Tokyo District Court, Reiwa 5 (Wa) 70527 [Cyclic protein tyrosine kinase inhibitors] <Presiding Judge Sugiura>
Updated: Oct 3
Article information
Article type: Case note
Classification: Patents
Issues: Claim interpretation
First published on this site: 2026-10-03
Court: Tokyo District Court
Case number: Reiwa 5 (Wa) 70527
Display/classification checked: 2026-10-03
Tokyo District Court, Reiwa 5 (Wa) 70527 [Cyclic protein tyrosine kinase inhibitors] <Presiding Judge Sugiura>
The scope of an extended patent right covers the product subject to the regulatory disposition (the originator drug Sprycel tablets) and products substantially identical to it as a pharmaceutical.
For an invention characterized solely by its active ingredient, differences in other ingredients fall within substantial identity if the changes are based on well-known, conventional technology.
Sprycel contains dasatinib hydrate and PEG as an excipient; the plaintiff's product contains anhydrous dasatinib, no PEG, and carnauba wax and other additives. These differences resulted from the plaintiff's own measures to address stability and dissolution issues caused by using the anhydrous form, which has lower photostability and higher solubility than the hydrate.
Replacing PEG with HPC and adjusting the coating ingredients, including adding carnauba wax, was inferred to be active formulation design to ensure bioequivalence, rather than mere application of conventional technology.
Thus, the plaintiff's product was not substantially identical to Sprycel as a pharmaceutical, and the extended patent right did not cover it.
⇒ Claim dismissed.
★ The same presiding judge, Sugiura, reached a different conclusion from the provisional-injunction proceedings (Reiwa 5 (Yo) 30214)!
⇒ Watch the appeal.
Many practitioners and scholars have expressed the view that infringement should be found in light of the IP High Court's oxaliplatin judgment, and I have heard no contrary view. The appeal deserves attention. The Remitch case also suggests that the IP High Court is pro-patent on pharmaceuticals.
Even if the dasatinib first-instance result stands, another point to watch is whether the reasoning focusing on the technical significance of different additives in relation to a problem is maintained, or confined to cases involving different active ingredients. If the former reasoning remains, generic manufacturers could readily avoid the scope of protection by creating a problem, changing additives, and obtaining a patent.
Revision history
Revision history is maintained by appending entries.
2026-10-03: First published on this site; classification, article information, and consultation link added.
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