Strategic Antibody Patent Characterisation Shapes Enforcement and Validity in Brazil

Patent disputes involving antibodies remain relatively rare in Brazil, yet the prosecution strategies employed can profoundly affect how courts assess patent validity and enforceability. Senior legal experts at Licks Attorneys emphasize that the characterisation of antibodies during patent prosecution is pivotal in determining the ultimate scope of protection granted by the Brazilian Patent and Trademark Office (BPTO).

While the necessity to characterise antibodies is a global patent prosecution standard, Brazil’s approach places particular importance on the structural definition of antibodies within claims. This focus directly influences the breadth of protection, the patent’s resilience against validity challenges, and the extent to which claims can be enforced against competing products.

These factors are interrelated. The degree of structural detail used to define an antibody affects patentability assessments—such as novelty and non-obviousness—as well as compliance with support and enablement requirements during prosecution. Post-grant, this characterisation shapes claim interpretation and infringement analyses, making it a cornerstone of effective antibody patent strategy in Brazil.

Under Article 24 of the Brazilian Patent Statute (Law No. 9,279/1996), the patent specification must clearly and sufficiently describe the invention to enable a skilled person to carry it out, including the best mode of implementation where applicable. Complementing this, Article 25 mandates that claims be fully supported by the specification, clearly and precisely defining the scope of protection sought.

In antibody patent applications, Brazilian practice requires claims to be characterised by one of the following methods: either the amino acid sequences of the complementarity-determining regions (CDRs) of each heavy and light chain, or the hybridoma producing the antibody, identified by the biological material deposit number, provided the deposit was made by the filing or priority date.

Importantly, these characterisation methods do not confer identical claim scope. Claims reciting complete heavy- and light-chain variable-region sequences tend to be more specific and narrower in scope. Conversely, claims defined solely by CDR sequences may cover antibodies with varying framework regions, potentially broadening protection beyond the exemplified antibodies disclosed in the application.

During substantive examination, the BPTO often requires applicants to align antibody claim scope with the disclosure in the specification. Broad claim language lacking adequate experimental or structural support typically prompts examiners to insist on limitations tied to the antibodies specifically exemplified in the application. This ensures compliance with the enablement and support mandates of Articles 24 and 25.

Thus, the breadth of antibody claims is not determined solely by claim wording but also by the extent to which the original disclosure substantiates and enables the full range of embodiments claimed. This issue parallels the central question in the landmark US Supreme Court case Amgen v Sanofi.

In its 2023 decision, the US Supreme Court invalidated Amgen’s patents claiming a broad genus of PCSK9 antibodies. Although Amgen disclosed 26 exemplary antibodies and methods to identify others, the Court found the specification did not enable the full scope of claims covering many additional antibodies. This ruling highlights the critical balance between claim breadth and enabling disclosure.

The implications of Amgen v Sanofi extend beyond enablement. The manner in which an antibody is characterised during prosecution influences later assessments of validity, claim interpretation, and infringement. Consequently, the characterisation and enablement of antibodies are fundamental not only to what can be patented but also to the enforceability of the resulting patent.

While Brazil’s legal framework differs from that of the US, both jurisdictions require an enabling disclosure commensurate with claim scope. Therefore, broad antibody claims in Brazil may face challenges if the specification does not adequately support and enable their full breadth.

Regarding infringement, the form of antibody characterisation sets the starting point for analysis. However, under Article 186 of the Brazilian Patent Statute, infringement may be found even if a product or process does not literally reproduce every claim element but contains equivalent elements. The statute does not, however, define equivalence criteria or specify whether the analysis should be performed element by element, leaving some interpretative uncertainty.

In summary, patent applicants and practitioners in Brazil must strategically characterise antibodies with sufficient structural detail and robust disclosure. This approach not only facilitates prosecution success but also strengthens the patent’s enforceability and resilience against validity challenges, aligning with evolving jurisprudence both domestically and internationally.