Increasingly, Mexican patents have a different (often broader) scope from their foreign equivalents due to opposition proceedings or postgrant reviews held abroad. This situation has led patentees to consider the post- grant amendment of the scope of such patents more often. However, patentees must consider certain issues when assessing the feasibility of amending the claims of a granted patent in Mexico.
According to Article 61 of the Industrial Property Law, postgrant amendments are permitted for patent claims. However, such provision allows only amendments that comply with precise requirements: this kind of amendment is permitted only when it is to correct an obvious or formal error or to limit the scope of patentable interests.
A postgrant amendment is an administrative procedure held before the Mexican Institute of Industrial Property (IMPI), wherein the patentee or its representative submits a written request along with the substitution sheets for the patent claims to be amended. The IMPI will then assess whether the proposed amendment complies with Article 61 of the Industrial Property Law, and usually takes around six months to issue a letter accepting or rejecting the amendment. If the IMPI rejects the amendment, the patentee may consider appealing to revoke or nullify the IMPI’s decision.
On the other hand, the partial invalidation of a patent is available through an administrative declaration of nullity, similar to an amendment order following re-examination in other jurisdictions. Both a challenge of the validity of a granted patent and a declaration of patent infringement are appealable inter partes administrative proceedings held before the IMPI. Further, nullity and infringement proceedings are independent of each other.
Therefore, nullity proceedings may be initiated by a defendant in an infringement action against the allegedly infringed patent, or by a third party on the basis that a potentially null patent is affecting legitimate commercial interests. However, when these proceedings are conducted simultaneously, the infringement proceedings will not be resolved until the nullity proceedings are complete.
When a patent may be used as legal standing for an infringement action against a third party, the patentee shall consider whether the scope of the foreign equivalent patent has been narrowed for reasons that are material to patentability, or for only strategic reasons. In either case, in principle it is preferable to limit the scope of the claims before the infringement action is initiated in order to strengthen the patent’s position, as the infringer will often defend itself by initiating nullity proceedings against the patent, and any weakness will delay the infringement decision.
In contrast, if a patent is challenged by a third party, the patentee may consider amending the patent during the litigation as a defence strategy; if the subject matter of the litigation is modified appropriately, the IMPI may dismiss the nullity action because the substance of the proceedings has changed.
In light of the above, and considering that nullity proceedings against a patent do not necessarily lead to complete annulment of the patent, if a Mexican patent has no obvious weakness or there are no nullity proceedings against it, the patentee may consider amendment to be unnecessary. Leaving the patent as it was originally granted has the advantage of keeping it strong, even if there is need to interpret the scope of the patent in order to encompass a determined embodiment.
In practice, the IMPI has considered that lawful amendments include:
- the correction of the description and the claims based on an erroneously described drawing of the patent;
- the incorporation of features of a dependent claim into the claim on which it depends; and
- the limitation of a claimed range or group of inventions to specific embodiments.
Therefore, the decision of whether to carry out postgrant amendment of a Mexican patent depends on the balance between the advantages and disadvantages of so doing, given the different possible scenarios. Such analysis requires a deep understanding of Mexican patent law regarding the particulars of the case at hand.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.