PLAFEST Regulation Reform: What Changes for the Use of Technical Information and Access Letters?
The PLAFEST reform introduces significant changes to the treatment of technical information previously submitted in support of pesticide registrations. We examine the scope of these changes, the circumstances in which they may affect access letters, and their practical implications for existing registration holders and new applicants.
COFEPRIS-PLAFEST
2026 PLAFEST Reform: What Happens to Access Letters After Ten Years?
HEALTH REGULATION · PLAFEST
The April 2026 reform to Mexico’s PLAFEST Regulation raises a particularly significant question for the pesticide and plant nutrient industries:
What happens when the technical information supporting a registration was submitted more than ten years ago?
The question matters because the new regulatory framework expressly establishes a ten-year period during which certain safety and efficacy data may not be relied upon by a third party without the consent of the data holder.
At the same time, the reform left Article 13 of the Regulation in force. That provision has traditionally been associated with the authorization required to access technical information previously submitted to Mexico’s Federal Commission for Protection against Health Risks (COFEPRIS).
The reform therefore cannot be reduced to a simple conclusion that the access authorization letter — commonly referred to in Mexico as a carta de acceso — has been eliminated.
Instead, it requires a more careful analysis of when consent remains necessary, what information is protected, and what legal consequences arise once the new ten-year protection period has expired.
The Key Change: Regulatory Data Protection Now Has an Express Time Limit
The new Article 10, section I, subsection f), introduces a specific requirement when an application seeks to rely, in whole or in part, on safety and efficacy information relating to a previously registered new agricultural chemical product.
In that situation, the Regulation requires the express consent of the information holder when no more than ten years have elapsed since the relevant registration was granted.
This rule is complemented by the newly added Article 13 Bis.
That provision establishes a ten-year period beginning on the date of the first registration of the new agricultural chemical product in Mexico. During that period, the authority may not allow a third party, without the consent of the information holder, to obtain a registration to market the same or a similar product by relying on that protected information or on the previously granted registration.
The reform therefore introduces an element that was not previously expressed in this manner in the Regulation:
a regulatory data protection regime with a defined term.
What Information Is Covered by This Protection?
Article 13 Bis identifies information relating to the safety and efficacy of a new agricultural chemical product.
The protected information includes:
physicochemical information;
formulation-related physical information;
toxicological information;
ecotoxicological information; and
environmental fate information.
The issue is therefore not merely a documentary formality associated with obtaining an authorization letter.
The new framework concerns the regulatory use of technical information that may represent substantial scientific and financial investment by the party that originally obtained the registration.
Did the Reform Eliminate the Access Letter?
Not as an absolute matter.
This distinction is important.
The 2026 Decree amended Article 10 and Article 23 Bis 4, added section XXXII Bis to Article 2, and introduced the new Article 13 Bis.
It did not repeal or amend Article 13.
Article 13 continues to address the situation in which an applicant does not possess certain information required for its application and seeks to have COFEPRIS rely on information previously submitted by the supplier of an already registered product.
In that scenario, the provision continues to refer to authorization from the supplier to access that information.
It would therefore be overly broad to conclude that the reform simply “eliminated the access letter.”
The real legal issue arises from the interaction between the existing Article 13 and the new Articles 10 and 13 Bis.
The Critical Question: What Happens After the Ten-Year Period Expires?
This is arguably one of the most significant consequences of the reform.
During the first ten years, the rule is comparatively clear: where the new provisions apply, the relevant safety and efficacy information is protected and the consent of the information holder has legal significance.
Article 13 Bis, however, establishes that protection for an expressly defined period.
Once that period expires, the temporary prohibition established by Article 13 Bis against a third party obtaining a registration by relying on the protected information or on the previously granted registration ceases to apply.
That immediately raises a further question:
How should the still-effective Article 13 be interpreted after the ten-year exclusivity period has ended?
A Possible Systematic Interpretation
From a systematic interpretation of the Regulation, it appears difficult to argue that Article 13 should operate in a manner that converts into indefinite protection an exclusivity period that the new Articles 10 and 13 Bis expressly limit to ten years.
If permanent consent were still required for the regulatory use of the same information after the statutory protection period had expired, the ten-year limitation introduced by the reform would lose a substantial part of its practical effect.
This is a legal interpretation derived from the interaction among the relevant provisions. The Decree does not expressly resolve this tension.
Each application should therefore be assessed on its own facts, including:
the type of product involved;
the nature of the information being relied upon;
the date of the first registration; and
the manner in which the new applicant intends to support its regulatory dossier.
Ten Years Does Not Mean Free Access to a Competitor’s Regulatory Dossier
A separate distinction is equally important.
The expiration of the regulatory data protection period should not automatically be understood as granting a third party the right to obtain the original registrant’s studies, confidential documents, or technical dossier.
These are two different issues.
One concerns the temporary regulatory restriction preventing an authority from allowing another applicant to rely on certain previously submitted information.
The other concerns physical or documentary access to confidential information submitted by a third party.
The reform expressly addresses the first issue.
It does not provide that, once ten years have elapsed, the original technical dossier becomes publicly accessible.
Accordingly, the post-ten-year analysis should focus primarily on the extent to which the authority may take into account regulatory information or prior assessments already on file, rather than on the assumption that private studies must be delivered to a subsequent applicant.
Why Ten Years? The USMCA Connection
The structure of the new Mexican regime is consistent with Article 20.45 of the United States-Mexico-Canada Agreement (USMCA), known in Mexico as the T-MEC.
For new agricultural chemical products, the Agreement provides protection for undisclosed safety or efficacy data submitted as a condition for obtaining marketing authorization and establishes a protection period of at least ten years.
The Agreement also allows a Party to limit that protection to ten years.
The USMCA further addresses situations in which a domestic marketing authorization relies on a prior marketing authorization granted in another territory.
The new Mexican Article 13 Bis also reflects that scenario.
This context helps explain the broader rationale of the reform:
the access letter or consent requirement should not be viewed merely as an administrative document, but as one component of a broader system of time-limited regulatory data protection.
What If a Patent Is Still in Force?
That requires a separate analysis.
The reform also amended Article 10 to require evidence of ownership or, where applicable, a corresponding license when the product is protected by a patent in force in Mexico.
Accordingly:
regulatory data protection is not the same as patent protection.
The fact that ten years have elapsed since the first registration does not necessarily mean that every other exclusive right relating to the product has expired.
Each form of protection must be assessed independently.
The Reform Is Already in Force
The Decree expressly provided that it would enter into force on the day following its publication.
It also granted the Ministry of Health 180 calendar days to make the regulatory and administrative adjustments necessary to implement the new framework.
That implementation period does not mean that the reform remains suspended until those adjustments are completed.
The transitional provisions establish that, until the relevant adjustments are issued, the prior rules continue to apply only to the extent that they do not conflict with the Decree.
Where a conflict exists, the authority must apply the new provisions directly.
What Happens to Applications That Were Already Pending?
The Decree also contains an express transitional rule.
Matters that were already pending when the reform entered into force must continue through completion under the provisions that were in effect when the relevant application was filed.
Accordingly, before attempting to rely on the new data protection framework, the filing date of the application must first be established.
Before Determining Whether an Access Letter Is Required
The reform makes it necessary to address at least five questions before structuring a new registration strategy.
1. When was the first registration of the agricultural chemical product granted in Mexico?
The date is critical in determining whether the ten-year protection period remains in effect.
2. What information does the new applicant intend to rely upon?
It must be determined whether the information falls within the safety or efficacy data protected by the new regime.
3. Has the ten-year period already expired?
The answer can materially change the analysis of whether consent remains required.
4. Is the application relying on information from a supplier, on a prior registration, or on independently generated data?
These are not legally equivalent scenarios.
5. Are there other independent rights or regulatory requirements?
Patent rights, manufacturer identity, product information, biological efficacy data, and other dossier requirements must be analyzed separately.
SALGADO MARETTE Perspective
The 2026 reform should not be reduced to the statement that “the access letter has been eliminated.”
The change is more significant than that.
The Regulation now expressly establishes a ten-year protection period for certain safety and efficacy information and links the consent of the information holder to that period.
At the same time, Article 13 remains in force, creating an interaction between the existing access mechanism and the new regulatory data protection framework that will need to be interpreted as the new system is implemented.
The practical consequence is that an access letter can no longer be analyzed in isolation or treated as an identical requirement regardless of the age of the underlying registration.
For registrations that are more than ten years old, there is a meaningful legal basis for arguing that the exclusivity established under the new Articles 10 and 13 Bis has expired.
That conclusion, however, does not automatically eliminate other regulatory requirements, nor does it create unrestricted access to the original registrant’s confidential technical dossier.
The appropriate strategy must therefore be developed on a case-by-case basis, taking into account:
the age of the original registration;
the information the applicant seeks to rely upon;
any rights that remain in force; and
the manner in which COFEPRIS implements the new framework administratively.
The relevant question is no longer simply whether an access letter exists. The more important questions are what information remains protected, for how long, and on what legal basis it may be relied upon once that protection period has expired.