United States Court of Appeals
for the Federal Circuit
__________________________
INTERVET INC.,
Plaintiff-Appellee,
v.
MERIAL LIMITED AND MERIAL SAS,
Defendants-Appellants.
__________________________
2009-1568
__________________________
Appeal from the United States District Court for the
District of Columbia in case no. 06-CV-0658, Judge Henry
H. Kennedy, Jr.
__________________________
Decided: August 4, 2010
__________________________
WILLIAM G. JAMES, II, Kenyon & Kenyon LLP, of
Washington, DC, argued for plaintiff-appellee. With him
on the brief were JOHN R. HUTCHINS and YARIV WAKS;
RICHARD L. DELUCIA and MICHAEL D. LOUGHNANE, of New
York, New York. Of counsel was PATRICE P. JEAN, of New
York, New York.
J. PATRICK ELSEVIER, Jones Day, of San Diego, Cali-
fornia, argued for defendants-appellants. With him on
the brief were FRANK G. SMITH, III and KRISTEN L.
INTERVET v. MERIAL LIMITED 2
MELTON, Alston & Bird LLP, of Atlanta, Georgia;
MADISON C. JELLINS, of Palo Alto, California. Of counsel
on the brief were JUDY JARECKI-BLACK, Merial Limited, of
Duluth, Georgia; EDGAR H. HAUG, and THOMAS J.
KOWALSKI, Frommer Lawrence & Haug LLP, of New
York, New York.
__________________________
Before BRYSON, DYK, and PROST, Circuit Judges.
Opinion for the court filed by Circuit Judge PROST.
Opinion concurring-in-part, dissenting-in-part filed by
Circuit Judge DYK.
PROST, Circuit Judge.
The present patent infringement case arises from a
declaratory judgment action brought in the United States
District Court for the District of Columbia on April 11,
2006. Plaintiff Intervet Inc. (“Intervet”) denies infringing
U.S. Patent No. 6,368,601 (“’601 patent”), owned by
Defendants Merial Limited and Merial SAS (collectively
“Merial”), directed to DNA constructs encoding a type of
porcine circovirus. The district court entered summary
judgment of noninfringement based on its construction of
six disputed claim terms. Merial appeals the district
court’s claim construction for three of the terms, and, in
the alternative, appeals the district court’s summary
judgment of noninfringement based on the doctrine of
equivalents.
Because we agree with Merial that the district court
erred in its construction of two disputed claim terms, we
reverse the district court’s claim construction, vacate the
judgment of noninfringement, and remand for a finding of
whether the accused device infringes under the claim
3 INTERVET v. MERIAL LIMITED
construction articulated herein. Additionally, because we
agree with Merial that the district court misapplied the
law of prosecution history estoppel, we instruct the dis-
trict court to consider on remand arguments related to
literal infringement and to infringement under the doc-
trine of equivalents, consistent with the analysis herein.
BACKGROUND
Postweaning Multisystemic Wasting Syndrome
(“PMWS”) is a disease affecting livestock pigs. Research-
ers at Merial learned that PMWS is associated with a
particular type of porcine circovirus. 1 The scientific
community was aware of porcine circoviruses prior to
Merial’s findings. Known porcine circoviruses, however,
were not observed to be pathogenic, meaning they did not
appear to cause disease in infected pigs. Merial filed for
the ’601 patent pertaining to the discovery of what it
described as a previously unknown pathogenic type of
porcine circovirus that the inventors dubbed “PCV-2.”
PCV-2 stands for “porcine circovirus type II.” Merial’s
patent categorizes previously known, nonpathogenic
porcine circoviruses as belonging to “type I” or “PCV-1”.
The patent identifies a particular known DNA sequence
isolated from pig kidney cells called PK/15 as being repre-
sentative of type I. The ’601 patent then identifies five
isolated pathogenic porcine circovirus strains as being
representative of type II.
The patentee placed the five representative strains on
deposit with the United States Patent and Trademark
Office (“PTO”) as part of the description of the invention.
The written patent disclosure provides the full DNA
1 The prefix “circo” refers to the circular genome
of the virus. A porcine circovirus is thus a virus having a
circular genome that infects pigs.
INTERVET v. MERIAL LIMITED 4
sequence for four of these strains, as well as the full
sequence of PK/15.
The disclosure explains that the deposited PCV-2
strains had been detected in lesions of pigs with PMWS,
but not in healthy pigs. The patent description observes
that the sequenced strains exhibit 96% nucleotide homol-
ogy with each other, and only 76% nucleotide homology
with PK/15. 2 The description concludes from these obser-
vations that there are two types of porcine circoviruses,
and that nonpathogenic “type I,” as represented by PK/15,
is “thus” distinct from pathogenic “type II,” as represented
by the five isolated strains. ’601 patent col.1 ll.48-62. The
disclosure then identifies the subject of the present inven-
tion as “the group II porcine circovirus, as defined above,
isolated or in the form of purified preparation.” Id. at
col.1 ll.63-65.
The patent disclosure goes on to analyze the se-
quenced PCV-2 strains in more detail, providing tables
comparing the sizes and alignments of the strains. The
disclosure then identifies one of the sequenced strains,
designated SEQ ID 4, as being further representative of
the other strains, and identifies thirteen open reading
frames (“ORFs”) for PCV-2 using that sequence. The ’601
specification identified nine of the thirteen disclosed
ORFs that are unique to PCV-2, and four that are present
in both PCV-2 and PCV-1.
“ORF” is a commonly used term in molecular genetics
that has a standard textbook meaning. An ORF is a
portion of a gene that contains a sequence of nucleotide
2 “Homology” is a measure of the similarity of
sequences. Sequences with 96% nucleotide homology, for
instance, are 96% identical at the nucleotide level.
5 INTERVET v. MERIAL LIMITED
bases that may be translated into a protein. Each amino
acid of a protein is encoded by a DNA codon. A codon
consists of three adjacent nucleotide bases. The first
codon in an open reading frame is the “start” codon, which
encodes a modified form of methionine. Each amino acid
in the polypeptide chain is encoded by a subsequent set of
three base pairs, until the translation is terminated at a
stop codon that does not itself encode an amino acid, but
rather signals the end of translation. Thus, a double-
stranded length of DNA can have six different reading
frames, depending on the starting base-pair of the first
codon and the direction in which the strand is read. 3 The
length of an ORF is thus defined by the number of codons
that lie between a start codon and a stop codon within the
same frame.
Identifying the ORFs of a gene sequence differentiates
the portions of the sequence that may encode a protein
from the portions that do not encode a protein. It allows
those skilled in the art to estimate the size and composi-
tion of potential amino acid sequences for the proteins
encoded by the gene. Identifying ORFs is especially
important in the context of viral or prokaryotic DNA,
which can contain several overlapping ORFs in the same
gene sequence.
There are two groups of claims in the ’601 patent
relevant to the present case. The first group can be
represented by independent claim 9, which reads:
9. A vector comprising an isolated DNA molecule
comprising a sequence selected from the group
3 Two strands times three base pairs per codon
equals six reading frames.
INTERVET v. MERIAL LIMITED 6
consisting of ORFs 1 to 13 of porcine circovirus
type II.
The second group can be represented by independent
claim 32, which reads:
32. An isolated DNA molecule comprising a nu-
cleotide sequence encoding an epitope which is
specific to PCV-2 and not specific to PCV-1.
An epitope is an immunodominant region of a protein,
meaning it is the part of an antigen peptide that is recog-
nized by antibodies of the immune system. The patent
explains that certain epitopes found among strains of
PCV-2 are not present in PCV-1. Thus, the regions of
DNA encoding these epitopes are unique to PCV-2.
Epitopes unique to PCV-2 are relevant to diagnostics or
treatments, because antibodies specific to these epitopes
will recognize and bind to the pathogenic PCV-2, but will
ignore the benign PCV-1.
Merial’s patent claims cover certain vectors and other
DNA molecules that contain portions of the PCV-2 gene
sequence. These molecules are believed to be useful in
diagnosing and vaccinating against PMWS, by stimulat-
ing the production and activity of antibodies against PCV-
2.
Intervet is an animal healthcare company that manu-
factures vaccines for livestock. Intervet developed a
vaccine called “Porcine Circovirus Vaccine Type 2” that
contains a porcine circovirus nucleotide sequence in a
vector for treating PMWS in pigs. Merial alleges that
Intervet’s PMWS vaccine uses an infringing PCV-2 se-
quence.
7 INTERVET v. MERIAL LIMITED
At a Markman hearing, the United States District
Court for the District of Columbia construed six disputed
claim terms of the ’601 patent. Among these construc-
tions, the district court defined the term “porcine circovi-
rus type II” as consisting of the five nucleotide sequences
that Merial placed on deposit with the PTO. The district
court construed the term “ORFs 1-13” as the DNA se-
quences of the thirteen ORFs of SEQ ID 4 listed in the
table under Example 13 of the patent. Finally, the dis-
trict court construed claim 32 in its entirety to refer (in
part) to a construct comprising at least one DNA molecule
that is unique to one of the five sequences on deposit with
the PTO.
The district court then entered summary judgment of
noninfringement based on these claim constructions. It
was undisputed that Intervet’s vaccine contained a nu-
cleotide sequence that was 99.7% homologous to one of
the deposited sequences. The accused product was there-
fore held to be outside the literal claim scope of PCV-2,
which required strict identity to one of the five deposited
sequences. The district court also held that the doctrine
of prosecution history estoppel precluded Merial from
arguing that the accused sequence infringed under the
doctrine of equivalents.
Merial timely appealed to this court, arguing that the
district court erred in its claim construction and erred in
applying the doctrine of prosecution history estoppel to
Merial’s equivalence arguments for the accused product.
For the reasons discussed below, we agree with Merial
that the district court erred in its claim construction and
application of prosecution history estoppel. 4
4 We do not address the issues of validity and
non-patentable subject matter discussed by the dissent
INTERVET v. MERIAL LIMITED 8
DISCUSSION
Claim Construction
Claim construction is a question of law that is re-
viewed de novo. Markman v. Westview Instruments, Inc.,
52 F.3d 967, 978 (Fed. Cir. 1995) (en banc). To the extent
possible, claim terms are given their ordinary and cus-
tomary meaning, as they would be understood by one of
ordinary skill in the art in question at the time of the
invention. Phillips v. AWH Corp., 415 F.3d 1303, 1312-13
(Fed. Cir. 2005) (en banc). Idiosyncratic language, highly
technical terms, or terms coined by the inventor are best
understood by reference to the specification. Id. at 1315.
Such understanding is informed, as needed, by the prose-
cution history, if it is in evidence. Id. Construing the
claims in light of the specification does not, however,
imply that limitations discussed in the specification may
be read into the claims. It is therefore important not to
confuse exemplars or preferred embodiments in the
specification that serve to teach and enable the invention
with limitations that define the outer boundaries of claim
scope. Id. at 1323.
It is with an eye to these tenets of claim construction
that we review the district court’s Markman order and
conclude the district court erred. We discuss each term in
turn.
“Porcine Circovirus Type II”
The district court found that the claim term “porcine
circovirus type II” was limited to the five sequences that
because these issues were not addressed by the district
court or raised on appeal.
9 INTERVET v. MERIAL LIMITED
were deposited with the PTO as part of the description of
the invention. The district court was persuaded by In-
tervet’s arguments that the patent specification defined
the invention as being these five sequences, and contained
no disclosure from which to infer that any other se-
quences were also part of the invention.
It is clear enough to us, however, that the patent
states that the five deposited strains and listed sequences
are “representative of” a “type of porcine circovirus,” and
thus do not constitute the entire scope of the invention.
’601 patent col.1 ll.60-61 (emphases added). Sequences
are representative of the scope of broader genus claims if
they indicate that the patentee has invented species
sufficient to constitute the genera. Enzo Biochem, Inc. v.
Gen-Probe, Inc., 323 F.3d 956, 967 (Fed. Cir. 2002); In re
Smythe, 480 F.2d 1376, 1383 (C.C.P.A. 1973). Here, the
deposited strains are representative species of the larger
“type II” genus, where the genus is identified and claimed
as the invention.
Claims properly directed to a genus may be ade-
quately supported by the patent disclosure if a sufficient
number of species is disclosed so as to properly identify
the scope of the genus. Id. Here, the patentee has dis-
closed five species of PCV-2, provided the full sequences
for four, and identified the potential coding portions of the
sequences. The patentee also provided a counterexample,
PCV-1, that by definition lies outside the scope of the
claimed genus, as well as a representative species of the
counterexample, its sequence, and potential coding por-
tions for the representative.
Neither the claim itself nor the specification provides
a homology threshold above or below which a particular
PCV strain is properly considered PCV-2 rather than
INTERVET v. MERIAL LIMITED 10
PCV-1. It refers instead to strains of the invention having
“significant serological similarity” and stringent, selective
cross-hybridization to the deposited strains over PK/15.
The only quantitative boundaries disclosed in the patent
are the 96% homology among representative PCV-2
sequences, and the 76% homology between those se-
quences and the representative of PCV-1.
The patent’s stated conclusion that the disclosed PCV-
2 sequences “thus” represent a new type of porcine cir-
covirus is based on the pathogenicity of the isolated
strains, as well as the observed homology patterns. See,
e.g., ’601 patent col.5 ll.59-61. This conclusion comports
with the way that viruses are typically classified in the
relevant art. Cf. Universal Virus Database of the Inter-
national Committee on Taxonomy of Viruses available at
http://www.ictvdb.rothamsted.ac.uk/. The invention is
then defined as being the type II porcine circovirus, which
is in turn “as defined above.” ’601 patent col.5 ll.64.
Thus, the pathogenicity and homology patterns are the
defining properties of the new type of virus. The claim
construction of “porcine circovirus type II” is therefore
properly limited to porcine circoviruses that have these
two defining properties.
We therefore construe the claim term “porcine circovi-
rus type II” to be “a pathogenic pig virus having a circular
genome that is at about 96% or more homologous with the
four sequences disclosed in the present specification, and
about 76% or less homologous with the PK/15 sequence.”
Strains that fit this definition would be expected to have
strong serological similarity and cross-hybridize to the
deposited strains under high stringency conditions. As
such, limiting the claim scope according to these proper-
ties is not inconsistent with the other descriptive lan-
guage in the specification.
11 INTERVET v. MERIAL LIMITED
“ORFs 1-13”
The district court’s claim construction of ORFs 1-13
defines the claim scope as consisting of the DNA sequence
of the thirteen ORFs enumerated in Example 13 of the
patent specification as those ORFs apply to SEQ ID 4.
Merial argues that the term should instead read on any
translatable length of DNA between a start and stop
codon in the PCV-2 gene sequence. Although the district
court is correct that the disclosed ORFs define the claim
term, the court erred in confining the scope of the term to
the precise limits of the representative ORFs listed in
Example 13, and the exact DNA sequence of SEQ ID 4.
The ORFs listed in Example 13 are identified as cor-
responding to one representative PCV-2 sequence, desig-
nated in the patent as SEQ ID 4. Although the patent
explains that the listed ORFs are identical for some of the
deposited strains of PCV-2, it also identifies some varia-
tion. The specification explains that the ORFs listed in
the table are representative, and one of skill in the art
would understand that slight natural variation is to be
expected. Indeed, limiting the construction of the term to
the exact ORF sequences of SEQ ID 4 would even exclude
from the claimed ORFs two of the four sequenced strains
of PCV-2, the ORF variations for which sequences are
expressly disclosed following the table in Example 13.
Thus, we hold that the district court’s construction is
improperly narrow in scope.
We reject the dissent’s position that the specification
limits “ORFs 1-13” to the ORFs of the four sequenced
strains. The discussion in Example 13, which explains
that the limits of ORFs 1 to 13 are “identical” for certain
sequenced strains (and not for others), strongly implies
that the term “ORFs 1-13” does not refer to a specifically
INTERVET v. MERIAL LIMITED 12
defined list of limits, but instead contemplates the poten-
tial for variation in any given strain of PCV-2. Further-
more, the specification describes the analysis set forth in
Example 13 as “representative of the other circovirus
strains associated with the multi-systemic wasting syn-
drome.” We have already construed that set of circovirus
strains to be broader than just the four sequenced strains,
so it would be incongruous to selectively impose the
narrower construction here, as the dissent suggests.
We note that because isolates of the same viral type
will have essentially the same proteins, they will have the
same number of ORFs. The ORFs will be approximately
the same size and located in the same relative regions of
the genome. By identifying the thirteen ORFs of repre-
sentative sequence SEQ ID 4, the specification purports to
disclose to one of skill in the art the expected ORFs of all
PCV-2 isolates. Thus a broader claim construction that
allows for some variation in the precise limits of the ORFs
and of the underlying DNA sequence is consistent with
the expectations of a skilled artisan reading the patent
disclosure.
Thus the term ORFs 1-13 is properly construed as
“lengths of translatable DNA between pairs of start and
stop codons, corresponding to the 13 ORFs identified in
the patent specification.” ORFs of some PCV-2 strains
may not have limits 100% identical to the thirteen illus-
trated in the patent, but one of skill in the art would
readily recognize those ORFs as corresponding to ORFs
identified in the patent. Indeed, ORFs 1-13 could corre-
spond to ORFs in other circoviruses, or even other species,
as indicated by the examiner’s initial rejection of the
claim. It is the “of porcine circovirus type II” limitation,
rather than Example 13, that confines the claim scope to
ORFs of PCV-2.
13 INTERVET v. MERIAL LIMITED
“Specific to PCV-2 and Not Specific to PCV-1”
The parties below could not agree on what terms of
claim 32 were disputed, and the district court decided to
construe the claim in its entirety. The district court
construed claim 32 to mean “an isolated DNA molecule
that includes, but is not necessarily limited to, a DNA
sequence which codes for an immunodominant region of a
protein, wherein the sequence is from the genome of a
PCV-2 circovirus, and not from the genome of a PCV-1
circovirus.” The district court explained that due to the
“comprising” transition term, the claim may read on
molecules that contain sequences that encode epitopes
common to PCV-1 and PCV-2, as long as the molecule
contains at least one sequence that encodes an epitope
unique to PCV-2. We see no error in this construction,
and it appears that at the time of the Markman hearing,
Merial did not see any either.
Merial challenges this construction on appeal because
in the district court’s subsequent infringement analysis,
the court explained that the part of the claim construction
specifying that the sequence be “from” the genome of a
PCV-2 circovirus, etc., excluded sequences that were
physically derived from a non-PCV-2 source. Merial
argues that such a manufacturing requirement has no
place in a proper analysis of this claim, and is inconsis-
tent with the district court’s otherwise correct claim
construction. We agree. For purposes of our review of the
district court’s opinion, we focus our analysis on the term
“specific to” in claim 32, since it appears that this term is
the hook for the requirement that the sequence be unique
to and derived from PCV-2.
As Intervet explains, the term “specific to” is a spe-
cialized term of art in immunology that typically refers to
INTERVET v. MERIAL LIMITED 14
one structure’s proclivity for binding to another structure.
For example, antibodies will attack a viral antigen if
paratopes of those antibodies are “specific to” an epitope
in the viral antigen. The specialized definition of this
term does not make sense in the context of claim 32,
however, because the claimed epitope is not described as
binding to porcine circoviruses; it is described as located
within a porcine circovirus. The epitope is thus bound by
antibodies that are “specific to” PCV-2. In light of the
patent description and a general understanding of the
relevant art, the claim would be understood by one of skill
in the art to be using the term “specific to” in a colloquial
or non-technical sense. Cf. Intervet, Inc. v. Merial Ltd.,
No. 1:06-cv-00658 (D.D.C. Nov. 28, 2007) (claim construc-
tion order at 21). As construed, a nucleotide sequence
encoding an epitope that is specific to PCV-2 and not
specific to PCV-1, as that term is used in claim 32, is a
nucleotide sequence that encodes part of a polypeptide
sequence of PCV-2, but not part of a polypeptide sequence
of PCV-1. More specifically, it encodes at least one epi-
tope found on the PCV-2 virus, but not found on the PCV-
1 virus.
The district court found that Intervet’s vaccine could
not have contained a sequence encoding an epitope spe-
cific to PCV-2 because the sequence was derived from a
non-PCV-2 source. This analysis may be mooted by our
reversal of the district court’s claim construction of “PCV-
2”, since it is no longer clear that the source of the se-
quence in Intervet’s product is not PCV-2. Nevertheless,
to the extent that the district court’s application of its
claim construction requires that the encoded epitope be
unique to PCV-2 among all possible antigens, it is errone-
ous. If the term “specific to PCV-2” meant that the epi-
tope must be found only on PCV-2 and no other antigen,
then the subsequent limitation “and not specific to PCV-
15 INTERVET v. MERIAL LIMITED
1” would be redundant. Thus an infringing epitope may
be common to PCV-2 and some other antigen, as long as it
is not also common to PCV-1. Whether one isolates the
sequence directly from a PCV-2 virus or engineers a
sequence obtained from another source such that it en-
codes a PCV-2 epitope makes no difference to the proper
application of the district court’s otherwise correct claim
construction.
Accordingly, we reverse the district court’s claim con-
structions of the terms “porcine circovirus type II” and
“ORFs 1-13,” clarify the proper interpretation of the
construction of the term “specific to PCV-2 and not spe-
cific to PCV-1,” and remand the question of infringement
for a determination consistent with the claim construc-
tions articulated herein.
Doctrine of Equivalents
The district court found that prosecution history es-
toppel precluded Merial from invoking the doctrine of
equivalents. Merial was thus estopped from arguing that
the accused PCV strain was equivalent to the claimed
“porcine circovirus type II,” as that term was construed by
the district court. 5 The district court erred, however, in
applying controlling Federal Circuit and Supreme Court
law to the prosecution history of the ’601 patent. As a
result, the scope of the district court’s bar on Merial’s
ability to invoke the doctrine of equivalents was overly
broad.
5 Because we are reversing the judgment of lit-
eral infringement, it may not be necessary for the district
court to reach the doctrine of equivalents claim, but we
are addressing the issue in the event that the district
court on remand finds it necessary to decide.
INTERVET v. MERIAL LIMITED 16
Whether prosecution history estoppel applies to a par-
ticular argument, and thus whether the doctrine of
equivalents is available for a particular claim limitation,
is a question of law. Bai v. L & L Wings, Inc., 160 F.3d
1350, 1354 (Fed. Cir. 1998); Cybor Corp. v. FAS Techs.,
Inc., 138 F.3d 1448, 1460 (Fed. Cir. 1998) (en banc).
Where an amendment narrows the scope of the claims,
and that amendment is adopted for a substantial reason
related to patentability, the amendment gives rise to a
presumption of surrender for all equivalents that reside
in “the territory between the original claim and the
amended claim.” Festo Corp. v Shoketsu Kinzoku Kogyo
Kabushiki Co., 535 U.S. 722, 740 (2002) (Festo VIII). This
presumption can be overcome by showing that “at the
time of the amendment one skilled in the art could not
reasonably be expected to have drafted a claim that would
have literally encompassed the alleged equivalent.” Id. at
741. One way to make this showing is to demonstrate
that “the rationale underlying the narrowing amendment
bore no more than a tangential relation to the equivalent
in question.” Festo Corp. v. Shoketsu Kinzoku Kogyo
Kabushiki Co., 344 F.3d 1359, 1368 (Fed. Cir. 2003) (en
banc) (Festo IX). Although there is no hard-and-fast test
for what is and what is not a tangential relation, it is
clear that an amendment made to avoid prior art that
contains the equivalent in question is not tangential. See
Pioneer Magnetics, Inc. v. Micro Linear Corp., 330 F.3d
1352, 1357 (Fed. Cir. 2003).
The applicability of prosecution history estoppel does
not completely bar the benefit of the doctrine of equiva-
lents from all litigation related to the amended claim. See
Festo VIII, 535 U.S. at 737-38 (“There is no reason why a
narrowing amendment should be deemed to relinquish
equivalents . . . beyond a fair interpretation of what was
surrendered.”) The scope of the estoppel must fit the
17 INTERVET v. MERIAL LIMITED
nature of the narrowing amendment. A district court
must look to the specifics of the amendment and the
rejection that provoked the amendment to determine
whether estoppel precludes the particular doctrine of
equivalents argument being made.
Merial’s independent claim 9 as originally drafted
read, “9. A vector comprising an isolated DNA molecule
comprising a sequence selected from the group consisting
of ORFs 1-13.” The examiner rejected this claim, noting
that for purposes of the rejection “[t]he ORFs are assumed
to be derived from porcine circovirus, but as written, the
claims could encompass ORFs from any organism.” The
claim was then rejected in view of ORFs from PK/15. The
inventors disagreed that these ORFs could be derived
from any other organism, and argued that the specifica-
tion defined ORFs 1-13 based on the limits of the ORFs in
the PCV-2 genome. Nevertheless, the claim was amended
to add the limitation that the ORFs were “of porcine
circovirus type II”. The examiner then allowed the claim.
We agree with the district court that this amendment
was a narrowing amendment, despite Merial’s arguments
that it was merely clarifying. As noted in the patent
specification, four of the thirteen claimed ORFs are pre-
sent in the “type I” circovirus. The original claim only
required that a vector comprise a nucleotide sequence
comprising one of the thirteen ORFs. Thus, the claim as
originally written read on ORFs of PCV-1, and was prop-
erly rejected over PK/15. We therefore also agree with
the district court that the amendment was substantially
related to patentability.
The amendment thus raises a presumption of surren-
der for all equivalents that reside in the territory between
the identified ORFs of PCV-2 and ORFs of PCV-1, as well
INTERVET v. MERIAL LIMITED 18
as corresponding ORFs, if any, for any non-porcine organ-
ism. Merial is thus estopped from arguing that ORFs of
pathogenic circoviruses found in other organisms are
equivalent to ORFs of PCV-2. It is also estopped from
arguing that ORFs of a pathogenic strain of PCV-1 are
equivalent to ORFs of PCV-2, despite the strain having
strong homology with PK/15 and weak homology with the
representative strains disclosed in the patent. Merial is
not, however, estopped from arguing that a pathogenic
porcine viral sequence with over 99% nucleotide homology
with one of the five representative strains is equivalent to
that strain. 6 Such a draconian preclusion would be
beyond a fair interpretation of what was surrendered. Cf.
Festo VIII, 535 U.S. at 737-38. The rationale for the
amendment was to narrow the claimed universe of ORFs
down to those of PCV-2, and bore only a tangential rela-
tion to the question of which DNA sequences are and are
not properly characterized as PCV-2. Cf. Festo IX, 344
F.3d at 1369.
The district court thus erred in finding that prosecu-
tion history estoppel precluded Merial from arguing that
the accused product is equivalent to one of the exemplary
embodiments of the asserted claim. The district court is
thus instructed on remand to compare the accused prod-
uct with the claims as construed herein for a determina-
tion of infringement literally or pursuant to the doctrine
of equivalents, if applicable.
6 Merial is thus not estopped from arguing that
such a sequence would infringe even though it did not
meet the exact homology limitations required for literal
infringement of the claims as construed by this court.
19 INTERVET v. MERIAL LIMITED
CONCLUSION
The district court erred in construing the disputed
claims of the patent in suit and in barring the doctrine of
equivalents from its infringement analysis. Accordingly,
we reverse the district court’s claim construction, vacate
the entry of summary judgment of noninfringement, and
remand to the district court with instructions to deter-
mine, consistent with the analysis in this opinion,
whether the accused product infringes the asserted claims
of the ’601 patent.
REVERSED-IN-PART, VACATED-IN-PART, AND
REMANDED
United States Court of Appeals
for the Federal Circuit
__________________________
INTERVET INC.,
Plaintiff-Appellee,
v.
MERIAL LIMITED AND MERIAL SAS,
Defendants-Appellants.
__________________________
2009-1568
__________________________
Appeal from the United States District Court for the
District of Columbia in case no. 06-CV-0658, Judge Henry
H. Kennedy, Jr.
__________________________
DYK, Circuit Judge, concurring-in-part and dissenting-in-
part.
I agree with the majority’s construction of claim 32 of
U.S. Patent No. 6,368,601 (“the ’601 patent”), but as
discussed below, I disagree with its construction of claim
9. I write separately primarily to make clear that in
construing the claims, we are not deciding that the claims
as construed are limited to patentable subject matter. As
we noted in Phillips v. AWH Corp., 415 F.3d 1303 (Fed.
Cir. 2005) (en banc), we do not take validity into account
in construing claims, unless “the court concludes, after
applying all the available tools of claim construction, that
the claim is still ambiguous.” Id. at 1327 (quoting Liebel-
Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 911 (Fed.
INTERVET v. MERIAL LIMITED 2
Cir. 2004) (quotation marks omitted)). That is not the
case here.
At least claim 32 of the ’601 patent raises substantial
issues of patentable subject matter under 35 U.S.C. § 101.
That claim is not limited to the use of a particular isolated
DNA molecule in a vaccine or other application. Rather,
it broadly encompasses “[a]n isolated DNA molecule
comprising a nucleotide sequence encoding an epitope
which is specific to PCV-2 and not specific to PCV-1.” ’601
patent col.28 ll.40-42 (emphasis added). Neither the
district court nor the parties provided a precise definition
of “isolated” DNA. In order to analyze the DNA or use it
for applications (for example, the production of vaccines),
DNA must be extracted from the cell of the living organ-
ism and separated from other cell components, such as
RNA, protein, lipids, or in the case of plasmid DNA isola-
tion, from chromosomal DNA. See generally, Peter B.
Kaufman et al., Handbook of Molecular and Cellular
Methods in Biology and Medicine 1-26 (1995). DNA
“isolation” applies generally to the process of extracting
DNA from a cell for purposes of genetic analysis. See
James D. Watson et al., Molecular Biology of the Gene 740
(6th ed. 2008); see also Kaufman et al., supra, at 1-2.
Isolation also encompasses techniques for selective ampli-
fication or cloning of such fragments, which allows for a
large number of fragments to be available for analysis
and sequencing. See Watson et al., supra, at 746. The
’601 patent indicates that the isolation of the genomic
DNA of the viral strains was performed by a method well
known in the art. See ’601 patent col.10 l.5-col.11 l.43.
The majority interprets “PCV-2” to mean “a patho-
genic pig virus having a circular genome that is at about
96% or more homologous with the four sequences dis-
closed in the present specification, and about 76% or less
homologous with the PK/15 sequence,” Majority Op. at 9,
3 INTERVET v. MERIAL LIMITED
reversing the district court’s construction limiting PCV-2
to the five viral strains specifically disclosed in the ’601
patent. Additionally, the majority construes “specific to
PCV-2 and not specific to PCV-1” to read on molecules
that contain sequences that encode epitopes 1 common to
PCV-1 and PCV-2, as long as the molecule contains at
least one sequence that encodes an epitope unique to
PCV-2. Id. at 11-12. Patent claim 32 reads on an isolated
DNA molecule that comprises a nucleotide sequence that
encodes an epitope unique to PCV-2, which is defined
with respect to its homology with the known PCV-1 virus.
Thus, under the majority’s claim construction, claim 32
covers DNA sequences that were not in fact isolated by
the inventor and are distinct from the five isolated strains
disclosed in the ’601 patent.
The question is whether the isolated DNA molecule,
separate from any applications associated with the iso-
lated nucleotide sequence (for example, the production of
a vaccine) is patentable subject matter. Neither the
Supreme Court nor this court has directly decided the
issue of the patentability of isolated DNA molecules.
Although we have upheld the validity of several gene
patents, see, e.g., In re Deuel, 51 F.3d 1552 (Fed. Cir.
1995); In re Bell, 991 F.2d 781 (Fed. Cir. 1993); Amgen,
Inc. v. Chugai Pharm. Co., Ltd., 927 F.3d 1200 (Fed. Cir.
1991), none of our cases directly addresses the question of
whether such patents encompass patentable subject
matter under 35 U.S.C. § 101. Although the U.S. Patent
and Trademark Office (“PTO”) believes that at least some
of these patents satisfy section 101, see Utility Examina-
1 An epitope is an immunodominant region of a
protein, meaning it is the part of an antigen that is recog-
nized by antibodies of the immune system.
INTERVET v. MERIAL LIMITED 4
tion Guidelines, 66 Fed. Reg. 1092 (Jan. 5, 2001), 2 thus
far the question has evaded judicial review.
I think that such patents do in fact raise serious ques-
tions of patentable subject matter. The Supreme Court’s
recent decision in Bilski v. Kappos has reaffirmed that
“laws of nature, physical phenomena, and abstract ideas”
are not patentable. No. 08-964, slip op. at 5 (U.S. June
28, 2010) (quoting Diamond v. Chakrabarty, 447 U.S. 303,
309 (1980)); Funk Bros. Seed Co. v. Kalo Inoculant Co.,
333 U.S. 127, 130 (1948). Just as the patentability of
abstract ideas would preempt others from using ideas
that are in the public domain, see Bilski, slip op. at 13, so
too would allowing the patenting of naturally occurring
substances preempt the use by others of substances that
should be freely available to the public. Thus, “a new
mineral discovered in the earth or a new plant found in
the wild is not patentable subject matter. Likewise,
Einstein could not patent his celebrated law that E=mc2;
nor could Newton have patented the law of gravity.”
Chakrabarty, 447 U.S. at 309. These aspects are properly
conceptualized as representing a public domain, “free to
2 In response to comments urging the PTO not to
issue patents for genes on the ground that genes are
products of nature, the PTO remarked:
An isolated and purified DNA molecule that has
the same sequence as a naturally occurring gene
is eligible for a patent because (1) an excised gene
is eligible for a patent as a composition of matter
or as an article of manufacture because that DNA
molecule does not occur in that isolated form in
nature, or (2) synthetic DNA preparations are eli-
gible for patents because their purified state is dif-
ferent from the naturally occurring compound.
66 Fed. Reg. at 1093.
5 INTERVET v. MERIAL LIMITED
all men and reserved exclusively to none.” Id. (quoting
Funk Bros., 333 U.S. at 130) (quotation mark omitted).
In Funk Brothers, the Court considered the pat-
entability of a mixture of several naturally-occurring
species of bacteria. 333 U.S. at 128-31. The patented
product was a mixture of bacteria used in agricultural
processes, enabling plants to draw nitrogen from the air
and convert it for usage. The inventor discovered that
certain strains of the bacteria were effective in combina-
tion with one another, and contrary to existing assump-
tions, did not exert mutually inhibitive effects on each
other. The Court held that the invention was not pat-
entable subject matter. Id. at 131. The inventor “did not
create a state of inhibition or of non-inhibition in the
bacteria. Their qualities are the work of nature. Those
qualities are of course not patentable.” Id. at 130. The
Court furthermore noted:
The qualities of these bacteria, like the heat of the
sun, electricity, or the qualities of metals, are part
of the storehouse of knowledge of all men. They
are manifestations of laws of nature, free to all
men and reserved exclusively to none. He who
discovers a hitherto unknown phenomenon of na-
ture has no claim to a monopoly of it which the
law recognizes. If there is to be invention from
such a discovery, it must come from the applica-
tion of the law of nature to a new and useful end.
Id.
In Chakrabarty, the Court considered whether a hu-
man-made microorganism is patentable subject matter
under section 101. 447 U.S. at 305. The microorganism
in question was a bacterium that had been genetically
engineered to break down crude oil. In concluding that
the man-made bacteria was patentable, the Court ob-
INTERVET v. MERIAL LIMITED 6
served that the claim “is not to a hitherto unknown natu-
ral phenomenon, but to a nonnaturally occurring manu-
facture or composition of matter.” Id. at 309. The Court
went on to distinguish Funk Brothers on the ground that
the Chakrabarty bacterium possessed “markedly different
characteristics from any found in nature. . . . His discovery
is not nature’s handiwork, but his own; accordingly it is
patentable subject matter under § 101.” Id. at 310 (em-
phasis added).
Thus, it appears that in order for a product of nature
to satisfy section 101, it must be qualitatively different
from the product occurring in nature, with “markedly
different characteristics from any found in nature.” It is
far from clear that an “isolated” DNA sequence is qualita-
tively different from the product occurring in nature such
that it would pass the test laid out in Funk Brothers and
Chakrabarty. The mere fact that such a DNA molecule
does not occur in isolated form in nature does not, by
itself, answer the question. It would be difficult to argue,
for instance, that one could patent the leaves of a plant
merely because the leaves do not occur in nature in their
isolated form.
Finally, I disagree with the majority with respect to
its construction of “ORFs 1-13” in claim 9. 3 Merial ar-
gues, and the majority appears to accept, the proposition
that one of ordinary skill in the art would read the phrase
“ORFs 1-13” to read on any translatable length of DNA
between a start and stop codon in the PCV-2 sequence
that could encode for a protein greater than twenty amino
3 An Open Reading Frame (“ORF”) is a region or
length of DNA that contains a sequence of nucleotides
that contains the instructions for making proteins. All
ORFs begin and end with a set of three nucleotides known
respectively as a start and stop codon.
7 INTERVET v. MERIAL LIMITED
acids in size. In contrast, the district court concluded that
the plain language of the claims indicated that ORFs 1-13
were limited to the ORFs in the disclosed isolates. 4
I agree with the district court that the phrase must be
limited to the specific DNA sequences defined as ORFs 1-
13 in the ’601 patent based on the intrinsic evidence. The
majority holds that the district court’s construction is
improperly narrow in scope because “limiting the con-
struction of the term to the exact ORF sequences of SEQ
ID 4 would even exclude from the claimed ORFs two of
the four sequenced strains of PCV-2.” Majority Op. at 10.
I disagree. The specification appears to specifically define
“ORFs 1-13” to include the ORFs from all four of the
4 It is unclear whether the district court’s claim
construction limited “ORFs 1-13” to the relevant ORFs in
Imp. 1010, or whether the phrase also encompasses ORFs
1-13 of the other isolates disclosed in the patent, namely,
Imp. 1011-48121, Imp. 1011-48284, and Imp. 999. The
court’s infringement determination is also unclear. See
Intervet, Inc. v. Merial Ltd., 643 F. Supp. 2d 97, 103
(D.D.C. 2009) (“Example 13, however, also states that the
positions of the start and end of each ORF refer to the
sequence presented in figure 4. Figure 4 contains the
precise DNA sequence of one of the five listed strains and
thus Example 13, while it does not include the specific
DNA sequence of each ORF, refers to a figure from which
those specific DNA sequences can be determined. Given
this, the Court declines to read the language ‘specific
DNA sequence’ out of its claim construction, and therefore
concludes that Intervet’s vaccine does not contain one of
ORFs 1-13.”).
INTERVET v. MERIAL LIMITED 8
sequenced strains, not just Imp. 1010, 5 represented by
SEQ ID 4. The specification provides:
It was possible to detect 13 open reading frames
(or ORFs) of a size greater than 20 amino acids on
this sequence (circular genome). These 13 ORFs
are the following:
’601 patent col.13 ll.33-34 (emphasis added). The specifi-
cation then proceeds to detail the ORF sizes and stop and
start codons for the Imp. 1010 isolate in table form, and
describes the stop and start codons for the other three
isolates by reference to Imp. 1010:
The positions of the start and end of each ORF
refer to the sequence presented in FIG. No. 4
(SEQ ID No. 4), of the genome of strain 1010. The
limits of ORFs 1 to 13 are identical for strain 999.
They are also identical for strains 1011-48121 and
1011-48285, except for the ORFs 3 and 13:
ORF3 1432-1549, sense, 108 nt, 35aa
ORF1,3 314-1377, antisense, 705 nt, 234 aa.
Id. col.13 ll.53-61. Thus, “ORFs 1-13” is properly read to
include the relevant ORFs on all of the disclosed isolates,
because a description of those ORFs follows the assertion
that “[t]hese 13 ORFs are the following.” Id. col.13 ll.33-
34. Because the patentee acted as his “own lexicographer
and clearly set forth a definition of the disputed claim
term,” Edward Lifesciences LLC v. Cook Inc., 582 F.3d
1322, 1329 (Fed. Cir. 2009), the definition in the specifica-
tion controls, see Phillips, 415 F.3d at 1321. In my view,
5 The “Imp.” designation, an abbreviation for “im-
ported,” is a tracking number assigned by the inventors to
their pig tissue samples and to any virus they isolated
from that tissue.
9 INTERVET v. MERIAL LIMITED
claim 9 is not literally infringed, and I would also hold
that it is not infringed under the doctrine of equivalents.