Case Briefs

Novartis Pharmaceutical Corp. v. HEC Pharm Co. LTD:

Written Description Requirement Can Be Satisfied by Silence? 

35 USC §112(a) provides “[t]he specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art…to make and use the same.”  In Novartis Pharmaceutical Corp. v. HEC Pharm Co., LTD (Fed. Cir. Jan 3, 2022), the Federal Circuit considered whether a written description may be satisfied by silence.

Norvatis is an assignee of U.S. Patent No. 9.187, 405 (‘405 patent) which claims methods to treat relapsing remitting multiple sclerosis (RRMS) with fingolimod.  Claim 1 of the ‘405 patent recites:

A method for reducing or preventing or alleviating relapses in Relapsing-Remitting multiple sclerosis in a subject in need thereof, comprising orally administering to said subject 2-amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol, in free form or in a pharmaceutically acceptable salt form, at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen. (Emphasis added).

Novartis markets a 0.5 gm daily dose of fingolimod hydrochloride under the brand name Gilenya, to treat RRMS.  HEC Pharm filed an ANDA (Abbreviated New Drug Application) with FDA, seeking approval to market a generic version of Gilenya. Novartis sued, alleging that HEC’s ANDA infringes all claims of ‘405 patent.   

The district court found that HEC’s ANDA product would infringe claims 1-6 of the ‘405 patent.  Then the district court turned to the validity of the ‘405 patent, and considered whether the specification provided an adequate written description of the negative limitation (“absent an immediately preceding loading dose regimen”).  The expert testified that, “loading dose” (first dose that is higher-than-therapeutic level dose to get therapeutic levels up quickly) was well-known in the medical field.  The court relied on the expert testimony and held that “[i]f a loading dose were directed, the Patent would say that a loading dose should be administer ‘initially’” and concluded that the patent provided sufficient written description of the negative limitation. 

On appeal, HEC argued that there is no written description of the negative limitation because the ‘405 specification contains no recitation of a loading dose.  HEC asserted that “it is well-settled law that silence alone cannot serve as a basis for a negative limitation.  The Federal Circuit disagreed, stating that HEC “ignores a central tenet of our written description jurisprudence – that the disclosure must be read from the perspective of a person skilled in the art.”  The Federal Circuit added “[i]n other words, context and the knowledge of those skilled in the art matter.  And, as the Supreme Court has made clear, when assessing what the written description reveals to a skilled artisan, common sense also matters…The dissent notes that the Manual of Patent Examining Procedure (“MPEP”) states: “The mere absence of a positive recitation is not a basis for an exclusion.”  MPEP §2173.05(i)…But the dissent, like HEC, ignores that it is how a skilled artisan reads a disclosure that matters.  Written description may take any form, so long as a skilled artisan would read the disclosure as describing the claimed invention.”  The Federal Circuit further stated, “[w]hat is critical is how a person of skill in the art would read the disclosure – not the exact words used.”

However, dissenting judge disagreed stating “[t]he majority dramatically expands a patentee’s ability to add, years after filing a patent application, negative claim limitation that have zero support in the written description.  By doing so it contradicts our well-established precedent and nullifies the Patent Office’s guidance in the [MPEP]… Silence is not disclosure.” 

In Novartis v. HEC, the Federal Circuit has illustrated the importance of reading the disclosure as a whole by a person of skill in the art, with his/her interpretation using common sense.  After all, what matters is how a person of skill in the art would read the disclosure – not the exact words used.

Fleming v. Cirrus Design Corporation

Is Claim Obvious, Although References Do Not Explicitly Disclose Claim Limitations?

35 USC §103 provides that “a patent for a claimed invention may not be obtained…if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art.”  The inquiries of whether the prior art discloses a claim limitation, whether a skilled artisan would have been motivated to modify or combine teachings in the prior art, and whether a person would have had a reasonable expectation of success in doing so are questions of fact, reviewed for substantial evidence.  University of Strathclyde v. Clear-Vu Lighting LLC, 17 F.4th 115, 160 (Fed. Cir. November 4, 2021).  In Hoyt Augustus Fleming. v. Cirrus Design Co., (Fed. Cir. March 10, 2022), the Federal Circuit considered whether a claim is obvious although references do not explicitly disclose any claim limitations.

US Patent No. RE47,474 (‘474 patent) describes ballistic parachute systems on aircraft.  The specification explains that ballistic parachutes use a rocket to quickly deploy a parachute, slowing the fall of a crashing aircraft.  Claim 137 (one of the claims at issue) states:

            wherein the machine readable-instructions include the action comprising:

based at least upon the receipt of the whole-aircraft ballistic parachute deployment request, command the autopilot to increase aircraft pitch. (Emphasis added).

Claims 138 and 139 are identical except for the final phrase describing the action to be taken upon receipt of the parachute deployment request.  In claim 138, the autopilot is commanded to “reduce aircraft roll” and in claim 139 it is commanded to “change the altitude of the aircraft.” 

Cirrus Design Corporation (Curris) petitioned for IPR of Fleming’s ‘474 patent.  The PTAB cited two references:  Cirrus’ Pilot Operation Handbook (“POH”) that familiarizes operators with Cirrus’ airplane, and US Patent No. 6,460,810 (“James”) entitled “Semiautonomous Flight Director” which describes a “device for programming industry standard autopilots” to allow “for the safe operation of any aircraft by an unskilled pilot.”  Then the PTAB determined that ‘474 patent would have been obvious over a combination of POH and James. 

On appeal, Fleming argued that none of the prior arts disclosed commanding an aircraft’s autopilot to perform claimed flight maneuvers (i.e., increase pitch, reduce roll, or change altitude) upon receiving a parachute deployment request.  The Federal Circuit acknowledged that neither POH nor James specifically taught an autopilot to perform the claimed flight maneuvers, but disagreed stating “[the PTAB’s] finding is supported by substantial evidence…  James discloses that upon receiving a signal, ‘an aircraft may automatically initiate shut down procedures, including deploying an emergency parachute’…And James also discloses, as found by the [PTAB], that an autopilot is capable of performing certain flight maneuvers on an aircraft, such as ‘slow[ing] the aircraft to landing speed and maintain[ing] a slow steady landing descent.’  Further, POH emphasizes that these standard autopilot maneuvers – slowing aircraft speed, maintaining a steady altitude, and changing aircraft pitch – should preferable be completed before deploying an emergency parachute…  This evidence amply supports the [PTAB’s] finding that a person of ordinary skill would have been motivated to program James’ autopilot in view of POH so that, upon the receipt of a parachute deployment request, James’ autopilot would seek to ensure safety by following POH’s guidance for safe parachute deployment, including changing the aircraft’s pitch, reducing aircraft roll, and/or achieving a level altitude as needed.” 

Fleming also argued that the prior art teaches away from the claimed invention in the ‘474 patent.  In particular, Fleming argues that the prior art cautioned that autopilots should not be used in certain emergency situations where a ballistic parachute may be needed, and cited various passages from the prior art indicating that the use of an autopilot should not be used in certain emergency situations (for example, upon takeoff and landing or when the aircraft is below a certain altitude, circumstances in which aircraft parachute is likely to be needed).  The Federal Circuit disagreed stating “James discloses that the continuous use of an autopilot is of particular benefit for unmanned aerial vehicles… POH discloses that the use of the ballistic parachute system ‘would be appropriate’ in the event of pilot incapacitation, suggesting use of an autopilot to deploy the ballistic parachute system…  Substantial evidence thus supports that [PTAB’s] finding that the prior art does not teach away from the claimed invention.”  Furthermore, Fleming argued that the PTAB ignored his argument that “a skilled artisan would have been dissuaded from making the proposed combination because using James’s autopilot would be unsafe in many emergency situations.”  Again, the Federal Circuit disagreed, stating “the obviousness inquiry does not require that the prior art combination is the ‘preferred, or the most desirable’ configuration…  That the prior art cautioned pilot not to use an autopilot in some emergency situations on some aircraft does not mean that the skilled artisan would have been dissuaded from doing so in all emergency situations on all aircraft.”  The Federal Circuit affirmed the PTAB’s obviousness determination.

Take away

In Hoyt Augustus Fleming. v. Cirrus Design Co., the CAFC determined that a claim is obvious even if the references did not disclose a part of the claim limitation, but it can be supplied by using common technical knowledge.   Previously, we have introduced Novartis Pharmaceutical Corp. v. HEC Pharm Co., LTD (Fed. Cir. Jan 3, 2022), which the CAFC determined that an amendment that introduces unreferenced negative limitation into a claim may be permitted based on common technical knowledge.  “Common technical knowledge” is subjective and remains in the gray area.  In Novartis Pharmaceutical Corp. v. HEC Pharm Co., LTD the court approved claim amendments based on testimony of the expert witness on common technical knowledge.  In this case, if Fleming had introduced testimony from the expert witness to support his position, we might have different outcome.

Dyfan, LLC v. Target Corp.

Means-Plus-Function claims in Software Patents

35 USC §112 governs the specification of a patent.  Section 112 paragraph 6 provides:

An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalent thereof.

In Dyfan, LLC v. Target Corp. (Fed. Cir. March 24, 2022), the Federal Circuit considered whether a patent challenger rebutted the presumption that 112 paragraph 6 does not apply by showing that persons of ordinary skill in the art have understood the claim limitations to connote structure in light of the claim as a whole. 

On February 28, 2019, Dyfan LLC (“Dyfan”) sued Target Corporation (“Target”) for patent infringement.   The patents at issue are US Patent Nos. 9,973,899 and 10,194,292 titled “System for Location Based Triggers for Mobile Devices.”  These patents describe improved systems for delivering messages to users based on their locations.  The shared specification discloses a communication system that provides users with information tailored to their particular interests or needs based on their presence within a specified location.  During claim construction proceedings, Target argued that each of the asserted claims included limitations that should be construed as means-plus-function limitations, and the specification failed to disclose structure corresponding to these means-plus-function limitations.  For these reasons, Target argued that the claims were invalid as indefinite.  The United States District Court for the Western District of Texas held that §112 paragraph 6 applied to the “code”/“application” and “system” limitations.  For the “code”/“application” limitations, the District Court did not find “algorithm for the claimed special-purpose computer-implemented function” in the specification, and concluded that “the relevant claims were ‘indefinite for failing to disclose corresponding structure.’”  Likewise, the District Court held that the “system” limitation was subject to §112 paragraph 6 “because they recited ‘purely functional language without sufficient structure’” and concluded that “those relevant claims were ‘indefinite for lack of corresponding structure.”  Dyfan appealed, claiming that the district court erred in finding the claims indefinite for including means-plus-function limitation lacking corresponding structure in the specification.   

The Federal Circuit provided a two-step process for analyzing means-plus-function claim.  First, the court needs to determine “whether a claim limitation is drafted in means-plus-function format, which requires us to construe the limitations to determine whether it connotes sufficiently definite structure to a person of ordinary skill in the art.  If the limitation connotes sufficiently definite structure, it is not drafted in means-plus-function format, and §112 ¶ 6 does not apply.  If, however, [the court] conclude[s] that the limitation is in means-plus-function format, [the court will] perform the second step of determining ‘what structure, if any, disclosed in the specification corresponds to the claimed function.”  The Federal Circuit added, “[b]ecause invoking §112 ¶ 6 is typically a choice left to the claim drafter, we presume at the first step of the analysis that a claim limitation is subject to §112 ¶ 6 when the claim language includes the term ‘means.’… The inverse is also true – we presume that a claim limitation is not drafted in means-plus-function format in the absence of the term ‘means.’  We have made clear, however, that this presumption is rebuttable…We have emphasized that ‘the essential inquiry is not merely the presence of absence of the word ‘means,’ but whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.”  The Federal Circuit analyzed the terms in question separately.

The “Code”/ “Application” Limitations

The Federal Circuit stated, “[t]he district court correctly ‘start[ed] with the presumption that §112 ¶ 6 does not apply’ because ‘means’ does not appear in the limitation” but agreed with Dyfan that the district court erred in finding that Target had rebutted the presumption.  The Federal Circuit stated “[t]o overcome this presumption, Target had to show, by a preponderance of the evidence, that persons of ordinary skill in the art would not have understood the ‘code’/‘application’ limitations to connote structure in light of the claim as a whole.  From a procedural standpoint, this presumption imposes on [the party challenging the presumption] the burden of going forward with evidence to rebut…the presumption by showing that a person of ordinary skill in the art ‘believes the term does not recite sufficiently definite structure.’…But the district court erred by ignoring key evidence – unrebutted deposition testimony from Target’s own expert, Dr. Goldberg – regarding how a person of ordinary skill would have understood the ‘code’/‘application’ limitation.  Dr. Goldberg testified that here, ‘application’ is ‘a term of art’ that a person of ordinary skill in the art would have understood as a particular structure.  More specifically, Dr. Goldberg testified that the term ‘application’ would have been commonly understood to mean a ‘computer program intended to provide some service to a user,’ and that developers could have, at the relevant time, selected existing ‘off-the-shelf software’ to perform specific services and functions.  Additionally, Dr. Goldberg testified that persons of ordinary skill would have understood that the word ‘code,’ when coupled with language describing its operation, here connotes structure…None of this testimony is rebutted. Dr. Goldberg’s testimony thus demonstrates that, contrary to the district court’s unsupported assertion, the claim limitations do not recite ‘purely functional language.’  Instead, Dr. Goldberg’s unrebutted testimony demonstrates that the ‘code’/‘application’ limitations here connote a class of structures to a person of ordinary skill…Unlike in the mechanical arts, the specific structure of software code and applications is partly defined by its function.  In determining whether software limitations like those at issue here recite sufficient structure, we can look beyond the initial ‘code’ or ‘application’ term to the functional language to see if a person of ordinary skill would have understood the claim limitation as a whole to connote sufficiently definite structure.”  The Federal Circuit concluded that “the ‘code’/‘application’ limitations were not written in means-plus-function format because they would have connoted sufficiently definite structure to person of ordinary skill in the art.” 

The “System” Limitations

Next, the Federal Circuit stated “[i]n the absence of the word ‘means,’ Target bore the burden of demonstrating by a preponderance of the evidence that the ‘system’ limitation in the wherein clause fails to recite sufficiently definite structure…We conclude that Target did not satisfy this burden…in this case, the claim language itself defines the ‘system’ to include specified structure…For the reasons above, we conclude that the ‘system’ limitations are not written in means-plus-function format because they connote sufficiently definite structure to persons of ordinary skill in the art.”  As in “code/“application” limitations described above, the Federal Circuit did not have to proceed to step 2 of the analysis for “system” limitations.

The Federal Circuit stated, “[w]e recognize that the asserted claims are not models of clarity, but poor claim drafting does not allow courts to bypass the presumption that a claim does not invoke §112 ¶ 6 in the absence of the word ‘means.’  Nor does it relieve the court of their duty to evaluate whether that presumption has been overcome.” The Federal Circuit overturned a district court judgment of invalidity.


Since there are lots of patent applications filed in foreign jurisdictions that enter the US via PCT, a style of claim drafting in the foreign jurisdiction may not fit the style of the US.  This is another concern for a patent practitioner to consider when prosecuting a patent application originally filed in another jurisdiction.

*Some citations are omitted for readability and length.

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