Patent disputes involving antibodies in Brazil are not abundant, but experience shows that decisions made during prosecution can significantly influence how courts will rule on enforcement and validity assessment.
Although the need to characterise an antibody is not unique to Brazil, the level and form of characterisation required may vary across jurisdictions. The Brazilian patent and trademark office’s (BPTO’s) practice places particular emphasis on the structural definition of the antibody in the claims. This may affect the scope of protection ultimately obtained, the patent’s ability to withstand validity challenges, and how broadly the claims may be enforced against competing products.
These issues are closely interconnected. The level of structural detail used to define an antibody may influence the assessment of the patentability requirements (novelty and non-obviousness), as well as the support and enablement during prosecution, while also shaping claim interpretation and infringement analysis after grant. Understanding this relationship is therefore a key aspect of patent strategy in Brazil in the context of antibodies.
Characterisation, enablement, and support of antibody inventions
Article 24 of the Brazilian Patent Statute (Law No. 9,279/1996, or the BPS) requires that the specification shall clearly and sufficiently describe the invention so as to enable a person skilled in the art to carry it out and, where applicable, disclose the best mode of implementation. Complementarily, Article 25 requires that the claims be fully supported by the specification, characterising the particularities of the patent application and defining in a clear and precise way the object of protection.
In the context of antibody inventions, the Brazilian practice establishes that claims shall be characterised by one of the following:
Their specific amino acid sequences (SEQ ID NOs);
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 corresponding biological material deposit number, provided that the deposit was made by the filing date of the patent application or, where applicable, the claimed priority date.
Importantly, these forms of characterisation do not necessarily confer the same scope of protection. A claim reciting complete heavy- and light-chain variable-region sequences generally provides a more specific definition and a narrower scope. On the other hand, a claim defining an antibody solely by its CDR sequences may encompass antibodies with different framework regions, potentially extending protection beyond the specific antibodies embodied and exemplified in the application.
This distinction is particularly relevant, as during substantive examination, the BPTO frequently requires applicants to align the scope of their antibody claims with the disclosure provided in the specification, especially where broad claim language is not adequately supported by the experimental data or structural information originally filed. In this context, limitations based on the antibodies specifically exemplified in the application are often necessary to demonstrate compliance with the enablement and support requirements set forth in articles 24 and 25 of the BPS.
Consequently, the breadth of antibody claims is not determined exclusively by the wording adopted in the claims themselves but also by the extent to which the original disclosure substantiates and enables the full range of embodiments encompassed by the proposed claim language. This is particularly relevant because the same issue was central to Amgen v Sanofi.
Amgen v Sanofi shows the risks of excessive breadth
The US Supreme Court’s 2023 decision in Amgen v Sanofi is an example of how central the relationship between claim breadth and enablement is. The court held invalid Amgen’s patents claiming a broad genus of PCSK9 antibodies. Although the patents disclosed 26 exemplary antibodies and methods for identifying others, the court found that the specification did not enable the full scope of claims encompassing many additional antibodies.
The lessons from Amgen v Sanofi are not limited to enablement. The definition used to support claim scope during prosecution may later influence validity, claim interpretation, and infringement. How an antibody is characterised and enabled by the specification is, therefore, important both to what can be patented and to how far the resulting patent may be enforced.
Although the Brazilian and US frameworks differ, both require an enabling disclosure commensurate with claim scope. Broad antibody claims may therefore face challenges in Brazil where the specification does not support and enable their full breadth.
How characterisation influences infringement analysis
The form in which an antibody is characterised defines the starting point for infringement analysis, but the assessment does not necessarily end with a literal comparison. Under Article 186 of the BPS, infringement may be found where a product or process contains elements equivalent to those claimed, even if it does not reproduce every claim term literally. The BPS, however, does not define the criteria for equivalence or specify whether the analysis should be performed element by element.
Brazilian courts have not yet established uniform parameters for infringement by equivalence and frequently rely on court-appointed experts, who often apply the tripartite test, assessing whether the accused product or process performs substantially the same function, in substantially the same way, to obtain substantially the same result. They less typically also use approaches combining aspects of that test with an assessment of whether the accused product reproduces the patented technical solution or inventive concept.
Regardless of the methodology adopted, the analysis is certainly influenced by how the claims were shaped during prosecution. Amendments and arguments to overcome novelty and obviousness, for instance, may become relevant when interpreting the scope of protection and assessing the extent to which the patentee may rely on equivalence arguments. Although Brazilian law does not expressly provide for a prosecution history estoppel doctrine, case law and scholars consider that statements and limitations introduced during prosecution may be taken into account when assessing claim scope and equivalence arguments.
A patent may ultimately be tested in invalidity or enforcement proceedings, often with court-appointed experts guiding Brazilian judges, who do not have a technical background. Therefore, prosecution strategy should anticipate litigation, seeking a scope broad enough for effective enforcement but sufficiently clear, supported, and enabled to withstand validity challenges.
