United States: A Split Decision On Patentability: What Worked For The Petitioner And What Did Not

Holding

In Nanofiber Solutions, LLC v. Acera Surgical, Inc., IPR2021-01016, Paper 8 (P.T.A.B. Dec. 13, 2022), the Patent Trial and Appeal Board ("the Board") found claims 1, 2, 4-7, and 13 of Acera's US Pat. No. 10,632,228 ("the '228 patent") unpatentable. The Board also held that Nanofiber did not establish by a preponderance of the evidence that claims 3, 8-12, or 14-20 of the '228 patent are unpatentable.

Background

The '228 patent describes using non-woven graft materials, comprising at least two distinct fiber compositions, to repair tissue following surgical procedures. '228 patent at 1:6-13. The claims recite the use of poly(glycolic acid) (PGA) and poly(lactide-co-caprolactone) (PLCL) as the two fiber compositions. Id. at 19:45-46, 56-59.

Claim 1 of the '228 patent is illustrative of the subject matter:

1. A resorbable non-woven graft material consisting of a single layer comprising:

Id. at 19:45-59.

Nanofiber challenged claims 1-5 and 13 of the '228 patent as anticipated by Johnson (US 2016/0317706). IPR2021-01016, Paper 38 at *6. Johnson discloses "electrospun fiber scaffolds for use in the healing of wounds, in which the scaffold comprises a first material...and a second material." Id. at *11. Johnson further teaches that the scaffold may be a single nonwoven layer and be created with approximately 50% pure PGA fibers and 50% pure PLCL fibers. Id.

Nanofiber argued that the remaining claims of the '228 patent would have been obvious over Johnson alone, or in view of various other publications: Liu, Cheng, US 2014/0030315 (hereafter "Johnson '315"), and Detamore. Id. at *6.

Anticipation

The Board began by addressing whether Johnson disclosed (1) a single-layer scaffold; (2) two distinct fiber compositions; or (3) the claimed mean pore size of the fibers.

Acera argued that Nanofiber improperly combined teachings within Johnson involving single and multi-layer scaffolds to arrive at the claimed subject matter. Id. at *12-13. The Board disagreed, finding that "Patent Owner has not directed us to anything in the disclosure of Johnson that indicates that this is a 'distinct' teaching or embodiment, instead of a general description of the types of scaffolds that Johnson encompasses." Id. at *14 (citing Net MoneyIn v. Verisign, 545 F.3d 1359, 1371 (Fed. Cir. 2008)). Thus, the Board saw "no reason why the general descriptions regarding Johnson's scaffolds should be limited to specific embodiments, or precluded from applying to the method" teaching a single-layer scaffold. IPR-2021-01016, Paper 38 at *14-15.

Acera also argued that Johnson did not disclose a scaffold formed with two distinct fiber compositions, stating that a person of ordinary skill in the art ("POSITA") "would not have believed that Example 1 of Johnson refers to a co-spinning process using two needles—one for PLCL and a second for PGA." Id. at *15 (quoting PO Resp. at 13). Again, the Board disagreed with Acera's interpretation of Johnson, finding that "Johnson clearly states that the result of Example 1 is two sets of fibers, with approximately 50% being pure PGA and the other 50% being pure PLCL." Id. at *16. Thus, a person of ordinary skill in the art "would have interpreted Example 1 of Johnson to describe the use of multiple needles to cospin two distinct fibers into a combined scaffold." Id. at *17.

Lastly, regarding claim 3, Acera argued that Johnson fails to disclose "the claimed mean pore size of about 10 μm²to about 10,000 μm²." Id. In its petition, Nanofiber argued that this limitation was inherently met by Johnson's disclosure of fiber diameters of about 0.1 μm to 10 μm. Id. This time, the Board agreed with Acera, noting that Nanofiber (1) did not sufficiently demonstrate the link between fiber size and pore diameter in its Petition, and (2) failed to address a reference provided by Acera which disclosed a fiber diameter like Johnson's but a pore area outside the claimed range. Id. at *18.

Thus, the Board concluded that claims 1-2, 4-5, and 13 were anticipated by Johnson but that Nanofiber failed to meet its burden with respect to claim 3.

Obviousness over Johnson alone

Nanofiber contended that claim 6, which depended on claim 1 and further required that the two fibers be "independently distributed in a pattern throughout the material," would have been obvious over Johnson alone. '228 patent at 20:7-10. Nanofiber pointed to Johnson's disclosure "of an electrospinning system with multiple injectors, which [its expert] testifie[d] would be used to independently distribute two separate polymers in a pattern." IPR-2021-01016, Paper 38 at *19. Acera disagreed, arguing that claim 6 requires "a pattern in the material itself" rather than a pattern of the two fiber components. Id. (quoting PO Resp. at 24). The Board agreed with Nanofiber, noting that the claim requires the two fibers to be "independently distributed in a pattern throughout the material." Id. at *20. The Board likewise found that Nanofiber proved that a POSITA would have applied either of the patterns disclosed in Johnson to the scaffold in its Example 1 "in order to improve porosity and further promote wound healing." Id. Thus, the Board found that Nanofiber met its burden of proving claim 6 would have been obvious over Johnson.

Obviousness over Johnson in view of Liu

Nanofiber also asserted that claims 3, 7, 8, 10, 12, 14, 16, and 18-20 would have been obvious over Johnson in view of Liu. Like Johnson, Liu disclosed average pore diameters. Id. at *21 (quoting Ex. 1011, Abstract). Nanofiber argued that a POSITA would have had reason to combine Johnson and Liu "as both are directed to fiber scaffolds that increase cell growth and proliferation" and adding Liu's ridges and grooves to Johnson would "relate[] directly" to such goals. Id. (citing Pet. at 35). Acera disputed Nanofiber's position on three points:

1. whether Liu discloses "projections and indentations" as required by claims 7, 8, 10, 12, 14, 16, and 18-20;
2. whether any such "projections and indentations" were "randomly distributed" as required by claims 8, 10, 12, 14, 16, and 18-20; and
3. whether a POSITA would have had reason to incorporate Liu's pore size in Johnson.

(1) Whether Liu discloses "projections and indentations"

Regarding the first issue, Nanofiber argued that Liu's "distinct ridge and groove morphologies" teach the "at least one projection arising from a surface of the non-woven graft material" and the "at least one indentation in a surface of a non-woven graft material." Id. at *22 (citing '228 patent at 9:6-11). Acera argued that Liu teaches a single undulating top surface and a single flat bottom surface rather than projections and indentations. Id. at *23. Nanofiber disputed Acera's interpretation in its Reply and presented additional related analysis from its expert. Id. at *24. Acera asserted that Nanofiber's Reply arguments were improper. Id. at *24.

Ultimately, the Board agreed with Nanofiber's original interpretation of Liu and did not consider the propriety of its additional argument. Id. at *25. Relying on the '228 patent's definitions of (1) "projection" as a "protrusion" or "bulge" of "any desired shape" and "any desired height as measured from the surface of the material"; and (2) "indentation" as a "recess" or "depression," the Board concluded that a POSITA would consider Liu's ridge and grooves to fall within the "projections" and "indentations" of the '228 patent. Id. (citing '228 patent at 9:6-7). The Board also found that a POSITA would have been motivated to combine Liu's surface features with the scaffolds of Johnson to mimic "complex extracellular matrices" and achieve related benefits regarding cell spatial distribution and alignment within the scaffold. Id. at *25-26.

(2) Whether any such "projections and indentations" were "randomly distributed"

Regarding the second issue, Nanofiber argued that Liu discloses "randomly distributed" projections and/or indentations because a POSITA would understand that its grooves and ridges "could be employed on the surface of a scaffold in a randomly distributed manner simply by randomly distributing those features on the patterned collector." Id. at *26 (citing Pet. at 40). Interestingly, Nanofiber again presented an alternative argument in its Reply—comparing Liu to images from Acera's infringement contentions in related district court litigation. Id. at *27. Acera again argued the argument was improper.

The Board found that Liu's "ridges and grooves appear to be uniformly or regularly distributed" per its disclosure of "well organized topical structures" that "provide the potential to construct complex tissues of well organized multiple cell types and spatially distributed [extracellular matrices]." Id. (citing Ex. 1011 at 141). Moreover, the Board was unconvinced by Nanofiber's assertions that a POSITA could, rather than would, alter Liu's "well organized" arrangement into a random distribution. Id. at *26-27. And whether or not its Reply argument was properly raised, Nanofiber's comparison of Liu to an accused infringing product in related litigation would not provide this missing link. Id. at *27. Thus, the Board held that Nanofiber failed to meet its burden with respect to claims 8, 10, 12, 14, 16, and 18-20.

(3) Whether a POSITA would have had reason to incorporate Liu's pore size in Johnson

Regarding the third issue, Nanofiber asserted that Liu teaches ridge-area fibers with "an average pore [diameter] of around 5.9 μm" and groove-area fibers with an average pore diameter in the groove area of "around 7.2 μm." Id. at *28 (citing Pet. at 37). Likewise, Nanofiber insisted that pores having those diameters would have areas falling within the range in claim 3. Id. However, Nanofiber's petition did not articulate a motivation to combine Liu's pore size into Johnson, and its expert did not testify as to that topic. Id. at *29. Accordingly, the Board found that Nanofiber failed to sufficiently articulate why a POSITA would have incorporated Liu's pore size into Johnson, and concluded Nanofiber had failed to carry its burden on the Johnson and Liu ground. Id. at *28-29.

Obviousness over Johnson in view of Liu and Cheng

Nanofiber argued that claims 9, 11, 15, and 17 would have been obvious over Johnson in view of Liu and Cheng. The Board noted that Nanofiber "does not rely on Cheng to supply the teachings [it] found missing from the Johnson/Liu combination" but rather for its disclosure of protrusions having a gradual gradient. Accordingly, because Nanofiber's combination of Johnson, Liu, and Cheng did not teach a "random distribution" of protrusions, the Board held that Nanofiber failed to meet its burden to prove that claims 9, 11, 15, and 17 would have been obvious to a POSITA. Id.

Obviousness over Johnson '315, Detamore, Liu, and Cheng

The Board rejected all of Nanofiber's alternative obviousness arguments based on combinations of Johnson '315, Detamore, Liu, and Cheng.

Johnson '315 disclosed polymer scaffolds useful for transplantation in a biologic organism which include "at least one layer of polymer fibers that have been deposited by electrospinning." Id. at *31 (quoting Johnson '315 at ¶ 7). Unlike Johnson, which disclosed scaffolds made of PGA and PLCL, Johnson '315 only disclosed use of PGA and polycaprolactone (PCL). Similarly, Detamore disclosed a scaffold "that is primarily PCL" and may incorporate other polymers including PGA. In its petition, Nanofiber conceded that both references disclosed PCL "as opposed to PLCL." Id. (quoting Pet. at 54). However, Nanofiber's expert testified that a POSITA "would have used PLCL as the second polymer instead of PCL disclosed by Johnson '315 and Detamore because it 'would be a simple replacement for PCL in view of their similar degradation rates.'" Id. (quoting Ex. 1002 ¶ 383).

The Board was unconvinced by Nanofiber's argument because Nanofiber's expert did not (1) "provide any evidence setting forth the[] degradation rates;" nor did he (2) "establish that skilled artisans at the time of the invention considered PCL and PLCL to be simple substitutes for one another." Id. at *32. And though in its Reply Nanofiber cited a different portion of Detamore as evidence that PLCL and PCL can be used as substitutes, that Board found this argument improper because Nanofiber's original expert declaration did not provide such support. Id. ("It is improper for [Nanofiber] to raise this evidence, necessary to support its case-in-chief, for the first time with its Reply."). "[D]isregarding [Nanofiber's] improper reply arguments," the Board found that a POSITA would not have combined Johnson '315 and Detamore to arrive at a scaffold of cospun PGA and PLCL as required by the claims. Id. at *33.

Because Nanofiber relied on Johnson '315 and Detamore "for essentially the same purposes . . . as it relied on Johnson alone" in its other set of grounds and neither reference remedied the deficiencies in those grounds, Nanofiber's alternative obviousness grounds did not alter the Board's prior patentability determinations. Id.

Takeaways

• When drafting a petition requesting inter partes review, practitioners should consider including alternative arguments and/or evidence establishing why cited references disclose the subject matter of the challenged claims. If an argument or piece of evidence is not timely presented, it may be rejected by the Board as improper.
• Likewise, when presenting alternative grounds of unpatentability, practitioners should consider whether those alternative grounds can stand on their own if the primary grounds are rejected. Here, the flaws from Nanofiber's first set of obviousness grounds carried over into its alternative arguments—leading to a quick resolution of those arguments in Acera's favor.
• Additionally, when challenging claims on obviousness grounds, practitioners should be sure to articulate reasons why a POSITA would have combined the asserted references rather than simply stating what a POSITA could do.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.