Authored by Charles E. Lipsey
I. Demystifying The Written Description Requirement
A. Why Does it Make Sense to Have Separate Written Description and Enablement Requirements?
The logical need for separate written description and enablement requirements under 35 U.S.C. §112, first paragraph, arises from fundamental principles developed in other areas of the patent law. Specifically, when dealing with the question of what is "described" in the prior art so as to defeat patentability of a subsequently presented claim under 35 U.S.C. § 102, it has long been clear that subject matter can be "enabled" by the prior art yet not be "described" by it. The case of In re Ruschig, 343 F.2d 965 (C.C.P.A. 1965), decided more than forty years ago, is illustrative. There, a generic disclosure in the prior art of a genus of chemical compounds, the synthesis of each of which would have been enabled by the prior art disclosure, was nonetheless found not to "describe" a later claimed species within the genus under 35 U.S.C. § 102. Indeed, the Federal Circuit has now made clear that a generic disclosure in the prior art (again in the context of a genus of chemical compounds), which presumably "enables" the synthesis of each and every member of the genus, may nonetheless not even render obvious certain compounds encompassed by that generic disclosure. In re Baird, 16 F.3d 380, 382 (Fed. Cir. 1994).
It is thus seen that the law relating to substantive patentability over the prior art requires something more by way of description than naked enablement in order to conclude that the prior art has placed something in the public domain. The purpose of 35 U.S.C. § 112, first paragraph, is to ensure that the disclosure of each patent application places the claimed invention in the public domain so that it may be enjoyed by the public after patent expiration. It makes logical sense, therefore, that a patent applicant should not be able to withdraw technical subject matter from the public domain by claiming it in a patent without giving at least the same type and quality of disclosure that is required of the prior art to place that subject matter within the public domain.
It is to be expected, therefore, that there will be situations where a patent applicant may have "enabled" the practice of certain technological subject matter when he has nonetheless failed to "describe" that subject matter in a manner that makes it clear to the reader of the patent application that that subject matter was within the possession of the inventor and part of his invention. Accordingly, the Federal Circuit and its predecessors have required that the disclosure of the patent application relied upon not only enables practice of the claimed invention but also "reasonably conveys to the artisan that the inventor had possession at that time of the later claimed subject matter." In re Kaslow, 707 F.2d 1366, 1375 (Fed. Cir. 1983); Ralston Purina Co. v. Far-Mar-Co, Inc., 772 F.2d 1570, 1575 (Fed. Cir. 1985); Vas-Cath Inc. v. Mahurkar, 935 F.2d 1555, 1563 (Fed. Cir. 1991).
Much of the difficulty in applying the written description requirement is also foreshadowed by the law relating to substantive patentability. Specifically, the law relating to what is "described" within the meaning of 35 U.S.C. § 102 makes clear that the text of a patent can "describe" something that is not actually described there at all. The case of In re Petering, 301 F.2d 676 (C.C.P.A. 1962), is illustrative. There, the disclosure of a handful of preferred chemical substituents was found actually to "describe," and, therefore, to anticipate, each member of a genus of compounds containing combinations of the preferred substituents. It is, therefore, equally unsurprising that the Federal Circuit and its predecessors have repeatedly said that compliance with the written description requirement does not require description of the subject matter ultimately claimed "in haec verba," or "in ipsis verbis," or in other words, in the same words. See, e.g., In re Lukach, 442 F.2d 967, 969 (C.C.P.A. 1971). It is because things encompassed by a generic patent disclosure may nonetheless not be described by that disclosure and because things not explicitly described in a patent specification can be found to have been "described" for purposes of 35 U.S.C. § 112, first paragraph, that litigation of issues relating to the written description requirement is so challenging.
B. Does the Written Description Requirement Apply Only in Chemical or Biological Cases?
It is well settled that issues relating to the written description requirement can arise not only in chemical and biological cases but also in mechanical and other types of applications. Indeed, the decision of the Court of the Customs and Patent Appeals that most clearly articulated the need and reasons for a written description requirement separate and distinct from the enablement requirement, In re Barker, 559 F.2d 588 (C.C.P.A. 1977), was a mechanical case. The patent applicant disclosed the manufacture of prefabricated shingle panels. The specification described panels having a repetitive series of 8 or 16 shingles. The claim, however, was directed to panels having a width of "at least 6 shingles." The court found no disclosure suggesting that the patent applicant had invented that particular subject matter even though the disclosure unquestionably would have enabled the manufacture of such panels.
Application of the written description requirement in mechanical cases of more recent vintage is illustrated by Gentry Gallery, Inc. v. Berkline Corp., 134 F.3d 1473 (Fed. Cir. 1998). That case involved a sectional reclining sofa with a console containing controls. The court found claims directed to sofas where the controls were not in the console invalid for failing to comply with the written description requirement.
C. Is the Written Description Requirement Applied Differently in Connection with Biotechnology Inventions?
Much of the current debate about the appropriate scope of the written description requirement arises from the Federal Circuit's handling of biotechnology inventions and, more specifically, its holding in Regents of the University of California v. Eli Lilly and Company, 119 F.3d 1559 (Fed. Cir. 1997). There, the patent owner had isolated and sequenced the DNA encoding rat insulin. Alleging generic applicability of the methods used to isolate the rat DNA, the patentee claimed the DNA encoding human insulin, which had not then been isolated, and the genus of DNAs encoding mammalian insulin. The Federal Circuit held that the claims to human insulin DNA and the generic claims to mammalian insulin DNA were invalid for failure to comply with the written description requirement. The court did so even assuming that the basic techniques of recombinant DNA that had been used to isolate the rat DNA would in fact enable a successful search for human and other mammalian insulin DNA. Notwithstanding the current controversy to the contrary, this was not the result of applying the written description requirement differently in biotechnology inventions than in other inventions.
The UC v. Lilly court was not writing on a clean slate. There had been a substantial body of jurisprudence developed dealing with the substantive patentability of inventions in the field of recombinant DNA where it had been determined that merely identifying a desired result (DNA encoding a protein of interest) and a general method of obtaining the result (the basic techniques of recombinant DNA technology) was not sufficient to conceive, anticipate, or render obvious a claim to the resulting DNA once actually isolated and identified. See generally Amgen, Inc. v. Chugai Pharm. Co., 927 F.2d 1200 (Fed. Cir. 1991); Fiers v. Revel, 984 F.2d 1164 (Fed. Cir. 1993); In re Bell, 991 F.2d 781 (Fed. Cir. 1993); and In re Deuel, 51 F.3d 1552 (Fed. Cir. 1995). Thus the requirement in UC v. Lilly for a written description of the human DNA itself in terms of its structure or other identifying characteristics was totally consistent with the jurisprudence that had developed in the area of substantive patentability regarding what type of information had to be in the prior art in order to place such subject matter in the public domain. So viewed, the holding in UC v. Lilly is entirely consistent with application of the written description requirement in other areas of the law. The apparent differences arise from differences in the previously developed substantive law relating to the quality of the disclosure required to cross the line between anticipating the future before it had arrived and actual possession of DNA encoding a protein of interest for purposes of substantive patentability.
The second prong of the UC v. Lilly decision—relating to the nature and extent of disclosure required to support a generic claim—was equally in conformity with established law in other areas of practice. More specifically, it has long been settled that an appropriate generic disclosure may be based upon the disclosure of a sufficiently large number of representative species within the genus. See, e.g., In re Wertheim, 541 F.2d 257 (C.C.P.A. 1976) (claimed range supported by description of a number of species within the range). The UC disclosure, however, did not describe any other species, beyond the rat insulin DNA, in the manner that would have been required by the previously developed substantive law in that area to establish possession of that subject matter. Accordingly, it is not surprising that the generic claim to a family of undescribed mammalian insulin DNAs was similarly found violative of the written description requirement.
This type of analysis was carried to its logical extreme in University of Rochester v. G.D. Searle & Co., 358 F.3d 916, 69 U.S.P.Q.2d 1886 (Fed. Cir. 2004), where no compound needed to practice the claimed invention was described. There, it was contended that claims directed to "a method for selectively inhibiting PGHS-2 activity" using a "non-steroidal compound that selectively inhibits activity of the PGHS-2 gene" lacked adequate written description under § 112, first paragraph. The specification disclosed neither a particular compound capable of inhibiting PGHS nor a method for obtaining such a compound beyond trial and error. Id. at 923 (citations omitted). The Federal Circuit found that the contested patent did not disclose any compounds that could be used in its claimed method and concluded that the claims in question were invalid for inadequate written description.
A petition for rehearing en banc of the Rochester case was predictably denied, but with four judges dissenting. Univ. of Rochester v. G.D. Searle & Co., 375 F.3d 1303 (Fed. Cir. 2004). Judges Radar, Linn, and Gajarsa indicated a belief that UC v. Lilly should be overturned because a separate written description requirement beyond enablement and best mode creates confusion. Id. at 1326 (Linn dissenting). The fourth dissenter, Judge Newman, while believing that UC v. Lilly was correctly decided, noted that the issue of written description has "percolated" enough and should be laid to rest by an en banc hearing. Id. at 1305.
II. Utilization Of The Written Description Requirement In Patent Infringement Litigation
The written description requirement arises in patent infringement litigation in three basic areas. First, it can be used to deny a patentee the benefit of an earlier U.S. or foreign application filing date, thereby expanding the scope of prior art available to invalidate the patent. Second, it can be used as a substantive validity defense to invalidate claims just like the enablement or best mode requirements. Third, it can be used as a wedge to force a narrowing claim construction that may give rise to a noninfringement defense.
A. Use of the Written Description Requirement to Expand the Applicable Prior Art
Experience teaches that it is not at all uncommon for patent applications originally filed either in the United States or abroad to be modified, altered, or expanded, either through refiling of "continuation-in-part" applications in the United States or in the course of initial filing in the United States based on an original foreign patent application. Experience also teaches that information is often discovered in the course of litigation that would invalidate a patent claim if the patent is not entitled to an earlier application filing date. For example, there may be public uses, offers for sale, or publications by the inventor himself describing his invention, or similar activities by others, that would anticipate or render obvious patent claims unless those claims are entitled to the benefit of an earlier application filing date.
With respect to earlier United States applications, 35 U.S.C. § 120 makes clear that benefit to the earlier application filing date depends upon the earlier application satisfying the requirements of 35 U.S.C. § 112, first paragraph, with respect to the subject matter ultimately patented. A similar requirement has been imposed by judicial decision on foreign applications whose filing date is relied upon under 35 U.S.C. § 119. See, e.g., Kawai v. Metlesics, 480 F.2d 880 (C.C.P.A. 1973). Thus, failure of the earlier application to satisfy any of the three requirements contained in 35 U.S.C. § 112, first paragraph, including the written description requirement, will defeat a patentee's claim to benefit of an earlier application filing date.
Use of the written description requirement in patent infringement litigation to deny the patent owner benefit of an earlier application filing date, and thereby expand the applicable prior art, is illustrated by Lockwood v. American Airlines, Inc., 107 F.3d 1565 (Fed. Cir. 1997). The patent claims at issue required an individual terminal containing a video disk player. Yet, one of the intermediate applications through which priority to an earlier application filing date had to be claimed lacked a description of this feature. Accordingly, the patent owner was denied benefit of the earlier application filing date. The result was that the later presented claims were anticipated by the published disclosure of one of the patent owners earlier applications, which was a statutory bar under 35 U.S.C. § 102(b) unless the patent owner were entitled to the original application filing date.
B. Use of the Written Description Requirement as a Substantive Defense
The cases are legion where failure to comply with the written description requirement has resulted in the invalidation of patent claims under 35 U.S.C. § 112, first paragraph. UC v. Lilly and Gentry Gallery discussed above illustrate the point.
A widely held misconception in this regard is that written description defects arise only through presentation of claims (like those in UC v. Lilly) that are broader than the corresponding written description. In fact, many written description issues arise from attempts to narrow the claims to undescribed species, subgenera, or narrowed ranges later found to be particularly valuable or needed to avoid the prior art. See, e.g., In re Barker, discussed above.
The utilization of the written description requirement as a substantive defense, of course, suffers from all the negatives that a patent challenger faces in raising any substantive validity defense. Specifically, the challenger bears the burden of proof on the question of compliance with the written description requirement by clear and convincing evidence. Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956, 962 (Fed. Cir. 2002). The difficulty in carrying the burden is heightened somewhat by the Federal Circuit's conclusion that compliance with the written description requirement is a question of fact, not a question of law, thereby often requiring trial on the merits to resolve disputed factual questions rather than resolution of the issue on motion for summary judgment. Id. at 962-63. Finally, the patent owner will always argue that the issue was among those which had to have been considered by the patent examiner in allowing the claim in the first place.
Moreover, written description issues are intensely factual and case specific. On more than one occasion, the Federal Circuit and its predecessors have commented on the general uselessness of judicial precedent as an aid to resolution of particular cases.
[I]t should be readily apparent from recent decisions of this court involving the question of compliance with the [written] description requirement of § 112 that each case must be decided on its own facts. Thus, the precedential value of cases in this area is extremely limited.
In re Driscoll, 562 F.2d 1245, 1250 (C.C.P.A. 1977); Vas-Cath, 935 F.2d at 1562. Accordingly, there is a greater degree of uncertainty regarding the outcome of litigation of these issues.
Beyond the foregoing, there is a need to package written description defenses in a manner that is appealing to the judge or jury. Defenses that appear to be predicated on hypertechnical nitpicking usually have little judge or jury appeal. It is unnecessary, however, to present a written description defense in this manner. The essence of any meritorious written description defense is that the patentee is attempting to reap where he did not sow. Properly pled and presented, the argument is that the patentee is attempting to assert exclusive rights in subject matter that he did not possess at the time he filed his patent application. In so doing, the patentee is failing to comply with his part of the bargain that is fundamental to the proper operation of the patent system. Exclusive rights are only given for full and complete disclosures that reveal to the public possession of the subject matter later said to be the invention.
C. Use of the Written Description Requirement to Force a Narrow Claim Construction
A third use, and occasional misuse, of the written description requirement is to force a narrow construction of the patent claims that may give rise to a noninfringement defense. In this regard, it is a longstanding tradition in patent law that claims "amenable to more than one construction should, when it is reasonably possible to do so, be construed to preserve their validity." Kartsen Mfg. Corp. v. Cleveland Golf Co., 242 F.3d 1376, 1384 (Fed. Cir. 2001). Accordingly, it is frequently alleged that broad claim constructions urged by the patent owner should be rejected because they would cause the claim to be invalid for lack of an adequate written description due to the narrowness of the disclosure.
The prototypical fact pattern is one where the plain meaning of a claim term is broad and would encompass the conduct of the accused infringer while the specification is narrower in terms of the feature described by the broad claim term. In such circumstances, the court has two possible options. First, it can take the patent claims at their face value and apply the general principle that it is the claims and not the specification that define the invention. This approach leaves the accused infringer to presentation of his substantive defenses, possibly including a written description defense, to the broadly construed claims. Dayco Products Inc. v. Total Containment Inc., 258 F.3d 1317 (Fed. Cir. 2001), is illustrative of cases of this sort. Notwithstanding the accused infringer's protestations that the narrow nature of the patentee's disclosure required a narrow construction of the claims, the court refused to read those limitations from the specification into the claim.
Alternatively, the court can construe the seemingly unlimited claim language to be limited to the narrower subject matter actually disclosed. SciMed Life Systems, Inc. v. Advanced Cardiovascular Systems, Inc., 242 F.3d 1337 (Fed. Cir. 2001), is illustrative of this alternative approach. In the Dayco approach, the court finds the specifically disclosed features to be at most a preferred embodiment. In the SciMed approach, the court finds some way to characterize the disclosed features as either essential to operation of the invention or as excluding the possibility of the use of other features. The line between the two situations may be difficult to perceive in particular cases. Indeed, there appears to have developed two independent lines of authority at the Federal Circuit, one supporting this type of narrowing claim construction and the other reviling it. Contrast Watts v. XL Sys., Inc., 232 F.3d 877 (Fed. Cir. 2000); Wang Labs., Inc. v. Am. Online, Inc., 197 F.3d 1377 (Fed. Cir. 1999); and O.I. Corp. v. Tekmar Co., 115 F.3d 1576 (Fed. Cir. 1997) (claims given narrow construction where written description seen to expressly limit invention) with Interactive Gift Express, Inc., v. Compuserve Inc., 256 F.3d 1323 (Fed. Cir. 2001); Gart v. Logitech, Inc., 254 F.3d 1334 (Fed. Cir. 2001); Tate Access Floors, Inc. v. Maxcess Techs., Inc., 222 F.3d 958, 966 (Fed. Cir. 2000) (claims given broader construction when invention seen as not unambiguously limited by written description). The situation thus presented provides fertile ground for result-oriented advocacy as well as result-oriented decision making.
The fundamental problem with utilization of a narrow written description to narrow otherwise broad claim language is the risk that a substantive validity defense, on which the accused infringer bears the burden of proof by clear and convincing evidence, and which the Federal Circuit has said is a question of fact and not a question of law, will be resolved as a question of law, with no burden of proof, by the judge, and without a trial.
III. Defenses To Written Description Challenges
There are a variety of options for defense against a written description challenge that can be used either before or during patent infringement litigation to improve the patent owner's likelihood of success. Some of these are discussed below.
A. Enhanced Description in Drafting Patent Applications
While it is usually too late once patent infringement litigation is commenced to do anything other than wish that the patent specification had been written differently, prudent patent drafters will prepare their applications today with an eye toward litigating written description issues tomorrow. Basic rules include avoiding expressions of exclusion. If you say something is not part of the invention, there is little likelihood that a claim will later be construed as encompassing it. Similarly, avoidance of characterization of features as "necessary" or "essential" would minimize the likelihood that broader claims will be found to violate the written description requirement.
Another common problem can be avoided by never removing subject matter from continuing applications. As was the case in Lockwood, priority to an earlier application can be lost, even when the original application contains an adequate written description, if that description is not carried forward through intervening applications and into the patent in suit.
The identification of additional species within the scope of a generic disclosure is also helpful. In this regard, the inclusion of intermediate or preferred ranges within the operable scope of an invention may also be useful for supporting narrower claims. This practice, unfortunately, has been carried to ridiculous extremes in some cases, leading to disclosures such as "Compound A should be present in an amount of at least about 10%, preferably 20%, more preferably 30%, more preferably 40%, more preferably 50%, more preferably 60%, … and for very best results 90% by weight."
B. Deposits of Biological Material
It has long been recognized in connection with biological inventions that preparation of an enabling written disclosure may be very difficult. In such cases, the law has long permitted the deposit of any needed biological material, which would be made available to the public upon issuance of the patent, in order to satisfy the requirement for an enabling disclosure. See, e.g., In re Argoudelis, 434 F.2d 1390 (C.C.P.A. 1970). It should not have been surprising, therefore, that the Federal Circuit recently held that deposits of biological material can similarly satisfy the written description requirement of 35 U.S.C. § 112, first paragraph. Enzo Biochem, Inc. v. Gen Probe, Inc., 323 F.3d 956, 965 (Fed. Cir. 2002). Obviously, arrangements for such deposits need to be made at the time of filing and do not appear to be a viable defensive strategy once the litigation is commenced.
C. Defensive Theories Available in Litigation
Once in litigation, the patentee's options for defense are more narrowly circumscribed. Often the patent owner is left to make the best argument that can be made based on the fixed disclosure of the specification. The decided cases give some guidance with respect to possible theories useful in this context.
1. Ranges Constructed from Disclosed Species
As noted above, cases such as In re Wertheim indicate that support for a claimed range, or possibly any other claimed genus, can be established by reference to a sufficient number of illustrative species that are described in the specification. In Wertheim, for example, the specification disclosed a process broadly as employing from 25-60% solids and also included specific examples with 36% and 50% solids. On this record, the court found an adequate written description for the narrower range of 35-60% solids.
2. Genus Minus Disclosed Species
Another possible basis for supporting intermediate ranges or sub generic claims is suggested by In re Johnson, 558 F.2d 1008 (C.C.P.A. 1977). There, the specification contained a generic disclosure as well as a disclosure of several species within the genus. The court found the subgenus formed by deleting two of the disclosed species from the otherwise disclosed genus to be adequately described by that specification.
3. Expert Testimony Regarding Operable Limits
It may also be possible to support otherwise undescribed ranges through expert testimony regarding upper limits, lower limits, or optimal ranges dictated by the scientific principles underlying the invention or the realities of commercial practice of the technology. Such evidence was heavily relied upon, for example, in finding written description support for patent claims in the Ralston Purina case. For example, the Federal Circuit there sustained claims calling for a moisture content of "at least 25%" on the theory that these open-ended claims would be limited by what those of ordinary skill in the art would regard as workable.
4. Broadening Based on Disclosed Properties and Functions
An argument in support of claims broader than the specifically disclosed invention can sometimes be made based on the description of the properties and functions of the elements of the disclosed invention. In In re Smythe, 480 F.2d 1376, 1384 (C.C.P.A. 1973), the court offered the following graphic hypothetical showing how the argument might work:
If the original specification of a patent application on the scales of justice disclosed only a 1-pound "lead weight" as a counterbalance to determine the weight of a pound of flesh, we do not believe the applicant should be prevented, by the so-called "description requirement" of the first paragraph of §112, or the prohibition against new matter of § 132, from later claiming the counterbalance as a "metal weight" or simply as a 1-pound "weight," although both "metal weight" and "weight" would indeed by progressively broader than "lead weight," including even such an undisclosed, but obviously art-recognized equivalent, "weight" as a pound of feathers. The broader claim language would be permitted because the description of the use and function of the lead weight as a scale counterbalance in the whole disclosure would immediately convey to any person skilled in the scale art the knowledge that the applicant invented a scale with a 1-pound counterbalance weight, regardless of its composition.
5. Reliance on PTO Guidelines
Finally, with particular reference to biological inventions, the U.S. Patent and Trademark Office has promulgated Guidelines for Examination of Patent Applications Under 35 U.S.C. § 112, 1, "Written Description" Requirement, 66 FR 1099 (Jan. 5, 2001). These guidelines are quite detailed and quite complicated. Possibly for that reason, they have often been accepted as dispositive of written description issues by judges. The Enzo Biochem case is illustrative. There, the court stated "We are persuaded by the Guidelines on this point and adopt the PTO's applicable standard for determining compliance with the written description requirement." 323 F.3d at 964.
Written description challenges have a variety of uses in patent infringement litigation, can often be appealingly packaged as failures of the patentee to deliver the quid pro quo needed to justify the patent grant, and, due to their intensely case specific nature, are rarely foreclosed by prior judicial precedent. While the resulting inability to predict the outcome of such challenges does result in some degree of confusion, the wholesale abandonment of the doctrine urged in some quarters is probably unwarranted. As Judge Rich wrote in the sequel to the Ruschig case cited at the outset of this paper, "The life of a patent solicitor has always been a hard one." In re Ruschig, 379 F.2d 990, 993 (C.C.P.A. 1967).
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