The Mexican Patent Linkage System was designed to prevent the granting of Marketing Authorizations (MAs) for generic or biosimilar pharmaceutical products that might infringe an active patent. This system requires cooperation and communication between the Federal Commission for the Protection Against Sanitary Risks (FCPASR, the Health Authority), which oversees the regulatory process for pharmaceutical products —including the granting or denial of MAs— and the Mexican Institute of Industrial Property (MIIP), which is responsible for granting and publishing patents.

Briefly, the MIIP must issue —at least biannually— the “Gazette of Patents of Medicaments,” commonly known as the Linkage Gazette, which serves as a source of information not only for the Health Authority but also for third parties on active patents that must be observed during the regulatory process^[1] and can be used to reject MA approval of unauthorized generic or biosimilar drugs.

To be listed in the Linkage Gazette, patent holders, on their own initiative, should file a request before the MIIP. Afterwards, the MIIP verifies that the patent of interest covers active pharmaceutical ingredients (APIs), or compositions or formulations that comprise an active pharmaceutical ingredient related to a pharmaceutical product. In this regard, even though only process/method patents are expressly excluded from the list, the MIIP has systematically rejected the inclusion of medical use patents.

According to MIIP’s criterion, medical use patents cannot be listed because they do not cover a pharmaceutical product or an API per se. Therefore, including medical use patents in the Linkage Gazette has required a court order upon appealing MIIP’s rejections of the listing requests.

Notwithstanding the above, on October 30, 2025, against its historical practice, the MIIP published an extraordinary issue of the Linkage Gazette to proactively list multiple medical use patents.

In this special issue of October 2025, 139 medical use patents were listed: 100 more patents compared to the latest August 2025 Gazette and the two subsequent Addenda of September 2025, which accumulated only 39 medical use patents listed because of individual litigation efforts.

The newly listed medical use patents comprise not only patents for which an inclusion request was recently filed and MIIP’s rejection was pending, but also patents which listing had been rejected by the MIIP in previous Linkage Gazette issues (for instance, 2025 and 2024 issues), patents for which appeal procedures against MIIP’s rejection were ongoing, and patents which listing had been unsuccessful after appeal since the court affirmed MIIP’s rejection.

This change has occurred without prior notice, and, to date, no official notice has been given to patent holders of the medical use patents which listing was previously denied and that have now been included in the October 2025 Linkage Gazette. Nonetheless, it can be understood in the context of trade-related political negotiations, as preparations for the upcoming review in 2026 of the United States-Mexico-Canada Agreement (USMCA) are taking place, and Mexico’s partial implementation of the trade agreement as well outstanding concerns regarding pharmaceutical Industrial Property (IP) protection^[2] are key issues to be addressed in the negotiations.

It also follows the entry into force in May 2025 of a new collaboration agreement^[3] between the MIIP and the Health Authority, that simplified the contents of the Linkage Gazette, specified the information that should be exchanged between the patent and regulatory authorities within the Linkage System, and formalized a mechanism to allow patent holders to oppose the grant of an MA, as mandated by art. 20.50 and Annex 20-A of the USMCA.

It should be noted that the broad language of both the USMCA and the Federal Law of Protection of Industrial Property (FLPIP) supports the listing of any type of patent that covers a pharmaceutical product, and that the courts have consistently decided in favor of listing medical use patents. Therefore, the listing of use patents in the Linkage Gazette may well be a government strategy to enhance IP protection for pharmaceuticals to better comply with international commitments.

While the MIIP will likely return to regular biannual publications in the upcoming years, the permissibility of medical use patents in the Linkage Gazette is expected to remain. The new criterion should at least be confirmed in February 2026, when the next issue of the Linkage Gazette is published with an updated notice on the types of patents that cannot be listed, and more medical use patents are added to the list.

The publication of medical use patents on MIIP’s initiative and without appeal is good news for pharmaceutical patent holders, who will no longer need to appeal to have their medical use patents included in the Linkage Gazette and will hence benefit from simpler listing procedures and stronger patent barriers against unauthorized MA applications. At the same time, generic applicants will need to reinforce their regulatory and launch strategies in view of the increased number of listed medical use patents.

For further information on the implications of this change or case-specific advice, please do not hesitate to contact us. Our team of experts is at your full disposal to assist you at any time.

[1] For further information on how the Linkage System works, see https://www.clarkemodet.com/en/articles/the-mexican-patent-linkage-system-present-and-future/

[2] As evidenced in the USTR 2025 Special 301 Report, available at https://ustr.gov/sites/default/files/files/Issue_Areas/Enforcement/2025%20Special%20301%20Report%20(final).pdf

[3] See our report at https://www.clarkemodet.com/en/legislative-news/cooperation-between-cofepris-and-impi-opportunities-and-challenges-for-the-pharmaceutical-industry-in-mexico/