2023 (Gyo-Ke) 10090 [Fulvestrant Formulation] <Nakadaira>
更新日：2 日前
Article information
Article type: Case note
Category: Patents
Topics: Inventive step, Motivation and teaching away
First published on this website: 2026-11-01
Display and classification checked: November 2, 2026
Originally published on Ameblo: 2025-07-14 (Japan time). Full English translation.
2023 (Gyo-Ke) 10090 [Fulvestrant Formulation] <Nakadaira>
*The journal Cancer published an experiment using a composition identical to that of the patented invention for the medical use at issue (the composition was supplied by the patentee), but there was no common general technical knowledge of administering that composition, unchanged, to humans by intramuscular injection.
⇒ Inventive step affirmed.
[Difference] Corrected Invention 1 is “a pharmaceutical formulation for administration to humans by intramuscular injection” and “a pharmaceutical formulation suitable for intramuscular injection,” whereas the Exhibit Ko 1 invention is an experimental composition, administered subcutaneously to ovariectomized tumor-bearing mice inoculated with breast cancer cells (MCF-7 cells) transfected with fibroblast growth factor (FGF), for verifying FGF autocrine activity as a mechanism of tamoxifen-resistant breast cancer.
(Excerpt from the court's reasoning)
(a) Common general technical knowledge I (concerning intramuscular injection of fulvestrant)
At the priority date at issue, pharmaceutical formulations containing fulvestrant were undergoing clinical trials and had not yet been approved in any country …. Thus, fulvestrant is not found to have been established as a breast cancer treatment. Accordingly, common general technical knowledge I (concerning intramuscular injection of fulvestrant) is not found to have existed.
Nevertheless, according to the results of pharmacokinetic studies (PK studies) and clinical trials concerning fulvestrant conducted at the priority date at issue …, there is room to say that it was common general technical knowledge at that date that fulvestrant was under investigation as a possible breast cancer treatment and was being administered by intramuscular injection in the trials. However, even if such common general technical knowledge existed, a person skilled in the art is not found to have readily recognized that the composition administered to mice as an antiestrogen in the Exhibit Ko 1 reference could immediately be used, with its composition unchanged, as a pharmaceutical formulation for administration to humans by intramuscular injection.
(b) Common general technical knowledge II (concerning subcutaneous injection in mice)
The references cited by the plaintiff … include statements that intramuscular injection is difficult in small laboratory animal species such as mice, and examples in which drugs administered intramuscularly to humans were administered subcutaneously in experiments using small laboratory animal species such as mice. However, they also contain descriptions of intramuscular injection in rats …. Even in light of these references, it cannot be found that common general technical knowledge II (concerning subcutaneous injection in mice), as asserted by the plaintiff, existed at the priority date at issue. Moreover, even if common general technical knowledge II existed, that would not mean there was common general technical knowledge that a drug injected subcutaneously in experiments using mice is always injected intramuscularly in humans. Furthermore, even if common general technical knowledge existed to the extent that “a pharmaceutical formulation administered intramuscularly to humans may be administered subcutaneously in experiments using mice,” it cannot be found to have been common general technical knowledge to inject humans intramuscularly with a drug having the same composition as a drug injected subcutaneously into mice. Still less could there be said to be motivation to inject humans intramuscularly with a drug having the same composition as the fulvestrant administered to mice in the Exhibit Ko 1 invention, where that fulvestrant was used as an adjunct to eliminate estrogen activity in an experiment intended to test a hypothesis.
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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.
