. . . These issues appear to be questions of first impression in Japan, the resolution of which will significantly shape the scope and enforceability of patents directed to patient therapies administered by medical professionals in Japan. . . .
The Tokyo District Court’s ruling in Tokai Medical Products Inc. v. [Defendant], Case No. 2022 (wa) 5905 (Tokyo Dist. Ct. Mar. 2024) raises significant questions about patent enforcement in Japan, particularly in the context of medical practices. The case presents an issue of first impression in Japan—whether administering separate components that combine in the body to form a patented composition constitutes infringement under Japanese law. The resolution of this case, now on appeal before the Japanese Intellectual Property (“IP”) High Court, could have far-reaching consequences for the scope and enforceability of medical patents in Japan.
In Tokai Medical, the Tokyo District Court considered allegations of patent infringement related to an injectable composition used for breast augmentation. The patent, Japanese Patent No. 5,186,050 (“the ’050 patent”), covers a composition made of autologous plasma, basic fibroblast growth factor (b-FGF), and a fat emulsion. The patent owner, Tokai Medical, argued that the defendant, an unnamed doctor operating a cosmetic surgery clinic, infringed the ’050 patent by administering the claimed composition to patients during breast augmentation procedures.
During trial, Tokai Medical attempted to prove that the defendant administered the composition to his patients as a single formulated composition. The defendant, however, presented contrary evidence showing that his procedure involved administering the patent’s three components separately to avoid congealing prior to injection. Finding that Tokai Medical failed to sufficiently refute the defendant’s evidence of separately administered components, the district court ruled in favor of the defendant. According to the district court, the defendant did not use or administer the claimed composition and therefore did not infringe the patent.
On appeal, the Japanese IP High Court took the unusual step of requesting amicus briefs to weigh in on several key issues not addressed by the district court, including whether in vivo production of the patented composition—from the separate administration of its components—constitutes patent infringement under Japanese law. The IP High Court also requested guidance on whether medical procedures are patentable under Japanese law and if so, whether any exemptions from liability for patent infringement apply to medical practitioners.
These issues appear to be questions of first impression in Japan, the resolution of which will significantly shape the scope and enforceability of patents directed to patient therapies administered by medical professionals in Japan. While not commenting on the Japanese law aspects of the Tokai Medical case, this article briefly examines, by way of comparison, how those same issues might be addressed under U.S. patent law, if the case had been brought in U.S. courts.
Comparison with U.S. Law
Infringement by in vivo production
In contrast to Japan, U.S. courts have previously addressed the question of infringement by in vivo production of patented compounds and compositions. Under U.S. law, in vivo production of a patented compound or composition is, as a basic principle, recognized as infringement. See, e.g., Ortho Pharmaceutical Corp. v. Smith, 1990 WL 121353 (E.D. Pa. 1990), aff'd, 959 F.2d 936 (Fed. Cir. 1992) (in vivo conversion of non-infringing norgestimate to infringing norgestral). However, such in vivo theories of infringement often fail for other reasons. For example, it can be difficult to prove in vivo conversion to, or production of, an infringing compound. See, e.g., Zenith Laboratories v. Bristol-Myers Squibb, 19 F.3d 1418 (Fed. Cir. 1994) (demonstrating only 22 of the claimed 37 x-ray diffraction peaks of patented crystal polymorph failed to prove infringement in vivo). Also, in the case of patents that claim in vivo production of a metabolite, courts sometime rule that the patent claiming the metabolite is invalid because a previously filed compound patent inherently disclosed the later-claimed metabolite. See, e.g., Schering Corp. v. Geneva Pharm., Inc., 339 F.3d 1373 (Fed. Cir. 2003) (later-issued metabolite patent lacked novelty because metabolite was necessarily produced by metabolism of the compound disclosed in previously filed patent application). Finally, the court’s interpretation of the patent’s claim language may preclude in vivo infringement. See, e.g., Marion Merrell Dow Inc. v. Baker Norton Pharm., Inc., 984 F. Supp. 1050 (S.D. Fla. 1996) (patent claims state that the “purified” compound is administered to the patient and therefore preclude infringement by in vivo production of a non-purified compound).
Returning to the Tokai Medical case, the U.S. counterpart to the Japanese ’050 patent includes such limiting language that could affect its scope of coverage. For example, claim 1 of U.S. Patent No. 10,849,930, includes the language, “wherein injecting the composition promotes an increase in subcutaneous tissue.” A court therefore might interpret the U.S. patent claim to apply only to compositions that are “injected” into the body, not compositions that are produced within the body.
In contrast, the Japanese ’050 patent claims have no such limiting language that would exclude in vivo production from their scope. The claims simply describe a “composition” without specifying any purification, administration, or pre-injection conditions. For example, claim 1 merely says, “A composition for promoting subcutaneous tissue growth that contains autologous plasma, basic fibroblast growth factor (b-FGF), and a fat emulsion.”
Because there is no language in the ’050 patent claims precluding in vivo production of the composition, under U.S. law, the major question would likely be whether the patent owner can sufficiently prove in vivo production of the claimed composition inside the patient's body. During the initial trial, the Tokyo District Court did not receive or consider any evidence of in vivo production of the claimed composition. Thus, the issue of in vivo production is presented for the first time to the Japanese IP High Court on appeal to determine whether in vivo production of a claimed composition can constitute patent infringement as a matter of law.
In such circumstances in the U.S., where the Court of Appeals for the Federal Circuit determines that the claim scope includes in vivo production, but the district made no factual findings concerning that issue, the Federal Circuit would remand the case to the district court for further fact finding on the issue of infringement by in vivo production. In the Tokai Medical case, it remains to be seen how the IP High Court will rule on this issue of first impression and how any attendant factual issues will be resolved.
Patentability & enforceability of medical therapies
U.S. patent law generally recognizes the patentability of novel medical procedures and therapies. However, 35 U.S.C. § 287(c) immunizes doctors and clinics from liability for patent infringement when performing certain medical procedures. The scope of that immunity, however, is not unlimited. The statute expressly carves out three substantial exceptions to the immunity, including the use of (1) patented medical devices, (2) patented compositions of matter, and (3) biotechnology patents.
U.S. law, therefore, would likely not immunize the defendant doctor in the Tokai Medical case from liability for patent infringement because the ’050 patent expressly claims a composition of matter, falling within the second exception to the immunity provided in Section 287(c). Additionally, a U.S. court might also determine that the ’050 patent is a biotechnology patent within the scope of the third exception.
According to the ’050 patent, the claim term “autologous plasma” means plasma derived from the patient’s own blood. The plasma is thus produced outside the body (ex vivo) by drawing blood from the patient and then separating the plasma for reintroduction into the patient’s body. Indeed, the defendant doctor in the Tokai Medical case admitted to ex vivo processing of blood drawn from his patients to produce the autologous plasma used in his procedure.
Under U.S. law, this ex vivo processing of the patient’s plasma would likely trigger the biotechnology patent exception in Section 287(c). Relying on the statute’s legislative history discussing applied biological therapies, the U.S. District Court for the Central District of California determined that the biotechnology patent exception applies in cases where biological material obtained from the patient is manipulated outside the body before being reintroduced to the patient as part of the patented therapy. See VetStem Biopharma, Inc. v. Cal. Stem Cell Treatment Ctr., Inc., No. 2:19-cv-04728, slip op. (C.D. Cal., Oct. 31, 2019) (patient’s fat-derived stem cells processed outside the body before reintroduction). According to this precedent, the ’050 patent would likely be treated as a biotechnology patent under Section 287(c).
Responses to the Japanese IP High Court’s Amicus Request
On October 5, 2024, Japan’s Nikkei News published an article under the heading, “Are Medical Treatments Patentable? Ambiguous Japanese Rules at Issue in Cosmetic Surgery Litigation.” The article provides a brief synopsis of the responses submitted in response to the IP High Court’s request for amicus briefing. According to the article, the IP High Court received 19 responses to its amicus request, with approximately 80% taking a neutral stance or presenting arguments from both sides without drawing clear conclusions. The lack of a decisive direction likely reflects the complexities and ambiguities of existing Japanese patent law.
The article specifically reports that Professor Ken Maeda of Kobe University believes that the judiciary may not be the appropriate forum for resolving these complex issues, suggesting instead that legislative or administrative action may be better suited to address the broader policy implications of the issues presented to the court. Adding to that viewpoint, patent attorney Naho Ebata advocated that, like the approach followed in the U.S., novel medical procedures should be recognized as patentable inventions but should be subject to clear exemptions for medical professionals to practice the patents without fear of infringement.
Conclusion
The IP High Court's decision could follow one of several paths—it might take a narrow approach and focus on the specific facts of the case reflecting the analysis by the Tokyo District Court, or it could address the broader issues of in vivo infringement, patentability, and medical exemptions. The outcome may set important precedent for whether in vivo production of patented compositions constitutes infringement under Japanese law. And more generally, the court’s decision may indicate whether the judiciary can play any role in clarifying how medical acts are treated under Japanese patent law or whether resolution of these issues must be deferred to lawmakers.
The IP High Court’s decision could set lasting precedent for how Japanese courts handle cases involving in vivo production and may ultimately shape the future of patent enforcement in fields involving patient therapies. Practitioners would do well to monitor this case closely for its potential to influence these and other related aspects of Japanese patent law and practice.
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