Durаmed 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.,
Background
Duramed owns U.S. Patent 5,908,638 (“'638 patent”), which claims conjugated estrogen pharmaceutical compositions for use in hormone replacement therapies. The claimed conjugated estrogens are extremely water sensitive and thus highly susceptible to moisture degradation during storage. See '638 patent col.6 11,46-56. Accordingly, Duramed developed a formulation for conjugated estrogens that includes a moisture barrier coating (“MBC”) to inhibit the absorption of moisture and reduce storage-rеlated degradation. See id. col.6 11.36-45.
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 limitations of claim 7. In a response received December 3, 1998, Durаmed 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, menopausal and post-menopausal disorders in a woman comprising:
conjugated estrogens coated onto one or more organic excipients forming a powdered conjugated estrogen composition where said composition is substantially free of inorganic excipients and further comprises about 30-70% gel-forming organic excipient and about 30-70% non-gel forming organic 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 replacemеnt 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 bаrred by amendment-based prosecution history estoppel from alleging that PVA
In its motion for summary judgment, Paddock relied on several pre-amendment references, including an international рatent 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 Groppenbácher 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) threе 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 summary judgment of noninfringement, holding that prosecution history estoppel barred Duramed’s infringement allegations.
Duramed,
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 decision: (1) the pre-September 1996 invoices for the sale of Opadry AMB; and (2) the Groppenbácher patent, which teaches coating tablets with PVA to ensure “ ‘moisture tightness]’ and ‘insolubility] in the gastrointestinal tract.’ ” 1 Id. at 561-62. Finally, the court rejected Duramed’s argument that the Colorcоn PCT’s disclosure of PVA MBCs’ technical drawbacks raised serious questions 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 unforeseeable.” Id. at 563.
Duramed timely appealed to this court. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
Discussion
We review a district court’s grant of summary judgment
de novo,
reapplying the same standard applied by the district
Under the doctrine of the equivalents, “a product or process that does not literally infringe ... the express terms of a patent claim mаy 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.,
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,
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 fоreseeable 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 pharmaceutical 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 applications 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 Groppenbácher patent, and the other references not considered by the district court.
We agree with Paddock that Duramed failеd 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 conjugated estrogens,
we have previously rejected such a restrictive definition of the fiеld of invention.
See Schwarz Pharma, Inc. v. Paddock Labs., Inc.,
The Colorcon PCT discloses PVA MBCs for use with pharmaceutical compositions: “A dry powder moisture barrier coating composition is made to form а 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 Colorcon PCT states:
[Practical 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 furthеr problem with the use of PVA is in identifying or selecting a plasticizer which does not compromise the moisture barrier properties of the final coating.
Id.
The Colorcon PCT then, in the “Summary of the Invention,” discloses preferred PVA grades and identifies a plasticizer that does not comprоmise PVA’s properties as a moisture barrier. The application states that “[excellent 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 dispersion may not be necessary, while still maintaining excellent moisture barrier properties in the inventive coating.” J.A. 4468-69. The Color-con 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 moisture 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, rendering such PVA MBCs “known in the field of the invention,” and thus foreseeable.
Festo X,
Duramed argues that the Color-con PCT’s disclosure fails to establish that PVA-based Opadry AMB was suitable 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 require such precise evidence of suitability.
See Honeywell Int’l, Inc. v. Hamilton Sundstrand Corp.,
In rejecting a foreseeability rebuttal in
Glaxo Wellcome, Inc. v. Impax Laboratories, Inc.,
Conclusion
For the foregoing reasons, we affirm the district court’s grant of summary judgment of noninfringement.
AFFIRMED.
Notes
. The district court did not consider Paddock’s remaining 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 еstablish foreseeability. Id.
. 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 applications, аnd 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 ethylsuccinate stored for twelve weeks under high relative humidity. The data reveal that "the PVA formulation gives much superi- or 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 developed.” J.A. 4498. The district cоurt 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,