The courts have long stated that one goal of patent law is to provide certainty to both inventors and the public regarding the law that is applied in determining the metes and bounds of a patent claim. Patent claims that are ambiguous and vague in scope leave the public in doubt as to what is protected by the patent and is considered to exert a chilling effect on further innovation. What is one sure fire way to destroy certainty? Having two differing legal standards applied to claim interpretation seem to fit the bill. This is exactly the situation encountered when patent claims are evaluated for indefiniteness under 35 USC §112(b) by courts in the context of patent litigation and the Patent Trial and Appeal Board (PTAB) in pre- and post-issuance proceedings.

Lower Threshold for Indefiniteness Confirmed by PTAB in Ex Parte McAward

Differing Standards for Indefiniteness

District courts and the CAFC apply the now familiar standard for claim indefiniteness under Nautilus as set forth by the Supreme Court, which states a claim is invalid as indefinite if the claim “read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.” Nautilus replaced the prior test for indefiniteness which required a claim to be “insolubly ambiguous.” The PTAB however has stated that it is not bound by the USSC’s decision in Nautilus. The PTAB standards for determining indefiniteness are whether a claim “contains words or phrases whose meaning is unclear” as set forth in In re Packard or “when a claim is amenable to two or more plausible constructions” as discussed in Ex Parte Miyazaki.

The PTAB explained in Ex Parte Miyazaki that in pre-issuance proceedings the board is justified in using a lower threshold “because the applicant has an opportunity and a duty to amend the claims during prosecution to more clearly and precisely define the metes and bounds of the claimed invention and to more clearly and precisely put the public on notice of the scope of the patent.”

The same standard has been applied in post-grant proceedings in Google, Inc. v. SimpleAir, Inc., where the board stated the basis for applying the lower threshold for indefiniteness in pre-issuance proceedings “stems from two factors: (1) the broadest reasonable interpretation claim construction standard; and (2) the lack of a presumption of validity before the Office.” As the board found the same two factors apply to post-grant proceedings, the lower standard for indefiniteness was proper. This approach was also confirmed in Tinnus Enterprises, LLV v. Telebrands Enterprises, where the board stated “We do not understand Nautilus, however, to mandate the Board’s approach to indefiniteness in patent examination or reexamination matters or in AIA proceedings, in which the claims are interpreted under the broadest reasonable interpretation standard, and an opportunity to amend the claims is afforded.”

As we discussed previously, these differing standards can result in different outcomes in the CAFC and the PTAB (Tinnus Enterprises, LLV v. Telebrands Enterprises).

Ex Parte McAward Confirms PTAB Approach in Pre-Issuance Proceedings

The PTAB issued a precedential decision, a rare occurrence, in Ex parte McAward on August 25, 2017. The decision serves as clear confirmation that the PTAB will continue to use the lower threshold for indefiniteness as set forth in In re Packard and Ex Parte Miyazaki in pre-issuance proceedings. However, the board’s decision expressly limits the holding to pre-issuance proceedings, leaving some doubt as to the continued application of the lower standard to post-grant proceedings. Specifically, the board stated “We do not address, in this decision, the approach to indefiniteness that the Office follows in post-grant trial proceedings under the America Invents Act.” Therefore, until a precedential decision from the board addresses the application of the lower standard in post-grant proceedings, the proper standard for the evaluation of claim indefiniteness for post-grant proceedings is still in some doubt.

While the same factors relied on by the PTAB in applying the lower threshold are arguably present in post-issuance proceedings, the issue of how freely claim amendments are entered in post-grant proceedings has recently been called into question. In In re Aqua Products (CAFC, 2015-1177), the CAFC granted en banc review in December 2016 to determine if the board’s approach to claim amendments during post-grant proceedings is too limiting. While a decision still has not been handed down, if it is found that patent owners do not have the opportunity to freely amend their claims (as required by the logic of Google, Inc. v. SimpleAir, Inc. and Tinnus Enterprises, LLV v. Telebrands Enterprises) the PTAB’s logic in applying the lower standard is called into question, arguing that the proper standard for evaluating claim indefiniteness in post-grant proceedings should in fact be the Nautilus standard as applied by the district courts and the CAFC.

Points to Consider

For the present, it should be expected that the PTAB will continue with its current approach to evaluating claim indefiniteness in both pre- and post-issuance proceedings. As a result, it will remain the case that patent claims will be easier to invalidate on indefiniteness grounds in front of the board as compared to district court. While the situation may change with respect to post-grant proceedings, it is unlikely to change with respect to pre-issuance proceedings.

Therefore, those wishing to challenge claims on the ground of indefiniteness should carefully consider their options and consider taking advantage of the lower threshold available in front of the board. Likewise, patent applicants and owners should evaluate their cases for vulnerability under the PTAB’s current standards.

Tinnus v. TelebrandsIn Tinnus Enterprises, LLV v. Telebrands Enterprises (Fed. Cir. 2016-1410), the CAFC considered whether a claim requiring that a container (think water balloon) be “substantially filled” was indefinite under 35 USC §112. Complicating the issue, in this case the district court and the Patent Trial and Appeal Board (PTAB) reached different conclusions regarding the claims at issue in Tinnus, with the district court finding the claims valid and the PTAB finding the claims invalid under 35 USC §112.

The technology at issue in this case is simply a device for filling a plurality of balloons with a liquid. In operation, an elastic connector provides a connecting force that connects each balloon to an individual tube in communication with a liquid source. When the balloon becomes filled to a certain level (referred to as “substantially filled”) and the device is shaken, the weight of the “substantially filled” balloon overcomes the connecting force, the balloon is detached and sealed by the elastic connector. Telebrands challenged the validity of the claims contending the term “substantially filled” rendered the claims indefinite.

PTAB Reasoning

The indefiniteness issue at the PTAB centered on the phrase “a connecting force that is not less than a weight of one of the containers when substantially filled with water” recited in claim 1. Telebrands argued that determining whether a container is filled or substantially filled “is a hopeless exercise contingent upon a user’s subjective desire.” Indeed the specification of the patent at issue equated the concept of “substantially filled” as being subjectively determined (for example, equating substantially filled with a “desired size”). Tinnius countered by arguing that in the context of the patent, the term “substantially filled” was clear based on the experience of the user and the structure of the claims. Tinnius also argued that the “substantially filled” limitation was analogous to the claim limitations in Orthokinetics (claim requiring a leg portion of the chair to be “so dimensioned as to be insertable through the space between the doorframe of an automobile and one of the seats thereof). Regarding the Orthokinetics argument, the PTAB held there was no reference to a well-defined reference as in Orthokinetics because the connecting force could be varied by the user (with the result that a water balloon filled to the same level might infringe the claim in one instance but not another based on the selection of the connecting force). The PTAB also gave little weight to Tinnius’ expert, in part due to the failure of the expert opinion to place limits on the term substantially (the expert opinion equated “substantially” to “approximately”).

The PTAB concluded that there was no objective standard given in the specification for measuring whether something was filled, stating “A person of ordinary skill in the art could not interpret the metes and bounds of the phrase so as to understand how to avoid infringement because neither claim 1 nor the specification provides any objective standard for measuring the scope of the term ‘filled.’”

Federal Circuit Reasoning

Like before the PTAB, the issue at the district court/CAFC was the meaning of the term “filled” and “substantially filled.” As an initial matter, the CAFC found that the specification did not equate “substantially filled” with a “desired size” (a factor relied on in the PTAB decision), instead holding that the structure of the claims provides for a determination of when a balloon is “substantially filled” (stating that “if the balloons detach after shaking, then they are substantially filled”). The CAFC also found it incredulous that a person of ordinary skill in the art could not read the specification and determine with reasonable certainty when a balloon was “substantially filed.” The CAFC found no clear error with the district court’s determination that the claims met the Nautilus standard.

Differing Standards

The district court and CAFC applied the now familiar standard for claim indefiniteness under Nautilus, which states a claim is invalid as indefinite if the claim “read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

The PTAB, however, applies the standard under In re Packard, which states a claim is indefinite “when it contains words or phrases whose meaning is unclear.” The PTAB does not interpret Nautilus “to mandate the Board’s approach to indefiniteness in patent examination or reexamination matters or in AIA proceedings, in which the claims are interpreted under the broadest reasonable interpretation standard, and an opportunity to amend the claims is afforded.” The PTAB also recognized that the analysis under Packard may make it easier for a claim to be invalidated under 35 USC §112 in front of the Board than in federal court.

Reasons for the different outcomes?

This decision makes it clear that the Federal Circuit does not feel the need to defer to the PTAB, particularly when different legal standards are at play. However, several other procedural factors could have led to differing conclusions as to the indefiniteness issue.

First, Telebrands did not object to the indefiniteness determination of the magistrate judge, which resulted in a more onerous plain error review of the decision on appeal. Second, Telebrands did not directly raise the same issues cited by the PTAB as a basis to deny the preliminary injunction. These factors may have contributed to the different outcomes. As a result, Telebrands was limited in the arguments it could make at the CAFC and how the previously decided issues were reviewed.

This case provides important factors to consider when considering claim indefiniteness. Clearly, the broadest reasonable interpretation standard makes it easier for a claim to be found indefinite.  Without the broadest reasonable interpretation standard, the CAFC found more meaning and clarity in the individual claim terms than the PTAB. In advancing such arguments, the choice of administrative appeal versus litigation must be carefully considered based on the facts of each case in order to bring the case in the venue that is most advantageous.

How Much Homology is Enough Under § 112?How much homology is required to claim a variant of a known nucleic acid sequence when the function of the nucleic acid is recited in the claims? The Patent Trial and Appeal Board (PTAB) provides some insight on this question in Ex parte Livshits (Appeal 2013-001807; US Patent Application 11/106,455).

Applicants claimed a method for producing certain L-amino acids (L-homoserine and L-threonine) by a method of over-expressing a DNA that encodes an efflux protein in E. coli. The relevant claims (see for example, claim 4) defined the DNA as having a sequence: i) of nucleotides 187-804 in SEQ ID NO:3; or ii) which hybridizes under stringent conditions (a defined term in the specification) under which said DNA is 70% or more homologous to the recited sequences in SEQ ID NO:3 and wherein the DNA encodes a protein that, when over-expressed, results in a larger amount of L-amino acid in the culture medium as compared to a non-modified E. coli. This claim defined the variant sequence in terms of both homology and function. Claim 4 was rejected under 35 USC § 112, first paragraph, as failing to comply with written description requirements.

PTAB’s Question and Resolution

The PTAB asked whether the specification provides sufficient descriptive support of a nucleic acid that is “70% or more homologous to the recited sequence that when over-expressed in E. coli results in increased amounts of L-amino acid in the culture medium than a non-modified E. coli.”

The answer in this case was no. The PTAB agreed with the Examiner that a PHOSITA could envision sequences that met the 70% homology requirement and hybridized under the recited conditions to SEQ ID NO:3. Further, the Examiner admitted that by using conservative substitutions, a PHOSITA could likely envision a DNA sequence that encoded a polypeptide having the same tertiary structure as the polypeptide encoded by SEQ ID NO:3. However, the PTAB found there was no teaching that the conservation of structure (whether in the DNA or encoded polypeptide) would be a surrogate for conservation of the function claimed (over-expression of L-amino acids in the culture medium).

In other words, PTAB wanted some teaching as to which of the 30 percent of the nucleotides in the recited DNA could be altered while still conserving the function of the encoded polypeptide. The specification demonstrated the recited function for the polypeptide encoded by SEQ ID NO:3, but offered no teaching as to what regions of the recited DNA or protein were critical for conservation of the recited function and which regions could be modified. The PTAB stated that the specification “leaves it to others to discover the nature and scope of substitutions, deletions, and insertions that can be made to arrive at a 70% homologous sequence that additionally allows for increased amino acid accumulation in the culture medium.” The applicants attempted to use BLAST homology data to argue that a PHOSITA would be able to address the issue, but the evidence was accorded little weight and characterized as an “invitation to experiment” by the PTAB.

The PTAB also noted that even though the DNA/polypeptides that could be envisioned by the PHOSTIA could be easily tested as set forth in the specification for conservation of the recited function, this was not enough to describe the structure so that a PHOSITA could determine “beforehand whether or not a particular structure meets the functional requirements.” As such, the PTAB held that for a nucleic acid variant which is claimed by homology and function of the expressed protein, the PHOSITA must be able to determine if the nucleic acids claimed produce a protein that accomplished the recited function from the specification itself in order to meet the written description requirement.

Implications for Claim Drafting

Given the PTAB’s decision, one wonders why the functional requirement was joined as a limitation to the sequence homology claims. In this case, a published protein sequence was a 100% match for the polypeptide encoded by SEQ ID NO:3. However, no corresponding nucleic acid was disclosed. Could the homology claims have stood on their own in a separate independent claim? Probably not given the Federal Circuits decision in In re Kubin. Note, the PTAB reversed the Examiner’s obviousness rejection of claim 4 based on this reference (as well as several others), reasoning that while the function of the polypeptide was known as a threonine export protein prior to the effective date, there was no evidence to show that when a DNA encoding the protein was over-expressed it would result in accumulation of L-amino acids in the culture medium as claimed.

An alternative approach could be comparing the sequence of the identified DNA to other transport proteins for amino acids to identify conserved regions and limit the substitutions allowed in the variants claimed to those regions outside the conserved regions. In this case, the specification did not contain this information, and the applicant’s attempt to recreate this after the fact was rejected.

Whatever approach is taken, when nucleic acids are claimed by homology and function is implicated, a patent applicant should provide as much information as possible regarding the structure/function relationship and specifically identify areas that may be subject to alteration while maintaining function.