2023 (Gyo-Ke) 10019 [Methods for Treating Atopic Dermatitis by Administering an IL-4R Antagonist] <Miyasaka>
Updated: 2 days ago
Article information
Article type: Case note
Category: Patents
Topics: Inventive step
First published on this website: 2026-11-01
Display and classification checked: November 2, 2026
Originally published on Ameblo: 2025-07-13 (Japan time). Full English translation.
2023 (Gyo-Ke) 10019 [Methods for Treating Atopic Dermatitis by Administering an IL-4R Antagonist] <Miyasaka>
*Even if the cited invention had reached a Phase 2 clinical trial, the success rate for Phase 2 was only 33%. A person skilled in the art therefore could not be said to understand that it was necessarily therapeutically effective without even seeing the Phase 2 results.
⇒ Inventive step affirmed.
[Difference] Corrected Invention 1 at issue is a pharmaceutical composition comprising a therapeutically effective amount of an anti-human IL-4R antibody or an antigen-binding fragment thereof, for use in a method of treating a patient with moderate-to-severe atopic dermatitis (AD) who does not respond adequately to treatment with topical corticosteroids or topical calcineurin inhibitors, whereas the cited invention is an investigational drug composition.
(Excerpt from the court's reasoning)
The trial in Exhibit Ko 1 is a Phase 2 clinical trial. It is common general technical knowledge that the preceding Phase 1 clinical trial ordinarily investigates the safety and pharmacokinetics of an investigational drug in a small number of healthy individuals, and that confirmation of efficacy in patients begins with Phase 2 clinical trials. According to Exhibit Ko 21 …, the probability of success in Phase 2 clinical trials is far lower than in any other phase and is approximately 33% for allergic diseases. In light of this, the mere fact that a Phase 2 clinical trial is being conducted does not mean that a person skilled in the art would understand that the investigational drug must be therapeutically effective without even examining the trial results.
Furthermore, examination of Exhibits Ko 2–6 reveals no evidence that, before the priority date of the patent at issue, an anti-human IL-4R antibody had been administered to patients with atopic dermatitis and had actually produced a therapeutic effect. In light of the common general technical knowledge at the priority date of the patent application concerning the roles of cytokines in the acute and chronic phases of atopic dermatitis, even if REGN668 (an anti-human IL-4R antibody), as used in Exhibit Ko 1, had the ability to block IL-4 and IL-13 activity, as did the antibody in Exhibit Ko 3, it cannot be said that a person skilled in the art could have conceived of using REGN668 (an anti-human IL-4R antibody) therapeutically effectively in the patients of the cited invention, who had suffered from chronic atopic dermatitis for at least three years and in whom production of interferon gamma and IL-12 was considered to predominate over IL-4, unlike the acute phase in which IL-4 predominates. Nor could improvement in clinical symptoms readily have been predicted in those circumstances.
Moreover, as described in Exhibit Ko 24 (Exhibit Otsu 4 in the trial proceedings), given the complexity of the immune pathways involved in atopic dermatitis, it is found difficult to predict, without awaiting clinical-trial results, that a therapeutic agent based on the particular mechanism of blocking IL-4 action—a mechanism with no track record of use in treating atopic dermatitis as of the priority date of the patent at issue—would have a therapeutic effect on moderate-to-severe atopic dermatitis. Accordingly, it cannot be said that a person skilled in the art could readily have arrived, from the descriptions in Exhibits Ko 1–6, at the cited invention having the configuration relating to the difference—namely a pharmaceutical composition comprising a therapeutically effective amount of an anti-human IL-4R antibody for use in a method of treating patients with moderate-to-severe atopic dermatitis who do not respond adequately to treatment with topical corticosteroids or topical calcineurin inhibitors—and actually producing, in patients falling within Corrected Invention 1 at issue, the improvement in clinical symptoms of atopic dermatitis demonstrated in the specification at issue.
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Update history
The first-published date remains unchanged. Display maintenance, classification changes, related-article updates, and text corrections are recorded separately.
November 1, 2026: First published on this website.
November 2, 2026: Added article information, classification, topics, language navigation, related articles where the same case was confirmed, consultation guidance, and SEO. The original text and first-published date were preserved.
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