Patents for Antibodies in Russia: Make your Protection Stronger

Olga Strokova

Antibody-based drugs are among the widest-selling in the world. They are being used to treat a widening range of conditions and their significance and value in treating cancer continues to grow. Accordingly, this makes them an indispensable component of the pharmaceutical industry; and it also means that their protection through invention [i.e. utility] patents is absolutely essential. Some aspects of the process for antibody-related patent applications within the Russian Federation are given below as a guide for properly drafting claims and obtaining patents with reasonable claims’ coverage.

Overview

Antibodies are proteins used by the immune system to neutralize pathogens. Able to recognize and bind to specific pathogens called antigens, monoclonal antibodies are used in cancer treatments that are based on finding specific differences between cancerous cells and normal cells. Antibodies can be combined (conjugated) with cytotoxic drugs (ones that are toxic to cancer cells) to target and kill cancer cells.

Like all proteins, antibodies are characterized by amino acid sequences. Antibodies consist of two heavy chains and two light chains. Heavy and light chains each include a variable domain having three complementarity determining regions (CDRs) that are responsible for binding to an antigen. The part of an antigen that is recognized by CDRs is called an epitope.

Patent application and claim requirements

In Russia, as in most countries, an invention must be novel, involve an inventive step, and have industrial applicability in order to be patentable.

Antibody claims are additionally checked for proper antibody characterization. According to Russian requirements, claims must specify the antibody’s name, the biological function defining an intended use (the activity type, the biological property) if that function does not follow from the name, the amino acid sequence number, or physicochemical or other characteristics that would distinguish it from other antibodies.

Defining a biological function is a strict requirement of antibody claims, while it is not required to indicate an amino acid sequence of the full-length antibody. Usually it is sufficient to define: variable domains by at least 90% identity to a specific sequence number, or three heavy chain CDRs and three light chain CDRs. A claim that identifies a smaller subset of CDRs can be allowed, in principle, if the application supporting that a smaller set of CDRs is sufficient for binding to the antigen. Claims directed to antibody-drug conjugates must recite the same characteristics as antibody claims.

Applicants often do not wish antibody claims to be limited to sequences when an applicant has revealed a new antigen/epitope, and would like to encompass all potential antibodies that specifically bind to it. A common type for such a broad claim is “an antibody that competes with antibody X for binding to antigen Y.” The other common type is the so-called “antibody via epitope” claim that reads as “an antibody that binds to the same epitope of antigen Y as the antibody X.” Another example of a broad antibody claim is a claim defining an antibody by the preparation process (“product by process“ claim). Under the current practice, these three types of claims are generally rejected for a lack of essential claim features that would allow one to distinguish the claimed antibodies from the prior art ones. Thus, although the Russian patent law states that distinguishing physicochemical or other characteristics can be used for defining antibodies, such characteristics are not sufficient in practice.

As of October 2014, applications for patents must meet the requirement of sufficiency of disclosure. For antibodies, besides the antibody sequence and biological function, an application should provide the preparation method and data supporting that an antibody shows the claimed biological function.

Examiners in the Russian Patent and Trademark Office (Rospatent) require applicants to limit the claimed antibodies to those that are supported in regard to a biological function. Under the current practice, post-filing data is acceptable.

In addition to such types of antibody-related claims as a pharmaceutical composition, use, and a product related to the production of antibodies (nucleic acid, vector, hybridoma, etc.), it is also important to note that method-of-treatment claims are allowed in Russia, in contrast to most international jurisdictions. However, since the Russian patent law does not recognize the concept of indirect infringement, “method of treatment” claims are very difficult to enforce.

Protection in Russia can also be covered by way of a Eurasian patent. The current practice of examination of antibody claims at the Eurasian Patent Office is similar to the Russian practice described above.

Antibody claims and corresponding composition claims of a Russian patent, and the Russian part of a Eurasian patent, are eligible for patent term extension (PTE).

Recommended practices

Upon drafting an antibody application for a Russian patent, one should consider the following:

• a claim should recite the protein’s name (antibody, antigen-binding protein), the biological function defining an intended use (usually, binding specificity), and the amino acid sequence (partial or complete);
• it is important to include several antibody claims characterized by the partial/complete amino acid sequence to give greater protection to the patent against potential nullity attacks;
• “use” claims are more valuable from the enforceability standpoint than “method of treatment” claims;
• “antibody” claims will likely be limited to antibodies supported by application data and post-filing data;
• product claims directed to antibodies and corresponding compositions are eligible for PTE.
  

Article previously published with IAM.

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