Abbott Laboratories v. Sandoz, Inc.

In this case, the same patent, U.S. Patent No. 4,935,507 (the '507 patent), occasions litigation in both the United States District Court for the Eastern District of Virginia and the United States District Court for the Northern District of Illinois. The Virginia District Court granted the motion of Lupin Ltd. and Lupin Pharmaceuticals Inc. (collectively Lupin) for summary judgment of noninfringement. In the other case, the Illinois District Court denied a preliminary injunction to Abbott Laboratories, the exclusive licensee of the '507 patent, based on the claim construction from the Eastern District of Virginia.

Because the Eastern District of Virginia correctly construed the claims of the '507 patent and correctly discerned no genuine issues of material fact on literal infringement of claims 2-5 or infringement by equivalents of claims 1-5, this court affirms its partial summary judgment of noninfringement. Likewise, this court affirms the Northern District of Illinois’ denial of Abbott’s motion for a preliminary injunction, based in large part on the same correct claim construction.

I.

Abbott Laboratories, the exclusive licensee of the '507 patent, markets crystalline cefdinir according to the '507 patent under the trade name Omnicef. The Virginia case arose when Lupin sought a declaratory judgment of noninfringement against Abbott Laboratories and Astellas Pharma Inc., the owner of the '507 patent (collectively Abbott). The Food and Drug Administration had previously approved Lu-pin’s Abbreviated New Drug Application (ANDA) to market a generic version of Omnicef. Lupin’s generic product contains almost exclusively the Crystal B form of crystalline cefdinir (cefdinir monohydrate), whereas Abbott’s Omnicef product contains the Crystal A form of crystalline cefdinir (cefdinir anhydrate). Further, Lupin makes its products with processes other than those claimed in the '507 patent. For these reasons, Lupin brought the Virginia action to clarify that its proposed product would not infringe a valid patent. Abbott counterclaimed for infringement. The Eastern District of Virginia construed the claims, Lupin Ltd. v. Abbott Laboratories, 484 F.Supp.2d 448 (E.D.Va.2007) (Lupin CC Order), and ultimately granted-in-part Lupin’s motion for summary judgment of noninfringement, as to both literal and equivalent infringement for claims 2-5 and as to equivalent infringement for claim 1, Lupin Ltd. v. Abbott Labs., 491 F.Supp.2d 563 (E.D.Va.2007) (Lupin SJ Order). The parties stipulated to the dismissal without prejudice of the remaining claims (invalidity) and counterclaims (literal infringement of claim 1).

In the Illinois action, Abbott sued San-doz, Inc. and Sandoz GmbH (collectively Sandoz), Teva Pharmaceuticals USA, Inc. *1286and Teva Pharmaceuticals Industries, Ltd. (collectively Teva), Ranbaxy Laboratories, Ltd., Ranbaxy, Inc., Par Pharmaceutical Companies, Inc., and Par Pharmaceutical (all defendants, collectively, Sandoz and Teva) for infringement of the '507 patent. Like Lupin, Sandoz and Teva had previously filed ANDAs, seeking to market generic versions of Omnicef. Abbott sought a preliminary injunction in the Illinois case. For purposes of that motion, the parties agreed to adopt the Eastern District of Virginia’s claim construction from the Lupin case. Abbott Labs. v. Sandoz, Inc., 486 F.Supp.2d 767 (N.D.Ill.2007) (Sandoz PI Order). Despite this agreement, the parties to the Sandoz case disagreed as to how to interpret some of the Eastern District of Virginia’s constructions, necessitating some clarification by the Northern District of Illinois. 486 F.Supp.2d at 770-71 (disputing “Crystal A,” “peaks,” and “about,” and seeking construction of “powder X-ray diffraction pattern,” which the Eastern District of Virginia had not defined). Ultimately, the Northern District of Illinois, based on the claim construction from Virginia, denied the preliminary injunction.

Both cases arrived at this court on appeal. This court heard the cases together and decides them together with this decision.

II.

The '507 patent has five claims, all of which Abbott asserts against Lupin as well as Sandoz and Teva. Claim 1 claims crystalline cefdinir, using its chemical name, and defining its unique characteristics with powder X-ray diffraction (PXRD) angle peaks:

1. Crystalline 7-[2-(2-a minothiazol-4-yl)-2-hydroxyiminoacetamido]-3-vinyl3-cephem.-4-carboxylic acid (syn isomer) which shows the peaks at the diffraction angles shown in the following table in its powder X-ray diffraction pattern:

diffraction angle (°)

about 14.7°

about 17.8°

about 21.5°

about 22.0°

about 23.4°

about 24.5°

about 28.1°

'507 patent, col.16 11.13-27. In contrast, claims 2-5 claim crystalline cefdinir, without any PXRD peak limitations, but with descriptions of processes used to obtain the crystalline cefdinir. Claims 2 and 5 are independent:

2. Crystalline 7-[2-(2-a minothiazol-4-yl)-2-hydroxyiminoacetamido] -3-vinyl-3-cephem-4-carboxylic acid (syn isomer) which is obtainable by acidifying a solution containing 7-[2-(2-aminothia-zol-4~yl)-2-hydroxyiminoacetamido]-3vinyl -3-cephem-4-carboxylie acid (syn isomer) at room temperature or under warming.

5. Crystalline 7-[2-(2~aminothiazol-4-yl)-2-hydroxyiminoacetamido]-3-vinyl - 3-cephem-4-carboxylic acid (syn isomer) which is obtainable by dissolving 7-[2-(2-aminothiazol-4-yl)-2 -hydroxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) in an alcohol, continuing to stir the solution slowly under warming, then cooling the solution to room temperature and allowing the solution to stand.

Id. at col. 16 11.29-34, 43-50.

These claims use PXRD as a way to claim the structure and characteristics of the unique crystalline form. PXRD is a method for identifying and distinguishing different crystalline compounds. The method beams X-rays toward a powdered chemical. The method then measures the ways the rays reflect or bend upon contact with the chemical. The diffraction angles *1287and intensities vary with the type and purity of the test compound. A graph then plots the diffraction angle on one axis and the intensity on another. These graphs yield a unique “fingerprint” for each crystalline form of a chemical. A more sensitive form of X-ray diffraction is single crystal X-ray diffraction (SCXRD). As this name suggests, this method uses only a single crystal as a sample. SCXRD does not detect intensity, but produces a more precise diffraction angle measurement.

The '507 patent was not the first cefdinir patent. Rather, Astellas’ prior art U.S. Patent No. 4,559,334 (the '334 patent) describes the discovery of cefdinir as a compound demonstrating high antimicrobial activity. '334 patent, col. 11 11.18-24. The '334 patent expired on May 6, 2007.

The '507 patent claims priority to Japanese Patent Application No. 62-206199 (the JP '199 application), which claimed two crystalline forms of cefdinir, “Crystal A” and “Crystal B.” The JP '199 application claimed Crystals A and B very specifically, defining Crystal A by three infrared (IR)-absorption wavelengths and sixteen PXRD angles and intensities. In contrast, Crystal B featured five IR-absorption wavelengths and twenty-one PXRD angles/intensities.

Despite using the JP '199 application for priority, the '507 patent’s specification differs significantly. Specifically, Abbott (actually Fujisawa Pharmaceutical Co., Ltd., Astellas’ predecessor in interest) jettisoned the Crystal B disclosure found in the JP '199 application and crafted broader claims in its prosecution of the '507 patent. Because the JP '199 applications defines Crystal A and Crystal B physiochemically rather than structurally, the forms actually represent subgenuses of crystalline cefdinir. Thus Crystals A and B comprise crystalline forms of varying structures, which in the context of this case means varying levels of hydration.

The Eastern District of Virginia construed the claim terms “crystalline,” “shows,” “peaks,” and “about” as follows:

1) “crystalline” means “Crystal A as outlined in the specification”;

2) “shows” requires the display of a powder X-ray diffraction pattern which demonstrates the existence of the relevant peaks to a scientifically acceptable degree of certainty either visually or by other appropriate means of data display;

3) “peaks” is the plural of “peak;” a “peak exists at a powder X-ray diffraction angle that corresponds to an intensity measurement greater than measurements attributable to “noise” if that angle is immediately preceded by and followed by powder X-ray diffraction angle with a lower intensity measurement; “noise” refers to those portions of a PXRD pattern produced by intrinsic measurement error, and which cannot be associated with a scientifically significant quantity of the material which is the subject of the PXRD test;

4) “about” encompasses measurement errors inherently associated with powder X-ray diffraction testing.

Lupin CC Order; 484 F.Supp.2d at 459, 466. The Eastern District of Virginia also concluded that claims 2-5 were product-by-process claims. Id. Later the district court concluded that the process terms of claims 2-5, indicated by the phrase “obtainable by,” limit the claims to the specified processes and process steps. In reaching that conclusion, the trial court followed this court’s opinion in Atlantic Thermoplastics Co. v. Faytex Corp., 970 F.2d 834 (Fed.Cir.1992). Lupin SJ Order, 491 F.Supp.2d at 567-68; Lupin Ltd. v. Abbott Labs., No. 3:06-CV-400 (E.D.Va. May 10, 2007) (Lupin PbyP Order). In the Lupin appeal, Abbott challenges only *1288the Eastern District of Virginia’s constructions of “crystalline” and “obtainable by.”

III.

Evaluation of a summary judgment of nonmfringement requires two steps: claim construction, which this court reviews without deference, Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448, 1451 (Fed.Cir.1998) (en banc), and comparison of the properly construed claims to the accused product, process, or composition of matter, which in the context of summary judgment also occurs without deference, see Ormco Corp. v. Align Technology, Inc., 498 F.3d 1307, 1312 (Fed.Cir.2007). Although infringement by equivalency is a question of fact, this court may affirm summary judgment “where no reasonable fact finder could find equivalence.” Sage Prods., Inc. v. Devon Indus., Inc., 126 F.3d 1420, 1423 (Fed.Cir.1997) (citing Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17, 39 n. 8, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997)).

A. Claim Construction

Because the claims define the patent right, see Innova/Pure Water, Inc. v. Safari Water Filtration Systems, Inc., 381 F.3d 1111, 1115 (Fed.Cir.2004), naturally “the claims themselves provide substantial guidance as to the meaning of particular claim terms.” Phillips v. AWH Corp., 415 F.3d 1303, 1314 (Fed.Cir.2005) (en banc). But the claims “must be read in view of the specification, of which they are a part.” Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed.Cir.1995) (en banc), aff'd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). A patent’s specification provides necessary context for understanding the claims, and “is always highly relevant to the claim construction analysis.” Phillips, 415 F.3d at 1315 (quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.Cir.1996)). While equally true in a general sense, sometimes the specification offers practically incontrovertible directions about claim meaning. For example, inventors may act as their own lexicographers and give a specialized definition of claim terms. See id. at 1316. Likewise, inventors and applicants may intentionally disclaim, or disavow, subject matter that would otherwise fall within the scope of the claim. See id.

When consulting the specification to clarify the meaning of claim terms, courts must take care not to import limitations into the claims from the specification. This court has recognized the “fine line between” the encouraged and the prohibited use of the specification. Comark Commc’ns, Inc. v. Harris Corp., 156 F.3d 1182, 1186 (Fed.Cir.1998). When the specification describes a single embodiment to enable the invention, this court will not limit broader claim language to that single application “unless the patentee has demonstrated a clear intention to limit the claim scope using ‘words or expressions of manifest exclusion or restriction.’ ” Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 906 (Fed.Cir.2004) (quoting Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1327 (Fed.Cir.2002)). By the same token, the claims cannot “enlarge what is patented beyond what the inventor has described as the invention.” Biogen, Inc. v. Berlex Labs., Inc., 318 F.3d 1132, 1140 (Fed.Cir.2003) (quoting Netword, LLC v. Centraal Corp., 242 F.3d 1347, 1352 (Fed.Cir.2001)). Thus this court may reach a narrower construction, limited to the embodiment(s) disclosed in the specification, when the claims themselves, the specification, or the prosecution history clearly indicate that the invention encompasses no more than that confined structure or method. See Liebel-Flarsheim, 358 F.3d at 908.

Along with the specification, the prosecution history is “intrinsic evidence” *1289of the meaning of the claims, because it “provides evidence of how the [United States Patent & Trademark Office (PTO) ] and the inventor understood the patent.” Phillips, 415 F.3d at 1317. Although often producing ambiguities occasioned by ongoing negotiations between the inventor and the PTO, “the prosecution history can often inform the meaning of the claim language by demonstrating how the inventor understood the invention and whether the inventor limited the invention in the course of prosecution, making the claim scope narrower than it would otherwise be.” Id. “[C]lear and unmistakable” statements during prosecution may also disavow claim scope. Computer Docking Station Corp. v. Dell, Inc., 519 F.3d 1366, 1374 (Fed.Cir.2008) (quoting Purdue Pharma L.P. v. Endo Pharms., Inc., 438 F.3d 1123, 1136 (Fed.Cir.2006)). Again owing in part to the inherent ambiguities of prosecution history, the doctrine of prosecution disclaimer only applies to unambiguous disavowals. See id. at 1375.

1. “crystalline”

The Eastern District of Virginia’s construction of “crystalline” in claims 1-5 as “Crystal A” included the important caveat “as outlined in the specification.” Lupin CC Order, 484 F.Supp.2d at 459. Although the Eastern District noted the parties agreed that “crystalline” ordinarily means exhibiting “uniformly arranged molecules or atoms,” id. at 454, the court relied on the language of the claims themselves, the specification, and the prosecution history to arrive at the more specific meaning recited in the specification.

The '507 specification states that “Crystal A of the compound (I) [cefdinir] shows its distinguishing peaks” at the seven particular PXRD angles enumerated in claim 1. '507 patent col.l 11.51-62. Indeed, the phrase “Crystal A of the compound (I)” appears throughout the written description, and the patent offers the following definition: “any crystal of the compound (I) which shows substantially the same diffraction pattern [as in the table in col.l/claim 1] is identified as Crystal A of the compound (I).” Id. at col.l 1.67-col.2 1.2. As the Eastern District correctly concluded:

Had Astellas intended, in the chart found in column 1, to distinguish Crystal A from other forms of crystalline cefdinir that also fall within the scope of claim 1, it would have listed, at a minimum, an eighth peak associated only with Crystal A. However, by listing in column 1 only the same seven ‘distinguishing’ peaks featured in Claim 1, Astellas confirmed that Crystal A was synonymous with the invention listed in Claim 1.

Lupin CC Order, 484 F.Supp.2d at 456-57. The problem, within the confines of claim 1, is that defining “crystalline” as “Crystal A, ” where “Crystal A” incorporates the seven PXRD peak limitations, arguably renders the remainder of that claim redundant. To distinguish the invention, however, the specification refers several times to “Crystal A of the compound (I) of the present invention,” see, e.g., '507 patent, col.2 11.15-17, and offers no suggestion that the recited processes could produce non-Crystal A compounds, even though other types of cefdinir crystals, namely Crystal B, were known in the art. As noted earlier, the Crystal B formulation actually appears in the parent JP '199 application. Thus, Abbott knew exactly how to describe and claim Crystal B compounds. Knowing of Crystal B, however, Abbott chose to claim only the A form in the '507 patent. Thus, the trial court properly limited the term “crystalline” to “Crystal A.” The trial court’s definition correctly identifies claim l’s literal scope.

*1290Unlike claim 1, claims 2-5 do not recite the seven PXRD peaks expressly associated with Crystal A in the '507 specification. Nonetheless, the Eastern District of Virginia limited “crystalline” to “Crystal A” in these claims as well, The trial court gave two reasons for this limitation. First, “[t]he process steps detailed in those claims [claims 2-5] correspond with the processes for making Crystal A disclosed in the specification under the heading ‘The Process For Preparing Crystal A of The Compound (I).’ ” Id. at 457 (quoting '507 patent, col.2 11.13-14). Second, the parent JP '199 application recited these steps “to distinguish between preparations of Crystal A and Crystal B.” Id. (citing JP '199 application, col.6 11.1-25).

In limiting “crystalline” to “Crystal A” in claims 1-5, the Eastern District of Virginia did not improperly import the preferred embodiment into the claims. Initially, Crystal A is the only embodiment described in the specification. As discussed above, the specification’s recitation of Crystal A as its sole embodiment does not alone justify the trial court’s limitation of claim scope to that single disclosed embodiment. See Liebelr-Flarsheim, 358 F.3d at 906 (“[T]his court has expressly rejected the contention' that if a patent describes only a single embodiment, the claims of the patent must be construed as being limited to that embodiment.”). In this case, however, the rest of the intrinsic evidence, including the prosecution history and the priority JP '199 application, evince a clear intention to limit the '507 patent to Crystal A as defined by the seven PXRD peaks in the specification and in claim 1.

Initially, the Eastern District of Virginia properly considered the JP '199 application as relevant objective evidence of the inventor’s knowledge at the filing of the '507 patent. While statements made during prosecution of a foreign counterpart to a U.S. patent application have a narrow application to U.S. claim construction, Pfizer Inc. v. Ranbaxy Labs. Ltd., 457 F.3d 1284, 1290 (Fed.Cir.2006), in this case the JP '199 application is part of the prosecution history of the '507 patent itself. Indeed the '507 patent claims priority from the JP '199 application. Furthermore, the trial court did not rely on attorney argument or amendments during a foreign prosecution as in Pfizer, but consulted only the contents of the foreign priority application. The JP '199 application strongly suggests that the '507 patent intentionally excluded Crystal B compounds. As discussed above, the JP '199 application establishes unequivocally that Abbott knew and could describe both Crystal A and Crystal B. Abbott could have retained the disclosure of Crystal B to support the broader claims of the '507 patent, but instead disclosed and claimed A alone.

Furthermore, the prosecution history of the '507 patent shows a clear and intentional disavowal of claim scope beyond Crystal A. Co-inventor Takao Takaya, who prepared samples according to Examples 14 and 16 of the prior art '334 patent and a sample of “Crystal A of the present application,” offered a declaration that Crystal A was more stable than the prior art samples from the '334 patent. An analytical chemist, Yoshihiko Okamato, corroborated this evidence. J.A. 501-04. Beyond these declarations, the applicant specifically limited the invention to Crystal A: “the method of preparation of the crystalline form of the presently claimed compounds is not considered the heart of the present invention. The crystalline form of the compound represents the inventive concept hereof, and it is clear that [the '334 patent] does not anticipate or suggest said crystalline form.” J.A. 511 (Response to Office Action of May 11, 1989, received October 27,1989, at 6).

*1291Given the exclusive focus on Crystal A in the specification as well as the prosecution history of the '507 patent, the Eastern District of Virginia properly limited “crystalline” in claims 1-5 to “Crystal A.”

2. proper interpretation of product-by process claims1

This court addresses Part III.A.2 of this opinion en banc, which addresses the proper interpretation of product-by-process claims in determining infringement.

Claims 2-5 of the '507 patent begin by reciting a product, crystalline cefdinir, and then recite a series of steps by which this product is “obtainable.” The Eastern District of Virginia correctly categorized claims 2-5 as product-by-process claims. On appeal, Abbott argues that the Eastern District erred in construing the process steps of claims 2-5 under the rule in Atlantic Thermoplastics, 970 F.2d at 846-47, that “process terms in product-by-process claims serve as limitations in determining infringement,” rather than in accordance with Scripps Clinic & Research Foundation v. Genentech, Inc., 927 F.2d 1565, 1583 (Fed.Cir.1991) (“[T]he correct reading of product-by-process claims is that they are not limited to product prepared by the process set forth in the claims.”). This court takes this opportunity to clarify en banc the scope of product-by-process claims by adopting the rule in Atlantic Thermoplastics.

In Atlantic Thermoplastics, this court considered the scope of product-by-process claim 26 in the patent at issue: “[t]he molded innersole produced by the method of claim 1.” 970 F.2d at 836. The patentee urged that competing, indistinguishable innersoles made by a different method nonetheless infringed claim 26. Id. at 838. This court rejected the patentee’s position. This court in Atlantic Thermoplastics construed product-by-process claims as limited by the process. Id. at 846-47.

This rule finds extensive support in Supreme Court opinions that have addressed the proper reading of product-by-process claims. See Smith v. Goodyear Dental Vulcanite Co., 93 U.S. 486, 493, 23 L.Ed. 952 (1877) (“The process detailed is thereby made as much a part of the invention as are the materials of which the product is composed.”); Goodyear Dental Vulcanite Co. v. Davis, 102 U.S. 222, 224, 26 L.Ed. 149 (1880) (“[T]o constitute infringement of the patent, both the material of which the dental plate is made ... and the process of constructing the plate ... must be employed.”); Merrill v. Yeomans, 94 U.S. 568, 24 L.Ed. 235 (1877); Cochrane v. Badische Anilin & Soda Fabrik, 111 U.S. 293, 4 S.Ct. 455, 28 L.Ed. 433 (1884) (BASF); The Wood-Paper Patent, 23 Wall. 566, 90 U.S. 566, 596, 23 L.Ed. 31 (1874); Plummer v. Sargent, 120 U.S. 442, 7 S.Ct. 640, 30 L.Ed. 737 (1887); Gen. Elec. Co. v. Wabash Appliance Corp., 304 U.S. 364, 58 S.Ct. 899, 82 L.Ed. 1402 (1938); see also Atl. Thermoplastics, 970 F.2d at 839-42 (discussing each of these cases). In these cases, the Supreme Court consistently noted that process terms that define the product in a product-by-process claim serve as enforceable limitations. In addition, the binding case law of this court’s predecessor courts, the United States Court of Customs and Patent Appeals (see In re Hughes, 496 F.2d 1216, 1219 (CCPA 1974) (acknowledging that “true product claims” are “broader” in scope than product-by-process claims)), *1292and the United States Court of Claims (see Tri-Wall Containers v. United States, 187 Ct.Cl. 326, 408 F.2d 748, 751 (1969)), followed the same rule.

This court’s sister circuits also followed the general rule that the defining process terms limit product-by-process claims. See, e.g., Hide-Ite Leather v. Fiber Prods., 226 F. 34, 36 (1st Cir.1915) (“It is also a well-recognized rule that, although a product has definite characteristics by which it may be identified apart from the process, still, if in a claim for the product it is not so described, but is set forth in the terms of the process, nothing can be held to infringe the claim which is not made by the process.”); Paeco, Inc. v. Applied Moldings, Inc., 562 F.2d 870, 876 (3d Cir.1977) (“A patent granted on a product claim describing one process grants no monopoly as to identical products manufactured by a different process.”). Indeed, this court itself had articulated that rule: “For this reason, even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself.” In re Thorpe, 777 F.2d 695, 697 (Fed.Cir.1985) (emphasis added).

The Supreme Court has long emphasized the limiting requirement of process steps in product-by-process claims. In BASF, the Court considered a patent relating to artificial alizarine. Specifically, the patent claimed “[a]rtificial alizarine, produced from anthracine or its derivatives by either of the methods herein described, or by any other method which will produce a like result.” 111 U.S. at 296, 4 S.Ct. 455 (quoting U.S. Pátent Reissue No. RE 4,321). In turn, the specification generally described a method for making artificial alizarine involving anthracine or its derivatives. Alizarine had been in use for thousands of years as a red textile dye, traditionally extracted from, madder root. Pure alizarine has the chemical formula C14H804, but “artificial alizarines” available in the market at the time of the litigation varied from almost completely pure alizarine, to combinations of alizarine and anthrapurpurine, to pure purpurine containing no alizarine whatsoever. Id. at 309-10, 4 S.Ct. 455. The defendant’s product contained approximately sixty percent anthrapurpurine. Thus both alizarine and artificial alizarines were known in the prior art. The Supreme Court clearly articulated some of the scope and validity problems that arise when process limitations of product-by-process claims are ignored:

[The defendant’s product] is claimed by the plaintiff to be the artificial alizarine described in No. 4,321, and to be physically, chemically, and in coloring properties similar to that. But what that is is not defined in No. 4,321, except that it is the product of the process described in No. 4,321. Therefore, unless it is shown that the process of No. 4,321 was followed to produce the defendant’s article, or unless it is shown that that article could not be produced by any other process, the defendant’s article cannot be identified as the product of the process of No. 4,321. Nothing of the kind is shown.

* * *

If the words of the claim are to be construed to cover all artificial alizarine, whatever its ingredients, produced from anthracine or its derivatives by methods invented since Graebe and Liebermann invented the bromine process, we then have a patent for a product or composition of matter which gives no information as to how it is to be identified. Every patent for a product or composition of matter must identify it so that it can be recognized aside from the description of the process for making it, or else nothing can be held to infringe the *1293patent which is not made by that process.

Id. at 310, 4 S.Ct. 455 (emphasis added).

After BASF, the Supreme Court continued to emphasize the importance of process steps in evaluating the infringement of product-by-process claims. See, e.g., Plummer, 120 U.S. at 448, 7 S.Ct. 640 (“[W]hatever likeness that may appear between the product of the process described in the patent and the article made by the defendants, their identity is not established unless it is shown that they are made by the same process.”); Gen. Elec. Co., 304 U.S. at 373, 58 S.Ct. 899 (“[A] patentee who does not distinguish his product from what is old except by reference, express or constructive, to the process by which he produced it, cannot secure a monopoly on the product by whatever means produced.” (footnote omitted)).

Thus, based on Supreme Court precedent and the treatment of product-by-process claims throughout the years by the PTO and other binding court decisions, this court now restates that “process terms in product-by-process claims serve as limitations in determining infringement.” Atl. Thermoplastics, 970 F.2d at 846-47. As noted earlier, this holding follows this court’s clear statement in In re Thorpe that “product by process claims are limited by and defined by the process.” 777 F.2d at 697.

More recently, the Supreme Court has reiterated the broad principle that “[e]ach element contained in a patent claim is deemed material to defining the scope of the patented invention.” Warner-Jenkinson, 520 U.S. at 19, 117 S.Ct. 1040. Although Wamer-Jenkinson specifically addressed the doctrine of equivalents, this rule applies to claim construction overall. As applied to product-by-process claims, Wamer-Jenkinson thus reinforces the basic rule that the process terms limit product-by-process claims. To the extent that Scripps Clinic is inconsistent with this rule, this court hereby expressly overrules Scripps Clinic.

The dissenting opinions lament the loss of a “right” that has never existed in practice or precedent — the right to assert a product-by-process claim against a defendant who does not practice the express limitations of the claim. This court’s en banc decision in no way abridges an inventor’s right to stake claims in prod