In re Sullivan

• Decision Date: 29 August 2007
• Docket Number: 454.,No. 2006-1507. Serial No. 08/405,2006-1507. Serial No. 08/405
• Citation: 498 F.3d 1345
• Parties: In re John B. SULLIVAN and Findlay E. Russell.
• Court: U.S. Court of Appeals — Federal Circuit

498 F.3d 1345

In re John B. SULLIVAN and Findlay E. Russell.

No. 2006-1507. Serial No. 08/405,454.

United States Court of Appeals, Federal Circuit.

August 29, 2007.

COPYRIGHT MATERIAL OMITTED

Lawrence M. Green, Wolf, Greenfield & Sacks, P.C., of Boston, MA, argued for appellants. With him on the brief were Michael T. Siekman and Charles T. Steenburg.

Janet A. Gongola, Associate Solicitor, United States Patent and Trademark Office, of Arlington, VA, argued for the Director of the United States Patent and Trademark Office. With her on the brief was Stephen Walsh, Acting Solicitor.

Before NEWMAN, LOURIE, and GAJARSA, Circuit Judges.

LOURIE, Circuit Judge.

Sullivan and Russell (collectively "applicant") appeal from the decision of the United States Patent and Trademark Office ("the PTO") Board of Patent Appeals and Interferences ("the Board") affirming the examiner's final rejection of claims 40-42 and 50 of application Serial No. 08/405,454 ("the '454 application") under 35 U.S.C. § 103 as having been obvious over two prior art references. In re Sullivan, No. 2006-0220 (B.P.A.I. Mar. 30, 2006). Because the Board failed to give any weight to the rebuttal evidence of record, we vacate the Board's decision and remand for further proceedings.

BACKGROUND

The subject matter of the appeal relates to an antivenom composition used to treat venomous bites from a snake of the Crotalus genus, i.e., a rattlesnake. An antivenom is created by injecting a small amount of the targeted venom into an animal such as a horse, sheep, goat, or rabbit. The animal will suffer an immune response to the venom, producing antibodies against the venom's active molecule. Those antibodies can then be harvested from the animal's blood and used to treat humans who have been injected with venom from a snake bite.

A whole antibody molecule, commonly referred to as an immunoglobulin, can be thought of as a Y-shaped protein comprised of three fragments. The v-shaped portion of the Y-shaped protein is called a F(ab)2 fragment. When separated, each arm of the v-shaped portion is called, in turn, a Fab fragment. F(ab)2 and Fab fragments recognize and bind to specific antigens, such as the toxin in rattlesnake venom. The lower stem of the Y-shaped antibody is called the Fc fragment and is not involved in antigen binding. Diagrams of an antibody and its components are provided below for reference. The diagram on the left shows a whole antibody and indicates the Fc region and the Fab region. The Fab region can be considered a F(ab)2 fragment. The diagram on the right shows two Fab fragments that are separated from the Fc region.

An intact antibody, F(ab)2, and Fab fragments have separate properties and utilities. Since 1969, most commercially available antivenom products have consisted of a class of whole antibodies, known as immunoglobulin G ("IgG"), but there have also been antivenom products that comprised only F(ab)2 fragments. Although antivenom products consisting of either IgG or F(ab)2 fragments are effective at binding to venom toxins, they often invoke adverse immune reactions in humans. Researchers did not experiment with antivenoms containing only Fab fragments because it was believed that their unique properties would prevent them from decreasing the toxicity of snake venom. Sullivan discovered, however, that Fab fragments are effective at neutralizing the lethality of rattlesnake venom, while reducing the occurrence of adverse immune reactions in humans.

Applicant filed the '454 application with claims directed to an antivenom composition comprising Fab fragments that bind specifically to venom from snakes of the Crotalus genus and a pharmaceutical carrier.¹ Representative claim 40, as originally filed, reads as follows:

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 examiner rejected the claim under 35 U.S.C. § 103 as being obvious over Sullivan² in view of Coulter³ and two additional references. In the first appeal to the Board, the Board affirmed the rejection of claim 40 as being obvious, but only relied upon Sullivan and Coulter for its rejection. In re Sullivan, No. 2001-1255 (B.P.A.I. Jan. 29, 2003). The Board found that Sullivan teaches whole antibodies purified from horse serum for use against venom from rattlesnakes, but fails to teach the use of Fab fragments. The Board also found that Coulter discloses a method for producing Fab fragments in place of whole antibodies. The Board noted that Coulter further teaches using Fab fragments in enzyme immunoassays ("EIAs")⁴ to detect textilotoxin, a kind of snake toxin from the venom of the Australian brown snake. Also, Coulter teaches that Fab fragments used in EIAs yielded results similar to those obtained with whole IgG.

Based upon those teachings, the Board agreed with the examiner that all the limitations of claim 40 were disclosed in Sullivan and Coulter. The Board concluded that a person of ordinary skill in the art would have been motivated to produce Fab fragments for use in EIAs to detect the venom from rattlesnakes because Coulter teaches that Fab fragments are able to detect textilotoxins. The Board further stated that the term "antivenom" in the preamble could not render claim 40 patentable over Sullivan and Coulter, reasoning that "the mere statement of new use, in this case `an antivenom' for an otherwise old or obvious composition, cannot render a claim to the composition patentable." Sullivan, No. 2001-1255, slip op. at 9. The Board also held that, although it was not previously addressed, Coulter discloses collecting Fab fragments in a phosphate buffered saline ("PBS"), which is a pharmaceutically acceptable carrier. The Board concluded that the asserted claims were prima facie obvious over the combination of Sullivan in view of Coulter.

The Board stated that since its decision contained a new ground of rejection, the applicant could either move for reconsideration by the Board or return to prosecution before the examiner.⁵ Applicant chose to return to prosecution before the examiner. Applicant then amended claim 40 to its current form, adding language to the preamble and to the end of the claim. Amended claim 40 reads as follows, with the underlined portions identifying the portions of the claim that were added:

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 rejected amended claims 40-42 and 50⁶ under 35 U.S.C. § 103 as obvious over the combination of Sullivan and Coulter. The examiner found that the additional language in claim 40 did not render the claim patentable. The examiner reasoned that the originally claimed composition contained the same components as the amended claimed composition. The examiner issued a final rejection, and applicant appealed to the Board. In the second appeal to the Board, the Board noted that there were only two differences between original claim 40 and amended claim 40:(1) the recitation of intended use that states that the pharmaceutical composition is for treating a snakebite victim, and (2) the functional limitation that requires the pharmaceutical composition to neutralize the lethality of the venom of a rattlesnake. The Board addressed each amendment in turn.

With regard to the first amended portion, the Board again stated that a statement of a new use for an otherwise old or obvious composition cannot render a claim to the composition patentable. The Board noted that the phrase, "an antivenom pharmaceutical composition for treating a snakebite victim," simply states the intended use for the invention. Sullivan, No. 2006-0220, slip op. at 11. The Board also noted that "all the elements of appellants' claimed composition are accounted for in the prior art relied upon on this record." Id. at 13. Thus, the Board held that the amended preamble did not render the claim patentable.

Most relevant to the resolution of the appeal, the Board then stated in a footnote: "The remainder of appellants sic 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 not sic weight on the intended use of appellants' composition we do not address these arguments or the Declarations." Id. at 13 n. 7.

The Board then considered the second amended portion of the claim, which includes the limitation of neutralizing the lethality of the rattlesnake venom. The Board found that Coulter teaches that neutralization tests performed in mice showed that whole antibodies and Fab fragments were equivalent in their neutralizing ability. Accordingly, the Board found that the additional requirement that the composition of claim 40 neutralize the lethality of the venom of a rattlesnake did not render the claim patentable. The Board thus held that the composition taught by the combination of Sullivan and Coulter would have been expected by a person of ordinary skill in the art at the time the invention was made to neutralize the lethality of the venom of a rattlesnake.

Applicant timely appealed, and we have jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A).

DISCUSSION

The determination whether an invention would have been obvious under 35 U.S.C. § 103 is a legal conclusion based on underlying findings of fact. In re Kotzab, 217 F.3d 1365, 1369 (Fed.Cir.2000). We review the Board's legal conclusion of obviousness de...