TOPICS

“Antipruritic Agent”

Overview:
This case pertains to an Intellectual Property High Court ruling to uphold a trial decision to dismiss a request for an invalidation trial relating to an extension of a registration term for a patent right.

▶Summary of Judgement and Link to Full Text (Japanese)

Main Issue:
The two reasons for invalidation were (A) Article 125^tres(1)(i) of the current Patent Act (identity between items subject to disposition under the Pharmaceuticals and Medical Devices Act (hydrochloride) and the patented invention (free base)), and (B) Article 125^tres(1)(iii) of the same act (the period during which the patented invention could not be worked).

Here, Point of Dispute (B) relates to whether the period incurred by clinical trials of the prior item subject to disposition (Remitch® OD Tablet; OD stands for “orally disintegrating”) could also be taken into account when calculating the extended term of the registration based on the items subject to disposition under the Pharmaceutical and Medical Device Act (Remitch® OD Tablet) for the present case.

Summary:
A) Item (i) (identity between the item subject to disposition under the Pharmaceutical and Medical Device Act (hydrochloride) and the patented invention (free base))
“A person skilled in the art who read the present specification would readily have understood that the chemical substance that exerts the antipruritic effect, which is the objective of the present invention, is a ‘κ receptor-agonistic compound’, and that the ‘pharmacologically acceptable acid addition salt’ form is not intended to change the antipruritic effect of the substance itself but is merely a form to improve solubility or stability as a pharmaceutical. … Reasoning that claim 1 simply recites ‘an antipruritic agent comprising as an active ingredient an opioid κ receptor-agonistic compound’, it is inconceivable that the skilled person would interpret this as meaning that ‘the compound and pharmacologically acceptable acid addition salts thereof’ are not equivalent to the active ingredients referred to in Subject Invention 1, and fall outside of the technical scope of the patent.”

“As such, the medicinal product of this case is recognized as being a medicinal product formulated with nalfurafine (which, being absorbed into the body, exerts an antipruritic effect and produces a therapeutic effect based on its property of being an opioid κ receptor-agonist) in the form of an acid addition salt thereof, nalfurafine hydrochloride, and thus the medicinal product of this case is recognized as having matter the invention of ‘an antipruritic agent comprising, as an active ingredient, an opioid κ receptor-agonistic compound represented by general formula (I)’ of Subject Invention 1.”

(B) Item (iii) (the period during which the patented invention could not be worked)
“In the approval application for the medicinal product (Remitch OD Tablet, 2.5 μg) relating to the disposition of this case, not only ‘bioequivalence’ materials required to be submitted at the time of an approval application for a ‘medicinal product pertaining to an additional dosage form’, but also attachments (drafts) containing descriptions regarding these tests conducted on the already approved medicinal product, and materials such as review reports concerning the already approved medicinal product (Remitch Capsule, 2.5 μg, etc.) were submitted; accordingly, it is inferred that each of the clinical trials in item (c) that were conducted by the defendant were used in the review at each stage as evaluation materials necessary to verify and confirm the efficacy and safety of the medicinal product relating to the disposition of this case, and that, as a result, the medicinal product of this case was approved for use in ‘improvement of pruritus in the following patients (limited to cases where existing treatment is insufficiently effective): hemodialysis patients; patients with chronic liver disease’, and there is no evidence sufficient to overturn this.”

“The plaintiff argues that recalculating the clinical trial period of the soft-capsule dosage form for the extended registration of this case accompanying approval of the OD tablet would, in substance, amount to restoring the clinical trial period twice and run counter to the purpose of the system. However, the ‘period during which the patented invention could not be worked in order to receive the disposition specified by Cabinet Order’ for a pharmaceutical is to be determined individually from the perspective of the Patent Act, taking into account the content of the approval procedure for the pharmaceutical under the Pharmaceutical and Medical Device Act and the interpretation of the scope of lifting the prohibition by virtue of the approval. Therefore, it cannot be said that taking into account the clinical trial period of an already approved medicinal product is categorically impermissible with respect to the extension registration for the medicinal product of this case.”

Comments:
Concerning Point of Dispute (A), the conclusion was clear, given that, in the judgment in 2020 (Gyo-ke) No. 10063 (Intellectual Property High Court, March 25, 2021), the trial decision denying identity between the item subject to disposition (hydrochloride salt) and the patented invention (free base) had been set aside and the extension registration for this case had been allowed.

Concerning Point of Dispute (B), it is considered appropriate to include, in the extension registration period based on the approval of the medicinal product of this case (Remitch OD Tablet), the period required for the clinical trials, etc. of the earlier item subject to disposition (Remitch Capsule), if, in fact, “in the approval application for the medicinal product of this case (Remitch OD Tablet, 2.5 µg), …materials such as review reports concerning the already approved medicinal product (Remitch Capsule) were submitted…and used in the review, and as a result the medicinal product of this case was approved”, as stated.

Further, the plaintiff (the party requesting the invalidation trial) argues that this would, “in substance, amount to restoring the clinical trial period twice and run counter to the purpose of the system”, but the Oxaliplatin grand panel judgment (2016 (Ne) No. 10046, Intellectual Property High Court, Special Division, January 20, 2017) ruled that it is a major premise that the effect of a patent right extended under Article 68^bis of the Patent Act only just extends to “substantively identical” items subject to disposition under the Pharmaceutical and Medical Device Act, and the effect of a patent right extended based on the already approved medicinal product (Remitch Capsule) would not extend to the medicinal product of this case (Remitch OD Tablets). Therefore, the objection of “double restoring the clinical trial period” seems to have missed the mark, at least from the perspective of enforcement under the Patent Act.

In a judgment relating to 2021 (Ne) No. 10037, handed down on the same day as the present case, two defendant companies were ordered to pay damages totaling over 20 billion yen. The judgment in the present case has been appealed to the Supreme Court.

Akiteru TAMURA