United States Court of Appeals
for the Federal Circuit
__________________________
DURAMED PHARMACEUTICALS, INC.
(NOW KNOWN AS TEVA WOMEN’S HEALTH, INC.),
Plaintiff-Appellant,
v.
PADDOCK LABORATORIES, INC.,
Defendant-Appellee.
__________________________
2010-1419
__________________________
Appeal from the United States District Court for the
Southern District of New York in Case No. 09-CV-1905,
Senior Judge Leonard B. Sand.
____________________________
Decided: July 21, 2011
____________________________
CHARANJIT BRAHMA, Kirkland & Ellis, LLP, of Wash-
ington, DC, argued for plaintiff-appellant. With him on
the brief were COREY J. MANLEY and J. JOHN LEE; and
ALEXANDER F. MACKINNON, of Los Angeles, California. Of
counsel was ROBERT G. KRUPKA, of Los Angeles, Califor-
nia.
EDGAR H. HAUG, Frommer Lawrence & Haug, LLP, of
New York, New York, argued for defendant-appellee.
With him on the brief was DAVID A. ZWALLY.
DURAMED PHARMA v. PADDOCK LABS 2
__________________________
Before LOURIE, GAJARSA, and DYK, Circuit Judges.
LOURIE, Circuit Judge.
Duramed Pharmaceuticals, Inc. (“Duramed”) appeals
from the decision of the United States District Court for
the Southern District of New York granting summary
judgment of noninfringement to Paddock Laboratories,
Inc. (“Paddock”). Duramed Pharms., Inc. v. Paddock
Labs., Inc., 715 F. Supp. 2d 552 (S.D.N.Y. 2010). Because
the district court did not err in holding that prosecution
history estoppel bars Duramed’s allegations of infringe-
ment under the doctrine of equivalents, we affirm.
BACKGROUND
Duramed owns U.S. Patent 5,908,638 (“’638 patent”),
which claims conjugated estrogen pharmaceutical compo-
sitions for use in hormone replacement therapies. The
claimed conjugated estrogens are extremely water sensi-
tive and thus highly susceptible to moisture degradation
during storage. See ’638 patent col.6 ll.46-56. Accord-
ingly, Duramed developed a formulation for conjugated
estrogens that includes a moisture barrier coating
(“MBC”) to inhibit the absorption of moisture and reduce
storage-related degradation. See id. col.6 ll.36-45.
Duramed filed a patent application on its formulation
on July 26, 1995. Original independent claim 1 recited a
conjugated estrogen pharmaceutical composition “coated
with a moisture barrier coating.” J.A. 254. Original
dependent claim 7 limited “said moisture barrier coating”
to one that “comprises ethylcellulose.” J.A. 255. The
examiner rejected both claims as obvious, but during an
interview advised that he would allow the application if
Duramed amended claim 1 to include, inter alia, the
3 DURAMED PHARMA v. PADDOCK LABS
limitations of claim 7. In a response received December 3,
1998, Duramed amended claim 1 to recite pharmaceutical
compositions with “a moisture barrier coating comprising
ethylcellulose.” J.A. 304. Claim 1 of the issued ’638
patent, the patent’s only independent claim, accordingly
reads as follows:
1. A pharmaceutical composition in a solid, unit
dosage form capable of oral administration for the
hormonal treatment of peri-menopausal, meno-
pausal and post-menopausal disorders in a
woman comprising:
conjugated estrogens coated onto one or more or-
ganic excipients forming a powdered conjugated
estrogen composition where said composition is
substantially free of inorganic excipients and fur-
ther comprises about 30-70% gel-forming organic
excipient and about 30-70% non-gel forming or-
ganic excipient by weight and having less than
about 2.5% free water by weight and greater than
2.5% total water wherein said solid unit dosage
form is coated with a moisture barrier coating
comprising ethylcellulose.
’638 patent claim 1 (emphasis added).
In March 2009, Duramed filed suit against Paddock
under 35 U.S.C. § 271(e)(2), alleging infringement of the
’638 patent based on Paddock’s Abbreviated New Drug
Application (“ANDA”) for a generic version of Duramed’s
hormone replacement therapy product, Cenestin®.
Duramed alleged infringement of claims 1, 4, and 6-8
under the doctrine of equivalents, because Paddock’s
proposed generic product uses a polyvinyl alcohol (“PVA”)
MBC, marketed as Opadry AMB. Paddock moved for
summary judgment of noninfringement, arguing that
Duramed was barred by amendment-based prosecution
DURAMED PHARMA v. PADDOCK LABS 4
history estoppel from alleging that PVA met the “moisture
barrier coating comprising ethylcellulose” limitation of
the asserted claims.
In its motion for summary judgment, Paddock relied
on several pre-amendment references, including an inter-
national patent application filed by Colorcon pursuant to
the Patent Cooperation Treaty (“the Colorcon PCT”). The
Colorcon PCT, published on January 25, 1996, discloses
formulations of PVA-based MBCs, including Opadry
AMB, but also, in a section entitled “Description of the
Prior Art,” notes several technical drawbacks of using
PVA as an MBC. Paddock also relied on (1) U.S. Patent
3,935,326 (“the Groppenbächer patent”), which issued in
1976 and discloses the use of PVA in moisture-tight
tablets; (2) an article in the December 1995 issue of
“Manufacturing Chemist” that tests PVA MBCs and
concludes that Opadry AMB is a highly effective moisture
barrier formulation; (3) three scientific articles on PVA
MBCs authored for distribution at scientific conferences
in May 1995, May 1998, and November 1998; and (4)
invoices indicating sales of Opadry AMB by Colorcon
before September 1996.
The district court granted Paddock’s motion for sum-
mary judgment of noninfringement, holding that prosecu-
tion history estoppel barred Duramed’s infringement
allegations. Duramed, 715 F. Supp. 2d at 555-56. The
district court first held that Duramed’s amendment
adding the ethylcellulose limitation was substantially
related to patentability and narrowed the scope of the
asserted claims, thus triggering the presumption under
Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344
F.3d 1359, 1366-67 (Fed. Cir. 2003) (en banc) (“Festo IX”),
that Duramed had surrendered all territory between the
original and amended claim scope. Duramed, 715 F.
Supp. 2d at 559-60.
5 DURAMED PHARMA v. PADDOCK LABS
The district court then held that Duramed had failed
to rebut the Festo presumption based on an argument of,
inter alia, the unforeseeability of the use of PVA as an
MBC in a pharmaceutical formulation. Id. at 560.
Rather, the court held that PVA MBCs were foreseeable
at the time of Duramed’s narrowing amendment based on
the Colorcon PCT’s description of PVA as “a moisture
barrier coating for pharmaceutical tablets and the like”
and its disclosure of the Opadry AMB formulation used in
Paddock’s proposed generic product. Id. at 560-61. The
court noted that several other facts reinforced this deci-
sion: (1) the pre-September 1996 invoices for the sale of
Opadry AMB; and (2) the Groppenbächer patent, which
teaches coating tablets with PVA to ensure “‘moisture
tight[ness]’ and ‘insolub[ility] in the gastrointestinal
tract.’” 1 Id. at 561-62. Finally, the court rejected
Duramed’s argument that the Colorcon PCT’s disclosure
of PVA MBCs’ technical drawbacks raised serious ques-
tions about PVA’s effectiveness as an MBC, concluding
that “even if the effectiveness of PVA was unknown in
1998, that would not mean that PVA MBCs were unfore-
seeable.” Id. at 563.
Duramed timely appealed to this court. We have ju-
risdiction pursuant to 28 U.S.C. § 1295(a)(1).
DISCUSSION
We review a district court’s grant of summary judg-
ment de novo, reapplying the same standard applied by
1 The district court did not consider Paddock’s re-
maining pre-1998 articles based on Duramed’s claim that
a bench trial would be necessary to determine if the 1995
“Manufacturing Chemist” article was publicly available in
a university library and if the conference articles were
actually distributed to the attendees. Id. at 561 n.8. The
court concluded that these articles were not necessary to
establish foreseeability. Id.
DURAMED PHARMA v. PADDOCK LABS 6
the district court. Iovate Health Scis., Inc. v. Bio-
Engineered Supplements & Nutrition, Inc., 586 F.3d 1376,
1380 (Fed. Cir. 2009). Summary judgment is appropriate
if there are no genuine issues of material fact and the
moving party is entitled to judgment as a matter of law.
Fed. R. Civ. P. 56(c).
Under the doctrine of the equivalents, “a product or
process that does not literally infringe . . . the express
terms of a patent claim may nonetheless be found to
infringe if there is ‘equivalence’ between the elements of
the accused product or process and the claimed elements
of the patented invention.” Warner-Jenkinson Co. v.
Hilton Davis Chem. Co., 520 U.S. 17, 21 (1997) (citing
Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S.
605, 609 (1950)). However, the doctrine of prosecution
history estoppel prevents a patent owner from recaptur-
ing through the doctrine of equivalents subject matter
surrendered to acquire the patent. See Festo Corp. v.
Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 734
(2002) (“Festo VIII”).
Because during prosecution Duramed narrowed the
scope of the ’638 patent’s claims in response to a prior art
rejection, a presumption of prosecution history estoppel
applies. See Festo IX, 344 F.3d at 1366-67. Nonetheless,
Duramed may rebut that presumption by showing, inter
alia, the “alleged equivalent would have been ‘unforesee-
able at the time of the amendment and thus beyond a fair
interpretation of what was surrendered.’” Id. at 1369
(quoting Festo VIII, 535 U.S. at 738). “[A]n alternative is
foreseeable if it is disclosed in the pertinent prior art in
the field of the invention. In other words, an alternative
is foreseeable if it is known in the field of the invention as
reflected in the claim scope before amendment.” Festo
Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 493 F.3d
1368, 1379 (Fed. Cir. 2007) (“Festo X”). Foreseeability is a
7 DURAMED PHARMA v. PADDOCK LABS
question of law based on underlying issues of fact. Id. at
1375.
On appeal, Duramed argues that the district court
applied the wrong legal test for foreseeability and thus
held that any mention of an alleged equivalent in the
prior art makes that equivalent foreseeable as a matter of
law. But, according to Duramed, an equivalent is not
foreseeable if it was not understood by one of ordinary
skill in the art to be suitable for use in the invention as
originally claimed. And, in this case, Duramed asserts,
the relevant art did not disclose either PVA or Opadry
AMB as suitable MBCs for moisture-sensitive pharma-
ceutical compounds, like conjugated estrogens.
Paddock responds that the district court applied the
correct foreseeability standard, which requires only that
PVA be foreseeable as an MBC for pharmaceutical appli-
cations at the time of Duramed’s narrowing amendment.
In this case, according to Paddock, the Colorcon PCT
alone renders PVA MBCs foreseeable, but this conclusion
is bolstered by Colorcon’s commercialization of Opadry
AMB, the Groppenbächer patent, and the other references
not considered by the district court.
We agree with Paddock that Duramed failed to rebut
the presumption of prosecution history estoppel based on
unforeseeability. We first note that, to the extent that
Duramed argues that foreseeability requires that PVA
must have been known as an MBC for use with conju-
gated estrogens, we have previously rejected such a re-
strictive definition of the field of invention. See Schwarz
Pharma, Inc. v. Paddock Labs., Inc., 504 F.3d 1371, 1377
(Fed. Cir. 2007). As we spelled out in Schwarz, when the
language of both original and issued claims begins with
the words “[a] pharmaceutical composition,” that lan-
guage defines the field of the invention for purposes of
DURAMED PHARMA v. PADDOCK LABS 8
determining foreseeability. Id. Accordingly, PVA MBCs
need only to have been known in the field of pharmaceuti-
cal compositions as of the time of Duramed’s narrowing
amendment, see Festo X, 493 F.3d at 1379, which we hold
that the Colorcon PCT establishes as a matter of law.
The Colorcon PCT discloses PVA MBCs for use with
pharmaceutical compositions: “A dry powder moisture
barrier coating composition is made to form a moisture
barrier film coating for pharmaceutical tablets and the
like, which comprises polyvinyl alcohol . . . .” J.A. 4466.
In the “Description of the Prior Art” the PCT states that
“[t]he use of the polymer polyvinyl alcohol, PVA, as a
moisture barrier coating has been previously suggested,”
but it also notes two drawbacks of PVA MBCs: stickiness
and plasticizer compatibility. Id. Specifically, the Color-
con PCT states:
[P]ractical usage [of PVA] has been inhibited by
the stickiness of grades of the polymer which have
a fast enough rate of going into solution in water
to make a dispersion to render them economical to
use in making the coating. A further problem
with the use of PVA is in identifying or selecting a
plasticizer which does not compromise the mois-
ture barrier properties of the final coating.
Id.
The Colorcon PCT then, in the “Summary of the In-
vention,” discloses preferred PVA grades and identifies a
plasticizer that does not compromise PVA’s properties as
a moisture barrier. The application states that
“[e]xcellent moisture barrier properties are obtained when
hot water soluble grades of PVA are used in the inventive
coating,” and that “[a] preferred grade of PVA for use in
the inventive coating is a grade in the medium range . . .
because the step of heating the water of the liquid coating
9 DURAMED PHARMA v. PADDOCK LABS
dispersion may not be necessary, while still maintaining
excellent moisture barrier properties in the inventive
coating.” J.A. 4468-69. The Colorcon PCT next discloses
that soya lecithin “surprisingly, and unexpectedly, acts as
a plasticizer by locking moisture in the coating so the
coating stays flexible and not brittle,” and thus soya
lecithin as a plasticizer “does not compromise the mois-
ture barrier properties of the overall coating.” J.A. 4469.
Finally, the Colorcon PCT lists a number of PVA MBC
formulations, including Opadry AMB. Accordingly, the
Colorcon PCT discloses PVA MBCs, including Opadry
AMB, in the field of pharmaceutical compositions, render-
ing such PVA MBCs “known in the field of the invention,”
and thus foreseeable. Festo X, 493 F.3d at 1379.
Duramed argues that the Colorcon PCT’s disclosure
fails to establish that PVA-based Opadry AMB was suit-
able as an MBC because it provides only conclusory
statements that the inventors had solved the technical
drawbacks of PVA MBCs and lacks any data on the
stability of the pharmaceutical compounds coated with
Opadry AMB. We disagree; foreseeability does not re-
quire such precise evidence of suitability. See Honeywell
Int’l, Inc. v. Hamilton Sundstrand Corp., 523 F.3d 1304,
1312-13 (Fed. Cir. 2008). And even if the PCT disclosure
indicates that PVA is less than ideal in some pharmaceu-
tical uses as an MBC, it is still disclosed to be useful as
such, and that renders it foreseeable for purposes of
prosecution history estoppel. Foreseeability does not
require flawless perfection to create an estoppel.
In rejecting a foreseeability rebuttal in Glaxo Well-
come, Inc. v. Impax Laboratories, Inc., 356 F.3d 1348 (Fed.
Cir. 2004), we held that “the record abundantly disclosed
[the alleged equivalent’s] use as a release agent at the
relevant time,” SmithKline Beecham Corp. v. Excel
Pharms., Inc., 356 F.3d 1357, 1365 (Fed. Cir. 2004) (de-
DURAMED PHARMA v. PADDOCK LABS 10
scribing Glaxo, 356 F.3d at 1355). Our holding relied on
statements from several references disclosing the alleged
equivalent’s use as an extended-release agent in drug
formulations; it did not rely on test data showing the
alleged equivalent’s precise characteristics or suitability
as an extended-release agent, and thus did not rely on the
type of evidence Duramed demands in this case. See
Glaxo 356 F.3d at 1355. Rather, the Colorcon PCT dis-
closes the use of PVA as MBCs in the field of pharmaceu-
tical compounds prior to December 3, 1998, rendering
such PVA MBCs foreseeable at the time of Duramed’s
narrowing amendment. 2
2 Although not necessary to our decision, we note
that the 1995 “Manufacturing Chemist” article also
supports a finding of foreseeability in the case. Like the
Colorcon PCT, the “Manufacturing Chemist” article
discloses PVA MBCs for use in pharmaceutical applica-
tions, and it discloses tests on the performance of PVA-
based coatings with moisture-sensitive drugs. The tests
compared PVA MBCs with hydroxypropyl-methylcellulose
MBCs coating tablets of aspirin or erythromycin ethylsuc-
cinate stored for twelve weeks under high relative humid-
ity. The data reveal that “the PVA formulation gives
much superior moisture protection under humid storage
conditions.” J.A. 4497. The article concludes that “[t]he
results presented here have shown a highly effective
moisture barrier formulation [based on the water soluble
polymer PVA, designated Opadry AMB] has been devel-
oped.” J.A. 4498. The district court did not rely on this
article based on Duramed’s claim that a bench trial would
be necessary to determine if the article was publicly
available. Duramed, 715 F. Supp. 2d at 561 n.8. We
disagree that there is a genuine issue of material fact on
the public availability of an article published in a scien-
tific journal three years before Duramed’s amendment.
See, e.g., In re Lister, 583 F.3d 1307, 1312 (Fed. Cir. 2009).
11 DURAMED PHARMA v. PADDOCK LABS
CONCLUSION
For the foregoing reasons, we affirm the district
court’s grant of summary judgment of noninfringement.
AFFIRMED