United States Court of Appeals for the Federal Circuit 

2007-1534 

(Reexamination No. 90/006,785) 

IN RE MELVIN J. SWANSON 

and PATRICK E. GUIRE 

 

Robert M. Asher, Bromberg & Sunstein LLP, of Boston, Massachusetts, argued 

for appellants. 

Mary L. Kelly, Associate Solicitor, United States Patent and Trademark Office, of 

Arlington, Virginia, argued for the Director of the United States Patent and Trademark 

Office. With her on the brief were Stephen Walsh, Acting Solicitor, and Robert J. 

McManus, Associate Solicitor. 

Appealed from: United States Patent and Trademark Office 

 Board of Patent Appeals and Interferences 
United States Court of Appeals for the Federal Circuit 

2007-1534 

(Reexamination No. 90/006,785) 

IN RE MELVIN J. SWANSON 

and PATRICK E. GUIRE 

Appeal from the United States Patent and Trademark Office, Board of Patent Appeals 

and Interferences. 

___________________________ 

DECIDED: September 4, 2008 

___________________________ 

 

Before LOURIE, BRYSON, and GAJARSA, Circuit Judges. 

GAJARSA, Circuit Judge. 

This is an appeal from the United States Patent and Trademark Office’s (“PTO”) 

Board of Patent Appeals and Interferences (“Board”). The Board upheld the examiner’s 

rejection of claims 22-25 of U.S. Patent No. 5,073,484 (“the ’484 patent”) in a 

reexamination proceeding. In re Swanson, No. 2005-0725, Reexamination No. 

90/006,785 (B.P.A.I. May 29, 2007). Previously, this court had affirmed a district court 

judgment that claims 22 and 23 of the ’484 patent were not invalid. Abbott Labs. v. 

Syntron Bioresearch, Inc., 334 F.3d 1343 (Fed. Cir. 2003) (“Abbott Labs. II”). We hold 

that under 35 U.S.C. § 303(a), as amended in 2002, despite consideration of U.S. 

Patent No. 4,094,647 (“Deutsch”) in the initial examination and our prior decision, there 

was a substantial new question of patentability regarding whether Deutsch anticipated 

and made obvious claims 22-25 that made reexamination warranted. As the patentee 
does not raise additional objections to the Board’s rejections over Deutsch, the Board’s 

finding that claims 22-25 of the ’484 patent were anticipated and would have been 

obvious in light of Deutsch is affirmed. 

I. 

A. The ’484 Patent 

The ’484 patent was filed on February 23, 1983, by Melvin Swanson and Patrick 

Guire. The patent discloses a method of quantitatively analyzing small amounts of 

biological fluids, such as milk, blood, and urine, or other solutions, to detect the 

presence of a particular substance (the analyte). In the method disclosed, one or more 

“reaction zones” containing a bound reactant are spaced out on a test strip made of a 

liquid-permeable solid. ’484 patent col.2 ll.6-10. A test solution is applied to the test 

strip and moves along a flow path, encountering these reactant-containing zones 

sequentially. When a solution containing the requisite analyte reaches each of the 

reaction zones, a predetermined product forms. Id. col.2 ll.12-14. Selected detectors in 

the reaction zones indicate, preferably by a change of color, the presence of analyte, 

reactant, or predetermined product. Id. col.8 ll.47-54. The specification does not limit 

the invention to any one type of detection and suggests that the analyte can be 

“substantially all chemical substances that are reactive with a reactant to form a 

product.” Id. col.7 ll.16-19.

Claim 22, the independent claim at issue, is characteristic of the patent and 

claims a method of detection in which the analyte and reactant form a ligand-antiligand 

binding pair: 

A method for analysis of an analyte which is a member of a ligandantiligand binding pair in a test solution comprising the steps of: 

2007-1534 2
(a) providing a non-diffusively immobilized reactant in each of one or more 

reaction zones spaced successively along a flow path defined by a liquid 

permeable medium, wherein said reactant is the other member of said 

binding pair and is capable of binding with the analyte to form a 

predetermined product; 

(b) flowing said solution along the medium and sequentially through the 

reaction zone(s); and 

(c) detecting the presence of analyte, said reactant or said predetermined 

product in the reaction zone(s), wherein the number of zones in which 

detection occurs is related to the presence [sic] of analyte solution. 

Id. col.18 ll.9-25. A preferred embodiment is an immunoassay, in which the ligandantiligand pair is an antigen-antibody pair. 

In addition to claim 22, there are three dependent claims relevant to this appeal: 

claims 23, 24, and 25. Claim 23 limits the ligand-antiligand pair by requiring that one 

part of the pair be “labeled with a chemical moiety, and wherein such detecting step 

comprises detecting the presence of said chemical moiety.” Id. col.18 ll.26-30. Claims 

24 and 25 additionally limit the chemical moiety to including an enzyme and being a 

radioisotope, respectively. Id. col.18 ll.31-34. 

B. Prior Art 

U.S. Patent No. 4,094,647 (“Deutsch”) also discloses a method of detecting 

ligand-antiligand binding pairs in order to determine the presence of a ligand (the 

analyte) in a biological fluid sample. In Deutsch, a test strip is prepared in which a 

reagent is immobilized in a downstream portion of the strip and the test solution is 

applied to the other end. The edge of the strip is then immersed in “developing fluid” 

which progresses upstream. Deutsch col.3 ll.59-62. When the developing fluid reaches 

the test solution, the two liquids combine and advance through the reaction zone(s) to 

2007-1534 3
the terminating end. Id. col.3 ll.63-64. If analyte is present, it binds with the reagents in 

the reaction zones and forms a detectable product. The detectable product may be 

labeled with “any chemical substance or moiety having a detectable characteristic” 

including radioactivity. Id. col.8 ll.60-67. A preferred embodiment is an immunoassay, 

or immunoreaction, in which the reactant contains an antibody capable of specifically 

binding to the antigen in the test sample. 

U.S. Patent No. 3,641,235 (“Weiss”) teaches a similar immunoassay method for 

visually detecting the presence of an analyte in biological fluid. In Weiss, the visual 

readout is an indicator that is either fixated in the reaction zone in the presence of the 

analyte or released in the presence of the analyte, in which case the release can be 

observed by the presence of the indicator material in the fluid front of the test solution 

moving forward on the strip. Weiss cols. 3-5. 

U.S. Patent No. 3,466,241 (“Tom”) discloses another immunoassay method, in 

which one of the reagents comprises “a signal creating system.” Tom col.3 ll.1-5, ll.47-

49. Tom’s signal producing system includes “radioactive substances, enzymes and 

chromogenic substances . . . .” Id. col.5 ll.1-10. 

C. Initial Examination 

The examiner initially rejected all the claims in the application that resulted in the 

’484 patent as obvious under 35 U.S.C. § 103, in light of various combinations of 

references. Office Action No. 467229, September 7, 1984 (“Original Office Action”). 

The method claimed in original claim 9 was nearly identical to the one claimed in claim 

22 of the issued patent, differing primarily in that it required multiple reaction zones and 

2007-1534 4
did not require that the analyte-reactant pair be a ligand-antiligand binding pair.1

 Claim 

9 was rejected (along with claims 1, 2, 4-6, and 8) “under 35 U.S.C. 103 as being 

unpatentable over either Morison or Bauer et al in view of Peurifoy et al.” Id. at 9. The 

examiner explained that Morison and Bauer each disclose a method that is “basically 

the same” as that disclosed by the applicants, and that it would have been obvious that 

the reagent in Morison and Bauer could be separated into multiple reaction zones to 

permit quantification, as described in Peurifoy. Id. In the application as filed, claim 10 

was dependent on claim 9 and added the limitation that the analyte and reactant be a 

“specific ligand-antiligand binding pair.” Claim 11 further specified that the reactant in 

the ligand-antiligand binding pair of claim 10 include an antibody. The examiner 

rejected these and similar dependent claims under 35 U.S.C. § 103 “as being 

unpatentable over either Morison or Bauer et al in view of Peurifoy et al as applied to 

claims 1, 2, 4-6, 8 and 9 above, and further in view of any one of Ruhenstroth-Bauer et 

 1

 Originally filed claim 9 claimed: 

Method for the quantitative analysis of an analyte in a carrier liquid, 

characterized by the steps of: 

providing a fluid-permeable solid medium defining a flow path and 

having predetermined number of successive, spaced reaction 

zones in the path of flow, said reaction zones having immobilized 

therein a reactant reactive with the analyte or an analyte derivative 

or both to result in the formation of a predetermined product; 

flowing said fluid along the flow path and sequentially through the 

spaced reaction zones; and 

detecting the presence of analyte, analyte derivative, reactant or 

predetermined product in the reaction zones; 

the amount of analyte in the fluid being a function of the number of 

zones in which such detection occurs.

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al, Brown et al and Deutsch et al.” Original Office Action at 9. The examiner explained 

that “it would be obvious that any known reaction within reasons [sic] could be 

incorporated in the modified method and apparatus of either Morison and [sic] Bauer, as 

see for example, the immunoreactions of Ruhenstroth-Bauer et al, Brown et al and 

Deutsch.”2 Id. at 9-10. 

The claims were amended, and on December 17, 1991, the ’484 patent was 

granted. Subsequently, the ’484 patent was assigned to Surmodics, Inc. (“Surmodics” or 

“patentee”), the real party at interest in the current proceedings, who exclusively 

licensed the patent to Abbott Laboratories (“Abbott”). 

D. Abbott v. Syntron

On December 30, 1998, Abbott sued Syntron Bioresearch, Inc. (“Syntron”) for 

infringement of two patents, one of which was the ’484 patent. Syntron counterclaimed 

that the patents were invalid, claiming, inter alia, that claims 22 and 23 of the ’484 

patent were invalid in light of Deutsch. On October 4, 2001, the jury returned a special 

verdict finding that the asserted claims of the patents-in-suit were not infringed and that 

Syntron had failed to prove by clear and convincing evidence that the claims were 

anticipated, obvious, or otherwise invalid. The district court entered judgment 

accordingly. Abbott Labs. v. Syntron Bioresearch, Inc., No. 98-CV-2359 (S.D. Cal. Oct. 

12, 2001) (“Abbot Labs I”). Abbott appealed, and Syntron cross-appealed to this court. 

 2

 The only other mention of Deutsch in the record provided is similar. 

Dependant claims 17 and 18 were rejected as obvious over Morison or Bauer et al in 

view of “any one of Ruhenstroth-Bauer et al, Brown et al and Deutsch et al.” Again the 

examiner explained, “it would be obvious to incorporate any reaction within reason in 

the apparatus of either Morison or Bauer et al, as see the immunoreactions of the 

secondary art.” Id.

2007-1534 6
On appeal, we affirmed-in-part and remanded-in-part the judgment of 

noninfringement of the ’484 patent and affirmed the judgment of validity on all asserted 

claims of the ’484 patent. Abbott Labs. v. Syntron Bioresearch, Inc., 334 F.3d 1343 

(Fed. Cir. 2003) (“Abbott Labs. II”). In particular, we sustained the judgment that 

Deutsch did not anticipate the asserted claims, noting that “the burden having been on 

Syntron to prove by clear and convincing evidence that the claims were anticipated, we 

cannot conclude that the jury verdict on anticipation was not supported by substantial 

evidence.” Id. at 1357. We explained that the only issue raised regarding anticipation 

was whether Deutsch teaches “flowing said solution along the medium.” We agreed 

that the jury reasonably could have found it did not because “the jury could have 

reasonably interpreted the language of the claims standing alone, as requiring that the 

solution itself provide the required flow.” Id. 

E. Reexamination 

Following the appeal, Syntron filed a request for an ex parte reexamination of the 

’484 patent, claiming that there was a substantial new question of patentability. See 35 

U.S.C. § 303(a). The examiner granted the request. After reviewing the claims in light 

of prior art, the examiner rejected claims 22, 23, and 25 as anticipated by Deutsch and 

claims 22 and 23 as anticipated by Weiss under 35 U.S.C. § 102(b), and claim 24 as 

obvious under 35 U.S.C. § 103 in light of Deutsch and a secondary reference, Tom. 

Office Action No. 006785, Nov. 15, 2004, at 3-6 (“Reexamination Office Action”). 

The Board affirmed the examiner’s rejections. In re Swanson, No. 2005-0725, 

Reexamination No. 90/006,785 (B.P.A.I. May 29, 2007). First, the Board rejected the 

patentee’s argument that Weiss lacks detection “in the reaction zone” and agreed with 

2007-1534 7
the examiner that, “detection may occur in a ‘reaction zone’ by determining if dye has 

been displaced from the particle or not.” Id. at 13. The Board also rejected the 

patentee’s argument that Weiss’s invention, which included using an indicator that is 

adsorbed by the antiligand, and which can be associated and dissociated with the 

ligand, did not meet the “labeled” requirement of claim 23. Second, the Board affirmed 

the examiner’s finding that Deutsch anticipated claims 22, 23, and 25, rejecting the 

patentee’s argument that Deutsch cannot anticipate the claims since it uses a 

developing fluid to provide the required flow through the test medium. The Board 

agreed with the examiner that “the claim is open to additional steps as it uses the term 

‘comprising’” and that “claim 22 does not contain a limitation requiring that the test 

solution itself provide the flow.” Id. at 17. Lastly, the Board rejected the patentee’s 

claim that reexamination was improper as to Deutsch because Deutsch does not raise 

“a substantial new question of patentability” as required by 35 U.S.C. § 303. The Board 

found that the reference did raise a substantial new question of patentability despite 

having been cited in the original office action because it was not cited in regard to the 

presently rejected claims and it was not relied upon for the same reason the examiner 

now relied upon it. The Board also dismissed the patentee’s argument that Deutsch 

could not raise a substantial new question of patentability because a jury had affirmed a 

finding of validity over the reference and the Federal Circuit had affirmed. Id. at 19. 

Surmodics filed this timely appeal, over which we have jurisdiction pursuant to 28 

U.S.C. § 1295(a)(4). 

Surmodics objects to the rejection of claims 22-25 on two grounds. First, it 

argues that the Board erred in affirming the examiner’s determination that Weiss 

2007-1534 8
anticipated claims 22 and 23. Second, it argues that the reexamination of claims 22-25 

on the basis of Deutsch was improper under § 303(a) because Deutsch does not raise a 

substantial new question of patentability. According to Surmodics, the consideration of 

anticipation by Deutsch in the district court litigation precludes a finding of a new 

question of patentability for the purposes of the reexamination, and it argues that to find 

otherwise would raise substantial questions regarding the constitutionality of the statute. 

In addition, Surmodics argues that the examiner’s consideration of Deutsch in the 

original proceedings also precludes finding a new question of patentability. 

The PTO’s rejection based on Weiss did not include any claims not also rejected 

under Deutsch. As we conclude that neither the district court action nor the initial 

examination bars the PTO’s consideration of Deutsch in the reexamination proceedings, 

and the patentee does not challenge the rejection of claims 22-25 in light of Deutsch on 

the merits, we consider only whether Deutsch raised a substantial new question of 

patentability and do not reach the issue of whether the Board properly found claims 22 

and 23 anticipated by Weiss. 

II. 

We review the Board’s legal conclusions including statutory interpretation de 

novo. In re Am. Acad. of Sci. Tech Ctr., 367 F.3d 1359, 1363 (Fed. Cir. 2004); Stevens 

v. Tamai, 366 F.3d 1325, 1330 (Fed. Cir. 2004).3 In interpreting statutes, we give effect 

 3

 While the Board’s statutory interpretation in a particular case is given no 

deference, deference may be owed to the PTO’s interpretation of statutory provisions 

concerning “the conduct of proceedings in the Office,” 35 U.S.C. § 2(b)(2)(A), made 

pursuant to its rulemaking authority under 35 U.S.C. § 2(b)(2)(A). See Cooper Techs. 

Co. v. Dudas, No. 2008-1130, __ F.3d__ (Fed. Cir. 2008) (applying Chevron deference 

to the PTO’s interpretation of a statutory provision concerning the conduct of 

proceedings in the PTO, instituted after notice and comment proceedings and published 

2007-1534 9
to the intent of Congress by “look[ing] not only to the particular statutory language, but 

to the design of the statute as a whole and to its object and policy.” Crandon v. United 

States, 494 U.S. 152, 158 (1990). We review the Board’s findings of fact for substantial 

evidence. In re Gartside, 203 F.3d 1305, 1316 (Fed. Cir. 2000). 

A. The Reexamination Statute and the Amendment to § 303(a) 

 Any person may file a request for an ex parte reexamination of an issued patent 

based on prior art patents or printed publications. 35 U.S.C. § 302. Congress intended 

reexaminations to provide an important “quality check” on patents that would allow the 

government to remove defective and erroneously granted patents. H.R. Rep. No. 107-

120 (2002); see also In re Recreative Techs. Corp., 83 F.3d 1394, 1396-97 (Fed. Cir. 

1996) (“The reexamination statute’s purpose is to correct errors made by the 

government . . . and if need be to remove patents that never should have been 

granted.” (quoting Patlex Corp. v. Mossinghoff, 758 F.2d 594, 604 (Fed. Cir. 1985))). 

The PTO, however, may only grant a reexamination request if it determines that 

“a substantial new question of patentability affecting any claim of the patent concerned 

is raised by the request.”4

 35 U.S.C. § 303(a); see also id. § 304. The “substantial new 

question of patentability” requirement prevents potential harassment of patentees by 

“act[ing] to bar reconsideration of any argument already decided by the [PTO], whether 

 

in the Federal Register). Deference is also given to the PTO’s interpretations of its own 

procedural rules. See Ballard v. Comm’r of Internal Revenue, 544 U.S. 40, 1288-89 

(2005) (“An agency’s interpretation of its own rule or regulation is entitled to ‘controlling 

weight unless it is plainly erroneous or inconsistent with the regulation.’” (quoting 

Bowles v. Seminole Rock & Sand Co., 325 U.S. 410, 414 (1945))). 

4

 The PTO may also instigate a reexamination proceeding on its own 

motion if it determines that prior art patents or printed publications raise a substantial 

new question of patentability. 35 U.S.C. §§ 303-04. 

2007-1534 10
during the original examination or an earlier reexamination.” H.R. Rep. No. 96-1307 

(1980). This court, in In re Portola Packaging Inc., 110 F.3d 786 (Fed. Cir. 1997), 

interpreted this statutory intent as precluding reexamination based on “prior art 

previously considered by the PTO in relation to the same or broader claims.” Id. at 791. 

Congress disagreed with the restrictive scope of reexamination imposed by this court. 

See H.R. Rep. No 107-120, at 2 (“[T]he Federal Circuit incorrectly interpreted Congress’ 

original intent underlying the reexamination statute and limited the application of the 

process.”). In 2002 Congress amended § 303(a) to include an additional sentence, 

explaining that the amendment “overturns the holding of In re Portola Packaging Inc., a 

1997 Federal court decision imposing an overly-strict limit that reaches beyond the text 

of the Patent Act.” Id. The reexamination statute now provides, in pertinent part: 

Within three months following the filing of a request for reexamination under the 

provisions of section 302 of this title, the Director will determine whether a 

substantial new question of patentability affecting any claim of the patent 

concerned is raised by the request, with or without consideration of other patents 

or printed publications. . . . The existence of a substantial new question of 

patentability is not precluded by the fact that a patent or printed publication was 

previously cited by or to the Office or considered by the Office. 

35 U.S.C.A. § 303(a) (2002) (emphasis added). According to the House Report 

accompanying the Bill, under the amended § 303(a), “the appropriate test to determine 

whether a ‘substantial new question of patentability’ exists should not merely look at the 

number of references or whether they were previously considered or cited but their 

combination in the appropriate context of a new light as it bears on the question of the 

validity of the patent.” Id.; see also H.R. Rep. No. 107-120, at 3 (“While this bill clarifies 

that previously considered prior art will not necessarily bar a request for reexamination, 

2007-1534 11
the bill does not eliminate the requirement for a ‘substantial new question of 

patentability’ to be present for the agency to permit reexamination.”). 

We have not had the opportunity to evaluate the scope of the “substantial new 

question of patentability” requirement since the 2002 amendment. Thus, this appeal 

presents issues of first impression. In determining the scope of the substantial new 

question requirement under the amended statute, “[w]e begin, as always, with the 

language of the statute.” Duncan v. Walker, 533 U.S. 167, 172 (2001). We then turn to 

the legislative history to further elucidate Congress’ intent. See Timex V.I. v. United 

States, 157 F.3d 879, 882 (Fed. Cir. 1998) (“Beyond the statute’s text, [tools of statutory 

construction] include . . . legislative history.”); Deluxe Corp. v. United States, 885 F.2d 

848, 850 (Fed. Cir. 1989) (explaining that in a matter of statutory interpretation, “where 

the text itself does not clearly exclude alternate interpretations, we look first to the 

legislative history for illumination of the intent of Congress.”); Ethicon, Inc. v. Quigg, 849 

F.2d 1422, 1426 (Fed. Cir. 1988) (using legislative history in construing a section of the 

statutory provisions on reexamination); see also Garcia v. United States, 469 U.S. 70, 

76 (1984) (“In surveying legislative history we have repeatedly stated that the 

authoritative source for finding the Legislature’s intent lies in the Committee Reports on 

the bill, which ‘[represent] the considered and collective understanding of those 

Congressmen involved in drafting and studying proposed legislation.’”). 

B. District Court Proceedings 

The patentee first argues that the district court’s consideration of Deutsch in 

determining the validity of the ’484 patent necessarily precludes the reference from 

raising a “new” question of patentability in subsequent reexamination proceedings. The 

2007-1534 12
district court and this court did consider the precise question at issue on reexamination: 

whether Deutsch satisfies the “flowing” limitation of the asserted claims and, thus, 

anticipates them. And both courts upheld the validity of the ’484 patent in light of 

Deutsch. Nevertheless, the statutory language, legislative history, and different 

purposes underlying reexamination and federal court proceedings suggest that the 

determination of a substantial new question is unaffected by these court decisions. 

The statute does not define what constitutes a “substantial new question of 

patentability.” However, the language added in the amended statute specifically 

discusses references “previously cited by or to the Office or considered by the Office,” 

35 U.S.C. § 303(a) (2002) (emphases added), but does not address any prior citation or 

consideration by courts. Similarly, the legislative history for both the original and 

amended reexamination statute suggest that Congress was concerned only with the 

consideration of issues in prior PTO examinations, not prior civil litigation. For example 

in passing the original reexamination statute, Congress stated that “this new procedure 

will permit any party to petition the patent office to review the efficacy of a patent, 

subsequent to its issuance, on the basis of new information about preexisting 

technology which may have escaped review at the time of the initial examination of the 

patent application,” and explained that the substantial new question requirement bars 

“reconsideration of any argument already decided by the office, whether during the 

original examination or an earlier reexamination.” H.R. Rep. No. 96-1307(I), at 3, 7 

(1980) (emphasis added). The legislative history of the 2002 amendment similarly 

states that the test for a substantial new question of patentability should focus on what 

“the examiner” considered. H.R. Rep. No. 120-107, at 3. Not once in the legislative 

2007-1534 13
history did Congress refer to references or issues addressed in prior civil litigation. See, 

e.g., H.R. Rep. No. 120-107; H.R. Rep. No. 96-1307(I); cf. Ethicon, 849 F.2d at 1427 

(explaining that nothing in the text or legislative history of the reexamination statute 

supports a finding that one of the purposes of reexamination was to avoid duplication of 

efforts by the PTO and courts). 

The focus on previous examinations rather than prior litigation follows from the 

fact that “reexamination[s are] conducted according to the procedures established for 

initial examination,” 35 U.S.C. § 305, and PTO examination procedures have distinctly 

different standards, parties, purposes, and outcomes compared to civil litigation, In re 

Etter, 756 F.2d 852, 856 (Fed. Cir. 1985). In particular, “the two forums take different 

approaches in determining validity and on the same evidence could quite correctly 

come to different conclusions.” Ethicon, 849 F.2d at 1428. 

In civil litigation, a challenger who attacks the validity of patent claims must 

overcome the presumption of validity with clear and convincing evidence that the patent 

is invalid. 35 U.S.C. § 282. If this statutory burden is not met, “[c]ourts do not find 

patents ‘valid,’ only that the patent challenger did not carry the ‘burden of establishing 

invalidity in the particular case before the court.’” Ethicon, 849 F.2d at n.3 (internal 

citations omitted) (emphasis in original). Therefore, “a prior holding of validity is not 

necessarily inconsistent with a subsequent holding of invalidity,” Stevenson v. Sears 

Roebuck & Co., 713 F.2d 705, 710 (Fed. Cir. 1983), and is not binding on subsequent 

litigation or PTO reexaminations. See Ethicon, 849 F.2d at 1429 & n.3 (rejecting the 

PTO’s argument that it was bound by a court’s decision upholding a patent’s validity); 

Mendenhall v. Cedarapids, 5 F.3d 1557, 1569-70 (Fed. Cir. 1993) (“A prior decision that 

2007-1534 14
a patent has previously survived an attack on its validity serves only to inform the district 

court . . . .”); cf. In re Trans Texas Holdings Corp., 498 F.3d 1290, 1296-97 (Fed. Cir. 

2007) (holding that the PTO during reexamination is not bound by a district court’s claim 

construction). 

In PTO examinations and reexaminations, the standard of proof—a 

preponderance of evidence—is substantially lower than in a civil case, In re Caveney, 

761 F.2d 671, 674 (Fed. Cir. 1985); there is no presumption of validity, Etter, 756 F.2d 

at 856; and the “examiner is not attacking the validity of the patent but is conducting a 

subjective examination of the claims in light of prior art,” id. at 857-58. And unlike in 

district courts, in reexamination proceedings “[c]laims are given ‘their broadest 

reasonable interpretation, consistent with the specification . . . .’” Trans Tex. Holdings, 

498 F.3d at 1298 (quoting In re Yamamoto, 740 F.2d 1569, 1571 (Fed. Cir. 1984)). 

Thus, considering an issue at the district court is not equivalent to the PTO having had 

the opportunity to consider it. See Ethicon, 849 F.2d at 1427 (“[P]recise duplication of 

effort does not occur because the PTO and the courts employ different standards of 

proof when considering validity . . . .”). 

In Ethicon, we held that because of these differences between reexaminations 

and court proceedings, the PTO did not have authority to stay a patent reexamination 

proceeding pending the outcome of a case in a district court given the requirement in 35 

U.S.C. § 305 that all reexaminations be conducted with “special dispatch.” 849 F.2d at 

1425-29. We explained that “the suspension of PTO [reexamination] proceedings does 

not prevent duplication;” instead, it improperly “precludes access to the forum where 

there is no presumption of validity.” Id. at 1427. In reaching this holding, we noted that 

2007-1534 15
“if the district court determines a patent is not invalid, the PTO should continue its 

reexamination because, of course, the two forums have different standards of proof for 

determining invalidity.” 849 F.2d at 1428-29. The PTO has recognized that while 

Ethicon did not directly interpret the meaning of a “substantial new question of 

patentability,” its reasoning is directly applicable to the issue of whether district court 

proceedings affect the “substantial new question” inquiry. Thus, prior to Ethicon the 

PTO had held that a substantial new question of patentability would not be found if the 

same issue had been addressed by a federal court, see In re Wichterle, 213 U.S.P.Q. 

868, 869 (Comm’r Pat. & Trademarks 1982), but it revised its position in the wake of 

Ethicon, instructing examiners that a final court decision of a claim’s validity will not 

preclude a finding of a substantial new question of validity based on the same art 

“because of the different standards of proof employed by the Federal District Court and 

the Office,” MPEP § 2242. 

We agree with the PTO’s current position. Section 303’s language and 

legislative history, as well as the differences between the two proceedings, lead us to 

conclude that Congress did not intend a prior court judgment upholding the validity of a 

claim to prevent the PTO from finding a substantial new question of validity regarding an 

issue that has never been considered by the PTO. To hold otherwise would allow a civil 

litigant’s failure to overcome the statutory presumption of validity to thwart Congress’ 

purpose of allowing for a reexamination procedure to correct examiner errors, without 

which the presumption of validity never would have arisen. See Patlex, 758 F.2d at 604 

(“A defectively examined and therefore erroneously granted patent must yield to the 

2007-1534 16
reasonable Congressional purpose of facilitating the correction of governmental 

mistakes.”). 

Surmodics argues that this reading of the statute—allowing an executive agency 

to find patent claims invalid after an Article III court has upheld their validity—violates 

the constitutionally mandated separation of powers, and therefore must be avoided. We 

disagree. The Supreme Court has repeatedly held that “Congress cannot vest review of 

the decisions of Article III courts in officials of the Executive Branch.” Plaut v. 

SpendThrift Farm, 514 U.S. 211, 219 (1995) (citing Hayburn’s Cases, 2 U.S. (Dall.) 409 

(1792)); see also Chi. & S. Air Lines, Inc. v. Waterman S.S. Corp., 333 U.S. 103, 113-14 

(1948) (“It has . . . been the firm and unvarying practice of Constitutional Courts to 

render no judgments not binding and conclusive on the parties and none that are 

subject to later review or alteration by administrative action.”). But the examiner’s 

rejection of claims in the ’484 patent pursuant to reexamination does not disturb this 

court’s earlier holding. There, the court held that Syntron had the burden of proving by 

clear and convincing evidence that the ’484 patent was invalid and concluded that, 

based on the evidence presented, the jury could have found that this burden was not 

met. Abbott Labs. II, 334 F.3d at 1357. The examiner did not reverse that holding and 

find that Syntron had met its burden; instead, the examiner evaluated the ’484 patent 

claims in light of prior art, some of which Syntron had presented at trial, and found that 

there was a preponderance of evidence supporting invalidity. Cf. Stevenson, 713 F.2d 

at 710 (holding that issue preclusion is generally not applicable in patent validity 

judgments). Thus, as discussed, the court’s final judgment and the examiner’s rejection 

are not duplicative—they are differing proceedings with different evidentiary standards 

2007-1534 17
for validity. See Ethicon, 849 F.2d at 1427. Accordingly, there is no Article III issue 

created when a reexamination considers the same issue of validity as a prior district 

court proceeding.5

 And as interpreting a “substantial new question of patentability” to 

include questions considered by a federal court but never by the PTO does not raise 

any constitutional concerns, the canon of statutory construction providing that a statute 

that is ambiguous should be interpreted to avoid raising “grave and doubtful 

constitutional questions” is not applicable. See Gonzalez v. United States, 128 S. Ct. 

1765, 1771 (2008) (“Under the avoidance canon, ‘when a statute is susceptible of two 

constructions, by one of which grave and doubtful constitutional questions arise and by 

the other of which such questions are avoided, our duty is to adopt the latter.’” (quoting 

Harris v. United States, 536 U.S. 545, 555 (2002))). 

We, therefore, conclude the Board did not err in holding that the prior district 

court litigation did not prevent the Deutsch reference from raising a “substantial new 

question of patentability” under § 303(a). As properly interpreted a “substantial new 

question of patentability” refers to a question which has never been considered by the 

PTO; thus, a substantial new question can exist even if a federal court previously 

considered the question. 

 

5

 In contrast, an attempt to reopen a final federal court judgment of infringement on 

the basis of a reexamination finding of invalidity might raise constitutional problems. 

2007-1534 18
C. Initial Examination 

Surmodics also argues that Deutsch does not raise “a substantial new question 

of patentability” because Deutsch was considered by the PTO during the initial 

examination and relied on as a secondary reference for rejecting various dependent 

claims as obvious. Surmodics recognizes that the 2002 amendment to § 303 overrides 

our prior rule in In re Portola Packaging, where we held that a reference could not raise 

“a substantial new question of patentability” if it was previously considered by the PTO 

in reference to the same or broader claims. It nevertheless urges this court to adopt a 

bright-line rule that “would preclude rejections in reexaminations based solely on 

references used in a rejection of claims in the original patent prosecution.” Appellant 

Reply Br. 14. We decline the invitation. Such a rule would be plainly inconsistent with 

the clear text of the amendment. Section 303(a) now mandates that “the existence of a 

substantial new question of patentability is not precluded by the fact that a patent or 

printed publication was previously cited by or to the Office or considered by the Office.” 

Thus, under § 303(a) as amended, a reference may present a substantial new question 

even if the examiner considered or cited a reference for one purpose in earlier 

proceedings. Nothing in the statute creates an exception to this rule for references 

considered in the context of a rejection of prior claims. Indeed, such an exception 

would overwhelm the rule and thwart a central purpose of the amendment, to overrule 

In re Portola Packaging. In that case, as here, the issue was whether a piece of prior 

art relied on for a prior rejection could nevertheless create a new question of 

patentability sufficient to warrant a reexamination. See In re Portola Packaging, 110 

2007-1534 19
F.3d at 787-89. After the amendment to § 303, the answer to that question must be 

yes. 

The 2002 amendment removes the focus of the new question inquiry from 

whether the reference was previously considered, and returns it to whether the 

particular question of patentability presented by the reference in reexamination was 

previously evaluated by the PTO. As was true before the amendment, an “argument 

already decided by the Office, whether during the original examination or an earlier 

reexamination” cannot raise a new question of patentability. H.R. Rep. No. 96-1307; 

see also H.R. Rep. No. 107-120, at 3 (explaining that the amendment did not diminish 

the “substantial new question requirement” and that “[t]he issue raised must be more 

than just questioning the judgment of the examiner.”). As we explained in In re 

Recreative Technologies Corp., the substantial new question requirement “guard[s] 

against simply repeating the prior examination on the same issues and arguments” and 

bars “a second examination, on the identical ground that had previously been raised 

and overcome.” 83 F.3d at 1396-97. As we recognized even in In re Portola 

Packaging, a single reference might, alone or in combination, create multiple possible 

grounds of rejection and thus raise more than one “question of patentability.” The 

bright-line rule in In re Portola Packaging was based on a presumption that the 

examiner had properly discharged his duties and thus had considered all question of 

patentability raised by any reference before him. 110 F.3d at 790. Congress, however, 

has now rejected this presumption of full consideration. Section 303(a) as amended 

instead requires a more context-specific approach that is based on an analysis of what 

the PTO actually did. 

2007-1534 20
As the legislative history clarifies, to decide whether a reference that was 

previously considered by the PTO creates a substantial new question of patentability, 

the PTO should evaluate the context in which the reference was previously considered 

and the scope of the prior consideration and determine whether the reference is now 

being considered for a substantially different purpose. See H.R. Rep. No. 107-120, at 3 

(“The appropriate test to determine whether a ‘substantial new question of patentability’ 

exists should not merely look at the number of references or whether they were 

previously considered or cited but their combination in the appropriate context of a new 

light as it bears on the question of the validity of the patent.”); see also 147 Cong. Rec. 

H5359 (statement of Rep. Berman) (“Ideally, a reexamination could be requested based 

on prior art cited by an applicant that the examiner failed to adequately consider . . . .”). 

Determining the scope of an examiner’s previous consideration of a reference 

will generally require an analysis of the record of the prior proceedings to determine if 

and how the examiner used the reference in making his initial decisions. As we believe 

that this inquiry is most accurately viewed as a question of fact, we will review the 

Board’s findings regarding the scope of consideration of a reference during prior 

examinations for substantial evidence. See also H.R. Rep. No. 107-120, at 3 (stating 

that there should be “substantial evidence” that the examiner “did not properly 

understand the reference, or did not consider a portion of the reference in making his 

decision.”). However, the ultimate question of whether the reexamination is based on a 

substantial new question of patentability, in light of how a reference was previously 

considered, remains a question of law, which we review de novo. While the standard is 

more flexible than before, we are mindful that Congress intended that the courts 

2007-1534 21
continue to “judiciously interpret the ‘substantial new question’ standard to prevent 

cases of abusive tactics and harassment of patentees through reexamination.” H.R. 

Rep. No. 107-120, at 3. 

We agree with the Board that whether Deutsch anticipates claims 22-24 raises a 

substantial new question of patentability under the amended § 303(a). Substantial 

evidence supports the Board’s conclusion that in the initial examination, “Deutsch was 

relied upon, as a secondary reference,” for the limited purpose of “teaching 

immunoreactions in general, and not for the specific method steps claimed.” In re 

Swanson, No. 2005-0725, Reexamination No. 90/006,785, at 18-19 (B.P.A.I. May 29, 

2007). Deutsch was not evaluated as a primary reference that taught or made obvious 

the specific analytical method claimed. The independent claims, such as original claim 

9, were found obvious without any reliance on Deutsch. Deutsch was cited only to 

reject the dependent claims that limited the analyte-reactant pair used in the method to 

a ligand-antiligand pair, e.g., original claim 10, or, more specifically, an antigen-antibody 

pair, e.g., original claim 11. Original Office Action at 9-10. The examiner explained that 

“it would be obvious that any known reaction within reasons [sic] could be incorporated 

in the modified method and apparatus of either Morison and [sic] Bauer” and cited to 

Deutsch as one of three references that disclosed immunoreactions. Id. In other 

words, since Deutsch and the other secondary references taught immunoreactions, 

immunoreactions were one type of “known reaction” that could be adopted to the 

method made obvious for any known reaction (within reason) by Morison and Bauer. 

Nowhere in its decision did the examiner consider the particular analytical method 

disclosed by Deutsch. 

2007-1534 22
In light of the extremely limited purpose for which the examiner considered 

Deutsch in the initial examination, the Board is correct that the issue of whether Deutsch 

anticipates the method disclosed in claims 22, 23, and 25 was a substantial new 

question of patentability, never before addressed by the PTO.6

On appeal, Surmodics’ only argument for why the Board erred in affirming the 

rejection of claims 22, 23, and 25 as anticipated by Deutsch is the alleged lack of a 

substantial new question of patentability. Accordingly, any arguments as to the merits 

of the Board’s rejection have been waived. Given our conclusion that Deutsch does 

raise a substantial new question of patentability, we, therefore, affirm the Board’s 

rejection of claims 22, 23, and 25. 

We also affirm the obviousness rejection of claim 24 in view of Deutsch and Tom. 

Surmodics has not argued the issue separately, but instead has stated that its appeal 

on this issue depends solely on whether Deutsch raises a substantial new question of 

patentability with regards to claims 22 and 23. See Appellant’s Br. 60 (“The 

patentability of claim 24 rises or falls with claims 22 and 23. The only question is as to 

Deutsch and that question is an old one addressed in a final court judgment and by the 

PTO in the original prosecution.”). Thus, in light of our affirmance of the rejection of 

 6

 In reaching this holding, we do not rely on the fact, discussed by the 

Board, that claim 22 differed from the rejected claims in the initial patent. While the 

difference between rejected claims and the claims at issue during a reexamination may 

be relevant to whether there is a substantial new question of patentability, a change in 

the scope of a claim will not, in itself, make all questions of patentability of the revised 

claim “substantial new question[s].” As the limited scope of the examiner’s 

consideration of Deutsch is sufficient to find that anticipation by Deutsch raises a 

substantial new question of patentability, we need not consider what effect the change 

in scope of the claims would have had had Deutsch been more fully considered during 

the initial proceeding. 

2007-1534 23
2007-1534 24

claims 22 and 23, any argument for why the rejection of claim 24 should nevertheless 

be reversed has been waived. 

CONCLUSION 

The Board did not err in finding that whether Deutsch anticipated claims 22, 23, 

and 25 of the ’484 patent or made obvious claim 24 in combination with Tom raised 

substantial new questions of patentability sufficient to warrant reexamination. 

Accordingly, the Board’s decision affirming the examiner’s rejection of claims 22-25 is 

affirmed. 

AFFIRMED