United States Court of Appeals for the Federal Circuit 

05-1324 

(Interference No. 105,187) 

FALKO-GUNTER FALKNER, GEORG HOLZER, and FRIEDRICH DORNER, 

Appellants, 

v. 

STEPHEN C. INGLIS, MICHAEL E.G. BOURSNELL, and ANTHONY C. MINSON, 

Appellees. 

John P. Isacson, Heller Ehrman LLP, of Washington, DC, argued for appellants. 

With him on the brief was Paul M. Booth. 

Robert G. McMorrow, Jr., Connolly Bove Lodge & Hutz LLP, of Wilmington, 

Delaware, argued for appellee. 

Appealed from: United States Patent and Trademark Office, Board of Patent Appeals 

 and Interferences 
United States Court of Appeals for the Federal Circuit 

05-1324 

(Interference No. 105,187) 

FALKO-GUNTER FALKNER, GEORG HOLZER, and FRIEDRICH DORNER, 

Appellants, 

v. 

STEPHEN C. INGLIS, MICHAEL E.G. BOURSNELL, and ANTHONY C. MINSON, 

Appellees. 

________________________ 

DECIDED: May 26, 2006 

________________________ 

Before GAJARSA, Circuit Judge, ARCHER, Senior Circuit Judge and DYK, Circuit 

Judge. 

GAJARSA, Circuit Judge. 

This is an appeal from a decision of the Board of Patent Appeals and 

Interferences (“Board”) in Interference No. 105,187, declared on December 24, 2003, 

between Falkner et al., U.S. Patent No. 5,770,212 (“the Falkner ’212 patent”) and Inglis 

et al., U.S. Application Serial No. 08/459,040 (“the Inglis ’040 application”). The 

Administrative Patent Judge (APJ) designated Inglis as the senior party. On December 

29, 2004, the Board issued a final decision, holding that Falkner could not antedate 

Inglis’ September 25, 1990 priority date, and entered judgment against Falkner on the 
sole count of the interference. It ordered that Falkner was not entitled to claims 1-19 of 

the Falkner ’212 patent. It further ordered that Inglis was entitled to claims 9, 10, 29 and 

30 of the ’040 application. Falkner filed a timely notice of appeal. This Court has 

jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A) and 35 U.S.C. §§ 141 and 142. For 

the reasons discussed below, we affirm the judgment of the Board. 

I. BACKGROUND 

A. The Invention 

Some vaccines against a virus (the “target virus”) incorporate harmless 

fragments of the target virus’s genetic material into a second virus, called a “viral 

vector.” When a person is vaccinated, the viral vector produces harmless fragments of 

the target virus, ultimately conferring immunity against it. To prevent the viral vector 

from itself causing a harmful infection in the inoculee, it must be attenuated. 

Attenuation is achieved by deleting or inactivating one or more genes responsible for 

the vector’s growth and infectiousness. However, because the vaccine is produced by 

essentially “growing” the vector virus (accompanied by its inserted target virus gene), 

attenuation makes it difficult to manufacture the vaccine. The traditional solution to this 

problem has been to inactivate genes known as “inessential” genes. With inessential 

genes inactivated, the viral vector is substantially less pathogenic. At the same time, 

because the vector virus can still fully reproduce itself, albeit more slowly, the vaccine 

can be produced in commercial quantities. However, the traditional approach carried a 

disadvantage, namely the risk that the vector virus, though attenuated, could still cause 

a harmful infection in the inoculee. 

05-1324 2
The inventors discovered a way of making vaccines safer by deleting or 

inactivating an essential, rather than an inessential, gene from the viral vector’s 

genome, while at the same time solving the production problem by growing the vaccines 

in cells that were complementarily modified to produce the absent essential viral gene 

product “on behalf of” the vector virus. Thus, the modified vector virus could be readily 

grown in these complementarily-modified cells, but not in other cells, such as those of 

an inoculee. 

This approach is applicable to many different kinds of vector viruses, e.g., 

adenoviruses, herpesviruses, poxviruses and retroviruses. The subject matter of this 

interference, however, is directed specifically to vaccines in which the vector virus is a 

poxvirus. For many vector viruses, there is a risk that vectors that have been 

attenuated in essential genes can “swap” genes with the host cell genome, thereby 

reacquiring their deleted genes and reverting to wild-type virus. This risk can be 

minimized through the use of viruses that are “cytoplasmic”, meaning that they are 

unlikely to enter the cell nucleus. Because a cell’s genes are located in the nucleus, 

cytoplasmic viruses such as poxvirus cannot swap genes with the cell genome and 

possibly revert to a virulent wild-type virus. 

B. Defining the Count and Assigning Priority 

The sole count of the interference was either “[a] vaccine according to Claim 1 of 

Falkner’s 5,770,212 patent or a vaccine according to Claim 29 of Inglis’ 08/459,040 

application.” Claim 29 of the Inglis ’040 application reads: 

A vaccine comprising a pharmaceutically acceptable excipient and an 

effective immunizing amount of a mutant virus, wherein said mutant virus 

is a mutant poxvirus and has a genome which has an inactivating mutation 

in a viral gene, said viral gene being essential for the production of 

05-1324 3
infectious new virus particles, wherein said mutant virus is able to cause 

production of infectious new virus particles in a complementing host cell 

gene expressing a gene which complements said essential viral gene, but 

is unable to cause production of infectious new virus particles when said 

mutant virus infects a host cell other than a complementing host cell; for 

prophylactic or therapeutic use in generating an immune response in a 

subject. 

(emphasis added) 

Claim 1 of the Falkner ’212 patent reads: 

A vaccine comprising (a) a defective poxvirus that lacks a function 

imparted by an essential region of its parental poxvirus, wherein (i) said 

defective poxvirus comprises a DNA polynucleotide encoding an antigen 

and said DNA polynucleotide is under transcriptional control of a promoter, 

and (ii) the function can be complemented by a complementing source; 

and (b) a pharmaceutically acceptable carrier.

The Administrative Patent Judge (APJ) designated claims 1-19 of the Falkner 

‘212 patent and claims 9,10, 29, and 30 of the Inglis ’040 application as corresponding 

to the interference count.1

 Both parties sought the benefit of earlier-filed applications to 

establish dates of constructive reduction to practice.2

 The ALJ accorded the Inglis ’040 

 1 Inglis’s claim 29 is his broadest claim, directed to poxvirus; and claim 30, 

which depends on claim 29, is a poxvirus vaccine for mammalian subjects. Claim 9 is 

directed to poxvirus but contains some additional limitations unrelated to the type of 

virus used; claim 10 depends on claim 9 and is directed to a single species of poxvirus, 

namely vaccinia virus. Falkner’s claims 2-10 depend on claim 1. Falkner claim 10 is 

directed to a method of producing the vaccine of claim 1, and the remaining method 

claims depend thereon. 

2 Priority in an interference goes to the first to invent, but a rebuttable 

presumption exists that the inventors made their inventions in the chronological order of 

their effective filing dates, namely that the senior party invented first, see 37 C.F.R. 

§ 1.657(a) (2004), and the junior party bears the burden of proving otherwise, see

§ 1.657(b), such as by proving that she actually reduced the invention to practice before 

the constructive filing date (priority date) of the senior party, or that she was first to 

conceive and diligently reduced the invention to practice, starting from a date prior to 

reduction to practice by the senior party. See 35 U.S.C. § 112(g) (2000). Falkner 

sought to rely, in part, on an alleged date of conception and beginning of reasonable 

diligence: April 27, 1994. 

05-1324 4
application (filed June 2, 1995) the benefit of several earlier-filed applications, dating 

back to September 25, 1990.3

 Likewise, the APJ accorded the Falkner ’212 patent 

(issued June 23, 1998 from an application filed February 21, 1997) the benefit of earlierfiled applications, but these dated back only to April 29, 1994.4

 Consequently, the APJ 

designated Inglis as the senior party. 

C. Board Decision 

The specifications of all of Inglis’ earlier applications were similar. Although they 

focused on herpesvirus vectors, they contained several passages related to poxvirusbased vaccines. Because Falkner believed that these passages did not adequately 

describe and enable the poxvirus invention, he challenged both Inglis’ entitlement to 

priority as to the count and the patentability of Inglis’ corresponding claims. Falkner 

brought these challenges in three closely-related preliminary motions before the Board. 

 

On September 13, 2004, the “600” rules expired in favor of new rules found at 37 

C.F.R. § 41.100 et seq. However, the Board correctly chose to decide the matter under 

the old rules, given the parties’ reliance on them in filing all motions, oppositions, and 

replies in the case, which were completed before the new rules took effect. See Singh 

v. Brake, 222 F.3d 1362, 1371 (Fed. Cir. 2000) (applying a new procedural rule if and 

only if it did not affect the parties’ reliance interests). 

3 The Inglis priority applications were U.S. Application Serial No. 08/384,963 

(“the Inglis ’963 application”), filed February 7, 1995; U.S. Application Serial No. 

08/030,073 (“the Inglis ’073 application”), filed May 20, 1993; WO/92/05263, 

PCT/GB91/01632 (“the Inglis PCT application”), filed September 23, 1991, published in 

English on April 2, 1992; GB 9104903.1 (“the Inglis 1991 British application”), filed 

March 8, 1991; and GB 9020799.4 (“the Inglis 1990 British application”), filed 

September 25, 1990. The Inglis ‘040 application is a continuation in part of the ’963 

application, which was in turn a continuation of the Inglis ’073 application. The ’073 

application corresponded to the Inglis PCT application. The Inglis PCT application 

claimed priority to, and was essentially identical to, the Inglis 1990 and 1991 British 

applications. 

4 The Falkner priority applications were U.S. Application Serial No. 

08/616,313 (“the Falkner ’313 application”) filed March 14, 1996; and U.S. application 

Serial No. 08/235,392 (“the Faulkner ’392 application”), filed April 29, 1994. 

05-1324 5
In each, as the moving party, Falkner carried the burden of proof by a preponderance of 

the evidence. See 37 C.F.R. § 1.637(a); see also Kubota v. Shibuya, 999 F.2d 517, 

520 n.2 (Fed. Cir. 1993) (explaining that “[t]he term ‘burden of proof’ . . . means the 

burden to establish the proposition at issue by a preponderance of the evidence”). 

Falkner brought his first preliminary motion pursuant to 37 C.F.R. § 1.633(a),5

arguing that the claims in Inglis’s involved (’040) application that corresponded to the 

count were unpatentable because they failed to meet the written description 

requirement of 35 U.S.C. § 112. In support of his argument, he stated, inter alia, that 

(1) the specification of Inglis’s ’040 application did not identify any essential genes in 

poxvirus or describe the inactivation of such genes, (2) vaccines based on vaccinia (a 

type of poxvirus) had not yet been produced, and (3) the bulk of the Inglis specification 

was directed not to poxviruses but to herpesviruses. The Board denied Falkner’s 

motion, based in part on his failure to address the perceived shortcomings of the ’040 

claims in light of the specification. 

Second, Falkner moved pursuant to 37 C.F.R. §§ 1.633(g) & 1.637(g) to deny 

Inglis the priority benefit of his earlier applications, arguing that they did not sufficiently 

 5 On September 13, 2004, the “600” rules expired in favor of new rules 

found at 37 C.F.R. § 41.100 et seq. However, the Board correctly decided the matter 

under the old rules, given the parties’ reliance on them in filing all motions, oppositions, 

and replies in the case, which were completed before the new rules took effect. See

Singh v. Brake, 222 F.3d 1362, 1371 (Fed. Cir. 2000) (applying a new procedural rule if 

and only if it did not affect the parties’ reliance interests); see also Brown v. Barbacid, 

436 F.3d 1376, 1379 n.1 (Fed. Cir. 2006) (holding that the Board did not err in applying 

the old rules “under which this case was decided”). 

05-1324 6
describe and enable the claims in question.6

 Falkner argued that without the benefit of 

these applications Inglis would be unable to establish constructive reduction to practice 

earlier than Falkner. Falkner would win priority as to the count, and 

Inglis’ corresponding claims would be unpatentable. In support of his motion, Falkner 

alleged deficiencies in Inglis’ benefit specifications similar to those raised in his first 

motion. The Board carefully articulated the legal standard, correctly explaining that 

“benefit with respect to priority in an interference is granted with respect to counts not 

claims” and that “[a]ll that is necessary for a party to be entitled to benefit of an earlier 

filed application for priority purposes is compliance with 35 U.S.C. § 112 with respect to 

at least one embodiment within the scope of the count.” Board Op. at 7 (citing Hunt v. 

Treppschuh, 523 F.2d 1386, 1389 (CCPA 1975) (holding that where a “parent 

application is relied upon as a prior constructive reduction to practice[,] . . . . the § 112, 

first paragraph requirements need only be met for an embodiment within the count”)). 

After careful review of the record, the Board held that Falkner had failed to meet his 

burden of proof. 

Third, Falkner moved for judgment pursuant to 37 C.F.R. § 1.633(a) that the 

claims in Inglis’ involved (’040) application that corresponded to the count were 

anticipated and therefore unpatentable. He argued that because Inglis’ earlier 

applications had failed to adequately describe and enable the full scope of his current 

claims, the current claims could not be accorded the benefit of 35 U.S.C. § 120 for the 

 6 Falkner did not argue lack of enablement with respect to the Inglis ‘963 

patent because he believed that the teachings of the Falkner ’392 patent, filed in 1994, 

would have enabled the subsequent ’963 patent. 

05-1324 7
purpose of antedating patent-defeating prior art.7

 The Board explained that 35 U.S.C. 

§§ 119 & 120 require benefit applications to comply with § 112, first paragraph, with 

respect to the full scope of what a party now claims, rather than with respect to merely 

one embodiment within the scope of the interference count. After carefully considering 

the written description and enablement issues, the Board denied the motion. As a result 

of the denial of Falkner’s several motions, Inglis remained the senior party, and the 

Board ordered judgment as to the subject matter of the count in favor of Inglis. 

D. Issue and Standard of Review 

On appeal, Falkner essentially reiterates the arguments that he made before the 

Board. While we recognize that each of these three arguments is distinct, they are 

nonetheless all related, and under the facts of this particular case, we need only to 

resolve the following common issue: whether the Inglis benefit applications adequately 

describe and enable a poxvirus-based vaccine. Falkner also argues that the Board 

committed other errors, such as initially designating Inglis as the senior party and failing 

to afford Falkner an opportunity for briefing prior to making this designation. These 

arguments lack merit, and we shall not further discuss them. We turn, therefore, to the 

central issues in this case: written description and enablement. 

Written description is a question of fact, judged from the perspective of one of 

ordinary skill in the art as of the relevant filing date. See Vas-Cath, Inc. v. Mahurkar, 

935 F.2d 1555, 1563-64 (Fed. Cir. 1991). Enablement is a question of law involving 

underlying factual inquiries. See Genentech, Inc. v. Novo Nordisk A/S, 108 F.3d 1361, 

 7 Here, Falkner points to his own U.S. Pat. No. 5,766,882 (“the ’882 

patent’), issued in March 1995, as the patent-defeating prior art. 

05-1324 8
1365 (Fed. Cir. 1997); see also In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988) 

(holding that whether undue experimentation is required is a “conclusion reached by 

weighing many factual considerations. . . . includ[ing] (1) the quantity of experimentation 

necessary, (2) the amount of direction or guidance presented, (3) the presence or 

absence of working examples, (4) the nature of the invention, (5) the state of the prior 

art, (6) the relative skill of those in the art, (7) the predictability or unpredictability of the 

art, and (8) the breadth of the claims.”).

This court applies the standards of the Administrative Procedure Act (“APA”) in 

reviewing decisions of the Board. See Dickinson v. Zurko, 527 U.S. 150, 152 (1999) 

(holding that 5 U.S.C. § 706 governs our review of PTO appeals). Accordingly, we will 

set aside actions of the Board if they are arbitrary, capricious, an abuse of discretion, or 

otherwise not in accordance with law, and we set aside factual findings that are 

unsupported by substantial evidence. See In re McDaniel, 293 F.3d 1379, 1382 (Fed. 

Cir. 2002) (citing 5 U.S.C. § 706); see also In re Sullivan, 362 F.3d 1324, 1326 (Fed. 

Cir. 2004) (substantial evidence review of factual findings). We review questions of law 

de novo. See Rapoport v. Dement, 254 F.3d 1053, 1058 (Fed. Cir. 2001). 

Substantial evidence is defined as that which a reasonable person might accept 

as adequate to support a conclusion. See In re Zurko, 258 F.3d 1379, 1384 (Fed. Cir. 

2001). It requires an examination of the record as a whole, taking into account both the 

evidence that justifies and detracts from an agency’s opinion. See In re Gartside, 203 

F.3d 1305, 1312 (Fed. Cir. 2000). An agency decision can be supported by substantial 

evidence, even where the record will support several reasonable but contradictory 

conclusions. See id.; see also In re Jolley, 308 F.3d 1317, 1320 (Fed. Cir. 2002). 

05-1324 9
II. DISCUSSION 

A. Contents of the Inglis Priority Applications 

The claims that correspond to the count of the interference are directed to a 

novel type of vaccine that is comprised of a “vector virus” in the poxvirus family. 

Conceptually, poxviruses are a “subgenus” of viruses that includes the “species” 

vaccinia. All of the prior Falkner applications described poxvirus vaccine vectors in 

detail, and to the exclusion of other types of vaccine vectors (e.g., herpesvirus vaccine 

vectors). These applications provided five detailed working examples regarding the 

preparation and use of vaccines from defective poxviruses. They also described the 

use of a particular species of poxvirus vaccine vector, namely vaccinia virus. 

In contrast, the Inglis applications described vaccine vectors in general, and then 

focused on the subgenus of herpesviruses, for which they provided a detailed example. 

Nevertheless, at least three passages discussed the poxvirus invention and specifically 

mentioned “vaccinia virus.”8

 For example, after introducing the concept of vaccine 

vectors, the specification states that “[t]ypically members of the pox virus family, e.g. 

vaccinia virus, are used as vaccine vectors.”9

 The specification later discusses the 

deletion of essential genes from vaccine vector genomes, noting that the “invention can 

 8 We recognize that the Inglis applications do not describe any actual 

reduction to practice of a poxvirus vaccine. See Carroll Declaration (stating that the 

‘040 application did not contain any discussion of the “actual creation of the recited 

‘mutant poxvirus’” and that the application in fact stated “that a vaccinia virus with a 

deletion in an essential gene had not been produced.”). As we discuss below, however, 

an actual reduction to practice is unnecessary to satisfy the written description 

requirement. 

9 Because of the substantial similarity in the specifications of all of the Inglis 

benefit applications, we shall refer in this opinion to representative passages from the 

earliest of the applications, the Inglis 1990 British application. 

05-1324 10
be applied to any virus where one or more essential gene(s) can be identified and 

deleted from or inactivated within the virus genome” (emphasis added). Moreover, it 

provides that “the virus may comprise an orthopox virus, for example, vaccinia virus, 

which may comprise a heterologous sequence encoding an immunogen derived from a 

pathogen.” Finally, it reads: 

For example vaccinia virus, a poxvirus, can carry and express genes from 

various pathogens, and it has been demonstrated that these form effective 

vaccines when used in animal experimental systems. The potential for 

use in humans is vast, but because of the known side effects associated 

with the widespread use of vaccinia as a vaccine against smallpox, there 

is reluctance to use an unmodified vaccine in humans. There have been 

attempts to attenuate vaccinia virus by deleting non-essential genes such 

as the vaccinia growth factor gene. . . However, such attenuated viruses 

can still replicate in vivo, albeit at a reduced level. No vaccinia virus with a 

deletion in an essential gene has yet been produced, but such a virus, 

deleted in an essential gene as described above, with its complementing 

cell for growth, would provide a safer version of this vaccine. 

The application provides a detailed example of an embodiment that comprised 

not a poxvirus, but a herpesvirus, including the identity of the deleted essential 

sequences therein. Nevertheless, for the reasons discussed below, we find no error in 

the Board’s determinations on the adequacy of written description and enablement in 

the various Inglis disclosures. 

B. Enablement 

Because the adequacy of the disclosure is judged from the perspective of one of 

ordinary skill in the art, we start our review of the Board’s decision by noting that the 

parties stipulated to a high level of skill in the art. They defined the skilled artisan as 

having 5-10 years experience creating recombinant poxvirus, as being familiar with the 

poxvirus literature, the use of poxvirus as a vector for the expression of heterologous 

genes, and having the “needed technical skill to practice the experimentation described 

05-1324 11
in the scientific literature relating to recombinant virus, including poxvirus.” The Board 

agreed with the parties’ stipulation as to level of skill. 

The Board did not err in finding Inglis’ claims to be enabled as a matter of law, in 

light of its articulated underlying factual findings. In support of its conclusion, it noted 

that “there is extensive disclosure of the selection of an essential gene, its deletion or 

inactivation and the production of a mutated virus with said deleted or inactivated gene, 

albeit for herpesvirus.” Moreover, because the differences between the herpesviruses 

and poxviruses were well known, this would have aided the person of ordinary skill in 

the art in her application of the lessons of the herpesvirus example in the construction of 

poxvirus vaccines. The Board observed that “the mere fact that the experimentation 

may have been difficult and time consuming does not mandate a conclusion that such 

experimentation would have been considered to be ‘undue’ in this art. Indeed, great 

expenditures of time and effort were ordinary in the field of vaccine preparation.” Thus, 

the Board found the Inglis applications to be enabling. 

Reviewing the Board’s legal conclusion of enablement, as based on its 

underlying findings of fact, we cannot say that the Board erred. With respect to a skilled 

artisan’s ability to identify “essential” poxvirus genes, as discussed below we note that 

there was undisputed testimony that as of the time of filing of the earliest Inglis 

application publications in professional journals had disclosed the DNA sequence of the 

poxvirus genome along with the locations of the “essential regions.” The person of 

ordinary skill in the art would clearly have possessed such knowledge, and given the 

ready accessibility of the journals, the absence of incorporation by reference is not 

problematic. Indeed, “[a] patent need not teach, and preferably omits, what is well 

05-1324 12
known in the art.” Spectra-Physics, Inc. v. Coherent, Inc., 827 F.2d 1524, 1534 (Fed. 

Cir. 1987). 

C. Written Description 

On appeal to this court, Falkner essentially reargues the positions on written 

description that he took before the Board. Although the Board erred in its articulation of 

the written description standard, that error is harmless. The Board held that “an actual 

possession standard is not required.” (emphasis added). But our precedent clearly 

establishes that “[t]he applicant must . . . convey to those skilled in the art that, as of the 

filing date sought, he or she was in possession of the invention.” Vas-Cath, Inc. v. 

Mahurkar, 935 F.2d 1555, 1563-64 (Fed. Cir. 1991). Nonetheless, we conclude there is 

no need for remand because the undisputed testimony supports the Board’s ultimate 

conclusion. 

As noted above, the Board found several passages in the Inglis ‘040 application 

(and in the benefit applications) that were directed to poxvirus. No length requirement 

exists for a disclosure to adequately describe an invention. See In re Hayes 

Microcomputer Prods., Inc. Patent Litig., 982 F.2d 1527, 1534 (Fed. Cir. 1992) (“[T]he 

adequacy of the description of an invention depends on its content in relation to the 

particular invention, not its length.”). Furthermore, the testimony of Falkner’s expert, Dr. 

Boursnell, established that the articles describing essential genes for poxvirus were 

well-known in the art. Dr. Boursnell testified that “the skilled person would have been 

readily able to choose an essential vaccinia gene” based on references that have been 

publicly available since 1990. The testimony of Inglis’ expert, Dr. Carroll, did not refute 

this claim. 

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The parties also dispute several aspects of our law of written description, which 

we now address. We conclude that the Board applied correct law. Specifically, we 

hold, in accordance with our prior case law, that (1) examples are not necessary to 

support the adequacy of a written description (2) the written description standard may 

be met (as it is here) even where actual reduction to practice of an invention is absent; 

and (3) there is no per se rule that an adequate written description of an invention that 

involves a biological macromolecule must contain a recitation of known structure. 

1. Examples Are Not Required 

First, it is clear that the absence of examples involving poxviruses in the Inglis 

applications does not render the written description inadequate. As we explained in 

LizardTech, Inc. v. Earth Resource Mapping, PTY, Inc.: 

A claim will not be invalidated on section 112 grounds simply because the 

embodiments of the specification do not contain examples explicitly 

covering the full scope of the claim language. That is because the patent 

specification is written for a person of skill in the art, and such a person 

comes to the patent with the knowledge of what has come before. Placed 

in that context, it is unnecessary to spell out every detail of the invention in 

the specification; only enough must be included to convince a person of 

skill in the art that the inventor possessed the invention and to enable 

such a person to make and use the invention without undue 

experimentation. 

424 F.3d 1336, 1345 (Fed. Cir. 2005) (citing Union Oil Co. v. Atl. Richfield Co., 208 F.3d 

989, 997 (Fed. Cir. 2000); In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir. 1995)). 

2. Actual Reduction to Practice Is Not Required 

As we explained in Capon v. Eshhar, “[t]he ‘written description’ requirement 

implements the principle that a patent must describe the technology that is sought to be 

patented; the requirement serves both to satisfy the inventor’s obligation to disclose the 

technologic knowledge upon which the patent is based, and to demonstrate that the 

05-1324 14
patentee was in possession of the invention that is claimed.” 418 F.3d 1349, 1357 

(Fed. Cir. 2005). The Board was correct, however, not to view as dispositive that Inglis 

had not actually produced a poxvirus vaccine,10 because an actual reduction to practice 

is not required for written description.11 See Univ. of Rochester v. G.D. Searle & Co., 

358 F.3d 916, 926 (Fed. Cir. 2004) (“We of course do not mean to suggest that the 

written description requirement can be satisfied only by providing a description of an 

actual reduction to practice. Constructive reduction to practice is an established method 

of disclosure . . . .”). Rochester, moreover, is consistent with Supreme Court precedent. 

In the context of interpreting 35 U.S.C. § 102(b), the Court held that “[t]he word 

‘invention’ must refer to a concept that is complete, rather than merely one that is 

‘substantially complete.’” Pfaff v. Wells Elecs., 525 U.S. 55, 66 (1998). It then 

proceeded to make clear that although “reduction to practice ordinarily provides the best 

evidence that an invention is complete. . . . it does not follow that proof of reduction 

 10 The Inglis specifications stated that “[n]o vaccinia virus with a deletion in 

an essential gene has yet been produced, but such a virus, deleted in an essential gene 

as described above, with its complementing cell for growth, would provide a safer 

version of this vaccine.” 

11 The Board believed that Falkner’s expert, Dr. Carroll, had premised his 

opinions on the misunderstanding that actual reduction to practice was required to 

prove written description, and it discredited his expert opinion. 

05-1324 15
to practice is necessary in every case.” Id. (emphasis added).12 Thus, to the extent that 

written description requires a showing of “possession of the invention,” Capon, 418 F.3d 

at 1357 (emphasis added), Pfaff makes clear that an invention can be “complete” even 

where an actual reduction to practice is absent.13 The logical predicate of “possession” 

is, of course, “completeness.” 

3. Recitation of Known Structure Is Not Required 

Falkner argues, inter alia, that the Inglis specifications do not adequately 

describe the poxvirus invention, in light of Eli Lilly, because they do not describe the 

“essential regions” of any poxvirus. 119 F.3d 1559. We note, in addition, that Inglis did 

not attempt to incorporate by reference any literature that described the DNA sequence 

of the poxvirus genome and the locations of the “essential regions.” However, it is the 

binding precedent of this court that Eli Lilly does not set forth a per se rule that 

whenever a claim limitation is directed to a macromolecular sequence, the specification 

must always recite the gene or sequence, regardless of whether it is known in the prior 

art. See Capon, 418 F.3d at 1357 (“None of the cases to which the Board attributes the 

requirement of total DNA re-analysis, i.e., Regents v. Lilly, Fiers v. Revel, Amgen, or 

 12 Similarly, this court has carefully explained the relationship between 

written description and possession, explaining that a showing of possession is not 

necessarily sufficient to demonstrate the adequacy of written description. See, e.g., 

Enzo Biochem, Inc. v. Gen-Probe Inc., 296 F.3d 1316, 1330 (Fed. Cir. 2002) (“[P]roof of 

a reduction to practice, absent an adequate description in the specification of what is 

reduced to practice, does not serve to describe or identify the invention for purposes of 

§ 112, P 1. As with ‘possession,’ proof of a reduction to practice may show priority of 

invention or allow one to antedate a reference, but it does not by itself provide a written 

description in the patent specification.”). 

13 In contrast to reduction to practice, conception is a prerequisite to an 

adequate written description. See Fiers v. Sugano, 984 F.2d 1164, 1171 (Fed. Cir. 

1993) (“[O]ne cannot describe what one has not conceived.”). 

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Enzo Biochem, require a re-description of what was already known.”). Thus, “[w]hen 

the prior art includes the nucleotide information, precedent does not set a per se rule 

that the information must be determined afresh.” Id. at 1358. Rather, we explained 

that: 

The descriptive text needed to meet these requirements varies with the 

nature and scope of the invention at issue, and with the scientific and 

technologic knowledge already in existence. The law must be applied to 

each invention that enters the patent process, for each patented advance 

is novel in relation to the state of the science. Since the law is applied to 

each invention in view of the state of relevant knowledge, its application 

will vary with differences in the state of knowledge in the field and 

differences in the predictability of the science. 

Id. at 1357. 

Indeed, a requirement that patentees recite known DNA structures, if one 

existed, would serve no goal of the written description requirement. It would neither 

enforce the quid pro quo between the patentee and the public by forcing the disclosure 

of new information, nor would it be necessary to demonstrate to a person of ordinary 

skill in the art that the patentee was in possession of the claimed invention. As we 

stated in Capon, “[t]he ‘written description’ requirement states that the patentee must 

describe the invention; it does not state that every invention must be described in the 

same way. As each field evolves, the balance also evolves between what is known and 

what is added by each inventive contribution.” Id. at 1358. Indeed, the forced recitation 

of known sequences in patent disclosures would only add unnecessary bulk to the 

specification. Accordingly we hold that where, as in this case, accessible literature 

sources clearly provided, as of the relevant date, genes and their nucleotide sequences 

(here “essential genes”), satisfaction of the written description requirement does not 

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require either the recitation or incorporation by reference14 (where permitted) of such 

genes and sequences. 

In conclusion, having reviewed the decision of the Board, we can discern no error 

in its conclusion that the disclosures relied upon by Inglis for priority purposes 

adequately described and enabled the invention directed to poxvirus, there being 

substantial evidence to support these findings. Consequently, we hold that the Board’s 

award of priority to Inglis was proper. 

AFFIRMED

No costs. 

 14 Here, the patentee did not attempt incorporation by reference. Where, of 

course, certain material that is not present in the specification is deemed nonessential 

to the satisfaction of the written description requirement, the issue of proper 

incorporation by reference vel non is irrelevant. 

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