Supplementary experimental data acceptance criteria in pharmaceutical patent grant and confirmation procedures

In the grant and confirmation procedures for pharmaceutical patents, supplementary experimental data submitted by the applicant after the filing date of the patent is generally to prove that the patent application possesses inventiveness or that the description of the patent application sufficiently discloses the invention.

The Chinese Patent Examination Guidelines describe the examination principles for supplementary experimental data in pharmaceutical patent applications as follows: “For experimental data submitted by the applicant after the filing date to meet the regulatory requirements – for example, the invention of the patent application shall have prominent substantive features and represent notable progress and thus possess inventiveness, and its description shall set forth the invention in a manner sufficiently clear and complete so as to enable a person skilled in the relevant field of technology to carry it out – the examiner shall review it. The technical effects proven by the supplementary experimental data should be obtainable by a person skilled in the art from the content disclosed in the patent application.”

The Provisions of the Supreme People’s Court on Several Issues Concerning the Application of Law in the Trial of Administrative Cases of Patent Grant and Confirmation states: “If the applicant of a pharmaceutical patent submits supplementary experimental data after the filing date – claiming to rely on such data to prove that the patent application complies with the inventiveness requirement, e.g. having prominent substantive features and representing notable progress, and providing a sufficiently clear and complete description of the invention so as to enable a person skilled in the relevant field of technology to carry it out – the People’s Court shall review it.”

In the practice of inventiveness determination, experimental data submitted after the filing date is usually closely related to technical effects. The acceptance criteria for supplementary experimental data mainly focus on a core issue: whether the technical effects proven by the supplementary experimental data can be obtained by a person skilled in the art from the contents disclosed in the patent application. This criterion not only clarifies the basis for the determination but also causes discussion in the industry.

This article cites two administrative judgments from the Supreme People’s Court – namely, Zui Gao Fa Zhi Xing Zhong No. 33 (2019) and Zui Gao Fa Zhi Xing Zhong No. 15 (2022) – in aiming to clarify the acceptance criteria for supplementary experimental data in the grant and confirmation procedures for pharmaceutical patents.

A Swedish company is the patentee of the patent No. ZL200610002509.5, titled ‘New Crystalline and Non-Crystalline Forms of Triazole(4,5-d)Pyrimidine Compounds’. The company submitted supplementary experimental data in an invalidation procedure to prove that the patent possessed inventiveness due to the “surprisingly high metabolic stability” recorded in the description, which is an unexpected technical effect in the art. However, the CNIPA held that the supplementary experimental data submitted by the company should not be accepted, and even if accepted, it could not prove the above technical effect, and the patent lacked inventiveness.

The company instituted a lawsuit before the Beijing Intellectual Property Court. The court did not acknowledge that the patent clearly recorded the above technical effect, on the ground that the above effect was only recorded in the “Background Art” of the patent, and ruled that the supplementary experimental data should not be accepted.

In the appellate case, the Supreme People’s Court held that the determination on the non-acceptance of the supplementary experimental data in the CNIPA’s decision and the first-instance judgment was incorrect, and that the supplementary experimental data should be accepted. However, since the supplementary experimental data cannot prove that the compound of claim 1 had unexpected technical effects, claim 1 did not have an inventive step, and the original judgment was upheld.

A Dutch company is the applicant of the patent application No. 201611028228.7, titled ‘New CC-1065 Analogs and Conjugates Thereof’. The company submitted supplementary experimental data in the re-examination procedure to prove that the claimed compounds had superior technical effects compared with the prior art and thus possessed inventiveness. However, the CNIPA held that the supplementary experimental data submitted by the company should not be accepted, because the ‘fact to be proven’ by the supplementary experimental data was not explicitly recorded or implicitly disclosed in the original patent application.

The company instituted a lawsuit before the Beijing Intellectual Property Court. The court and the appellate Supreme People’s Court ruled that the supplementary experimental data should not be accepted.

Through the rulings and the acceptance criteria for supplementary experimental data in the above cases, it can be seen that the key problem lies in how to determine that the fact to be proven by the supplementary experimental data can be obtained from the disclosure of the patent application.

In these two cases, the Supreme People’s Court expounded the essence of supplementary experimental data from a legal point of view, and specifically conducted its analysis from both positive and passive perspectives, focusing on whether supplementary experimental data would enable the patentee to improperly obtain the benefits of an earlier filing date.

For the positive condition, the original patent application document should explicitly record or implicitly disclose the fact to be proven by the supplementary experimental data. And for the passive condition, the applicant cannot use supplementary experimental data to remedy inherent defects in the original patent application documents.

The above aims to emphasise that supplementary experimental data should typically prove the authenticity of a fact that is explicitly recorded or implicitly disclosed in the original patent application document, thereby supplementing the proof of the legal factual matters that the applicant or patentee ultimately wants to prove, rather than proving content that is not disclosed in the original patent application document. This is illustrated in Figure 1.

The fact to be proven by the supplementary experimental data is that the compound of claim 1 had unexpected technical effects; namely, “surprisingly high metabolic stability and bioavailability”, as recorded in the specification.

For the positive condition, in the original application document, paragraph (0005) under the subtitle “Background” in the description explicitly recorded the fact to be proven, “surprisingly high metabolic stability and bioavailability”. The appellate court rectified the holding of the trial court that the submitted supplementary experimental data should not be accepted because such fact to be proven was only recorded in the “Background Art” section. Even if the fact to be proven is only recorded in the “Background Art” section, it still belongs to the disclosure of the application document.

For the passive condition, the supplementary experimental data was intended to prove the authenticity of the fact to be proven and, thus, to supplement the proof of the ultimate legal factual matter to be proven; that is, claim 1 had inventiveness. The supplementary experimental data was not used to overcome inherent defects in the original patent application document and therefore should be accepted. This is illustrated in Figure 2.

The fact to be proven by the supplementary experimental data submitted by the Dutch company is that the specific compounds as claimed in claim 1, corresponding to examples, had higher cytotoxicity than the specific compounds in reference 1, thus achieving unexpected technical effects in the treatment of gastric cancer and prostate cancer.

For the positive condition, the original description did not explicitly record the structures of the specific compounds as claimed in claim 1, and thus the technical effects of the selective cytotoxic activity of the specific compounds of claim 1 in this application could not be further confirmed by a person skilled in the art according to examples and other parts of the description. Therefore, according to the contents disclosed in the description of this application, a person skilled in the art cannot determine the fact to be proven, and the submitted supplementary experimental data should not be accepted.

For the passive condition, the original description did not disclose the specific structures of the compounds and cannot sufficiently prove that the compounds had better technical effects than those in reference 1. Therefore, the Dutch company’s submission of the supplementary experimental data to describe the structures of the specific compounds was not merely to illustrate the technical effects of the compounds through supplementary experimental data but to supplement content that was not sufficiently disclosed in the original application document and remedy inherent defects in the original application document, which does not meet the passive condition for the acceptance of supplementary experimental data. Therefore, the supplementary experimental data submitted should not be accepted. This is illustrated in Figure 3.

In the grant and confirmation procedures for pharmaceutical patents, the acceptance criteria for supplementary experimental data usually depend on two factors:

• Positive condition – the original patent application document should explicitly record or implicitly disclose the fact to be proven by the supplementary experimental data; and

• Passive condition – the applicant cannot use supplementary experimental data to remedy inherent defects in the original patent application document.

Supplementary experimental data can be accepted and used to assess inventiveness or sufficient disclosure of the description if these two conditions are met.

To avoid the issue of supplementary experimental data not being accepted during the grant or post-grant procedure, the applicant should sufficiently disclose the intended use and effect of the drug in the description when drafting the documents of a pharmaceutical patent application. If a person skilled in the art could not predict that the invention could achieve the stated use and effect based on the prior art, the description should include qualitative or quantitative experimental data sufficient to demonstrate that the technical scheme of the invention can achieve the intended use and the desired effect.

Moreover, in view of the dispute in case 1 between the trial court and the appellate court regarding whether the technical effect recorded in the “Background Art” section can serve as the fact to be proven, it is recommended that the applicant record the technical effects of the invention in the patent application in the “Summary of the Invention” or “Detailed Description of the Invention” section.

However, due to differences in understanding of the prior art, interpretation of the inventive aspects of a technical scheme, and varying perceptions of the technical level of a person skilled in the art, it is inevitable that specific experimental data may not be recorded in the original application documents. Therefore, when drafting patent application documents, it is recommended that the applicant anticipate a potential need for experimental data and leave room in the description for the supplementation of data.

Nevertheless, the patent applicant should avoid relying on supplementary experimental data to remedy or conceal inherent defects in the original application document, such as insufficient disclosure in the description or vague recitations. Since supplementary experimental data is submitted by the patent applicant after the filing date or the priority date, if certain contents that were disclosed or completed after the filing date or priority date are incorporated into the scope of patent protection, the benefit of an earlier filing date for such contents is improperly obtained, which would violate the first-to-file principle.

Similarly, using supplementary experimental data to supplement content that was not sufficiently disclosed in the original application document or to remedy inherent defects in the original application, as seen in case 2, would undermine the requirement for sufficient disclosure in the description and deviate from the fundamental principle of the patent system, which is based on the exchange of disclosure for protection. Therefore, including sufficient experimental data in the original specification is very important.

Furthermore, the acceptance of supplementary experimental data does not necessarily endow it with probative force to demonstrate inventiveness as a fact to be proven. For example, in case 1, although the appellate court held that the supplementary experimental data should be accepted, it also concluded that the experimental data was not sufficient to prove the unexpected technical effect and then the inventiveness. Therefore, when submitting supplementary experimental data to prove unexpected technical effects, its probative force should be evaluated in advance.

In patent cases, it is very helpful to comprehensively consider and clarify, by using both positive and passive conditions, the inherent nature of the substantive disclosure in the patent application and the fact to be proven by supplementary experimental data.

Through analysing the above two typical cases, the acceptance criteria for supplementary experimental data in the grant and confirmation procedures for pharmaceutical patents have been demonstrated, providing a reference for similar future cases and implying higher requirements for the drafting of patent application documents and patent prosecution. While various complex situations may arise in the future, continuous research into, and the study of, such topics will provide more theoretical and practical support for patent practice.