In Promega Corp. v. Life Technologies Corp., Nos. 13-1011, -1029, -1376 (Fed. Cir. Dec. 15, 2014), the Federal Circuit reversed the district court’s denial of summary judgment on invalidity, finding that the asserted claims, which used open-ended claim language, were not enabled by the specification.  The court closely examined how the use of the term “comprising” in the body of the claims―not the preamble—affected the scope of the claims.  This case also presents an interesting analysis of the impact of the level of predictability of the art in the enablement analysis.

At issue in the case were five patents that claim methods or kits for carrying out a technique of forensic DNA identification known as “short tandem repeat” (STR) profiling.  Id., slip op. at 5.  In particular, the claims related to multiplex amplification of STR loci, which allows the generation of a detectable amount of DNA that can be used to provide a DNA “fingerprint” unique to each individual.  Id.  Promega owned four patents (“Promega patents”) and licensed the fifth (“the Tautz patent”).  Id.  The accused products are genetic testing kits used by law enforcement agencies for forensic identification, and by clinical and research institutions for, for example, analyzing cancer cells, that use the claimed STR profiling technique.  Id. at 8-9.

Promega entered into a nonexclusive cross-license agreement with Applied Biosystems (AB)—now a wholly owned subsidiary of Life Technologies (LifeTech)―in 2006.  Id. at 9.  Under the license, AB had the right to use the claimed inventions in the Promega and Tautz patents for “Forensic and Human Identity Applications.”  Id.  Promega later sued LifeTech for infringement of the Promega and Tautz patents, alleging that LifeTech sold testing kits not covered by the cross-license.  Id.  LifeTech responded that it was licensed to practice all of the patents-in-suit and filed counterclaims alleging that the Promega patents were invalid.  Id. at 9-10.  LifeTech did not challenge the validity of the Tautz patent.  Id. at 10.  Among other things, the district court denied LifeTech’s summary judgment motion that the Promega patents were invalid due to lack of enablement and obviousness.  Id.  The Federal Circuit reversed, finding that the claims were not enabled by the specification, and did not address the issue of obviousness.  Id. at 20-21.

Each of the asserted claims includes a limitation that recites the phrase “a set of . . . loci ” followed by a list of particular STR loci multiplexes of varying complexity.  Id. at 5-6.  Some of the asserted claims included closed transitional language (“a set of . . . loci . . . consisting of . . .”), while others included open transitional language (“a set of . . . loci . . . comprising . . .”).  Id. at 6-7 (emphases added) (citation omitted).  As expected, the district court construed the open loci claims not to be restricted to “products that use no loci other than those listed in the claims,” and therefore allowing the claims to cover unrecited loci.  Id. at 6, 14.  The open loci claims were at the center of the lack of enablement challenge by LifeTech.  

The enablement requirement requires a specification to contain a written description of the invention that would enable a person skilled in the art to which it pertains to make and use the same without undue experimentation.  See Ortho-McNeil Pharm., Inc. v. Mylan Labs., Inc., 520 F.3d 1358, 1365 (Fed. Cir. 2008).  The guidance needed to enable the invention is generally inversely related to the knowledge in the state of the art and the predictability in the art.  In re Fisher, 427 F.2d 833, 839 (CCPA 1970).  The Federal Circuit determined that the technology at issue in Promega was highly unpredictable.  To illustrate its point, the Court relied on several allegations made by Promega during the prosecution of the patents describing the highly unpredictable nature of the technology field.  For example, Promega had alleged that its claims were patentable because the prior art did not disclose “methods for selecting, co-amplifying, and evaluating the specific sets of . . . loci” recited in the claims.  Promega, No. 13-1011, slip op. at 15 (citation omitted).  Promega characterized this lack of disclosure as critical, as the state of the art did not disclose or suggest that any arbitrary combination of loci can be co-amplified without undue experimentation.  Id.  Promega had also alleged during prosecution that “the addition of even a single locus to an existing loci combination rendered that new combination patentable” and that “‘the disclosure of some of the individual loci in the various [recited] sets of loci co-amplified’ was insufficient to render a claim unpatentable.”  Id. at 15-16 (alteration in original) (emphasis added) (citation omitted).  

Despite the overwhelming evidence that adding a single locus to an existing loci combination can fundamentally transform the character of the resulting multiplex reaction, Promega alleged that the accused kits infringe its claims because “any and all co-amplifying loci combinations that include the STR loci recited in the claims are encompassed by the claims.”  Id. at 17.  The enablement requirement ensures that “the public knowledge is enriched by the patent specification to a degree at least commensurate with the scope of the claims.”  Id. at 14 (quoting Nat’l Recovery Techs., Inc. v. Magnetic Separation Sys., Inc., 166 F.3d 1190, 1195-96 (Fed. Cir. 1999)).  The court found that, like in MagSil Corp. v. Hitachi Global Storage Technologies, Inc., 687 F.3d 1377, 1381 (Fed. Cir. 2012), instead of tying the key claim limitation to what the specification enabled, Promega sought to extend its scope advances in this unpredictable art by drafting claims that could cover thousands of undisclosed loci combinations.  See Promega, No. 13-1011, slip op. at 20-21.  The Court also found that, like in Wyeth & Cordis Corp. v. Abbott Laboratories., 720 F.3d 1380 (Fed. Cir. 2013), one of ordinary skill in the art would have to engage in undue experimentation to practice the claims because, while the Promega patents provide a starting point, they fail to provide disclosure that would have allowed a skilled artisan, absent laborious testing, to add any new loci to these recited loci combinations with a reasonable expectation that it would still successfully co-amplify.  See Promega, No. 13-1011, slip op. at 18-19.

Promega argued that if the Court found its claims to lack enablement, “every claim using the transitional phrase ‘comprising’ would be invalidated.”  Id. at 20.  The Court dispelled these fears by explaining that, while the term “comprising” in a claim preamble may create a presumption that a list of claim elements is nonexclusive, it does not reach into each limitation to render every word and phrase therein open-ended. Id.  Promega’s claims differ from such customary open-ended claims because its inclusion of “comprising” in its “open loci set” limitation, as construed, expands the claims at a key limitation, rather than in the preamble, to cover what are the identified advances in the art.  Id. at 20-21.  As drafted, the open loci claims cover potentially thousands of undisclosed embodiments in an unpredictable field.  Id. at 20.  Since the Promega patents do not enable a skilled artisan to practice the full breadth of the scope of its claims without undue experimentation, the Court held the claims invalid.

In the wake of Promega, strategic and careful drafting of a patent application continues to be the best method for satisfying the enablement requirement.  Such drafting must include a clear understanding of the level of knowledge available in the prior art, determining where that knowledge may fill any gaps in the disclosure, and providing numerous examples of varying scope for practicing the claimed invention.  It must also include a careful selection of every word that is added to the claims―not just of the technical terms used to substantively describe the invention—and a clear understanding on how each word may affect the claim.  In addition, Promega serves as yet another reminder to practitioners that every statement made during prosecution of a patent application can significantly affect the ability to successfully enforce the patent.  A careful practitioner should evaluate how arguments and statements made to overcome prior art may affect the claim’s ability to withstand § 112 challenges or limit its scope for infringement purposes.