Expert Committee Pilot for Managing Patent Disputes Under Japan's Patent Linkage Regime

Introduction : In November 2025, the Ministry of Health, Labour and Welfare ("MHLW") in Japan launched an Expert Committee pilot within the pharmaceutical patent linkage system of Japan. The pilot program is to be used in handling patent disputes involving generic medicines and biosimilars under a neutral panel of experts. In addition, there are recent amendments in Japan's patent linkage regime, which include increased patent disclosure requirements and the incorporation of biosimilars into the system.

The pilot program marks an important change in Japanese drug regulation because it aims at balancing between protection of pharmaceutical innovation through patents and timely market entry of affordable follow-on drugs. Unlike in the U.S. and Canada, the advisory and administrative approach is used in Japan in dealing with patent disputes instead of a litigation-based system. This blog discusses the Expert Committee system and its significance in the context of pharmaceutical patent disputes.

Background: Patent Linkage System in Japan

The Japanese patent linkage system is very different from those of other major countries. Unlike many countries that have a statutory patent linkage system that links the marketing authorization process with patent dispute procedures, the Japanese patent linkage process involves an administrative system in which the regulatory body examines if the new drug product would potentially infringe upon the patents of the reference product.

Under the old system, the emphasis of the patent analysis was mainly on patents for the active pharmaceutical ingredients and the medical use of the drug. The marketing authorization could be denied if there was a conflict between the launch of the product and a relevant patent. Information about patents was obtained from the originator companies using secret communications instead of a patent registry.

This ensured that there were minimal pre-market legal proceedings but put the onus of analyzing difficult patent matters on the regulatory body alone without any judicial assistance. This led to the introduction of the Expert Committee system.

The Expert Committee Pilot

The Expert Committee pilot is an extra level of review on the approval process of generics and biosimilar. If MHLW deems that there is a major patent controversy in the course of review of an application for registration, MHLW may opt to refer the application to the Expert Committee for deliberation. Upon such referral to the Expert Committee, the innovator company and the follow-on applicant are each afforded thirty business days to offer such relevant data as they deem it pertinent to establish the fact or legal consequence including any applicable patent documents, any related expert report, arguments and judgments related to infringement cases and related scientific data.

Then, the panel shall consist of three members (generally including a lawyer, a patent attorney, and an academic expert or a scientific and technical expert) selected by MHLW free from having conflicts of interest and obliged by secret.

The panel evaluates data and may require MHLW to provide information as necessary. Following thirty days of review, the Expert Committee is obliged to prepare a written report regarding an assessment on the issue whether a product described in the application may be considered as subject matter falling within the scope of the subject-matter of relevant claims of the concerned patents within thirty business days. The report serves merely as an aid to assist MHLW for its decision for approval and does not, by itself, influence any decision on regulatory actions and validity of patents.

Scope of Review

The Committee's mandate is designed to be narrow. The review will target the same group of patents i.e., those on active pharmaceutical ingredients and approved indications that the traditional linking scheme did, as well as new indications that have not yet been commercially introduced. Claims only related to formulation or manufacturing process, dosage forms or devices are largely not included within the review process.

It reflects a long-standing practice in Japan to only link based on the most pertinent patents affecting market exclusivity. This reform therefore, by design does not make the approval process a general patent dispute, it is seeking to address whether commercial introduction of the follow-on product will conflict with the primary patents on the listed products. The review also reiterates obligations on originator companies to submit timely notifications of applicable patents. Failure to list those patents could lead to the exclusion of the patents from the review process.

Confidentiality and Procedural Features

Perhaps the most notable aspect of the Expert Committee system is its emphasis on confidentiality. The parties' submissions to MHLW-with relevant information disseminated to the committee-are kept confidential and the parties don't have direct access to the other's submissions. The experts' names are also unknown to the parties.

After the review is complete, the parties are only given an edited version of the final report.

The system is designed to promote candor and it is intended to avoid issues where proprietary drug data and related information are disclosed and considered by a competitor. Pharmaceutical patent litigation often deals with the development and sale of highly secret, strategically valuable drugs. However, confidentiality can raise questions of procedural fairness by reducing a party's opportunity to respond to arguments from the other side, a concern expressed by some of its critics.

Legal Implications of the Written Opinion

The Expert Committee's written opinion is not legally binding. MHLW ultimately grants marketing authorization, and courts hold sole power to make findings of patent infringement and validity. This difference in power is crucial. The panel acts not as a tribunal, court or arbitrating body.

The panel cannot adjudicate disputes and its conclusions are not enforceable in the courts or anywhere else.

Notwithstanding these limitations, a determination by the panel that a product is unlikely to infringe patents may well contribute to the product’s obtaining marketing authorization, while also reinforcing the commercial position of the applicant. On the other hand, a negative conclusion finding risk of infringement may encourage regulator caution, and influence subsequent negotiations of the parties. This may effectively introduce a process of patent review for regulatory approval as a step between regulatory and legal proceedings.

Comparison with Other Jurisdictions

The Japanese system stands out as markedly different from other countries, notably, the U.S., Canada and South Korea. Unlike Japan’s Expert Committee approach, these jurisdictions’ patent linkage systems either have publicly searchable public patent registries and provide for a public forum for patent enforcement (US and Canada), or have a more structured patent link that includes formal stay of approval for patent disputes (Canada and South Korea). The Hatch-Waxman Act for instance establishes public access to patent information, allows for pre-market patent enforcement, and implements a legal mechanism for stays against regulatory approval.

Similarly, Canada has its Patented Medicines (Notice of Compliance) system which allows for deferral of a regulatory approval in order to allow for resolution of relevant patent disputes in a courtroom.

Korea too, has a formal patent link with patent listings, stays of approval and favorable terms for successful patentees and challengers.

Japan’s Expert Committee system provides a less confrontational and less litigation-friendly mechanism for addressing potential patent enforcement by linking an advisory procedure before an Expert Committee to an administrative regulatory decision by the PMDA. It does not offer a statutory cause of action for patent infringement, nor does it impose an automatic stay on marketing approval.

Potential Impact on Patent Litigation

This pilot's primary policy objective is to diminish costly post-approval patent litigation by addressing an overlap with intellectual property earlier in the process. Proponents believe that expert opinion would enhance decision-making quality and provide increased certainty for innovators and follow-on companies, facilitating settlement, clarifying IP ownership, and eliminating needless legal action.

In effect, this neutral prior-approval opinion could potentially limit future patent litigation. It is yet uncertain, however, how much litigation will ultimately be prevented or dissuaded. Given the nonbinding nature of the opinion panel, firms still can initiate post-approval infringement claims if the opinion is not in their favor. In certain situations, if the MHLW approves, patent holders could potentially litigate post-approval for infringement where their claims may have been previously overlooked. Hence, litigation will not necessarily be abolished but rather, the value that parties attribute to expert opinion will influence the likelihood of post-approval dispute resolution.

Strategic Implications for Industry

The reforms have the potential to impact both innovator firms and follow-on manufacturers. For example, early and accurate patent identification by originator firms is now a critical prerequisite to patent assertion, and those that are late to disclose such information might find it unavailable in the future. Innovator firms would thus be well served by having strong patent management processes and by readying solid evidence to present to expert adjudicators.

Firms seeking to enter as generic and biosimilar providers would be well served by having well- prepared technical and legal defenses of non-infringement, as well as a pool of patent counsel well versed in regulatory proceedings.

Moreover, the pilot also incentivizes earlier engagement. The prospect of impartial expert review may convince one side to initiate settlement discussions sooner, rather than waiting for the full-blown dispute resolution proceedings.

Conclusion

In a significant change from Japan's existing patent linkage system, the Expert Committee pilot programme provides the pharmaceutical industry with access to unbiased legal and technical expertise as part of the regulatory process, which enhances the quality of decision making between patent rights and market access.

The Innovative feature of the pilot is that it does not have a litigation-driven model like other countries (for example, the US and Canada) but adopts an advisory mechanism that acts as a supplement to the standard regulatory review process. The advisory mechanism allows for the efficient administrative process of regulatory review to be enhanced by providing regulatory bodies with dedicated technical and legal experts to assist them in resolving complex patent disputes.

There are, however, a number of concerns about the transparency, procedural fairness and long-term effectiveness of the system. The expert opinions are non-binding and do not preclude future litigation, which may result in the system failing to provide the type of legal certainty that the stakeholders desire.

Ultimately, the success of the pilot will depend on whether it is able to substantially reduce disputes, improve the quality of regulatory decisions, and build confidence between innovators and follow-on companies. If it is successful, the pilot will potentially inform the development of future reforms to patent linkage systems and will contribute to establishing a more balanced framework for resolving patent disputes in highly regulated markets.

Author :- Radhika Chugh, in case of any query, contact us at Global Patent Filing or write back us via email at support@globalpatentfiling.com.

Endnotes

1. Ministry of Health, Labour and Welfare (Japan), "Expert Committee Pilot for Patent Disputes under the Patent Linkage System", Notification of the Pharmaceutical Affairs Bureau, November 2025 (Japanese).
2. Ministry of Health, Labour and Welfare (Japan), "Handling of Patent Information in Drug Approval Reviews (Patent Linkage)", Pharmaceutical Safety and Environmental Health Bureau Notifications (as amended).
3. Japan Pharmaceutical Manufacturers Association (JPMA), Patent Linkage System in Japan, available at: https://www.jpma.or.jp/english/ (last accessed 25 July 2026).
4. International Trade Administration, U.S. Department of Commerce, Japan—Pharmaceuticals and Medical Devices, available at: https://www.trade.gov/country-commercial-guides/japan-pharmaceuticals-and-medical-devices (last accessed 25 July 2026).
5. World Intellectual Property Organization (WIPO), WIPO Lex Database: Japan Patent Act and Related Pharmaceutical Regulatory Framework, available at: https://www.wipo.int/wipolex/en/ (last accessed 25 July 2026).