still belongs to the category of the animal variety and cannot be granted patent right.

    Therefore, when judging whether an induced pluripotent stem cell product belongs to the patentable subject matter, we need to review the detailed disclosure in the description; if in the description, it does not definitely record that the stem cell can differentiate and develop into an animal body, then we could generally consider that the stem cell does not have totipotency, does not belong to the animal variety and is a patentable subject.

4. Method for inducing induced pluripotent stem cells to differentiate

    After obtaining induced pluripotent stem cells, in order to realize their medical value, people generally will induce the cells into cells having specific functions of therapeutical effects (such as neuron cells, neurogliocytes, cardiovascular cells etc.) through a directional differentiation under a specific differentiation condition. This method for induced differentiation generally is completed in vitro, and therefore, it does not belong to the category of methods for treating diseases. If in a few cases, the method for induced differentiation is completed in vivo after transplanting induced pluripotent stem cells into an animal body, then it generally will be considered to be for the purpose of treatment, so it belongs to methods for treating diseases and cannot be granted patent right.

5. Method for separating and purifying induced pluripotent stem cells which have been induced to differentiate

    After performing induced differentiation on induced pluripotent stem cells, it is generally needed to separate and purify them from the differentiation medium. Since this method for separating and purifying them is performed in vitro, it does not belong to the category of methods for treating diseases.

6. Transplant product containing induced pluripotent stem cells which have been induced to differentiate

    Generally, transplant product containing induced pluripotent stem cells which have been induced to differentiate can be granted patent right, unless the description of a patent application definitely records that the raw material for preparation of the transplant, i.e. somatic cells, are directly taken from living animal or human bodies, or unless the induced pluripotent stem cells contained in the transplant have totipotency which can differentiate and develop into animal bodies.

    In particular, if the description records that the induced pluripotent stem cells contained in the transplant are directly taken from living animal or human bodies, then the transplant product may be considered to relate to surgery for the purpose of non-treatment, it cannot be granted patent right due to lacking practical applicability; and if the description records that the induced pluripotent stem cells contained in the transplant have totipotency, then the transplant product is very likely to be considered to relate to the category of the animal variety and cannot be granted patent right according to Article 25.1 (4) in the Patent Law.

7. Method for transplanting transplant into human body or animal body

    In order to make the prepared transplant to effect its function, it is needed to transplant the transplant into animal or human bodies to be treated, this transplanting method generally is considered to be methods of surgery for the purpose of treatment, it falls in the category of methods for treating diseases and cannot be granted patent right according to Article 25.1 (3) in the Patent Law.

III. Novelty of induced pluripotent stem cell product

    As regard to induced pluripotent stem cells, a problem especially attracting the attention of the author is, whether they are novel with respect to embryonic stem cells.

    First, the author considers that "induced pluripotent stem cells" comprises features of preparation method from the definition. Specifically, induced pluripotent stem cells refer to cells obtained by inducing somatic cells of human or animal to be reprogrammed. In contrary, embryonic stem cells refer to stem cells directly taken from an embryo. Therefore, although the subject matter of induced pluripotent stem cell belongs to a product claim, it implicitly comprises features of the preparation method comprising inducing somatic cells to be reprogrammed.

    For the claim of a chemical product characterized by manufacturing process, the novelty shall be determined on the product per se, rather than merely comparing the manufacturing process therein with the process disclosed in a reference document to find whether or not the two processes are identical, according to the provisions of section 5.3, chapter 10, part II in "Guidelines for Patent Examination (2010)". A different manufacturing process does not always result in the change of a product per se. If, compared with a product disclosed in a reference document, the difference of said claimed product lies only in the manufacturing process, having neither parameters disclosed in the patent application, which may be used to prove its difference, nor indications of any change in its function and/or nature resulting from the difference of the process, then it is deduced that the product claim characterized by the process does not possess novelty as required in Article 22.2.

    Therefore, if induced pluripotent stem cells discussed herein only differ from embryonic stem cell in preparation method, and the preparation method does not bring any difference in function and nature, then the induced pluripotent stem cells will be considered to be lacking novelty under Article 22.2 of the Patent Law with respect to the prior art. In contrast, if the applicant can provide sufficient reasons and evidences to show that induced pluripotent stem cells have different compositions, such as different compositions of genes and proteins, or have any difference in function and nature, then it should be considered that these induced pluripotent stem cells have novelty with respect to the prior art.

IV. Conclusion

    Above, the author preliminarily discusses patentability of different technical subjects in the field of induced pluripotent stem cells, on the basis of a few working experiences in the patent practice of the biological field. The author wishes to provide a relatively simple and direct reference through above discussion for an applicant when estimating the patentability of an invention before filing a patent application in China.

V. References

[1] State Intellectual Property Office of the P.R.C., Guidelines for Patent Examination, Beijing: Intellectual Property Publishing House, 2010.

[2] LENG, Yushan and Li, Linxia, Discussion of methods for traumatic or interventional therapies or treatments in the sense of the Patent Law. China invention & patent, 2013, no. 5, pages 106-107.