Mexico’s patent linkage system: current state, effects and flaws


Mariana Gonzalez-Vargas and Hector Chagoya

Mexico’s patent linkage system: current state, effects and flaws

JayKJay21 /

A well-functioning linkage system for patents and drugs allows healthcare and patent authorities to maximise the impact of innovation, say Hector Chagoya and Mariana Gonzalez-Vargas of Becerril, Coca & Becerril, who report on the Mexican landscape.

The Mexican linkage system for patents related to the drug approval process was enacted on September 19, 2003. The main purpose was to improve the communication between the Federal Commission for Protection against Health Risks (COFEPRIS), which is the regulatory agency in Mexico, and the Mexican Institute of Industrial Property (IMPI), in order to prevent the granting of marketing authorisations (MAs) for generic versions of pharmaceutical drugs which might fall within the scope of valid patents. This system has also served as a tool for public health institutions to verify patent ownership in order to assign direct purchases.

The linkage system is established in article 167bis of the Health Supplies Regulations (HSR) and in article 47bis of the Industrial Property Law Regulation (IPLR). Based on these articles, the system was implemented as a Special Edition of the Official Gazette called “Special Gazette for Medicaments” (SGM), which is issued by the IMPI. The SGM consists of a list of granted patents arranged by active ingredient. Patent applications are not eligible to be listed in the SGM. The SGM is published every six months (in February and August) and each gazette substitutes the former entirely.

SGM listings are not granted or owned by a specific party but published by the IMPI as the patents authority, and the publication of a patent is not linked to a specific registered pharmaceutical product, but to the non-proprietary name of the active ingredient. Accordingly, it is possible to have more than one patent listed for the same active ingredient regardless of how many products are actually registered before COFEPRIS. Additionally, it is possible as well to list a patent more than once in relation to different active ingredients (e.g., in the case of a Markush claim).

According to article 167 bis of the HSR, when seeking marketing authorisation of a pharmaceutical product, along with the dossier filed to COFEPRIS for marketing authorisation, it is mandatory to file a statement under oath signed by the applicant (patents compliance declaration), which states that patents are not infringed by the product, either because the applicant is the assignee of record in Mexico or an authorised licensee of the relevant patents, or because the applicant is not aware of any patents covering the product.

Current practice

Eligible patents for the Mexican linkage system

According to article 47bis of the IPLR, only process or method patents are expressly excluded from the Mexican linkage system. However, because the IPLR refers to a patents list by active ingredient, in the beginning the IMPI established a general criterion that only patents covering active ingredients were eligible for the linkage system. As companies and practitioners disagreed, appeals were submitted for inclusion of patents covering formulations, compositions and second medical uses (Swiss or EPC style claims).

In consequence, a decision by the Supreme Court was issued in February 2010 for formulation patents, establishing a criterion whereby formulation patents became expressly eligible for listing in the SGM. The decision was silent regarding use patents. In spite of this decision, it was not until July 2012 that IMPI started publishing formulation patents in the SGM without litigation. Second medical uses patents are still rejected for publication by IMPI, in spite of the fact that IMPI has lost most of such cases and around 40 new use patents have been successfully included so far, all by judicial order.

Based on the historical publications of the SGM, from the first to the most recent—published on August 17, 2018—more than 1,000 granted patents have been listed. From these, around 23% have expired, so currently there are almost 770 patents in force listed in the SGM. Of these, 43.5% are active ingredient patents, 35.6% are combinations of active ingredients patents, 17.3% are formulation patents and 3.6% are use patents.

Biotechnology drugs patents are eligible for publication in the SGM, but the characterisation of the active molecule must be made clear in order to match the description of the International Non-proprietary Name (INN). To date, 89 biotechnology drug patents have been listed in the SGM (12%).

Procedure for listing a granted patent in the SGM

Regarding the procedure for listing a granted patent in the SGM, article 167bis of the HSR and article 47bis of the IPLR are silent. However, in practice there are two well established possible ways of listing a patent. One is a formal petition before IMPI and the other is a bona fide proceeding available only for companies having a membership to the National Chamber of Pharmaceutical Industry (CANIFARMA) under rules established in an official guideline issued by the IMPI. These proceedings are not mutually exclusive.

The bona-fide proceeding comprises submitting a letter of request for inclusion addressed to the Executive Director of either AMIIF (Mexican Association of Pharmaceutical Research Industries) or ANAFAM (National Association of Drug Manufacturers), both CANIFARMA members, along with a copy of the title and relevant claims of the patent.

This letter is forwarded to CANIFARMA, which shares the full list for comments with both AMIIF and ANAFAM. CANIFARMA submits to the IMPI those patents that have no objection to be published at the chamber level. Typically, only second medical use patents are currently opposed to by this procedure.

The formal petition comprises submitting a letter to request the inclusion of a patent in the SGM addressed to the Director of the IMPI. In such letter, the patent holder must prove that (i) the patent is related to a product considered an “allopathic medicament”; (ii) the correspondence between the INN and the active ingredient of the claimed product; (iii) its nomenclature or identification in the patent; and (iv) the claim covering the product.

“Biotechnology drugs patents are eligible for publication in the SGM, but the characterisation of the active molecule must be made clear in order to match the description of the INN.”

In addition to the legal requirements described above, the request must include specific bibliographic information about the patent, the claim(s) covering the product and licensees (if applicable), among others. Nevertheless, the information regarding each patent that is actually published in the SGM at the end is decided solely by IMPI.

There is not a statutory period of time for filing a request, so generally it could be filed at any time after the granting of a patent. However, usually those requests made at least one month in advance of the publication that will follow are in fact included or at least analysed. As mentioned before, the SGM is published about every six months.

In case the IMPI denies the inclusion of a patent in the SGM by issuing an official rejection and/or by omitting its inclusion in the next edition of the gazette, the applicant can file an appeal before the Federal District Court (FDC). The FDC’s decision, in turn, can be appealed in a final stage before a Federal Circuit Court (FCC) by the affected party (by the applicant or by the IMPI).

Practical effects of the Mexican linkage system

The guidelines issued by the IMPI for publication of patents in the SGM include a process for consultation triggered by COFEPRIS upon the patents compliance declaration of a health approval register applicant. If a relevant patent is detected, through IMPI or the SGM, COFEPRIS should not grant a marketing authorisation to an unauthorised third party. However, this burden of work has been an unexpected overload of analysis for examiners at IMPI, and IMPI has not been given or authorised more examiners to cover this issue.

In practice, the patent holder is seldom the holder of the marketing authorisation. Because of the same patents compliance declaration by the applicant of the marketing authorisation before COFEPRIS due to linkage, the patent must be licensed or assigned to the actual holder of the marketing authorisation.

Furthermore, under the patent law, in order to have effects before third parties, such as COFEPRIS or the general public, any licence or assignment must be registered before IMPI. This has complicated the launch of products in Mexico, mainly for subsidiaries, because generally this requirement is not part of the register process of a drug from the regulatory perspective.

A patent that has not been listed in the SGM will be equally enforceable through a normal infringement procedure in practice, but it will not be considered in the consultations of COFEPRIS with IMPI, and a health registration of an infringing product could be granted.

It is well known that policymakers promoting healthcare see linkage systems as undesirable as these systems are criticised as contrary to the promotion of public health. However, it is not well understood that the role of linkage systems is not to enforce patents per se or to make the availability of generic drugs harder, since the effect of patents will not change if linkage systems exist or not. The true aim of linkage systems is to provide information and certainty. In fact, the mere existence of a list of patents covering every approved drug is necessary for analysing access, and even for the sake of identifying the patents that could be subject to TRIPS Agreement-compliant compulsory licensing provisions and to identify who owns them.

Areas for improvement

Despite the fact that the Mexican linkage system has indeed given some degree of legal certainty for both generic drug manufacturers and drug patent holders, there is still significant uncertainty surrounding the interactions of drug patents with health regulations in Mexico.

HSR linkage provisions are applicable only to allopathic drugs and there are other products where patents and the regulatory process need coordination. For example, the linkage system is not available for medical devices and COFEPRIS is not considering them up to date. Veterinary medicines are also not considered in the linkage system in Mexico because the administrative authority in charge of such approvals is not COFEPRIS but the Ministry for Agriculture, Livestock, Rural Development, Fisheries and Food (SAGARPA). It is clear that the rationale behind patent enforcement during registration of a product before COFEPRIS is equally applicable to veterinary products.

The scope of the patents listed in the SGM also needs improvement. For instance, as a result of the first litigation cases related to formulation patents, currently there are some patents listed that cover multiple compounds but are published just once as “several active ingredients” without identifying the INN of the active ingredients. This practice must be eradicated because it does not give certainty in connection with the registered drug product that is actually protected by the patent.

With regard to biotechnology drugs, the role of process patents will increasingly have to be discussed given the stringent regulatory requirements for approval of these kinds of drugs, and the significant impact of processes on the quality of the end product.

Finally, there is no obligation for patent holders to list in the SGM all relevant patents related to a pharmaceutical product, nor is it an obligation to identify specifically all the patents covering a determined product when registered before COFEPRIS in the patent compliance declaration and updating the list with patents granted afterwards. Therefore, it is uncertain for generic drug manufacturers which versions of the products containing a determined active ingredient can or cannot have a generic version. In fact, this uncertainty is promoted by the reality that other kinds of patents such as those directed to second medical uses, are not clearly eligible for publication.

A well-implemented and fair linkage system, unlike the perception of some healthcare policymakers who qualify it as undesirable, provides high legal certainty to all stakeholders by promoting fair market competition and making possible for healthcare and patent authorities to take all measures available to them for maximising the impact of healthcare innovation.


Hector Chagoya is partner and director of patents and technology at Becerril, Coca & Becerril. He is in charge of the patent practice of the firm, one of the largest such practices in Mexico, and heads consulting services for leveraging value from IP assets. He can be contacted at:

Mariana Gonzalez-Vargas is junior partner at Becerril, Coca & Becerril. She focuses her practice on substantive issues of patent litigation, technological competitive intelligence, health regulation and strategic knowledge management, as well as other activities related to technology transfer. She is responsible for all patent analysis and drafting patents. She can be contacted at:

Mexico, patent, drugs, healthcare, Hector Chagoya, Mariana Gonzalez-Vargas, Becerril Coca & Becerril, IMPI