MEXICO Trends and Developments Contributed by: Carlos Perez de la Sierra and Ciara Cleary, Calderón & De La Sierra
Burden of proof in infringement cases: how do we prove the technical facts of cases involving process patents? Regarding the litigation of process patents, the technical facts of these cases may be difficult to prove in a case of infringement. For instance, it is commonplace that many different processes may exist for manufacturing the same biologic product. However, certain processes offer cer - tain advantages for a biologic product, which is why these processes are often patentable. Unfortunately, when it comes to the enforcement of such process patents, reverse engineering to determine the process used to manufacture the infringing product is often not possible. Thus, it may not be obvious or easy to determine if the biologic at the centre of the litigation case infringes on a process patent. This is where the reverse of burden of proof comes into play. Under normal circumstances, the burden of proof lies with the plaintiff. Yet, as mentioned above, in the case of manufacturing/process patents for biologics, this can pose a challenge. For instance, a particular process may increase the amount of product produced, but the final product produced is the same as that produced by any other process used to manufacture the same biologic. Or perhaps a specific process increases the quality of the product being man - ufactured, reducing the need for purification processes. For this reason, and through many binding precedents, the constitutional courts in Mexico have introduced the idea of a “dynamic” burden of proof, which permits that the burden of proof be reversed in certain situations. The cir - cumstances for such a situation are as follows: • the plaintiff has difficulty accessing the docu - ments required to demonstrate the facts of the case; and
surprise that process patents now play a central role in the litigation of biologic patents. Despite the important role that processes play in biologics and their IP protection, the Mexican Patent Office does not consider these types of patents as listable in the Mexican Linkage Sys - tem. The Mexican Linkage System’s purpose is to establish a direct line of communication between the Mexican Patent Office and the Mexican regu - latory authority to prevent the marketing authori - sation of generic versions of patented products. Under the Linkage System, the Mexican Patent Office publishes a special gazette (similar to the Orange Book) every six months. To be listed in this special gazette, the patents should refer to inventions “susceptible to be used in allopathic medicines”. Product, combi - nation and formulation patents are eligible for listing. However, medical use and process pat - ents, among others, remain an issue, despite their clear use in allopathic medicines. This outright rejection of medical use and process patents contradicts the objective of sanitary registrations (ie, pharmaceutical products with defined therapeutic indications) and there are numerous court cases where the Mexican Pat - ent Office has been compelled to list medical- use patents. Litigation is thus currently required to list use patents and process patents in the Linkage Gazette. In light of the recent increase in patents relating to biologics and their processes, increased efforts are being made to include such processes in the gazette, particularly since pro - cesses play an essential role in the development of “allopathic” medicines, such as biologics, and are becoming a common target for infringement cases. This issue is currently being debated and represents an area of evolvement. A close eye should be kept on developments in this area over the next few years.
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