Patentees in the antibody arts in Canada have long been dogged by policy-based objections to claims that seek protection that is broader than the example antibodies in their applications. Some of these objections were recently reviewed by the author in a paper “Antibody Examination Practice at the Canadian Patent Office: Immune to Change?” (Canadian Intellectual Property Review (2014), 29(2): 225-258). In a landmark decision, the Federal Court of Canada has upheld broad “use” claims including functionally defined antibodies.
Many patentees will know that even conservative sequence modifications in complementary determining regions (CDRs) are objected to because, in the view of the Canadian Intellectual Property Office (CIPO), undue experimental burden would be required to make candidate mutants and determine which ones maintain function. To sustain these objections, patent examiners point to decisions of the Commissioner of Patents dealing with applications from the late 1980s to early 1990s.
In a decision marking the first time that antibody technology has been extensively scrutinized by a Canadian court, the Federal Court of Canada upheld claims covering uses of a human anti-IL12 antibody for treating psoriasis in its recent decision in AbbVieCorporation v. Janssen Inc., 2014 FC 55.
AbbVie, the patent owner, had unexpectedly discovered that psoriasis resolved in a patient who inadvertently received a human anti-IL12 antibody, termed J695 (briakinumab), made using phage display technology. The “use” claims asserted by Abbvie were not, however, limited by specific epitope, antibody sequence, or method of production, though the claims did specify minimum affinity and potency values.
Janssen makes and markets a human anti-IL12 antibody for treating psoriasis under the name STELARA™ (ustekinumab). This antibody was not developed by phage display, but rather in mice having a reconstituted human immune system. In fact, the STELARA™ product shares only incidental sequence identity with J695 (about 50%), and also binds to a completely different epitope on IL-12.
The patent claims were counter-attacked by Janssen on the grounds of obviousness, over-broad or “covetous” claiming, and ambiguity. The Court upheld the claims, finding them to be both valid and infringed by Janssen.
In his analysis of obviousness, the trial judge provided a helpful and lengthy list of technologies from expert testimony that he accepted as forming the state of the art as of March 1999. These include methods of CDR modification and mutagenesis, CDR grafting, antibody fragmentation, and activity testing, as well methods of making human antibodies by either phage display or immune-reconstituted mice. These are many of the very technologies currently alleged to be non-routine by patent examiners in applications filed well after the year 2000.
The inventive concept of the claims in issue was found to be that psoriasis may be treated by the use of human antibodies that bind to human IL-12, which antibodies have a stickiness of at least the claimed amount and a potency of at least the claimed amount. Before this discovery there was only hope that binding IL-12 would treat disease, but this was an example where a patient had successfully been treated. The Court noted the distinction between the approaches to obviousness, where an invention that is “worth a try” may not be “more or less self-evident”. In this case, the invention was not self-evident having regard to the prior art, and thus it was not obvious. The Court also found that the claims were not unduly broad.
The attack on ambiguity focused on claim features pertaining to minimum affinity and potency variables. Patent applicants may recognize that such features often fall afoul of CIPO examining practice, with examiners alleging that such features are objectionable for “encompassing antibodies with spectacularly high affinities”. The trial judge found nothing ambiguous about these limitations, stating that they simply conveyed minimum standards. The trial judge indicated that the question of whether an antibody with vastly higher affinity or potency would be considered a patentable improvement was one best left for another day.
A decision like Abbvie v. Janssen has been long awaited in the field of biologics. Although the Court cautioned that the validity of the claims must be assessed on a case-by-case basis, the decision should nonetheless embolden patentees to argue against any objection to a pending application in which an examiner states that any departure from a specific set of CDR sequences would result in a lack of utility, or that putting a claimed invention into practice would require impermissible inventive work. If claims have previously been deleted from an application to expedite prosecution, applicants should consider reintroducing these.