On July 15, 2002, a three-judge panel of the United States Court of Appeals for the Federal Circuit restated the law of written
description in connection with biotechnology patents. The Federal Circuit's opinion in
Enzo Biochem, Inc. v. Gen-Probe Incorporated, 2002 WL 1540813, No. 01-1230 (Fed. Cir. July 15, 2002) ("
Enzo II"), reversed the same three-judge panel's previous decision issued on April 2, 2002 in
Enzo Biochem, Inc. v. Gen-Probe Incorporated, 285 F.3d 1013 (Fed. Cir. 2002) ("
Enzo I"). With its decision in
Enzo II, the Federal Circuit held that reference in a patent specification to a biological deposit in a public depository satisfies
the written description requirement of 35 U.S.C. § 112 1.
Background
Enzo is the assignee of U.S. Patent No. 4,900,659 (the "'659 patent"), which is directed to nucleic acid probes that selectively
hybridize to the genetic material of the bacteria that cause gonorrhea, Neisseria gonorrhoeae. Enzo, in developing a chromosomal DNA probe specific for N. gonorrhoeae, derived three sequences that hybridized to six common strains of the bacteria. Enzo deposited the three sequences "in the
form of a recombinant DNA molecule within an E. coli bacterial host at the American Type Culture Collection." Enzo II, 2002 WL 1540813 at *1.
Enzo later sued the defendants for infringing the '659 patent. Defendants moved for summary judgment on the grounds that the
asserted claims of the '659 patent were invalid for failure to meet the written description requirement of 35 U.S.C. § 112
1. The district court concluded that the specification described the claimed composition only by its function (the ability
to hybridize to N. gonorrhoeae in a certain ratio), and granted defendants' motion. The district court rejected Enzo's argument that reference in the specification
to the public deposit of biological materials "inherently disclosed that the inventors were in possession of the claimed sequences."
The first time around, the Federal Circuit affirmed the district court's ruling, relying on its previous decision in Regents of the University of California v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997) (holding that a claim to a microorganism containing a human insulin cDNA was not adequately
described by a statement that the invention included human insulin cDNA). In Eli Lilly, the Federal Circuit stated that an adequate written description of genetic material "requires a precise definition, such
as by structure, formula, chemical name or physical properties," and that a statement of mere wish or a plan to obtain the
claimed invention would not suffice. Applying Eli Lilly, the Federal Circuit in Enzo I reasoned that "while the description of the ability of the claimed probe to bind to N. gonorrhoeae may describe the probe's function, it does not describe the probe itself." Enzo I, 285 F.3d at 1018. The Federal Circuit reasoned that describing genetic material merely by what it does is insufficient to satisfy the written description requirement of § 112 1.
The Federal Circuit's Holding and Rationale
Enzo petitioned the Federal Circuit for rehearing. The same three-judge panel did not simply grant rehearing, it instead reversed
completely the holding of Enzo I.
In reversing its holding from Enzo I, the Federal Circuit emphasized that the written description requirement is separate from the enablement requirement, and
that "compliance with the written description requirement is essentially a fact-based inquiry that will 'necessarily vary
depending on the nature of the invention claimed.'" Enzo II, 2002 WL 1540813 at *4.
The Federal Circuit adopted the PTO's guideline that the written description requirement can be met by "show[ing] that an
invention is complete by disclosure of sufficiently detailed, relevant identifying characteristics . . . i.e., complete or partial structure, other physical and/or chemical properties, functional characteristics when coupled with a known or disclosed correlation between function and structure, or some combination of such characteristics." Id. at *5 (quoting Guidelines for Examination of Patent Applications Under the 35 U.S.C. § 112, 1 "Written Description" Requirement,
66 Fed.Reg. 1009 (Jan. 5, 2001)). In this case, the Federal Circuit found, the written description requirement would be met
for all of the claims of the '659 patent if the functional characteristic of preferential binding to N. gonorrhoeae (over the N. meningitidis bacteria) were coupled with a disclosed correlation between that function and a structure that is sufficiently known or disclosed.
The Federal Circuit (reversing its holding in Enzo I) concluded: "In light of the history of biological deposits for patent purposes, the goals of the patent law, and the practical
difficulties of describing unique biological materials in a written description, we hold that reference in the specification
to a deposit in a public depository, which makes its contents accessible to the public when it is not otherwise available in written form, constitutes an adequate description of the deposited material sufficient to comply with the written description requirement
of § 112, 1." Id. at *5. The Court ultimately sided with Enzo, finding that reference in the specification to deposits of nucleotide sequences
described those sequences, i.e., the deposited sequences, sufficiently to the public for purposes of meeting the written description requirement.
The Federal Circuit remanded the matter to the district court to determine whether a person of skill in the art would glean
from the written description (including information obtainable from the deposits of the claimed sequences) subsequences sufficient
to demonstrate that the inventors were in "possession" of the generic scope of the claims.
The panel went on to reject Enzo's argument that a mere showing of "possession" or "reduction to practice" is sufficient to
meet the written description requirement under 35 U.S.C. § 112, 1.
The Court remanded for consideration of whether describing biological materials in the specification "by their affinity to
other materials that are clearly identified in the specification and claims . . . inherently specifies structure." Enzo had argued that since the target bacterial genomes are deposited and available
to the public (and provided some structural description), the description in the specification of the preferential hybridization
limitation (or functional description) was sufficient under the PTO's Guidelines to satisfy 35 U.S.C. § 112, 1. Enzo reasoned
that the bacterial genome of N. gonorrhoeae was adequately described because it was both deposited and accessible to the public. Enzo urged the Court to hold that, by
describing the claimed sequences' affinity to the disclosed bacterial genome, Enzo adequately described the claimed sequences
within the PTO's Guidelines.
The Federal Circuit concluded that Enzo had raised "a genuine issue of material fact," and instructed the district court to
consider whether one of skill in the art would find the generically claimed sequences described on the basis of (1) Enzo's
disclosure of the hybridization function and (2) an accessible structure, consistent with the written description required
under the PTO Guidelines.
Implications
The Federal Circuit's holding in Enzo II-- that reference in the specification to a deposit in a public depository constitutes an adequate description of the deposited
material sufficient to comply with the written description requirement of § 112, 1 -- has broad implications for the rights
of biotechnology patent holders. The decision potentially bolsters the validity of numerous patents where the specification
refers to a deposit in lieu of providing the written sequence. The biggest beneficiaries of Enzo II may be the holders of patents filed in the 1980s and 1990s. (Indeed, the deposit of materials at issue in Enzo I and Enzo II occurred in 1986.) During this period, applicants were motivated to deposit biological materials in public depositories for
a number of reasons. Sequencing was more costly, more time consuming and far less accurate than it is today. Applicants also
feared that errors in sequencing would be replicated in a specification, thus potentially invalidating the patent for lack
of enablement or insufficient written description. As a result, many chose to deposit the materials and leave the sequencing
to the interested public.
Today, sequencing has become faster, cheaper and far more accurate than it was in 1986. In light of these advances, applicants
and patent practitioners often prefer to disclose the relevant sequences in the text of the specification instead of (or in
addition to) making a public deposit. As a result, the Federal Circuit's holding in Enzo II may have more of an impact on patents filed at a time when sequencing technology was more time consuming and less reliable.
There is also a broader implication to Enzo II than resolution of the "public deposit" issue. The Court reiterated that the sufficiency of written description is a fact
inquiry that may vary on a case-by-case basis, and that in order to satisfy the written description requirement under 35 U.S.C.
§ 112, 1, an applicant must do more than just show that he or she "possessed" an invention or reduced it to practice.
The deposit of biological material in a public depository previously pertained to satisfaction of the enablement requirement.
Reference to an accession number and deposit date in the specification had been held sufficient to meet the enablement requirement,
but not the written description requirement. In arguing for an extension of that practice to the written description requirement,
Enzo reasoned that reference to a deposit would show that the inventors "were in possession" of the claimed invention as of
the filing date. The Federal Circuit, however, reiterated that the written description requirement demands more than a showing
that inventors possessed the claimed invention at the time of filing.
In the case of biotech patents, an inventor must not only show that he was in possession of the invention at the desired filing
date (that he reduced it to practice), but must also describe the claimed invention so that one skilled in the art can "recognize
what is claimed." The written description requirement also mandates disclosure of "such descriptive means as words, structures,
figures, diagrams, formulas, etc. that fully set for the claimed invention." 2002 WL 1540813 at *9. Reference in a specification
to a public deposit of biological material does not satisfy § 112, 1 merely because it shows that the inventors reduced the
invention to practice; rather, it suffices because the reference in the specification to both accession numbers and deposit
dates adequately describes the invention to those skilled in the art.
In the end, the Federal Circuit justifies its holding by noting that a public deposit meets the quid pro quo underlying the patent system: the government's grant to the patentee of a monopoly to practice the invention in exchange
for a "meaningful disclosure" of what is claimed. The holding in Enzo II may ensure that patent holders who made public deposits of biological materials realize the benefit of the bargain which
forms that foundation of the U.S. patent laws.
