TOPICS

“Method for Treating Atopic Dermatitis by Administering an IL-4R Antagonist”

Overview:

This precedent is of the IP High Court supporting a determination made during an invalidation trial that an invention included an inventive step.

▶ Link to a summary and full text of the trial decision (Japanese)

Main Issue:

Whether it is possible to reject a medicinal use invention relating to the subject of clinical trials on the basis of phase II clinical trial protocols.

Conclusion:

(2) Error in Determining Ease of Conception

(a) The plaintiff asserts that phase I trials of REGN668 on atopic dermatitis patients in advance of the trials of plaintiff’s exhibit 1 (phase II trials) were undertaken, REGN668 according to the cited invention had already been determined as being potentially useful as a medicinal product, and given the correct common technical knowledge that atopic dermatitis is a disorder in which Th2/IL-4 and the like are predominant, one of ordinary skill in the art could have predicted the success of REGN668, which is an anti-human IL-4 antibody.

Even if the specific cells and cytokines (Th2/IL-4) which are the antigens that could act as targets of such compounds (antibodies, etc.) that would enable the treatment of atopic dermatitis had been known before the priority date, it cannot be said that one of ordinary skill in the art could have realized whether or not blocking the activity of Th2/IL-4 would have successfully had a therapeutic effect on chronic atopic dermatitis including the patients of this case, given that many other cells and cytokines are also known to be active.

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(c) Furthermore, the trial stage described in plaintiff’s exhibit 1 is the phase II trials, and according to plaintiff’s exhibit 21, the success rate of transitioning from the phase I trials is recognized to be 63.2% (n=3,582), the success rate of transitioning from the phase II trials to the phase III trials being even lower at a mere 30.7% (n=3,862; 33% in the case of allergic disorders). Moreover, the information provided in plaintiff’s exhibit 1 merely relates to clinical trial protocols, and nothing is mentioned about actual trial results. Therefore, it cannot be said that one of ordinary skill in the art would have understood that the investigational new drug mentioned in plaintiff’s exhibit 1 would have been therapeutically efficacious as a matter of course without seeing the trial results.

Comments:

Since the clinical trials were carried out up to the phase II, it is worth considering that, despite being an “investigational new drug”, one of ordinary skill in the art could realize it as a “medicinal drug” (medicinal use invention) with a high degree of certainty. However, plaintiff’s exhibit 1 provides information relating to the “investigational new drug”, but does not provide test results for the clinical trials, and thus it was determined that the inventive step of the “medicinal drug” (medicinal use invention) relating to the invention for this case could not be denied, given the complexity of the biological processes involved in “chronic atopic dermatitis”.

On the other hand, a judgement of lack of inventive step was entered 2020 (Gyo-Ke) No. 10094 as follows, despite a determination on inventive step based on the same “clinical trial protocols”.

a) Arguments Relating to the of Clinical Trial “Phases” for the Invention of Plaintiff’s Exhibit 1

The plaintiff asserts that the court decision for this case is incorrect in that it was determined on the premise of the common technical knowledge that the phase III trials targeted multiple patients diagnosed as having a disease for which they were expected to be effective and safe.

However, it can be said that one of ordinary skill in the art could have invented Invention 1 of this case based on the invention of plaintiff’s exhibit 1 and the common technical knowledge, even without considering that the clinical trials of the invention of plaintiff’s exhibit 1 were phase III, as stated in item (1) above.

As such, each trial decision was based on the “common technical knowledge” for the respective field of applicable diseases, but a different determination was made concerning the inventive step of the medicinal use invention. It is reasonable to consider that this trial decision is not a precedent applicable to medicinal use inventions in general, but rather that it is a “case-specific judgement” dependent on “common technical knowledge”.

Akiteru TAMURA