Summary of the Judgment
On May 27, 2025, the IPHC ruled that the manufacturing and sales of “Nalfurafin Hydrochloride OD Tablets” by generic drug manufacturers Sawai and Fuso constitute infringement of the patent rights in question, and granted Toray a claim for damages. Sawai was ordered to pay approx. 14 billion JPY (about 97,000 USD), and Fuso was ordered to pay approx. 7 billion JPY (51,000 USD) in damages, along with interest for delay. The IPHC decision judged the scope of the patent held by the original drug manufacturer regarding the active ingredient of the drug based on actual circumstances. Additionally, this case set a record for the highest damages awarded in an intellectual property litigation case.
For the original drug manufacturer, the practical interpretation of the technical scope of the extended patent and the recognition of fact-based rights are significant.
It has been reported that the parties to the lawsuit have requested restrictions on public attendance, and the detailed reasons for the ruling have not yet been disclosed. The ruling has not yet been published on the court website. It may not be disclosed due to considerations such as trade secrets.
On June 6 and 9, 2025, generic drug manufacturers, Fuso and Sawai filed appeals.
Case Overview
- Date of judgment: May 27, 2025
- Case Number: Reiwa 3 (Ne) No. 10037
- Court: Intellectual Property High Court (IPHC)
- Initial Judgement: Tokyo District Court, March 30, 2021, dismissed
Heisei 30 (Wa) No. 38504 and Heisei 30 (Wa) No. 38508 Patent Infringement Injunction
- Plaintiff: Toray Industries, Inc. (Toray)
- Patent in question: Use patent for oral pruritus improvement agent “Remitch® OD tablets”
Japanese Patent Registration No.: 3531170
Expiration date of the patent: November 2022
Application for Patent Term Extension (PTE) of Patent No. 3531170: Patent Application No. 2017-700154, Patent
Application No. 2017-700310 - Defendant: Sawai Pharmaceutical Co., Ltd. (Sawai)
Product which may infringe upon the aforementioned patent: “Nalfurafine Hydrochloride OD Tablets 2.5 µg ‘Sawai'” - Defendant: Fuso Pharmaceutical Industries Ltd. (Fuso)
Product which may infringe upon the aforementioned patent: “Nalfurafine Hydrochloride OD Tablets 2.5 µg ‘Fuso'”
Background of the Case
At the first instance, Toray had sought damages from two companies manufacturing and selling “Nalfurafine Hydrochloride OD Tablets,” a generic version of its itch-relieving drug “Remitch®,” on the grounds of patent infringement in 2021 at the Tokyo District Court. However, the Court dismissed the case on March 30, 2021. Toray appealed the Tokyo District Court decision to the IPHC in June of the same year.
This patent protects an antipruritic agent containing “free form” narflurifin as an active ingredient. Toray filed an application for patent term extension (PTE) for this patent in 2017, and based on the patent rights extended by this PTE application, it filed the above patent infringement lawsuit.
In the first instance, the scope of the active ingredient was interpreted narrowly, and it was determined that the active ingredient in the defendants’ preparations was “hydrochloride” of narflurin, not “free form,” and therefore did not infringe on Toray’s patent rights.
On the same day as the IPHC decision, regarding the decision to maintain the patent extension registration (Patent Application No. 2017-700154) related to the patent rights in question, the court also dismissed the lawsuit filed by Sawai seeking to overturn the decision (Case No. 10033 of 2024), and ruled to maintain Toray’s patent extension registration.
Furthermore, regarding the extension registrations related to the patent rights in question (Patent Application Nos. 2015-700061, 2017-700309, and 2017-700310), Sawai has also filed a request for invalidation of the extension registrations of Toray’s patents in question. However, the judgment upholding Toray’s extension registrations has become final and binding.
An interesting point in this lawsuit was that the phrase “or its pharmacologically acceptable acid addition salts” had been deleted from Claim 1 of “an antipruritic agent in which an active ingredient is an opiate k receptor agonist represented by …” during the examination stage. Therefore, one of the points of contention was whether the active ingredient, the “acid salt” of the compound, infringed on the patent. In the IPHC, as mentioned above, the IPHC ruled that “hydrochloride” of narflurin infringes the patent. The reason is not clear because the judgment has not been issued, but according to the judgement issued for the decision to maintain the patent extension registration, it seems that the IPHC decision judged that the phrase “or its pharmacologically acceptable acid addition salts” had not been intentionally excluded from the claim and the salt is also capable of exerting pharmacological effects as the active ingredient, and therefore the salt falls within the scope of the invention.
[Note] Remitch® was jointly developed by Toray, Japan Tobacco, and Torii Pharmaceutical, and Toray has obtained approval for manufacturing and sales in Japan. Remitch® is a registered trademark of Torii Pharmaceutical Co., Ltd.
PTE Registration
It generally takes ten to fifteen years to develop a new drug, including clinical trials, until the new drug is marketed.
The intention of a patent term extension is to recover the period during which a patented product could not be sold because it was necessary to obtain marketing approval for the drug during its development. The term of a patent right is 20 years in principle, but the PTE system allows an applicant to extend the period up to five years. During filing the PTE application, the term of the patent is deemed to have been extended.
We, Shiga International Patent Office, highly recommend utilizing this PTE system. We will provide you with strong support in protecting your patent rights.
Conclusion
Since Sawai and Fuso filed appeals with the Supreme Court, a final decision will be made at a later time. This IPHC decision demonstrates the significant advantages of the PTE system for the original drug manufacturer.
Reference
Toray Newsroom “Intellectual Property High Court Ruling on Patent Infringement Lawsuit Regarding Patent for Oral Pruritus Improvement Agent “Remitch®” (Japanese only): https://www.toray.co.jp/news/article.html?contentId=gkahdual