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PTO Must Consider Rebuttal Evidence of Nonobviousness

06-1507
August 29, 2007
Raich Ph.D., William B.

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Last Month at the Federal Circuit - September 2007

Judges: Newman, Lourie (author), Gajarsa

[Appealed from: Board]

In In re Sullivan, No. 06-1507 (Fed. Cir. Aug. 29, 2007), the Federal Circuit vacated the final rejection of claims 40-42 and 50 of U.S. Application No. 08/405,454 (“the ’454 application”) under 35 U.S.C. § 103 as obvious over two prior art references. The Court remanded the proceedings to the Board with instructions to consider the rebuttal evidence of record.

John B. Sullivan and Findlay E. Russell (collectively “applicant”) filed the ’454 application, which describes pharmaceutical compositions used to treat venomous rattlesnake bites. Most commercially available antivenoms include either whole antibodies or antibody fragments called F(ab)2 fragments. However, the compositions described in the ’454 application instead use smaller antibody fragments called Fab fragments. These antivenom compositions were observed to neutralize the toxicity of rattlesnake venom with less occurrence of adverse reactions.

The Board and the Federal Circuit considered claim 40 as representative and limited their discussions to this claim. Claim 40 was rejected by the examiner as obvious over an earlier publication by the named inventors (“Sullivan”) in view of a publication by Coulter and Harris (“Coulter”) and two additional references. In the first appeal to the Board, the Board affirmed the rejection of claim 40 as obvious, but relied only upon the Sullivan and Coulter publications. The Board found that Sullivan taught the use of a rattlesnake antivenom composed of whole antibodies, and that Coulter taught a method of producing Fab fragments from whole antibodies. The Board further found that a person of ordinary skill in the art would have been motivated to use Fab fragments because Coulter disclosed that Fab fragments could be used to detect toxins from the venom of the Australian brown snake.

Applicant subsequently amended the preamble of claim 40 to state that the antivenom composition was intended to be used “for treating a snakebite victim.” Applicant also amended the claim to add a “wherein” clause specifying that the antivenom composition “neutralizes the lethality of the venom of a snake of the Crotalus genus.” Despite these amendments, the examiner maintained the obviousness rejection, reasoning that the originally claimed composition and the amended composition contained exactly the same components.

The Board affirmed the obviousness rejection of amended claim 40. The Board held that the amended preamble could not confer patentability, because a new use for an otherwise old or obvious composition cannot render a claim to the composition patentable. With regard to the added “wherein” clause, the Board held that a person of ordinary skill would have expected that the composition taught by the combination of Sullivan and Coulter would neutralize rattlesnake venom because Coulter showed that whole antibodies and Fab fragments were equivalent in their neutralizing ability.

Critically, the Board decided that it would not consider other evidence of record, including several declarations, asserting that this evidence related only to the intended use of the composition as an antivenom. The Board reasoned that since the intended use could not confer patentability, it did not need to consider arguments or declarations that related to this intended use.

On appeal, applicant argued that the Board failed to establish that the claimed composition was prima facie obvious. In particular, applicant argued that a person of ordinary skill in the art would not have been motivated to combine the Sullivan and Coulter publications, because Coulter taught using Fab fragments to detect, rather than treat, venom. Applicant also argued that even if the Board had shown that the invention was prima facie obvious, the Board erred by ignoring extensive rebuttal evidence. Applicant argued that this rebuttal evidence described how the prior art taught away from using Fab fragments to neutralize rattlesnake venom and how Fab fragment antivenom exhibited unexpected properties.

The Federal Circuit accepted that the Board had established a prima facie case of unpatentability under § 103. However, the Court also held that the Board had improperly failed to consider the rebuttal evidence, which included evidence of unexpected results, evidence that the prior art taught away, and evidence of secondary considerations such as long-felt but unresolved need. According to the Court, “[w]hen a patent applicant puts forth rebuttal evidence, the Board must consider that evidence.” Slip op. at 9. The Court found that the previously submitted declarations constituted important rebuttal evidence. For example, a declaration from one of the inventors explained that Fab fragments, unlike whole antibodies or F(ab)2 fragments, are cleared quickly from the body. The declaration further explained that the field had not experimented with these relatively short-lived Fab fragments, because rattlesnake venom remains in the body for an extended period of time.

Based on the substance of these declarations, the Court held that the Board was mistaken in its assertion that the declarations related only to the intended use of the claimed composition. In particular, the Court found that the declarations showed unexpected results, teaching away, and long-felt need. The Court stated that “[h]ad the Board considered or reviewed the declarations in a meaningful way, it might have arrived at a different conclusion than it did.” Id. at 12-13.

The Court differentiated the facts of this case from those in In re Zierden, 411 F.2d 1325 (C.C.P.A. 1969), which was relied upon by the Board. The applicant in Zierden conceded that his composition was distinguished from a prior art composition only by the statement of intended use. In contrast, the applicant in this case argued that the claimed antivenom compositions exhibited the unexpected property of neutralizing rattlesnake venom while producing reduced adverse events. According to the Court, “[t]hat unexpected property is relevant, and thus the declarations describing it should have been considered by the Board.” Slip op. at 13.

The Board also asserted that the applicant raised secondary considerations for the first time on appeal, and that the Court should therefore consider this argument as waived. The Federal Circuit dismissed this assertion, noting that the previously submitted declarations extensively described these unexpected properties.