Nektar Therapeutics

Patent Trials and Appeals Board

Jun 10, 2020

IPR2019-01396 (P.T.A.B. Jun. 10, 2020)

Trials@uspto.gov Paper 28
571-272-7822 Entered: June 10, 2020

UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE PATENT TRIAL AND APPEAL BOARD

NOF CORPORATION,
Petitioner,
v.
NEKTAR THERAPEUTICS,
Patent Owner.

IPR2019-01396
Patent 8,809,453 B2

Before ERICA A. FRANKLIN, ZHENYU YANG, and
JON B. TORNQUIST, Administrative Patent Judges.

YANG, Administrative Patent Judge.

DECISION

Denying Petitioner’s Request on Rehearing of Decision
Denying Institution of Inter Partes Review
37 C.F.R. § 42.71(d)

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INTRODUCTION
NOF Corporation (“Petitioner”) filed a Petition (Paper 1, “Pet.”)
requesting an inter partes review of claims 1–18 of U.S. Patent
No. 8,809,453 B2 (Ex. 1004, “the ’453 patent”). We denied the Petition.
Paper 19 (“Dec.”). Petitioner filed a request for rehearing of the Decision.
Paper 21 (“Req. Reh’g”).
For the reasons discussed below, we deny Petitioner’s request for
rehearing.
STANDARD OF REVIEW
When rehearing a decision on institution, the Board reviews the
decision for an abuse of discretion. 37 C.F.R. § 42.71(c). An abuse of
discretion occurs when a “decision was based on an erroneous conclusion of
law or clearly erroneous factual findings, or . . . a clear error of judgment.”
PPG Indus. Inc. v. Celanese Polymer Specialties Co., 840 F.2d 1565, 1567
(Fed. Cir. 1988) (citations omitted). A rehearing request “must specifically
identify all matters the party believes the Board misapprehended or
overlooked, and the place where each matter was previously addressed.”
37 C.F.R. § 42.71(d).
DISCUSSION
The Decision addressed six grounds of unpatentability, four of which
rely on Bentley (Ex. 1015) as the primary reference, and the other two rely
on JP-542 (Ex. 1017) as the primary reference. Dec. 5. Petitioner requests
rehearing of our decision not to institute review of the grounds related to
Bentley. Req. Reh’g 1. According to Petitioner, “the Decision
misapprehends and overlooks the disclosures of the prior art, as a whole, the
proper level of skill, common knowledge and creativity to be applied by one
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skilled in the art, and failed to resolve material factual disputes in a light
most favorable to Petitioner.” Id. We are not persuaded.
Prior Art
Bentley relates to methods of coupling a PEG polymer to a
biomaterial. Ex. 1015, 1:8–10. Bentley’s method “includes in situ
preparation of PEG aldehyde hydrates, which can then be used in solution,
without isolation, to form conjugates by reductive amination with a range of
biologically active molecules.” Id. at 3:4–9.
In the Decision, we found “Petitioner has not shown the Bentley
polymer it relies on (depicted in the formula at lines 16–20 on column 7 of
Bentley) is suitable for conjugating with a biologically active molecule.”
Dec. 9. Petitioner contends that an ordinarily skilled artisan “would have
understood Bentley to expressly teach and suggest that all activated PEGs
thereof are for conjugation of biologically active molecules.” Req. Reh’g 8,
see also id. at 9 (“Bentley’s statements of his invention apply to ALL
Bentley activated PEG polymers.”). We disagree.
Bentley’s “invention provides a method for conjugating PEG and
related polymers with substances including biomaterials and biologically
active materials.” Ex. 1015, 3:2–4. For the polymers, Bentley teaches PEG
as well as a broad variety of other polymers. Id. at 3:49–62. For the materials
that can be conjugated to the polymers, Bentley teaches “any material
having a reactive amine group accessible to the activated polymer having an
aldehyde hydrate group can be used” in its invention. Id. at 6:15–18. In other
words, Bentley teaches that the aldehyde hydrate moiety can be used to
conjugate nearly any polymer to nearly any amine-containing substance.
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As noted in the Decision, Bentley teaches that PEG aldehyde hydrate
can be linked to either “a molecule or surface bearing one or more amine
groups.” Dec. 6 (quoting Ex. 1015, 2:12–20, emphasis added); see also id. at
9 (quoting Ex. 1015, 7:44–46 (“PEG aldehyde hydrate and its derivatives
can be used for attachment directly to surfaces and molecules having an
amine moiety.” (emphasis added in the Decision))). We also observed that,
in Bentley, “because biological properties may vary based on molecular
weight and the degree of branching, ‘not all of these [disclosed] derivatives
may be useful for biological or biotechnical applications.’” Id. (quoting
Ex. 1015, 6:36–39).
In other words, Bentley does not teach that all of the PEG conjugates
would be useful for all possible purposes. Nor does it describe how to
determine which conjugates will be useful for any particular desired
application. Instead, Bentley discloses a tool that can be used to conjugate a
broad variety of polymers to nearly any amine-containing substance or
surface. Petitioner does not persuasively explain why such a general
disclosure teaches or suggests a conjugate of any particular PEG polymer to
any particular type of amine-containing substance.
As noted by Petitioner, Bentley teaches a specific form of activated
PEG polymer, the structure of which is reproduced below:

The figure above is Petitioner’s depiction of the chemical structure identified
at column 7, lines 16–20 of Bentley. Pet. 28 (citing Ex. 1015, 7:12–20).
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According to Petitioner, “one of ordinary skill would understand the
‘−O−(CH2)nCH(OH)2’ of Bentley’s branched polymer would react with a
protein, or other amine-containing substance, to form –O-(CH2)n-CH2-NH-
PROTEIN.” Id. at 30. We reiterate, as explained in the Decision, we
disagree with Petitioner’s conclusion.
For the polymer the Petition relies on, Bentley does not provide any
properties or explain how this molecule is to be used. Instead, Bentley states
that this is a “star molecule” and that such molecules are generally described
in Merrill (U.S. Patent No. 5,171,264), which is incorporated by reference in
Bentley. Ex. 1015, 7:2–20. Merrill discloses that “star molecules” are useful
for creating hydrogels for use in affinity columns. Ex. 2020, Abstract (“This
invention pertains to a method for immobilizing polyethylene oxide (PEO)
star molecules in the form of hydrogels.”).
The Petition does not address Bentley’s incorporation of Merrill or
persuasively explain why an ordinarily skilled artisan would have
understood that the disclosed activated PEG polymer would be useful when
conjugated to a biologically active molecule, as opposed to a support surface
of an affinity column. Petitioner relies instead on Bentley’s broad disclosure
that an aldehyde hydrate moiety could be used to conjugate nearly any
polymer to nearly any amine-containing substance, including biologically
active molecules. Pet. 27–30. But, identifying a disclosure that something
could be done is not sufficient to demonstrate a reason to do so in a
particular instance or manner. See Polaris Indus., Inc. v. Arctic Cat, Inc.,
882 F.3d 1056, 1068 (Fed. Cir. 2018) (holding it is error to “focus[] on what
a skilled artisan would have been able to do, rather than what a skilled
artisan would have been motivated to do at the time of the invention”).
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In view of the foregoing, Petitioner has not established that we
overlooked Bentley’s teachings or that we erred in concluding that Petitioner
had not sufficiently demonstrated that Bentley teaches or suggests using the
“star molecules” for biologic applications.
Expert Testimony
Petitioner refers to the expert declaration in support of the Petition, in
which Dr. Yamamoto testifies that
. . . a POSA would appreciate that conjugation of the disclosed
aldehyde hydrate polymers to biologically active molecules . . .
is expressly disclosed . . . [and] [i]t would have been obvious to
POSA to conjugate the branched PEG aldehyde hydrate
disclosed by Bentley (Id. at 7:12-20) to a biologically active
molecule … as disclosed by Bentley (Id. at 6:1-29).
Req. Reh’g 12 (quoting Ex. 1083 ¶ 286). Petitioner points out that Patent
Owner did not provide any expert testimony. Id. at 13. According to
Petitioner, we erred for “discounting Dr. Yamamoto’s uncontroverted
testimony in favor of PO’s attorney argument.” Id. We are not persuaded.
Dr. Yamamoto is an employee of Petitioner. Ex. 1083 ¶ 10. “While
the opinion testimony of a party having a direct interest in the pending
litigation is less persuasive than opinion testimony by a disinterested party, it
cannot be disregarded for that reason alone and may be relied upon when
sufficiently convincing.” Ashland Oil, Inc. v. Delta Resins & Refractories,
Inc., 776 F.2d 281, 294 (Fed. Cir. 1985).
How much we credit an expert’s testimony, however, depends on
whether the opinion adequately addresses the disclosures of a reference as a
whole and adequately provides the justification for its conclusions. See TQ
Delta, LLC v. Cisco Sys., Inc., 942 F.3d 1352, 1359–60 (Fed. Cir. 2019).
Here, Dr. Yamamoto did not adequately explain why Bentley’s disclosure of
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being able to conjugate nearly any polymer to nearly any amine-containing
material teaches or suggests the specific polymer identified at column 7,
lines 14–20 of Bentley, would be useful when conjugated to biologically
active molecules.
Moreover, Bentley generally teaches that activated PEG polymers can
be conjugated to molecules or surfaces and specifically incorporates by
reference Merrill, which discloses conjugating “star” molecules to the
support surface of an affinity column. Ex. 1015, 6:12–13; Ex. 2020, 2:5–8.
Dr. Yamamoto did not address these disclosures or explain adequately why
one of ordinary skill in the art would have sought to conjugate the specific
activated PEG molecule disclosed in Bentley (Ex. 1015, 7:14–20) to a
biologically active molecule, as opposed to the support surface of an affinity
column (Ex. 2020, 2:5–8). Indeed, Dr. Yamamoto did not persuasively
identify any actual properties of the specific activated PEG molecule of
Bentley relied upon in the Petition.
As a result, although we considered Dr. Yamamoto’s testimony, we
accorded it proper weight. Petitioner has not established that we erred in
doing so.
Level of Ordinary Skill in the Art
Petitioner asserts that “a POSA would have had a Ph.D. in chemistry,
chemical engineering, materials science, or a related field and several years
of experience working in the field of synthesis of active PEG polymers for
PEGylation of biological molecules.” Pet. 24; Req. Reh’g 14. Petitioner
contends we overlooked and misapplied the level of skill in the art when we
declined to institute review in this case. Req. Reh’g 13–14.
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The level of ordinary skill in the art asserted by Petitioner is high. A
high level of skill in the art tends to favor an obviousness conclusion. See
Innovention Toys, LLC v. MGA Entm’t, Inc., 637 F.3d 1314, 1323 (Fed. Cir.
2011) (“A less sophisticated level of skill generally favors a determination of
nonobviousness, and thus the patentee, while a higher level of skill favors
the reverse.”). Despite so, to meet its burden for institution, Petitioner still
must adequately explain why the art and such a high skill level would have
led to the claimed invention. As noted above, we do not find that Petitioner
and Dr. Yamamoto did so. Thus, Petitioner has not established that we
overlooked its argument as to this issue.
Grounds Based on Bentley and Other References
Petitioner asserts three other grounds of unpatentability, relying on the
combinations of Bentley with MDD (Ex. 1029), Harris (Ex. 1016), and
Harris together with PSTT (Ex. 1030). Dec. 5. Petitioner contends that we
overlooked the teachings of these additional references. Req. Reh’g 14–15.
We, again, are not persuaded.
The Petition relies on the additional references for teaching the claim
limitation of molecular weight. See Pet. 41–42 (“To the extent that more is
need to show that POSA would arrive at the claimed molecular weight
ranges of the ‘453 patent in connection with the branched polymers of
Bentley, a POSA would have arrived at such ranges when considering
Bentley in view of MDD.”), id. at 53 (“A POSA would be motivated to
combine the teachings of the branched polymers of Bentley with the
molecular weight teachings of Harris.”), id. at 60 (“A POSA would have
been motivated to combine the teachings of Bentley and Harris with PSTT
to optimize the molecular weight of branched polymers.”). In other words,
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although certain teachings of the additional references may remedy the
deficiencies of Bentley, the Petition does not rely on those teachings. And
we could not have overlooked an argument that was not made in the
Petition.
CONCLUSION
We have considered Petitioner’s request for rehearing, but determine
that Petitioner has not established that we misapprehended or overlooked
any matter in declining to institute an inter partes review.
ORDER
In view of the foregoing, it is:
ORDERED that Petitioner’s Requests for Rehearing is denied.
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FOR PETITIONER:
Thomas J. Donovan
Mark A. Hagedorn
Vincent P. Liptak
BARNES & THORNBURG LLP
thomas.donovan@btlaw.com
mhagedorn@btlaw.com
vincent.liptak@btlaw.com

FOR PATENT OWNER:
Edgar Haug
Brian Murphy
Angus Chen
Andrew Wasson
Kaitlin Abrams
Erika Selli
Andrew Roper
HAUG PARTNERS LLP
ehaug@haugpartners.com
bmurphy@haugpartners.com
achen@haugpartners.com
awasson@haugpartners.com
kabrams@haugpartners.com
eselli@haugpartners.com
aroper@haugpartners.com