Despite the ongoing efforts to harmonize patent practice in all countries, some differences persist. When it comes to technological domains, like biotechnology, minor differences can yield a huge impact at the end. This is the case of antibody patentability. It is not news that the Brazilian practice is inspired by the European one. However, most Brazilian practitioners will agree that it comes with several kinds of restrictions.
In Europe, although antibodies are most commonly defined according to their amino acid sequences (VH and VL domains or CDRs), it is also acceptable to claim antibodies in terms of their functions, provided that the skilled person would be able to isolate or make such antibodies without experimental uncertainties (Hilary van der Hoff, Antibody claims granted by the European Patent Office, 2014). This flexibility observed in Europe is also reflected by granted claims on functional features related to aspects of antigen binding, such as binding to a defined epitope and competing for binding with another antibody. Such functional definition is regularly rejected in Brazil.
It is common to observe Brazilian applications with foreign priority claim defining antibodies by % identity/similarity and by functional languages. They will most likely face objections at the examination stage. So the question is: what is acceptable?
Article 10 (IX) of the Law of Industrial Property determines that biological materials found in, or isolated from, nature are not considered to be inventions. Polyclonal antibodies are interpreted as biological products isolated from nature and, therefore, excluded from patent protection.
On the other hand, once monoclonal antibodies have been produced by different techniques, such as hybridoma or genetic engineering, they are considered as not naturally occurring by the Brazilian PTO and therefore, liable to protection. The same is applicable for chimeric and humanized antibodies. The question now is: how to claim them?
First of all, it is important to note that the Brazilian PTO analyzes antibodies as proteins. In this sense, monoclonal antibodies should be defined according to the deposit number of the hybriboma producer cell or by their own SEQ ID NOs. Examples of accepted claims:
"Monoclonal antibody, characterized by being produced
by the cell line deposited under American Type Culture Collection
(ATCC) access number PTA-4837." (Brazilian patent PI
0303500-0, granted on September 2013);
"An artificial antibody with specific affinity for a characteristic epitope of the ED-B domain of fibronectin, characterized in that (...) the antibody has the following amino acid sequence: VH (...) (SEQ ID NO: 19), linker, VL (...) (SEQ ID NO: 21)." (Brazilian patent PI 9910394-0, granted on July 2013); and
"Humanized antibody that specifically binds to an epitope (...), characterized by comprising:
a humanized light chain variable region comprising the following sequence:
Asp Xaa Val Met Thr (...)
(SEQ ID NO: 7)
Xaa in position 2 is Val or Ile,
a heavy chain variable region comprising the following sequence:
Xaa Val Gln Leu Val (...)
(SEQ ID NO: 8)
Xaa in position 1 is Glu or Gln,
(Brazilian patent PI 0108676-6, granted on September 2015).
Hybridomas are considered by the Brazilian PTO to be products resulting from the direct human intervention that would not be possible to occur under natural conditions, thus being also liable to protection.
As for the chimeric/humanized antibodies, which are also liable to patent protection, their characterization requires the presentation of a SEQ ID NO: X containing an amino acid sequence of the variable portion of the antibody and the definition of the other elements (Fc portion) (item 188.8.131.52 of Resolution 144), as exemplified below:
"Humanized antibody against a-actin, characterized by comprising the murine variable region which consists of SEQ ID NO: X and human y chain regions."
"Humanized antibody against a-actin, characterized by comprising the murine complementarity determining regions (CDR1; CDR2; CDR3) which consist of SEQ ID NO: X, SEQ ID NO: Y and SEQ ID NO: Z in the light chain and SEQ ID NO: A, SEQ ID NO: B and SEQ ID NO: C in the heavy chain and human y chain regions."
As mentioned above, the Brazilian PTO will most probably raise objections as to clarity of any definition comprising binding, encoding and neutralizing features, as well as therapeutic and identity/homology functions (regardless of how high the identity/homology is).
For foreign cases that to be filed in Brazil, the Applicant may submit a separate claim set for Brazilian prosecution, wherein the claims are more adequate to the national practice. Nevertheless, it may be more strategic not to restrict the claims by excessive limitations upon filing, and instead, await the Brazilian PTO's position on patentability during examination of the application. At the end, correct delimitation of the scope of protection will always depend on the concepts behind the invention and, in many cases, on commercial strategies.
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.