US Pat 6,914,128 & 7,504,485 / anti-IL-12 antibodies / STELARA
Thanks to Alan Macek’s IPPractice for alerting me to the US Fed Cir STELARA decision, which addresses patents similar to those in AbbVie Corp v Janssen Inc 2014 FC 55, blogged here. Together, these decisions provide for an interesting comparison between the US written description requirement and the Canadian overbreadth objection. The Fed Cir affirmed that the claims at issue were invalid as lacking an adequate written description, while in the Canadian litigation, Hughes J held that the claims were not overbroad. But despite the differing results, there is no inconsistency between the decisions, as the claims at issue were different in an important respect. While the results were consistent in these cases, I am inclined to prefer the Canadian approach; the written description inquiry into whether the inventor “had possession” of the claimed invention strikes me as a Procrustean framework for what is essentially an overbreadth analysis.
To recap the facts, which are described in more detail in my post on Hughes J’s decision, the invention relates to human antibodies that bind human interleukin 12 ("IL-12"). Interleukins generally, and IL-12 in particular, were known to be implicated in immune system function, and antibodies capable of inhibiting the activity of IL-12 were known to be likely candidates for treating diseases related to immune system disorders. AbbVie and Janssen both developed human anti-IL-12 antibodies with similar affinity and potency, but they were developed independently using entirely different technologies, and they have different amino acid sequences, different variable region binding sites, and they bind to different epitopes. The evidence on this was consistent in the US and Canadian litigation.
The claims at issue in the US litigation were to an anti-IL-12 antibody with a specified binding affinity (slip op 7). The claimed antibodies were described functionally, by the binding affinity, not structurally. The question therefore was whether, having discovered one way of making such anti-bodies, AbbVie should be entitled to claim all antibodies with the specified binding affinity. The Fed Cir noted that the purpose of the written description requirement is to “ensure that the scope of the right to exclude, as set forth in the claims, does not overreach the scope of the inventor’s contribution to the field of art as described in the patent specification” (slip op 21). That is, the patentee cannot claim more broadly than it has invented. The written description requirement polices this principle by insisting that the patent applicant “must describe his or her invention so that the public will know what it is and that he or she has truly made the claimed invention” (slip op 20). In this case
analogizing the genus to a plot of land, if the disclosed species only abide in a corner of the genus, one has not described the genus sufficiently to show that the inventor invented, or had possession of, the genus. He only described a portion of it.
Because the antibodies developed by AbbVie “are not representative of the full variety or scope of the genus,” (slip op 24), the written description was inadequate.
In contrast, in the Canadian litigation, while the patent at issue did have a functional claim to anti-IL-12 antibodies with specified binding affinity, the only claims at issue were to the use of those antibodies “to treat psoriasis.” As in the US litigation, Janssen argued that AbbVie had claimed too broadly
 Janssen argues, as a policy issue, whether "functional claiming" should be allowable. It argues that, having discovered one antibody that binds to IL-12 so as to treat psoriasis, can AbbVie claim any antibody that binds to IL-12 and treats psoriasis?
But as Hughes J pointed out:
This argument does not come to grips with the fact that AbbVie was the one who confirmed that if an antibody did bind to IL-12, then psoriasis could be treated. Before AbbVie’s confirmation there was only hope or speculation, numerous other cytokines or a combination of one or more of them might have been the proper target .
That is, what AbbVie had discovered was not just one way of making anti-IL-12 antibodies; it had discovered that such antibodies could be used to treat psoriasis, and this, on the facts, was an inventive step.
The general problem of overbreadth was captured in the “roads to Brighton” metaphor, a century and a half ago:
It is extremely desirable that when a beneficial idea has been started by one man, he should have the benefit of his invention, and that it should not be curtailed or destroyed by another man simply improving upon that idea; but if the idea be nothing in the world more than the discovery of a road to attain a particular end, it does not at all interfere with another man discovering another road to attain that end, any more than it would be reasonable to say that if one man has a road to go to Brighton by Croydon another man shall not have a road to go to Brighton by Dorking.
Curtis v Platt (1863), 3 Ch D 135, quoted in (1995) 61 CPR(3d) 499 (FCA)
I suggested in my post on Hughes J’s decision that the discovery that anti-IL-12 antibodies could treat psoriasis is not a “road to Brighton”.
Rather than being a road to Brighton, it was the equivalent of an eighteenth century road from Europe to Australia. With a little historical licence, we might say that if Captain Cook was the first to discover a route to Australia, it would not be so unreasonable to give him a monopoly over all routes to Australia, given that it was not the route he really discovered, so much as the fact that Australia existed at all.
Where the inventor discovers one route to a goal which is known to be desirable, then it may claim only that one route, which is its contribution. But when the inventor reveals a goal which was never before suspected, its contribution is the very existence of that goal, and consequently it may claim any route to get there. The desirability of human anti-IL-12 antibodies was well-known before AbbVie found a way to get there, so making those antibodies was a road to Brighton. That such antibodies could treat psoriasis is a discovery analogous to eighteenth century Australia, and AbbVie was consequently entitled to a claim to any method of treating psoriasis with those antibodies.
I am inclined to think that the Canadian approach to this question, which asks simply whether the claim is overbroad, is preferable to the US approach, which asks whether the inventor “had possession” of what was claimed. Suppose the claim to the use of anti-IL-12 antibodies to treat psoriasis had been at issue in the US litigation. Would AbbVie’s discovery of one method of making such antibodies have given them “possession” of that invention? Has the inventor described the entire plot of land, or only a part of it? The Fed Cir cautioned that
It is important not to take the analogy of a plot of land too far in thinking of written description issues because, even if one builds a house only in one corner of the plot, one may still own the whole plot. One describes a plot of land by its furthest coordinates, in effect drawing a perimeter fence around it. That may be akin to the function of patent claims to particularly point out and distinctly circumscribe the outer boundaries of a claimed invention. With the written description of a genus, however, merely drawing a fence around a perceived genus is not a description of the genus. One needs to show that one has truly invented the genus, i.e., that one has conceived and described sufficient representative species encompassing the breadth of the genus. Otherwise, one has only a research plan, leaving it to others to explore the unknown contours of the claimed genus.
This seems to suggest that the claim to treat psoriasis would not be adequately described because AbbVie has discovered only one way to get there, and the species do not encompass the breadth of the genus. This seems to me to be the wrong result (always assuming that the discovery that anti-IL-12 antibodies could treat psoriasis was truly inventive). Alternatively, we might enter into a debate as to what exactly is the “genus.” If the genus is not the antibodies, but the treatment of psoriasis, then maybe describing one route does encompass the genus.
This convoluted analysis illustrates the limitations of the written description approach. The validity of functional claims should not turn on strained analogies to a plot of land. The real question is whether the patentee’s contribution is commensurate with the scope of the claims. This is no doubt a difficult question to answer, but at least it is the right question. It is made more difficult, not less, by asking whether the inventor “has possession” of the invention. My sense is that the US courts have latched onto the written description requirement in order to have a statutory hook for the overbreadth requirement. This may be satisfying from a statutory interpretation perspective, but it is analytically problematic. My inclination is to think that the Canadian approach, which simply recognizes overbreadth as an independent ground of attack, is preferable.