Written Description is Required When a Preamble is Limiting
Stephen G. Adrian | March 26, 2025
IN RE: XENCOR, INC
Date of decision: March 13, 2025
Panel: before Hughes, Stark and Schroeder (District Judge (Eastern District of Texas) sitting by designation), Opinion by Schroeder
Background
This precedential decision is from an appeal by Xencor from a decision by the Appeals Review Panel (ARP). The ARP was established July 24, 2023. The ARP may be convened by the Director sua sponte to review decisions of the Patent Trial and Appeal Board (PTAB or Board) in ex parte appeals, re-examination appeals, and reissue appeals.
The application at issue is 16/803,690, which is a continuation application having an earliest priority date of February 25, 2008. Claim 8 (a Jepson claim) and claim 9 are at issue:
8. In a method of treating a patient by administering an anti-C5 antibody with an Fc domain, the improvement comprising
said Fc domain comprising amino acid substitutions M428L/N434S as compared to a human Fc polypeptide,
wherein numbering is according to the EU index of Kabat,
wherein said anti-C5 antibody with said amino acid substitutions has increased in vivo half-life as compared to said antibody without said substitutions.
9. A method of treating a patient by administering an anti-C5 antibody comprising:
a) means for binding human C5 protein; and
b) an Fc domain comprising amino acid substitutions M428L/N434S as compared to a human Fc polypeptide,
wherein numbering is according to the EU index of Kabat, wherein said anti-C5 antibody with said amino acid substitutions has increased in vivo half-life as compared to said antibody without said substitutions.
The Examiner had rejected the claims as lacking written description. Xencor appealed to the Patent Trial and Appeal Board. The Board held that the preambles of the claims are limiting, and that Xencor had not shown that the application contained a sufficient written description for either claim. The Board decision also determined that Xencor had not shown that anti-C5 antibodies or methods of treating patients with anti-C5 antibodies were well-known in the art at the time of invention.
Xencor petitioned for reconsideration, and the Board again found against Xencor for the same reasons. Xencor appealed to the CAFC. Prior to being heard, the Patent Office requested remand to the ARP (presumably to address the preamble).
The decision of the ARP addressed whether written description was required for Jepson claim preambles. It found that Jepson preambles define the scope of the claim, and therefore a written description is required. The ARP found the preamble language “treating a patient” as limiting because it was necessary to give life, meaning, and vitality to both limitations “increased in vivo half-life” and “administering” (the sole method step).
The ARP decision then concluded the claims did not have sufficient written description. The specification did not provide a representative number of species to support the broad genus of anti C5 antibodies being claimed. The specification only disclosed one anti-C5 antibody (5G1.1). The ARP also adopted the Board’s findings that Xencor’s expert was not credible and that Xencor had not demonstrated that anti-C antibodies were well-known (in which case not requiring further support in the specification).
The ARP decision also found that “treating a patient” was not supported by an adequate written description since the specification does not describe what patients with what diseases or conditions can be successfully treated with an anti-C antibody.
Xencor appealed the decision of the ARP to the CAFC.
Discussion
The Director stated that the CAFC’s standard of review of ARP’s decisions is the same as for decisions from the Board. As such, legal determinations are reviewed de novo, while factual findings are reviewed for substantial evidence.
Xencor argues that the preamble “treating a patient” is not limiting, that the preamble of a Jepson claim does not require written description, and, in the alternative, written description was satisfied for the preambles of both claims.
Claim 9
With respect to a “method of treating a patient by administering an anti-C5 antibody”, Xencor argues the different sections of the preamble should be treated independently, that is “treating a patient” and “administering an anti-C5 antibody”, where the “treating a patient” is not limiting. As such, Xencor argues that only “administering an anti-C5 antibody” should be considered limiting.
The CAFC agreed with the Director that “treating a patient by” is limiting. The CAFC first noted that Xencor does not dispute that “administering an anti-C5 antibody” should be considered limiting. The CAFC noted that the phrases are connected by the term “by” which gives credence to the argument that the entire preamble should be considered limiting. The “treating a patient” is done by administering the anti-C5 antibody, which is not a mere statement of purpose or a statement of intended result. In addition, since the claim does not require a dosage and rate, a person of ordinary skill in the art would have read the claim language of “increased in vivo half-life” in conjunction with “treating a patient” in order to make sense. Still further, the preamble provides a “raison d’etre” (reason for being) for the claim. An increased in vivo half-life only makes sense with respect to a living being (otherwise it cannot be in vivo) and has a specific utility with respect to treatment. Lastly, the specification teaches longer in vivo half-lives allow more seldom injections such that the specification “gives further color to the language of the claims and the understanding we have of the language as limiting.”
The CAFC then considered whether the specification satisfied the written description requirement. No specific amount of efficacy is claimed, so no specific amount is required in the specification. The application does not define the meaning of “treating” and does not provide any data associated with treating any patient with any disease or condition with any anti-C5 antibody. As such, the specification does not limit the treatment to any specific disease. As such, “treating a patient” means “treating all patients and all diseases”. At best, the disclosure of three classes of diseases/conditions that might benefit from administration of various antibodies with an Fc modification and lists various unmodified antibodies that could be modified and used to that end. Such disclosure is found to be “inadequate to demonstrate possession of a method of treating any particular disease/condition with the claimed anti-C5 antibodies, let alone all diseases/conditions within the three enumerated classes.”
Xencor had argued that the claim does not require the treatment to be effective. However, the ARP merely required that the applicant had possession of a method of treating a patient with 5G1.1 and its equivalents and found that it did not.
Claim 8
Claim 8 raises the question of whether a Jepson claim requires written description since the preamble of a Jepson claim defines what the prior art is, followed by recitation of what the improvement is. Xencor argues that a written description is only needed for the improvement.
Under 35 U.S.C. 112, a specification must contain a written description of the invention. This requirement must “be met in some way so as to describe the claimed invention so that one skilled in the art can recognize what is claimed.”
Such a description is context-specific: “[T]he level of detail required to satisfy the written description requirement varies depending on the nature and scope of the claims and on the complexity and predictability of the relevant technology.” Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010); see also Univ. of Rochester, 358 F.3d at 923 (explaining that merely stating “automobile” in a claim would not have been sufficient written description at the time of invention of the automobile).
In a Jepson claim, the preamble is used to define the invention, thereby limiting the claim scope. The invention is not only the improvement but also the improvement as applied to the prior art. Simply asserting that something is well known in the art is not sufficient to show that the inventor had possession of the claimed invention. The CAFC gave an example:
For example, a patentee cannot obtain a Jepson claim with a preamble that says that a time machine is well-known in the art without describing a time machine, in sufficient detail to make clear to a person of ordinary skill in the art that the inventor is in possession of such a time machine. Adoption of Xencor’s position would leave the patent system vulnerable to such abuse.
Thus, an adequate written description for a Jepson claim requires the applicant to establish what is claimed to be well-known in the art is, in fact, well known in the art.
Takeaway
Claims need to be supported by a written description as required by 35 U.S.C. 112, including the preamble when the preamble is considered limiting.
Do not include language in a preamble of a Jepson claim if it is not well-known or not supported by the specification. For this application, perhaps simply stating a method of administering an anti-C5 antibody could have avoided the written description problem, but perhaps this could lead to other issues such as enablement.
At the time the specification was filed in 2008, the specification stated “the exact dose will depend on the purpose of treatment” and the characteristics of the patient. This likely raises questions whether the inventor was in possession of the claimed invention (treating all patients with all diseases).
In Re: Entresto -Written Description and Enablement Do Not Have To Be Complicated.
WHDA CAFC Alert | January 16, 2025
In re: Entresto; Novartis Pharm. Corp. v. Torrent Pharma Inc. et al.
Date of Decision: January 10, 2025
Before: LOURIE, PROST, and REYNA.
Summary:
The Federal Circuit reversed a finding by the District of Delaware that the drug patent covering the heart drug, Entresto was invalid for failing to provide a written description of future embodiments wherein a combination of two drugs where formed in a chemical complex. The Federal Circuit found that the District Court had erred by interpreting the written description requirement as demanding that a future embodiment needed to be adequately described in the patent in order for the claim to be valid. Instead, the CAFC noted that any written description sufficient to describe the claim satisfies the requirement.
Background:
The U.S. District of Delaware determined that claims 1-4 of U.S. Patent 8,101,659 (“the ’659 patent”) owned by Novartis were shown to be invalid for lack of written description. The ‘659 patent covers the heart failure treatment drug, Entresto. Entresto combines two different drug therapies, valsartan and sacubitril, in a specific form known as a “complex,” which combines the two drugs into a single unit-dose-form through weak, non-covalent bonds. During the District Court proceeding there had been a dispute as to the claim construction of the aspect of claim 1 “wherein said [valsartan and sacubitril] are administered in combination.” The District Court gave the term its plain and ordinary meaning as Novartis had argued for.
As a result of this construction, the District Court interpreted the claim to cover valsartan and sacubitril as a physical combination and as a complex (i.e. as used in Entresto). Torrent argued that the ’659 patent was required to enable and describe such complexes, since a patent must enable and describe the full scope of the claims. However, overwhelming evidence (in the form of later patents) showed that the complex of the two drugs was not invented until after the ‘659 patent issued.
As to enablement, the District Court found that because enablement is judged as of the priority date, later-existing state of the art may not be properly considered in the enablement analysis. As to written description, the District found because it was undisputed that complexes were unknown to a person of ordinary skill in the art, “‘[Novartis] scientists, by definition, could not have possession of, and disclose, the subject matter of [such complexes]’ and therefore, ‘axiomatically, [Novartis] cannot satisfy the written description requirement’ for such complexes.”
Novartis appealed. MSN (one of the Torrent defendants) remained for the appeal arguing that either the District Court’s written description determination should be affirmed or the enablement determination reversed.[1]
Discussion:
The CAFC took immediate issue with the manner in which the District Court had interpreted the written description requirement, noting that: “The issue is not whether the ’659 patent describes valsartan-sacubitril complexes. Because the ’659 patent does not claim valsartan-sacubitril complexes, those complexes need not have been described.” (Emphasis in original).
The Court restated the settled law that: “A specification adequately describes an invention when it ‘reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.’” Juno Therapeutics,Inc. v. Kite Pharma, Inc., 10 F.4th 1330, 1335 (Fed. Cir.2021) (quoting Ariad Pharms. Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc)). They then noted that the claim construction had given the term “administered in combination” its plain and ordinary meaning, and that the specification provided ample description of the two drugs being administered together. Therefore, concluding that the claim had adequate written description support and that the District Court had “erroneously conflated the distinct issues of patentability and infringement, which led it astray in evaluating written description.”
Turning to enablement, the CAFC reiterated that the same is true -that it is the claim that must be enabled and not future potential embodiments which are the subject of infringement. Thus, the Circuit Court affirmed the District’s interpretation of enablement.
The district court correctly recognized that valsartan-sacubitril complexes, which include the claimed invention along with additional unclaimed features, are part of a later-existing state of the art” that “may not be properly considered in the enablement analysis.”
Conclusion:
The CAFC concluded that the District Court had erred in finding there was insufficient written description support and reversed and affirmed the District Court’s finding that the claims of the ‘659 patent are enabled.
Take away:
- When reviewing issues of written description and enablement, the review must center on the claim language and the claim construction thereof being supported by the patent.
- Future embodiments of a claim which could not possibly be enabled or described within the patent may still infringe the claim if they read on all the terms thereof as construed. Enablement and written description are issues of patentability not infringement.
[1] Issues of obviousness and indefiniteness were also raised but are not covered herein.
Claim Construction and Doctrine of Equivalents: NexStep v. Comcast
Bo Xiao | December 5, 2024
Case Name: Claim Construction and Doctrine of Equivalents: NexStep v. Comcast
Date of Decision: October 24, 2024
Panel: Before: REYNA, TARANTO, and CHEN, Circuit Judges.
Summary
The Federal Circuit affirmed the District Court’s rulings in favor of Comcast Cable Communications, LLC, in a patent infringement suit brought by NexStep, Inc. The court upheld the findings of non-infringement, affirming the District Court’s claim construction and judgment as a matter of law.
Background
NexStep filed a suit alleging that Comcast’s products infringed multiple patents, with U.S. Patent Nos. 8,885,802 (the ’802 patent) and 8,280,009 (the ’009 patent) at the center of the disputes.
The ’802 patent is directed to a “digital butler” system that enables audio-based control of devices using Voice over Internet Protocol (VoIP). The key issue revolved around the interpretation of the term “VoIP” as represented in claim 1 of the ’802 patent:
1. A remote control device with slaved audio input, the device including:
a wireless link transceiver;
at least one slaved audio input built into the remote control;
a navigation control built into the remote control;
hardware resources coupled between the wireless link transceiver, the slaved audio input and the navigation control;
a stack running on the hardware resources and exchanging packets with a master device; and
an encoder logic running on the hardware resources, logically coupled to the stack, adapted to encode signals from the slaved audio input into a remote control audio format, and adapted to send audio packets in the remote control audio format to the master device;
wherein the remote control depends on the master device to transcode input from the slaved audio input to VoIP from the remote control device format and relies on the master device to respond to control signals sent by the remote control device in the packets.
NexStep argued for a broad interpretation of the term “VoIP,” asserting that it should encompass any audio data transmission, not limited to two-way voice communication. This interpretation would set the scope of the ’802 patent’s claims to include Comcast’s products, which utilized one-way audio communication protocols. In contrast, Comcast argued for an industry-standard interpretation of VoIP as requiring two-way voice communication. The District Court adopted Comcast’s interpretation, concluding that VoIP referred specifically to two-way communication protocols, which excluded NexStep’s infringement claims and led to a summary judgment of non-infringement.
The ’009 patent describes a “concierge device” designed to initiate technical support for a consumer device with a single user action. Claim 1 of the ’009 patent is representative::
1. A method of initiating a support session for a consumer device using a concierge device, the method including:
associating the concierge device with a selected consumer device;
responsive to a single action performed by a user, the concierge device communicating with a home gateway, including
causing the home gateway to buffer consumer device identification information for the selected consumer device and determine a support center for a support session; and
causing the home gateway to initiate the support session for the consumer device and to forward automatically the consumer device identification information during the support session, thereby allowing the support session either
to bypass an automated attendant or interactive voice recognition system or
to initiate an automated support protocol.
NexStep claimed that Comcast’s app infringed this patent under the doctrine of equivalents. NexStep argued that the app’s multi-step troubleshooting processes were equivalent to the “single action” requirement described in the patent. The District Court found NexStep’s evidence insufficient, concluding that the expert testimony failed to provide the specific and detailed analysis required under the doctrine of equivalents. As a result, the District Court entered a judgment as a matter of law in favor of Comcast.
Discussion
A key issue in the ’802 patent was the construction of the term “VoIP.” The District Court adopted Comcast’s narrower interpretation, relying on intrinsic evidence, including the patent’s specification and claims, as well as extrinsic sources like technical dictionaries. The specification consistently associated “VoIP” with two-way communication, analogous to traditional telephony services. NexStep had also conceded during earlier proceedings that “VoIP” was a term of art with an industry-standard meaning, which undermined its argument for a broader construction at trial.
The Federal Circuit upheld the District Court’s construction, finding no clear error in its reliance on both intrinsic and extrinsic evidence. The Federal Circuit also rejected NexStep’s argument that the ’802 patent supported an unconventional definition of “VoIP,” noting that this argument was forfeited because it had not been raised earlier. The court further noted that NexStep’s contentions regarding the intrinsic evidence were plainly incorrect, as the written description consistently associates VoIP with telephony services that require the capability for two-way voice communication.
This construction was decisive for the infringement claims under the ’802 patent. Comcast’s products used one-way communication protocols that transmitted voice commands to its servers via HTTP, a method incapable of supporting two-way voice conversations. As a result, they did not meet the claim limitations under the District Court’s interpretation, leading to a summary judgment of non-infringement. The Federal Circuit affirmed this judgment, concluding that the interpretation of “VoIP” aligned with industry norms and the intrinsic record.
The dispute over the ’009 patent centered on the “single action” limitation, a key feature of the patent’s claims describing a “concierge device” designed to simplify the process of initiating customer support. NexStep argued that Comcast’s products infringed the ’009 patent under the doctrine of equivalents. It claimed that even if Comcast’s processes required multiple steps, they were equivalent to the claimed “single action” because they achieved the same result of initiating a customer support session..
At trial, NexStep relied on the testimony of its expert, Dr. Ted Selker, to establish equivalence. However, the District Court found the testimony deficient, describing it as overly conclusory and lacking the specificity needed to support a finding of infringement under the doctrine of equivalents. Dr. Selker failed to provide detailed comparisons between the accused multi-step processes and the claimed single action. Instead, he offered generalized statements about overall functionality, asserting that several user actions could collectively be viewed as a single action without substantiating this claim with particularized evidence showing how the accused products met the criteria of equivalency.
The District Court set aside the jury’s finding of infringement under the doctrine of equivalents and granted Comcast judgment as a matter of law. On appeal, the Federal Circuit affirmed this decision, emphasizing that the doctrine of equivalents requires rigorous proof, including a limitation-by-limitation analysis supported by detailed expert testimony. The court emphasized that NexStep’s evidence was insufficient to demonstrate that Comcast’s multi-step processes performed the same function, in the same way, to achieve the same result as the “single action” limitation in the patent claims. Without this specificity, the jury’s verdict lacked a proper evidentiary foundation.
The Federal Circuit emphasized the importance of presenting clear and particularized evidence to establish equivalency for each claim limitation. The court further noted, “Consistent with our precedent, the patentee was required to provide ‘particularized testimony and linking argument as to the insubstantiality of the differences between the claimed invention and the accused device.’ ”
Takeaways
- Claim terms should align with established industry meanings unless explicitly redefined in the specification.
- The doctrine of equivalents requires detailed, particularized testimony to demonstrate equivalency for each claim limitation.
Standing Reminder for Inter Partes Review Decisions
Stephen G. Adrian | October 28, 2024
Case Name: LATINUM OPTICS TECHNOLOGY INC. V. VIAVI SOLUTIONS INC.
Date of Decision: August 16, 2024
Panel: Moore, Taranto and Cecchi (sitting by designation)
Summary
This decision serves as a reminder that standing to appeal a decision of the Patent Trial and Appeal Board (PTAB) can be lost in an inter partes review (IPR). This is because the Federal Circuit’s jurisdiction to review final decisions of the PTAB is limited to cases and controversies under Article III of the U.S. Constitution. If a civil action is dismissed before a final decision in an IPR, it is necessary to show that there is still an injury in fact so that an appeal can be taken to the CAFC.
Background
Viavi owns U.S. patent no. 9,354,369 which relates to optical fibers. Viavi sued Platinum Optics Technology (PTOT) for infringement in two civil suits in the Northern District of California. Thereafter, PTOT filed an IPR of the ‘369 patent. In the civil suits, the patent infringement claims were dismissed with prejudice. The PTAB subsequently issued a final written decision holding that PTOT failed to show the challenged claims in the ‘369 patent were unpatentable. PTOT appealed the decision to the Federal Circuit.
Discussion
A party does not need to establish Article III standing to appear before an administrative agency (such as the PTAB), as set forth in Cuozzo Speed Techs., LLC v. Lee, 579 U.S. 261, 279 (2016). However, standing is required when the party seeks review of an agency’s final decision in a federal court (Phigenix, Inc. v. Immunogen, Inc., 845 F.3d 1168, 1171–72 (Fed. Cir. 2017)). The party seeking judicial review bears the burden of proving standing (JTEKT Corp. v. GKN Auto. LTD., 898 F.3d 1217, 1220 (Fed. Cir. 2018)). As set forth in JTEKT “[o]ur cases establish that typically in order to demonstrate the requisite injury in an IPR appeal, the appellant/petitioner must show that it is engaged or will likely engage ‘in an activity that would give rise to a possible infringement suit,’…or has contractual rights that are affected by a determination of patent validity”.
PTOT asserts that it has standing based on potential infringement liability stemming from supplying its bandpass filters accused in one of the civil suits to parts integrators overseas and due to developing new models of bandpass filters. A declaration from the Deputy Director of Operations Management of PTOT was submitted to support the argument of injury in fact based on development of new bandpass filters.
Although Viavi dismissed the patent infringement suits, PTOT maintains that it has suffered an injury in fact based on its continued distribution of bandpass filters. In support of this argument, PTOT relies on a letter sent by Viavi sent prior to the first and second civil suits being filed, and PTOT’s expectation that Viavi would sue a third time. The CAFC pointed out that mere speculation about the possibility of another suit, without more, is insufficient to confer standing, particularly since the letters were sent prior to the first two civil actions which were subsequently dismissed.
Regarding the declaration submitted to the record, there was no explanation regarding detailed plans for development of new filters, nor any details regarding the particulars of the new filters or how they might relate to the ‘369 patent. The CAFC acknowledged that IPR petitioners do not need to concede infringement but need to at least establish that its development activities “will cause a substantial risk of infringement or will likely cause Viavi to assert a claim of infringement.” As such, PTOT has failed to establish an injury in fact to confer standing.
Takeaways
Although 35 U.S.C. §141(c)) statutorily authorizes appeal of an adverse IPR decision to the Court of Appeals for the Federal Circuit, the court requires Article III injury in fact to establish standing.
If the civil suit(s) are dismissed, an injury in fact needs to be established to appeal a PTAB decision to the CAFC.
A declaration can be sufficient to establish standing if it identifies specific, concrete plans to develop a product which may implicate a patent in suit.
