IP Court Reiterates the Importance of Unexpected Effect for Determining Inventive Step
Date: 13 September 2023
【Volume 120】
In asserting the inventive step of a patent application, when the differences between the patent application and the prior art are not significant, the Taiwan Intellectual Property Office and the court typically determine the inventive step based on whether these differences can achieve unexpected effects, are supported by data when compared to the prior art. The court reiterated the above standards in a judgment related to a biomedical patent application which is introduced below.
Case Fact
National Taiwan University (the plaintiff) applied for Patent Application No. 107102761 (the ‘761 application), titled "BIOINK SET AND APPLICATIONS THEREOF FOR THREE-DIMENSIONAL PRINTING OF CELLS." However, the application was rejected after examination. The plaintiff submitted a request for re-examination and amended the claims, but the application was rejected again upon further examination due to the lack of inventive step. The plaintiff filed an administrative appeal, which was dismissed by the Ministry of Economic Affairs. As a result, the plaintiff filed an administrative litigation.
The court ruled against the plaintiff1 , determining that claims 1-13 of the ‘761 application lacked inventive step based on the disclosure of exhibits 1-4.
Technical Features of the ‘761 Application
Claim 1 was amended in both the examination and re-examination as follows:
A bioink set for printing a cell-bearing construct, comprising a bioink and a divalent metal ion solution, wherein the bioink comprises a biodegradable polyurethane and a biopolymer selected from the group consisting of gelatin, agar, alginate salts, hyaluronic acid and salts thereof, chitosan, and any combinations thereof, the biodegradable polyurethane and the biopolymer are at a weight ratio ranging from 85:15 to 5:95.
Disclosure of the Exhibits
Table of comparison between the technical features of claim 1 and the exhibits
| Claim 1 of the ‘761 application | Exhibit 12 | Exhibit 23 | |
|---|---|---|---|
| Feature 1 | A bioink set for printing a cell-bearing construct, comprising a bioink and a divalent metal ion solution | Bioink can be used in conjunction with calcium chloride solution for secondary chemical solidification to facilitate cross-linking (4th paragraph of the left column on page 3129, 2nd paragraph of the left column on page 3130, 1st paragraph of the right column on page 3130) | The bioink was combined with CaCl2 and then printed with a needle to produce the appropriate gelation |
| Feature 2 | the bioink comprises a biodegradable polyurethane and a biopolymer selected from the group consisting of gelatin, agar, chitosan, and any combinations thereof | Bio-ink formulations may contain: 1. Polyurethane (PU) containing water-dispersible biodegradable material 2. Natural materials originating from animals such as gelatin (last paragraph of the right column on page 3122), cells, alginate, carboxymethyl-chitosan, etc. (4th paragraph of the left column on page 3129) | Bioink composed of gelatin modified with methyl methacrylate (GelMA), alginate, photoinitiator, and cells |
| Feature 3 | the biodegradable polyurethane and the biopolymer are at a weight ratio ranging from 85:15 to 5:95 | undisclosed | undisclosed |
Accordingly, the main differences between the ‘761 application and the exhibits are that the biopolymer composition is slightly different, and the exhibits do not disclose the ratio of the contents.
Opinions of the Court
- Exhibit 1 has revealed that the bioink formulation may contain gelatin, cells, alginate, carboxymethyl-chitosan, etc., which are equivalent to the gelatin, chitosan, and agar of the ‘761 application. Also, it is a common technique in the art to adjust the composition and content ratio of natural materials in bioink to enhance its performance.
- The plaintiff argues that the biopolymers used in the ‘761 application are distinct and require experimentation to identify their specific types. However, the plaintiff deleted the overlapping components, such as hyaluronic acid and alginate, disclosed in the exhibits during amendment. Nonetheless, exhibit 1 provides a specific example of the combination of components, including gelatin, in its bioink formulation. Additionally, claim 1 of the ‘761 application "comprises" both biodegradable polyurethane and biopolymer in its bioink, which means that the bioink may still contain other components, making it difficult to conclude that the presence of components like hyaluronic acid or alginate in exhibit 1 necessarily distinguishes it from the ‘761 application.
- The plaintiff argues that the chitosan disclosed in exhibit 1 is carboxymethylated and the gelatin disclosed in exhibit 2 is modified with methyl methacrylate, both of which are different from the ‘761 application and have different effects and mechanisms. However, the description of "chitosan," "gelatin," and other compounds in the claims of the ‘761 application does not include any specific limiting conditions, so the interpretation of the claim should not exclude any specific compounds of chitosan and gelatin. Therefore, whether or not they are processed with substituents, they should be considered to meet the definition of those compounds.
In addition, exhibit 1 specifically discloses that the bioink containing gelatin can utilize a cross-linking mechanism by chemically reacting with calcium ions (gelation), which is also substantially the same as the approach adopted in the ‘761 application.
- The plaintiff further argues that the ‘761 application can achieve superior structural stability effect (exceeding 24 hours) after a specific time of reaction with divalent metal ions. However, exhibit 1 has disclosed a composition that matches the specific combination in the ‘761 application, which would naturally have similar or identical effects. Since the ‘761 application does not include examples or comparative examples illustrating its contrast with prior art, comparisons of the achieved effects in terms of quantity or level cannot be made.
- The plaintiff also presented experimental data from exhibits 2 to 5, asserting that the weight ratio range defined in claim 1 of the ‘761 application has an effect. However, the effect of such experimental data is unclear, and none of them include comparative examples to what is already known in the prior art, which could be used to conduct a difference comparison. Therefore, it is difficult to determine that the ‘761 application has an inventive step over the prior art.
Wisdom Suggested Strategies
According to our analysis, the case mainly involves the following three issues:
- Whether "compound" and "compound subjected to substitution or modification" are independent and distinct substances
In this case, the plaintiff argued that gelatin and gelatin modified with methyl methacrylate are completely different, and their preparation processes differ. However, the court considered the modified gelatin as a specific concept of gelatin, and therefore the modified gelatin of the exhibit is included in the gelatin of the ‘761 application. This interpretation is important for applicants in the field of chemical materials, especially when the modified and unmodified compounds do not have significant differences in their chemical mechanisms in subsequent applications.
- Whether the exclusion of substances overlapping with exhibits demonstrates inventive step of the ‘761 application
In the prosecution of the ‘761 application, alginates and hyaluronic acid and their salts were deleted to distinguish from the prior art. The court considered the use of the term "comprising" in the ‘761 application to be open-ended, making it difficult to conclude that exhibit 1 differs from the ‘761 application in that exhibit 1 comprises hyaluronic acid or alginate.
Furthermore, according to our analysis, since the substances of the original claim 1 of the ‘761 application are written in the form of Markush group, it is evident that each substance should have a similar nature, and the preparation mechanisms would not result in significant differences or impacts on the effect. Moreover, if the fact that the substances have similar characteristics is known to a PHOSITA, the substitution of alginate or hyaluronic acid with other substances should be considered a simple modification. If the plaintiff wishes to argue the inventive step based on this point, they should provide experimental data proving that the other substances have significantly superior effects compared to hyaluronic acid or alginates.
- Whether limiting the numerical range undisclosed in the exhibits demonstrate inventive step
Limitations on numerical ranges require proof that the range can produce effects not anticipated by prior art. In this case, the plaintiff submitted multiple sets of experimental data to support their argument, but the court has set a high standard, requiring that experiments be conducted under the same conditions and that the effects achieved be both obvious and unambiguous. And the plaintiff must conduct further experiments under the same conditions as the exhibits to establish superiority over the exhibits.
It is our opinion that since the plaintiff's limitation of the numerical range is substantial (85:15 to 5:95) and that nearly all experimental conditions fall within this range, the plaintiff would face a higher burden of proof when proving that this range is not a routine selection that those skilled in the art would perform.
In conclusion, this judgment once again highlights the importance placed by Taiwan courts on the effect when assessing inventive step. When the difference between an application and a prior art is not obvious, the argument often centers on the effect achieved by the differences. It is advisable to use prior art as a control group to demonstrate the superior effect of the application compared to the prior art.
Moreover, when an office action is received during reexamination, applicants should consider requesting an interview. In this case, the applicant provided multiple sets of data and detailed technical content in response but still faced rejection by the examiner. To enhance the probability of approval and the efficiency of response preparation, it is recommended to request an interview with the examiner before submitting the response. This will facilitate a better understanding of the examiner's concerns and enable the applicant to explain the technical content in person.
[1] 2022 Xing Zhuan Su Zi No.2 Judgment of the Intellectual Property and Commercial Court
[2] Choi, Y.J., Yi, H.G., Kim, S.W., Cho, D.W. (2017). 3D Cell Printed Tissue Analogues: A New Platform for Theranostics. Theranostics, 7(12), 3118-3137. https://doi.org/10.7150/thno.19396.
[3] Hölzl K, Lin S, Tytgat L, Van Vlierberghe S, Gu L, Ovsianikov A. Bioink properties before, during and after 3D bioprinting. Biofabrication. 2016 Sep 23;8(3):032002. doi: 10.1088/1758-5090/8/3/032002. PMID: 27658612.
