Introduction

Since the Patent Act universally adopts the first-to-file system, under which a patent right is granted to the person who filed first, it is necessary to file as early as possible. Therefore, even in a situation where sufficient experimental data has not been obtained, it is general practice to file an application with minimum working examples, and thereafter supplement working examples and improvement inventions in a priority-claiming application.
In such cases, the question frequently arises as to whether the effect of the priority claim can be recognized for those portions supplemented in the later‑filed application, including additional working examples or improvements. In addition, since the determination of the validity of a priority claim is entrusted to the patent offices of each country and region, the determinations may differ depending on the jurisdictions.

In recent years, the Intellectual Property High Court (“IPHC”) in Japan has issued decisions of significant practical importance that set forth its views on the validity of priority claims. In this article, we introduce recent IPHC cases focusing on the validity of priority claims and discuss patent filing strategies in Japan for priority-claiming applications in the fields of pharmaceuticals, chemistry, and biotechnology.

Internal Priority (Patent Act Article 41) and Paris Convention Priority (Paris Convention Article 4)

Priority in Japan includes internal priority (Patent Act Article 41) and priority under the Paris Convention (Paris Convention Article 4).

Internal priority is to claim priority in a later application filed in Japan based on an earlier application filed in Japan. An applicant can file a patent application that combines the basic invention in the earlier-filed application and the later improvement invention as a comprehensive invention. As a result, it becomes possible to ensure that the developed technologies are smoothly protected by patent rights without omission.

Priority under the Paris Convention is to claim priority when a person who filed a patent application in a member country (the first country) of the Paris Convention files a patent application in another member country (the second country) of the Paris Convention for the contents described in the first patent application. When filing patent applications for the same invention in multiple countries, preparation such as translation and procedures that differ between countries are required. Therefore, filing patent applications simultaneously in multiple countries imposes a heavy burden on applicants, however, the Paris Convention priority system reduces this burden.

Article 41(2) of the Patent Act provides for the effect of claiming internal priority. In principle, internal priority is provided to have the same effect as the Paris Convention Priority (Paris Convention Article 4B). That is, with respect to an invention disclosed in an earlier-filed application (first priority application), a later-filed application (priority-claiming application) can obtain the effect that, for purposes of determining novelty, inventive step, etc., the later-filed application will be treated in the same manner as if it had been filed on the same filing date as the earlier-filed application. Therefore, in this article we do not distinguish between internal priority and Paris Convention Priority because for the purpose of understanding the Japanese priority system, the reasoning concerning internal priority claims may likewise be applied to the assessment of Paris Convention Priority claims.

 

Method of Determining Priority in Japan

According to the Examination Guidelines in Japan, in principle, the validity of the effect of a priority claim is determined by the following method. The same criteria as those for determining amendments adding a new matter at the examination stage are adopted.

[Excerpts from the Examination Guidelines]
(1) Basic ideas of the comparison 
    Assume that the description, claims and drawings of the application filed in Japan are amendments of the application filed in the first country. If the claimed invention of the application filed in Japan introduces any new technical matter in relation to the "matters stated in the application documents as a whole of the application filed in the first country," the effect of the priority claim of the Paris Convention shall not be recognized. Here, the "matters stated in the application document as a whole of the application filed in the first country" mean technical matters that a person skilled in the art understands from the whole description in the application documents of the application filed in the first country, and hereinafter may be referred to as the "matters stated in the application filed in the first country."

In addition, according to the Examination Guidelines in Japan, one of typical cases where the claimed invention in the priority-claiming application is not considered to be within the scope of the matters stated in the application filed in the first country is an invention which could not be carried out as of the priority date claimed. In other words, the “enablement” is also taken into account when determining priority.

Case 1: Appeal 2023 (Ke) No. 10057 (Fumakilla v. Earth Corporation)

This case concerns a patent application claiming internal priority. The dispute concerned the validity of the priority claim where, with respect to matters for which no working examples were described in the specification of the earlier-filed application, working examples were supplemented in the later-filed application.

This case is seeking revocation of a trial decision concerning Japanese Patent No. 6539407 (‘407 Patent) , “Spray Product and Spray Method” (patentee: Earth Corporation). The plaintiff (Fumakilla Co., Ltd., petitioner for invalidation trial) sought revocation of the JPO trial decision, arguing that the patent was invalid because it did not satisfy the requirements for an internal priority claim. The issue was that the specification of the first priority application (Application No. JP2016-71925, first priority date: March 31, 2016) did not include working examples containing a specific ingredient (Icaridin), and working examples containing Icaridin were expressly disclosed for the first time in the second priority application (Application No. PT2016-229406, second priority date: November 25, 2016).

Claim 1 after correction of ‘407 Patent is as follows:

[Claim 1]
A spray product is filled with a pest-repelling composition containing a pest-repelling ingredient and has an injection port for injecting the pest-repelling composition (excluding the case of containing a propellant),
wherein the pest-repelling composition has a vapor pressure at 20°C of 2.5 kPa or less, and contains 10% by mass or more, in the pest-repelling composition, of a volatilization-suppressing ingredient (excluding a case where the volatilization-suppressing ingredient is glycerin) for suppressing volatilization after spraying,
wherein the pest-repelling ingredient is at least one ingredient selected from the group consisting of 3-(N-n-butyl-N-acetyl)aminopropionic acid ethyl ester (EBAAP) and 1-methylpropyl 2-(2-hydroxyethyl)-1-piperidinecarboxylate (Icaridin),
wherein the particle diameter ratio (r30/r15) between the 50% average particle diameter r15 of the sprayed pest-repelling composition at a position 15 cm away from the nozzle and the 50% average particle diameter r30 of the sprayed pest-repelling composition at a position 30 cm away from the nozzle is adjusted to be 0.6 or more,
and wherein the 50% average particle diameter r30 of the sprayed pest-repelling composition at a position 30 cm away from the nozzle is adjusted to be 50 μm or more.

The plaintiff argued that, because the first priority application did not include any description of specific working examples containing Icaridin, the effect of the priority claim did not extend to the invention containing Icaridin, and that the ‘407 Patent lacked novelty and inventive step. In response, the defendant argued that, based on the overall description of the specification of the first priority application, it would have been possible for a person skilled in the art to carry out the invention containing Icaridin and, therefore, the invention containing Icaridin had already been disclosed as a technical matter.

Here, the first priority application includes the identifying matters of the corrected claim 1 in ‘407 Patent, and Icaridin is also explicitly stated as a pest-repelling ingredient similarly to EBAAP. In addition, (1) the technical field, (2) the background art and the problem to be solved, (3) the means for solving the problem (adjustment method, mechanism by which the effect is exhibited, technical significance of each constituent requirement), and (4) the effect of the invention are described.

The IPHC held that the validity of the internal priority claim should not be determined only from the formal viewpoint of whether working examples are described in the specification of the first priority application. Alternatively, validity of the effect of an internal priority claim should be determined from (a) the viewpoint that the invention does not introduce a new technical matter in relation to the technical matters described in the specification, etc., of the first priority application, and (b) the viewpoint of “enablement,” i.e., whether a person skilled in the art could implement the invention without undue trial and error based on the description of the specification.

On that basis, the IPHC determined that the specification of the first priority application specifically described configurations and technical ideas that could encompass Icaridin, and that a person skilled in the art could implement a spray product using Icaridin, and therefore the supplementation of working examples in the later application did not add a new technical matter. Accordingly, the IPHC recognized the effect of internal priority based on the first priority application for the invention at issue and dismissed the plaintiff’s claim.

This case is significant in patent practice and invalidation trial practice, in that, with respect to internal priority claims of the so-called “supplemented working example type,” it clarified that even if there is no explicit description of working examples in the first priority application, the effect of priority may be affirmed if a person skilled in the art could implement the invention based on the overall description of the specification of the first priority application.

 

Case 2: Appeal 2023 (Ke) No. 10147 (ToolGen v. University of California, University of Vienna)

This case is a trial decision revocation action in which the validity of the priority claim and the validity of a Japanese patent relating to CRISPR/Cas9, which is used worldwide as a genome editing technology, were disputed.

The subject was Japanese Patent No. 6692856 (‘856 Patent) , “Methods and Compositions for RNA-Directed Target DNA Modification and RNA-Directed Mutation of Transcription” (patentee: University of California and University of Vienna). The issue was the validity of the effect of the Paris Convention Priority, that is, whether it could be said that the invention of ‘856 Patent (in particular, application to eukaryotic cells) was substantively disclosed in the priority applications.

With respect to ‘856 Patent, the plaintiff (ToolGen Incorporated, petitioner for invalidation trial) sought revocation of the JPO “trial decision of no invalidation,” arguing that ‘856 Patent should be invalidated based on the prior art. The plaintiff contended that the first priority application (US 61/652,086; first priority date: May 25, 2012) and the second priority application (US 61/716,256; priority date: October 19, 2012) did not provide sufficient disclosure for causing CRISPR/Cas9 to function in eukaryotic cells, and therefore the effect of priority should not be valid.

Claim 1 of ‘856 Patent is as follows:

[Claim 1]
A method of modifying a target DNA, comprising contacting the target DNA with a complex in a cell,
wherein the complex comprises:
(a) a Cas9 polypeptide; and
(b) a DNA-targeting RNA comprising:
       (i) a DNA-targeting segment comprising a nucleotide sequence complementary to a sequence within the target DNA; and
       (ii) a protein-binding segment that interacts with the Cas9 polypeptide, wherein the protein-binding segment comprises two complementary stretches of nucleotides that hybridize to form a double-stranded RNA (dsRNA), wherein the dsRNA comprises complementary nucleotides of a tracrRNA and a CRISPR RNA (crRNA), 
wherein the cell is a plant cell, an animal cell, or a unicellular eukaryote;
wherein the cell is not a human cell in vivo, is not a human germ cell, and is not a human embryonic cell, and
wherein the modification is cleavage of the target DNA.

The IPHC held that whether the Paris Convention priority based on the priority applications is recognized should be determined not only on the basis of the claims but also on the basis of matters that are recognized, in a substantive sense, as being described in the application documents of the first priority application as a whole, including the specification. Furthermore, the IPHC held that, in order for the invention of claim 1 to be recognized as being substantively described in the application documents of the first priority application as a whole, it is necessary that a person skilled in the art could implement the invention of claim 1 without undue trial and error, etc., based on the description of the application documents of the first priority application as a whole and common general knowledge as of the priority date.

Specifically, the IPHC referred to the following two points.

• The first priority application documents specifically describe the configuration of the CRISPR/Cas9 system (a complex of a DNA-targeting RNA and a site-specific modifying polypeptide) that modifies a target DNA in a site-specific manner, and the structure and function of each constituent element, as well as the mechanism and framework leading to cleavage (double-strand break) of the target DNA.
• The working examples also specifically show that the complex can be created, and the target DNA can be cleaved.

Further, the IPHC cited numerous papers regarding common general knowledge as of the priority date, and held that “it is reasonable to find that the first priority application documents disclosed the technical idea of applying the CRISPR/Cas9 system to target DNA in eukaryotic cells, and that the first priority application contained a specific explanation of the invention in this case to such an extent that implementation was possible when combined with well-known technologies as of the priority date.”

In addition, in this case, based on the fact that it was reported during a short period between October 2012 and January 2013 that genome editing could be performed by applying the CRISPR/Cas9 system to eukaryotic cells, an unprecedented approach has been adopted in which enablement is judged based on the description of the first-filed application.

Conclusion

It has been stated that, as the method for determining whether the effect of a priority claim is valid or not, the criterion adopted is whether the priority-claiming application introduces a new technical matter in relation to the matters stated in the application documents as a whole of the priority applications. 

Furthermore, in priority-claiming applications, the validity of a priority claim cannot be assessed solely by the formal existence or absence of working examples or correspondence of wording, such as whether working examples are explicitly described or whether the wording matches exactly. Instead, the key issue is whether the invention is substantively enabled in light of the common general knowledge of a person skilled in the art. 

In both judgments, it appears that even where no working examples are disclosed in the priority applications, significant weight is placed on whether, based on the disclosure of the original specification, etc., and common general knowledge as of the priority date, a person skilled in the art could implement the invention without undue trial and error. In both cases 1 and 2, it seems that, even for inventions for which there is no disclosure of working examples in the priority applications, it is regarded as important whether a person skilled in the art could implement the invention without undue trial and error based on the common general knowledge on the priority date and the disclosure of the priority applications.

Therefore, if working examples or improvement inventions will be supplemented in a priority-claiming application, it is recommended that attention be paid to the following points at the time of filing the basic application and the priority-claiming application.

(1) The problem to be solved by the invention in the first priority application and in the priority-claiming application, and the effects achieved by the invention, should be common to both applications.

If, in the priority-claiming application, a new problem not described in the first priority application or an invention to achieve a new effect is added, there is a possibility that the effect of the priority claim will be invalid.

(2) In the first priority application, the effects achieved by the working examples to be supplemented in the priority-claiming application should be described.

(3) In the first priority application, the configuration of the invention corresponding to the working examples to be supplemented in the priority-claiming application should be explicitly described.

(4) In the first priority application, the mechanism of action and principle corresponding to the working examples to be supplemented in the priority-claiming application should be described.

(5) In the first priority application, the specific experimental methods of working examples to be supplemented in the priority-claiming application should be described.