The Reverse Doctrine of Equivalents Part 1 of 2

First, the history of the Reverse Doctrine of Equivalents will be discussed. In Boyden, the U.S. Supreme Court determined that literal correspondence between a patent claim and an accused product is but an initial hurdle in an infringement analysis. If literal correspondence is found, the Court stated that the accused device must also appropriate the principle, spirit and intent of the invention in order for the device to be found to infringe the patent. Id. at 568. Accordingly, the Court created the Reverse Doctrine of Equivalents to relieve an accused infringer of liability when the accused device meets the literal language of the claim but nevertheless does not appropriate the principle, spirit and intent of the patented invention.

The modern standard for the Reverse Doctrine of Equivalents was articulated by the Supreme Court in its 1950 Graver Tank opinion. Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605. According to the Court, “where a device is so far changed in principle from a patented article that it performs the same or a similar function in a substantially different way, but nevertheless falls within the literal words of the claim, the doctrine of equivalents may be used to restrict the claim and defeat the patentee's action for infringement” (emphasis added). Id. at 608-9.

Courts applying the Reverse Doctrine have generally interpreted the Graver Tank test as a two-step inquiry. See, eg, Phillips Petroleum Co. v. U.S. Steel Corp., 673 F. Supp. 1278, 1354 (D. Del. 1987). According to the first step, a court must first ascertain whether the principle of the asserted device and the principle of the accused device are substantially different. This is a threshold requirement. If the principles are not substantially different, the inquiry ends and liability is imposed. If the principles are substantially different, however, the second step of the inquiry is reached and the court must examine whether the accused device operates in a way substantially different from the way in which the patented device operates.

The Reverse Doctrine of Equivalents is conceptually similar to the Doctrine of Equivalents. While the Doctrine of Equivalents provides for the extension of claims to encompass non-literally infringing, but nevertheless equivalent, devices, the Reverse Doctrine of Equivalents argues against applying the claims to literally infringing, but nevertheless non-equivalent devices. Additionally, the respective standards operate in a similar manner. The Doctrine of Equivalents directs an investigation into whether two elements perform substantially the same function in substantially the same way to obtain the same result. Id. at 609. The Reverse Doctrine of Equivalents involves the same three inquiries but assumes that the accused device and the patented article perform substantially the same function and achieve substantially the same result. The focus of the analysis under the Reverse Doctrine of Equivalents is on the “way” component of the inquiry. If a product is so far changed in principle that it performs the function of the claimed invention in a substantially different way, no liability for infringement will be found.

The Reverse Doctrine of Equivalents has met some success in the district courts. See, eg, Jewish Hospital of St. Louis v. IDEXX Lab., 973 F. Supp. 24 (D.Me 1997); Brenner v. Recognition Equip., Inc., 593 F. Supp. 1275 (S.D.N.Y. 1984), Foster Wheeler Corp. v. Backcock & Wilcox Co., 512 F. Supp. 792 (S.D.N.Y. 1981). In Jewish Hospital, for example, the court accepted a Reverse Doctrine of Equivalents defense and excused literal infringement. In this case, Jewish Hospital asserted a patent claiming an assay for detecting circulating heartworm antigens against IDEXX. The relevant language of asserted claim 11 is as follows:

11. An assay method for determining the presence of circulating parasite antigens of Dirofilaria immitis [heartworm] in the serum or plasma of D. immitis-infected dogs which comprises combining a sample of serum or plasma from a dog infected with Dirofilaria immitis … with a first monoclonal antibody …, and detecting the presence of said antigens.

The court found that IDEXX's method literally fell within the scope of claim 11. Id. at 27. Specifically, the court determined that IDEXX performed the same method as recited in claim 11, but did so on a whole blood sample, not just on a plasma or serum sample. The court reasoned that since plasma or serum is a component of whole blood, claim 11 literally covered IDEXX's test. IDEXX argued that its accused test, the whole blood heartworm test, was non-infringing because of the Reverse Doctrine of Equivalents. IDEXX stated that its test detected heartworms in a substantially different way from the way in which the Jewish Hospital patent operated because its test utilized whole blood, as opposed to the Jewish Hospital's test that utilized only serum or plasma samples. The court found this difference sufficient and excused IDEXX's liability under the Reverse Doctrine of Equivalents. Id. The court was also influenced by the fact that the IDEXX whole blood test was not known at the time Jewish Hospital received its patent.

Unlike the district courts, the higher courts have encountered the Reverse Doctrine of Equivalents only a limited number of times. Although the Federal Circuit has provided useful guidance and seems to have approved the doctrine, it has yet to allow such a defense to succeed.

In Scripps Clinic & Research Found. v. Genentech, Inc., 972 F.2d 1565, 1580 (Fed. Cir. 1991), the Federal Circuit endorsed the Reverse Doctrine of Equivalents. In this case, Scripps obtained a patent directed to the protein Factor VIII:C isolated and purified from blood. The patent includes, inter alia, six product claims, of which claim 24, recites in relevant part: “A human VIII:C preparation being substantially free of VIII:RP.” Genentech, who produced Factor VIII:C recombinantly, was found by the district court to literally infringe the product claims. The district court explained that “Human Factor VIII:C as claimed in the [product claims] therefore applies to any Factor VIII:C preparation, regardless of how produced, having the same material structure and functional characteristics as the plasma-derived preparation.” Id. Thus, the district court refused to distinguish between the recombinantly-produced and plasma-derived protein.

Genentech attempted to avoid liability by invoking the Reverse Doctrine of Equivalents and trying to convince the court that its product was changed in principle, particularly in the context of the prior art. Genentech asserted that the specific activities and purities that are exhibited by the protein as produced by its recombinant method exceed those obtainable by the protein as obtained by the Scripps purification method. On appeal, the Federal Circuit was influenced by this argument and stated that this “assertion … if found to be correct could provide ' depending on the specific facts of similarities and differences ' sufficient ground for invoking the reverse doctrine.” Id. at 1581. The Federal Circuit ultimately reversed the district court's grant of summary judgment of infringement and remanded for a full trial since those aspects were not considered by the district court.

An example of how the Reverse Doctrine of Equivalents might have been applied to a particular case will be provided in the next issue.

The ability of patents to encourage innovation by granting exclusive rights is well-recognized. However, patents can serve an antithetical role as well by, in certain circumstances, deterring, rather than encouraging, innovation.

The Reverse Doctrine of Equivalents can help to reduce the potential for patents to hinder innovation. Created by the U.S. Supreme Court in 1898, the Reverse Doctrine of Equivalents provides an accused infringer with an opportunity to escape liability if it can demonstrate that the device (or process) at issue is so far changed in principle from the patented article (or process) that the device performs the same or similar function as the patented article but in a substantially different way. Boyden Power-Brake Co. v. Westinghouse , 170 U.S. 537 (1898).

As an initial impression, readers familiar with the current Federal Circuit emphasis on strict claim construction may believe that the Reverse Doctrine of Equivalents would not be well received in the Federal Circuit. On the contrary, the Federal Circuit has never demonstrated an attitude adverse to this doctrine.

First, the history of the Reverse Doctrine of Equivalents will be discussed. In Boyden, the U.S. Supreme Court determined that literal correspondence between a patent claim and an accused product is but an initial hurdle in an infringement analysis. If literal correspondence is found, the Court stated that the accused device must also appropriate the principle, spirit and intent of the invention in order for the device to be found to infringe the patent. Id. at 568. Accordingly, the Court created the Reverse Doctrine of Equivalents to relieve an accused infringer of liability when the accused device meets the literal language of the claim but nevertheless does not appropriate the principle, spirit and intent of the patented invention.

The modern standard for the Reverse Doctrine of Equivalents was articulated by the Supreme Court in its 1950 Graver Tank opinion. Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605. According to the Court, “where a device is so far changed in principle from a patented article that it performs the same or a similar function in a substantially different way, but nevertheless falls within the literal words of the claim, the doctrine of equivalents may be used to restrict the claim and defeat the patentee's action for infringement” (emphasis added). Id. at 608-9.

Courts applying the Reverse Doctrine have generally interpreted the Graver Tank test as a two-step inquiry. See, eg, Phillips Petroleum Co. v. U.S. Steel Corp., 673 F. Supp. 1278, 1354 (D. Del. 1987). According to the first step, a court must first ascertain whether the principle of the asserted device and the principle of the accused device are substantially different. This is a threshold requirement. If the principles are not substantially different, the inquiry ends and liability is imposed. If the principles are substantially different, however, the second step of the inquiry is reached and the court must examine whether the accused device operates in a way substantially different from the way in which the patented device operates.

The Reverse Doctrine of Equivalents is conceptually similar to the Doctrine of Equivalents. While the Doctrine of Equivalents provides for the extension of claims to encompass non-literally infringing, but nevertheless equivalent, devices, the Reverse Doctrine of Equivalents argues against applying the claims to literally infringing, but nevertheless non-equivalent devices. Additionally, the respective standards operate in a similar manner. The Doctrine of Equivalents directs an investigation into whether two elements perform substantially the same function in substantially the same way to obtain the same result. Id. at 609. The Reverse Doctrine of Equivalents involves the same three inquiries but assumes that the accused device and the patented article perform substantially the same function and achieve substantially the same result. The focus of the analysis under the Reverse Doctrine of Equivalents is on the “way” component of the inquiry. If a product is so far changed in principle that it performs the function of the claimed invention in a substantially different way, no liability for infringement will be found.

The Reverse Doctrine of Equivalents has met some success in the district courts. See, eg, Jewish Hospital of St. Louis v. IDEXX Lab., 973 F. Supp. 24 (D.Me 1997); Brenner v. Recognition Equip., Inc., 593 F. Supp. 1275 (S.D.N.Y. 1984), Foster Wheeler Corp. v. Backcock & Wilcox Co., 512 F. Supp. 792 (S.D.N.Y. 1981). In Jewish Hospital, for example, the court accepted a Reverse Doctrine of Equivalents defense and excused literal infringement. In this case, Jewish Hospital asserted a patent claiming an assay for detecting circulating heartworm antigens against IDEXX. The relevant language of asserted claim 11 is as follows:

11. An assay method for determining the presence of circulating parasite antigens of Dirofilaria immitis [heartworm] in the serum or plasma of D. immitis-infected dogs which comprises combining a sample of serum or plasma from a dog infected with Dirofilaria immitis … with a first monoclonal antibody …, and detecting the presence of said antigens.

The court found that IDEXX's method literally fell within the scope of claim 11. Id. at 27. Specifically, the court determined that IDEXX performed the same method as recited in claim 11, but did so on a whole blood sample, not just on a plasma or serum sample. The court reasoned that since plasma or serum is a component of whole blood, claim 11 literally covered IDEXX's test. IDEXX argued that its accused test, the whole blood heartworm test, was non-infringing because of the Reverse Doctrine of Equivalents. IDEXX stated that its test detected heartworms in a substantially different way from the way in which the Jewish Hospital patent operated because its test utilized whole blood, as opposed to the Jewish Hospital's test that utilized only serum or plasma samples. The court found this difference sufficient and excused IDEXX's liability under the Reverse Doctrine of Equivalents. Id. The court was also influenced by the fact that the IDEXX whole blood test was not known at the time Jewish Hospital received its patent.

Unlike the district courts, the higher courts have encountered the Reverse Doctrine of Equivalents only a limited number of times. Although the Federal Circuit has provided useful guidance and seems to have approved the doctrine, it has yet to allow such a defense to succeed.

In Scripps Clinic & Research Found. v. Genentech, Inc., 972 F.2d 1565, 1580 (Fed. Cir. 1991), the Federal Circuit endorsed the Reverse Doctrine of Equivalents. In this case, Scripps obtained a patent directed to the protein Factor VIII:C isolated and purified from blood. The patent includes, inter alia, six product claims, of which claim 24, recites in relevant part: “A human VIII:C preparation being substantially free of VIII:RP.” Genentech, who produced Factor VIII:C recombinantly, was found by the district court to literally infringe the product claims. The district court explained that “Human Factor VIII:C as claimed in the [product claims] therefore applies to any Factor VIII:C preparation, regardless of how produced, having the same material structure and functional characteristics as the plasma-derived preparation.” Id. Thus, the district court refused to distinguish between the recombinantly-produced and plasma-derived protein.

Genentech attempted to avoid liability by invoking the Reverse Doctrine of Equivalents and trying to convince the court that its product was changed in principle, particularly in the context of the prior art. Genentech asserted that the specific activities and purities that are exhibited by the protein as produced by its recombinant method exceed those obtainable by the protein as obtained by the Scripps purification method. On appeal, the Federal Circuit was influenced by this argument and stated that this “assertion … if found to be correct could provide ' depending on the specific facts of similarities and differences ' sufficient ground for invoking the reverse doctrine.” Id. at 1581. The Federal Circuit ultimately reversed the district court's grant of summary judgment of infringement and remanded for a full trial since those aspects were not considered by the district court.

An example of how the Reverse Doctrine of Equivalents might have been applied to a particular case will be provided in the next issue.