The IP High Court decided that a person skilled in the art could easily conceive of the invention characterized by the usage and dosage of the drug based on the invention described in the published clinical trial plan (clinical trial protocol) and the common technical knowledge. The court dismissed the request for cancellation of the invalidation trial decision (IP High Court Judgment, June 29, 2021(Case number: 2020 (Gyo-Ke) 10094).
Invention 1 (after the Correction)
Recurrence inhibitor of a proton pump inhibitor resistant reflux esophagitis containing rabeprazole sodium as an active ingredient, which is used by administration of rabeprazole sodium 10 mg twice daily for 4 weeks or longer for maintenance therapy for patients with proton pump inhibitor (“PPI”) -resistant reflux esophagitis who have been cured by treatment prior to maintenance therapy.
The IP High Court dismissed EA Pharma's request for cancellation of JPO’s Decision (June 29, 2021).
Exhibit No. 1
Exhibit No. 1 is information prepared about the phase III clinical trial plan (clinical trial protocol) of Pariet for maintenance therapy for patients with PPI-resistant reflux esophagitis to be carried out by Eisai, which is the parent company of EA Pharma and manufacturing and marketing approval holder of Pariet. Exhibit No. 1 was published before the priority date of the Patent (the “Priority Date”).
Exhibit No. 1 disclosed the usage and dosage consistent with the Invention 1 in which "10 mg was administered twice daily for 52 weeks," but did not describe the results of clinical studies.
Point of Difference
The Invention 1 is a "PPI resistant reflux esophagitis recurrence inhibitor" which is administered "for maintenance therapy" containing "rabeprazole sodium" as an active ingredient, whereas the invention described in Exhibit No. 1 differs in that it is "in maintenance therapy for patients with PPI-resistant reflux esophagitis" and "rabeprazole sodium for phase III clinical trials to investigate efficacy and safety."
Based on the common technical knowledge at the time of the Priority Date, it was judged that a person skilled in the art at the time of the Priority Date could easily conceive of adopting the limitation of the Invention 1 relating to the Point of Difference.
Moreover, it was judged that since there is also no disclosure that the Invention 1 has any unexpected and remarkable effect in the present specification, the Invention 1 could be easily conceived by a person skilled in the art at the time of the Priority Date based on the invention described in Exhibit No. 1 and the common technical knowledge.
In order to obtain a patent claiming a usage / dosage of a drug in Japan, it is usually necessary to show the test results of using the usage / dosage of the drug in the specification in order to meet the enablement requirements and support requirements.
It is difficult to predict the usage / dosage of the drug to be launched from animal experiments alone. Usually, Phase II clinical trials are performed for the purpose of setting usage (number of administrations, administration period, administration interval, etc.) and dosage (most effective dose) to conduct Phase III clinical trials. The usage / dosage of the drug to be launched will be confirmed by the results of Phase III clinical trials, which are set based on the results of Phase II clinical trials.
On the other hand, from the viewpoint of ensuring the transparency of clinical trials, it is virtually obligatory to disclose clinical trial plans (clinical trial protocols) in advance.
Therefore, if a patent application claiming usage / dose of the drug used in a clinical trial is filed after the expected effects have been obtained in the clinical trial, the patentability will be denied by the common technical knowledge and the publication of the clinical trial protocol according to this decision.
As above, it is difficult to obtain a patent covering the usage and dosage of a launched drug.
Written by: Ms. Emiko Yano (Patent Attorney)