Monoclonal antibodies now patentable in Canada without working example

In a recently published decision the Canadian Patent Appeal Board endorsed the principle established in other jurisdictions that in cases where an antigen is a novel polypeptide and has been fully characterised, a pioneering applicant can claim monoclonal antibodies that are immunoreactive with the polypeptide without the applicant actually having made or deposited a specific embodiment of such antibody. Prior to that decision, the Canadian Intellectual Property Office (CIPO) followed and relied on a previous decision where claims to a monoclonal antibody were not enabled when the application failed to set out a detailed protocol or when the specification did not provide evidence of enablement in the form of the actual preparation of a monoclonal antibody.

In arriving at its decision, the board referred to relevant case law from the United States and the United Kingdom, where it has been recognised that generally it does not require undue effort to make and identify monoclonal antibodies that are capable of specifically binding to a novel and defined polypeptide. In the present case, the board found that anti-Type I IL-1R monoclonal antibodies were properly enabled because the specification of the patent application provided a full description of novel Type I IL-1 receptors and of the DNA sequences encoding such receptors, thereby allowing for their production in high quantities through recombinant means. The board also considered a post-filing document establishing that it is possible to generate anti-Type I IL-1R monoclonal antibodies as an indicator that the specification was enabling, even as early as the filing date, since there was no indication that the post-filing work involved undue experimentation or undue adaptation of methods already known to the skilled person.

The board acknowledged that:

• Broad claims can be envisioned.
• Such claims could embrace antibodies implicitly or explicitly defined in relation to well-known monoclonal antibody production methods.
• The claims would not necessarily need to be restricted to any one species of monoclonal antibody since there is neither commonality among the particular structures of the monoclonal antibodies’ binding regions (CDRs) nor a predictable structural relationship between such binding regions and their target epitopes.

The board also addressed an objection concerning the lack of support for the utility of the claimed monoclonal antibodies. The board concluded that the skilled person would appreciate that the monoclonal antibodies have at least one utility and, provided that the utility is apparent to that skilled person, neither the description nor the claims need explicitly mention the utility of these novel antibodies.

The conclusion of the board that the application met the requirements of enablement, sufficiency and utility was confirmed for Type I IL-1 receptors only. Since the claims covered both Type I and Type II IL-1R polypeptides, the board invited the applicant to limit the claims to the Type I IL-1 receptors for enabling allowance of the application.

This decision is a significant change in the CIPO’s previously rigid position on the patenting of monoclonal antibodies. Applicants will welcome the fact that actual physical preparation of monoclonal antibodies is no longer a strict requirement for patentability, and that the criterion of sufficiency of description of monoclonal antibodies in Canada is being aligned with that of other countries. It remains to be seen how this decision will impact on the examination of other types of antibody, such as chimeric or humanised antibodies.