In re Sullivan (Fed. Cir. 2007)

    By Kevin E. Noonan --

Easily lost in the understandable outrage over the new PTO continuation rules, the Board of Patent Appeals and Interferences is proceeding to chart the metes and bounds of the PTO's reaction to the Supreme Court's decision in KSR Int'l Co. v. Teleflex Inc. (see Patent Docs report).  Fortunately, the Federal Circuit's jurisprudence survived Supreme Court scrutiny with sufficient remaining vitality for the CAFC to continue to exercise oversight over the Board's more arbitrary application of the "new" obviousness standard explicated in KSR.  As it has done in the recent Ex parte Kubin case (see Patent Docs report), the Board misapplies the Supreme Court's decision, and in doing so appears ready to revive the times in the early 1990's when the PTO was noted more for denying than for granting patents in biotechnology.

The technology at issue involves immunological reagents for neutralizing snake venom (specifically rattlesnake venom).  The antiserum comprised F(ab) fragments of horse antibodies raised against the venom, and an understanding of the issues in the case requires a brief synopsis of antibody technology.  Antibodies are produced in a form represented by a "Y" (at right), where the stem of the Y represents effector functions for interaction with other components of the immune system (and that are shared by any antibody of particular type regardless of its antigenic specificity), and the two "arm" portions, each of which provide the particular antibodies antigenic specificity.  Also known in the art are proteolytic fragments of antibodies; proteolytic cleavage at a position in the antibody stem results in F(ab)2 fragments (at left) comprising both copies of the antigen-specific arm portions of the antibody.  F(ab) fragments (at left), in contrast, are produced by proteolytic cleavage that separates the two antigen-specific portions of the antibody.  Thus, F(ab) fragments have half the antigen-binding capacity of an equal number of F(ab)2 fragments.

The claims at issue are represented by the following claim:

An antivenom composition comprising Fab fragments which bind specifically to a venom of a snake of the Crotalus genus and which are essentially free from contaminating Fc as determined by immunoelectrophoresis using anti-Fc antibodies, and a pharmaceutically acceptable carrier.

The claims were initially rejected under 35 U.S.C. § 103 for obviousness over prior art disclosure of horse antibodies against rattlesnake venom, in combination with art disclosing production of F(ab) fragments from whole antibodies for use in detecting venom from an Australian brown snake.  The Board in its first decision on these claims found that reciting that the composition was an "antivenom" was not sufficient to distinguish the invention from the art, since it represented merely an intended use.  In response to the Board's decision, Sullivan amended the claims as follows:

An antivenom pharmaceutical composition for treating a snakebite victim, comprising Fab fragments which bind specifically to a venom of a snake of the Crotalus genus and which are essentially free from contaminating Fc as determined by immunoelectrophoresis using anti-Fc antibodies, and a pharmaceutically acceptable carrier, wherein said antivenom pharmaceutical composition neutralizes the lethality of the venom of a snake of the Crotalus genus.

The Examiner did not find these amendments persuasive, maintaining rejection under § 103 for obviousness over the same references.  The Board affirmed, finding that reciting that the claim encompassed an "antivenom pharmaceutical composition" was no more effective at distinguishing the prior art than the originally-presented (and rejected) claim, being merely a recitation of an intended use.  Regarding the functional limitation regarding venom neutralization, the Board held that the secondary reference taught that F(ab) fragments could neutralize snake venom in mice, and thus that this limitation did not render the claims patentable.  Importantly, the Board asserted in a footnote that:

"[t]he remainder of appellants arguments on this record, in addition to the Declarations of record, relate to the use of the claimed composition as an antivenom.  Since we have placed [no] weight on the intended use of appellants' composition we do not address these arguments or the Declarations."

This failure to consider the declaration evidence proved fatal to the Board's decision.  These declarations included two by the inventors and a third by an independent expert.  Sullivan contended that these declarations described "how the prior art taught away from using Fab fragments to neutralize rattlesnake venom, how a person having ordinary skill in the art would not have known how to use Fab fragments to neutralize rattlesnake venom, and how Fab fragment antivenom exhibits an unexpected property." In addition, Sullivan argued that this evidence was relevant to the secondary considerations under the Supreme Court's Graham v. John Deere Co. analytical framework, and that the Board erred for refusing to consider it.

The Federal Circuit agreed, and accepted the PTO's contention that it had established a prima facie case of obviousness of the claimed invention over the prior art of antivenom antibodies and methods for making F(ab) fragments from them.  Citing KSR, the CAFC stated that "if a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious unless its actual application is beyond his or her skill" in making this determination.  But making out a prima facie case is not enough.  Once the prima facie case is made, the burden shifts to the applicant to rebut it.  Rebuttal depends on evidence, such as the declaration evidence supplied by Sullivan but not considered by the Examiner or the Board.  The Federal Circuit held that the Board was obligated to consider this evidence, which was directed to relevant issues relating to the question of non-obviousness.  The evidence included applicants' distinctions over the art, including why the skilled worker would not have expected F(ab) fragments to be effective in neutralizing venom because inter alia it is more readily cleared from a bitten animal's circulation (in contrast to the venom itself which persists in the individual).  The Federal Circuit rejected the Board's contention that the evidence related merely to the intended use of the antivenom composition, stating that the evidence related to unexpected results, teaching away by the prior art, and the long-felt need in the art.  The CAFC agreed that recitation of an intended use of a known compound could not impart patentability to the compound, but noted that the claimed F(ab) fragments were not known (there were no rejections based on § 102), and the question of non-obviousness required consideration of all evidence of record.  Since the Board did not consider Sullivan's rebuttal evidence, the Federal Circuit vacated the decision and remanded the case back to the Board.

For Sullivan, the decision does nothing more than put the obviousness question back before the Board for reconsideration in view of the rebuttal evidence.  For the rest of us, however, it is a reminder to the Board that it must consider all the relevant evidence even under the post-KSR climate that is more permissive to the PTO asserting that an invention is obvious.  It is at least minimally reassuring that the Federal Circuit has not responded to the recent spate of negative commentary and reversals by the Supreme Court by abnegating its role in assuring that the PTO apply the law, rather than their own (hindsight-informed) opinions, in making obviousness determinations.

In re Sullivan (Fed. Cir. 2007)
Panel: Circuit Judges Newman, Lourie, and Gajarsa
Opinion by Circuit Judge Lourie

Additional information regarding this case can be found at Patently-O.