  United States Court of Appeals
      for the Federal Circuit
                ______________________

   THE GENERAL HOSPITAL CORPORATION,
                Appellant

                          v.

     SIENNA BIOPHARMACEUTICALS, INC.,
                    Appellee
             ______________________

                      2017-1012
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 106,037.
                  ______________________

                 Decided: May 4, 2018
                ______________________

   PHILIPPE BENNETT, Alston & Bird LLP, New York,
NY, argued for appellant. Also represented by WALTER
SCOTT; AOIFE BUTLER, Chicago, IL; PETER CARL LAURO,
BRIAN LANDRY, Saul Ewing Arnstein & Lehr LLP, Boston,
MA.

    BRENTON R. BABCOCK, Knobbe, Martens, Olson &
Bear, LLP, Irvine, CA, argued for appellee. Also repre-
sented by EDWARD M. CANNON.
                ______________________

  Before MOORE, REYNA, and TARANTO, Circuit Judges.
2    GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS



MOORE, Circuit Judge.
    General Hospital Corp. (“GHC”) appeals the Patent
Trial and Appeal Board’s dismissal of an interference
determining it lacked standing because claims of U.S.
Patent Application No. 13/789,575 lacked sufficient writ-
ten description under § 112 of the Patent Act. It further
appeals the Board’s denial of its contingent motion to add
a new claim. We vacate the Board’s termination of the
interference and remand for further proceedings.
                       BACKGROUND
     The claims at issue relate to methods of removing hair
using nanoparticles to damage hair follicles. GHC is the
named applicant on the ’575 application, and Sienna
Biopharmaceuticals, Inc. (“Sienna”) owns U.S. Patent
No. 8,821,941. On October 8, 2015, at GHC’s suggestion,
the Board declared an interference. The Board identified
claim 1 of the ’941 patent as the sole count. Claim 1 is
directed to a method of localizing thermal damage to a
hair follicle by applying a composition comprising a
plurality of unassembled plasmonic nanoparticles to a
skin surface. Relevant to this appeal, claim 1 requires
“the unassembled plasmonic nanoparticles have a concen-
tration of 109 to 1023 particles per ml of the composition,
wherein said concentration is sufficient to, after exposure
to irradiation, induce thermal damage in the hair follicle.”
    The Board identified claims 65–67 of the ’575 applica-
tion and claims 1–20 of the ’941 patent as corresponding
to that count. Claim 65 is representative of the ’575
claims. Like claim 1, it is directed to a method of localiz-
ing thermal damage to a hair follicle by applying a com-
position comprising a plurality of unassembled plasmonic
nanoparticles to a skin surface. In claim 65, “the unas-
sembled plasmonic nanoparticles have a concentration of
about 6.6 × 1011 particles per ml of the composition.” The
Board construed “about” as it appears in claim 65 to mean
“within 10%.” Therefore, “about 6.6 × 1011 particles per
GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS      3



ml” encompasses of a range of at most from 5.94 × 1011 to
7.26 × 1011 particles per ml.
    Sienna moved for a determination that claims of the
’575 application were unpatentable for failure to meet the
written description requirement. The disclosure in the
’575 application describes formulations by reference to
optical density (OD) rather than particles per ml. The
parties disputed the proper extinction coefficient to be
used in converting optical density to concentration in
particles per ml. The Board accepted an extinction coeffi-
cient of 4.2, crediting the testimony of Sienna’s expert Dr.
Tao over the testimony of GHC’s expert Dr. Dmochowski.
Applying this coefficient, the Board found no concentra-
tions disclosed in the ’575 disclosure were between 5.94 ×
1011 and 7.26 × 1011 particles per ml. The Board, there-
fore, found claims 65–67 lack written description support
and are unpatentable under § 112.
    GHC moved to add new claim 74 expressly limiting
the nanoparticles to have “an Optical Density of 250 O.D.
when measured at a wavelength of about 810 nm.” The
Board denied this motion, determining that GHC did not
show interference-in-fact with Sienna claim 1, or corre-
spondence to Count 1, and failed to provide supporting
evidence that this claim was patentable.
   GHC appealed.        We have jurisdiction under 28
U.S.C. § 1295(a)(4)(A).
                         DISCUSSION
                              I
    Sufficiency of written description is a question of fact,
reviewed for substantial evidence. Inphi Corp. v. Netlist,
Inc., 805 F.3d 1350, 1354 (Fed. Cir. 2015). In determining
whether the written description requirement is met, we
consider “whether the disclosure of the application relied
upon reasonably conveys to those skilled in the art that
the inventor had possession of the claimed subject matter
4    GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS



as of the filing date.” Ariad Pharm., Inc. v. Eli Lilly &
Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc).
    As a preliminary matter, the parties dispute the prop-
er construction of the claim term “about.” “We review the
Board’s claim construction de novo except for subsidiary
fact findings, which we review for substantial evidence.”
Perfect Surgical Techniques, Inc. v. Olympus Am., Inc.,
841 F.3d 1004, 1012 (Fed. Cir. 2016). Here, the Board
properly construed “about” to mean “within 10%.” The
’575 application defines “about,” giving a broadest value of
10%:
    Unless otherwise specifically stated or obvious
    from context, as used herein, the term “about” is
    understood as within a normal tolerance in the
    art, for example within 2 standard deviations of
    the mean. About can be understood as within
    10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.1%,
    0.05%, or 0.01% of the stated value. Unless oth-
    erwise clear from context, all numerical values
    provided herein are modified by the term about.
Although the specification and prosecution history of the
’941 patent do not expressly define “about,” the Board
considered Dr. Tao’s testimony that a range of 10% is
consistent with the use of the word “about” in the ’941
specification. None of the intrinsic or extrinsic evidence
cited by GHC supports GHC’s construction that “about”
includes ± 20% variation. Moreover, GHC waived its
argument that the broadest reasonable interpretation of
“about” was ± 20%. In the interference, GHC only con-
tested Sienna’s proposed construction by generally deny-
ing that the broadest reasonable interpretation was
“within 10%.” J.A. 812. GHC did not present an alterna-
tive construction or explain why it disagreed with Sien-
na’s proposed construction. Although GHC’s expert Dr.
Dmochowski stated in a declaration that a skilled artisan
would have considered a 20% variation to be acceptable,
GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS     5



the Board expressly stated that it would not consider this
testimony because GHC did not rely on it or argue Dr.
Tao’s 10% variation was incorrect. We conclude that the
Board properly determined that the claim limitation
“about 6.6 × 1011 particles per ml” encompasses of a range
of at most from 5.94 × 1011 to 7.26 × 1011 particles per ml.
    Given this claim construction, substantial evidence
supports the Board’s findings that none of the disclosed
values in the ’575 application fall within 10% of the
claimed value. Claims 65–67 of the ’575 application,
which include the “about 6.6 × 1011 particles per ml”
limitation, are not original claims. The ’575 application
broadly discloses that “the composition comprises plas-
monic particles that have an optical density of at least
about 1 O.D.” J.A. 3164. GHC has identified seven
specific compositions in the ’575 application, which it
argues have optical densities of 132, 144, 250, 275, 300,
715, and 780. When converted to particles per ml, these
optical densities give values of 4.10 × 1011, 4.46 × 1011,
7.77 × 1011, 8.44 × 1011, 9.31 × 1011, 22 × 1011, and 24 ×
1011 particles per ml.
     The disclosure of a broad range of values does not by
itself provide written description support for a particular
value within that range. Instead, where a specification
discloses a broad range of values and a value within that
range is claimed, the disclosure must allow one skilled in
the art to “immediately discern the limitation at issue in
the claims.” Purdue Pharma L.P. v. Faulding Inc., 230
F.3d 1320, 1323 (Fed. Cir. 2000). In Purdue Pharma, we
affirmed a district court finding that a claim requiring a
pharmacokinetic concentration ratio (Cmax/C24) above 2
was not supported by sufficient written description where
the specification (1) included examples of ratios above and
below 2; (2) did not emphasize the Cmax/C24 ratio as an
aspect of the invention; and (3) “disclose[d] a multitude of
pharmacokinetic parameters, with no blaze marks direct-
6    GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS



ing the skilled artisan to the Cmax/C24 ratio or what that
ratio should exceed.” Id. at 1326.
    Here, the specification discloses a range of optical
densities and several discrete values within that range.
The specification broadly states that in one embodiment
the particles have an optical density of at least “about 1
O.D.,” J.A. 3164, which GHC argued corresponds to less
than 1 × 1011 particles per ml. The specification does not
expressly identify a maximum concentration, and GHC
did not argue any upper limit to the range disclosed other
than “some value greater than 9.31 × 1011.” J.A. 804.
Several of the discrete values provided in the specification
are even higher than that. As we stated in Purdue Phar-
ma, “one cannot disclose a forest in the original applica-
tion, and then pick a tree out of the forest and say here is
my invention.” Purdue, 230 F.3d at 1326. The disclosure
of a range of concentrations from less than 1 × 1011 parti-
cles per ml to some unidentified maximum, does not
provide written description support for the claimed con-
centration of “about 6.6 × 1011 particles per ml,” nor does
the disclosure of particular discrete values within that
range, none of which are the claimed value.
    While GHC argues the written description require-
ment is met because when a 10% variability is applied to
both the claimed value and one of the disclosed values,
the ranges overlap, this argument is unavailing. The
specification discloses an optical density of 250 OD, which
GHC argues corresponds to 7.77 × 1011 particles per ml.
GHC argues a 10% variability should be applied to this
value, generating a range from 6.99 × 1011 to 8.55 × 1011
particles per ml. Because this range overlaps with the
claimed range of “about 6.6 × 1011 particles per ml” or
from 5.94 × 1011 to 7.26 × 1011 particles per ml, GHC
argues the written description requirement is met. This
argument relies on language in the specification that
states “[u]nless otherwise clear from context, all numeri-
cal values provided herein are modified by the term
GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS      7



about.” J.A. 92. Even if we accept GHC’s argument that
the specification may be read to convert each disclosed
value into a range with 10% variation, GHC’s argument
still fails, as a disclosed range that minimally overlaps
with the claimed range does not provide written descrip-
tion support for the claimed range. In Eiselstein v. Frank,
52 F.3d 1035, 1040 (Fed. Cir. 1995), we determined that
the range of “about 45–55% . . . is not the same as a very
different 10% range, viz., 50–60%.” There, half of each
range overlapped with the other. Here, the overlap is
even less. Whether written description support exists for
the claimed “6.6 × 1011 particles per ml” in light of the
disclosures in the ’575 specification is a question of fact.
We conclude that substantial evidence supports the
Board’s determination that the examples provided in the
specification do not provide written description support
for the claim term. Accordingly, the Board did not err in
its analysis, and substantial evidence supports its finding
of a lack of sufficient of written description.
                             II
    The Board also denied GHC’s contingent motion to
amend to add new claim 74, determining that GHC failed
to show claim 74 was patentable and failed to meet its
burden of showing the proposed claim interferes with any
of Sienna’s claims. We review the Board’s denial of a
motion to amend to determine if it is arbitrary or capri-
cious. Veritas Techs. LLC v. Veeam Software Corp., 835
F.3d 1406, 1408 (Fed. Cir. 2016).
    The Board’s determination that GHC failed to meet
its burden to show that the claim 74 is patentable was
arbitrary and capricious. GHC certified it was not aware
of any reason why the claim was not patentable. The
Board stated GHC failed to direct it to evidence support-
ing the certification, but it did not engage in a substantive
analysis of the claim’s patentability or identify any par-
ticular ground on which GHC failed to establish patenta-
8    GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS



bility. The Board has adopted a Standing Order for
conducting interferences, which in accordance with Board
practice, was entered into the docket. See In re Sullivan,
362 F.3d 1324, 1328 (Fed. Cir. 2004) (affirming the use of
the Standing Order). The Standing Order expressly
instructs the moving party to “certify” that it is not aware
of any reason why the claim is not patentable. Standing
Order ¶ 208.5.1. It explains that “[a] certification that is
inconsistent with the prosecution history of an involved or
benefit file will be accorded no weight unless the incon-
sistency is explained.” Id. Here, the Board did not point
to any inconsistency with the prosecution history or
otherwise challenge the merits of the certification, but
still afforded the certification no weight. Given GHC’s
compliance with the Standing Order, the Board acted
arbitrarily and capriciously in holding GHC failed to show
the proposed claim was patentable absent evidence of
inconsistency with the prosecution history.
    The Board’s determination that GHC had not estab-
lished claim 74 interferes with any of Sienna’s claims was
not in accordance with our controlling precedent. Neither
the parties nor the Board dispute that proposed claim 74
covers a particular species of the genus set forth in the
’941 claim. Nevertheless, the Board determined GHC had
not met its burden because it had not provided evidence
that a skilled artisan “would have considered it obvious to
have chosen the narrow range of nanoparticle diameter
and optical density recited in its proposed claim 74.”
    Where a prior art patent discloses a range of values,
showing a claimed value falls within that range meets a
party’s burden of establishing the narrower claim would
have been obvious where there is no reason to think the
result would be unpredictable. See, e.g., Galderma Labs.,
L.P. v. Tolmar, Inc., 737 F.3d 731, 738 (Fed. Cir. 2013)
(holding where the claimed value fell within prior art
range, burden of production switched to the party oppos-
ing the obviousness challenge, while burden of proof
GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS     9



remanded with challenger); Alcon Research, Ltd. v. Apotex
Inc., 687 F.3d 1362, 1368 (Fed. Cir. 2012) (holding a prior
art reference disclosing a range of concentrations express-
ly disclosed a particular concentration within that range).
In doing so, we have stated that “[t]he normal desire of
scientists or artisans to improve upon what is already
known provides the motivation to determine where in a
disclosed set of percentages is the optimum combination
of percentages.” In re Peterson, 315 F.3d 1325, 1330 (Fed.
Cir. 2003); accord In re Applied Materials, Inc., 692 F.2d
1289, 1295 (Fed. Cir. 2012). Although such a showing
may not ultimately be sufficient to establish obviousness
where other facts cut against that conclusion, see, e.g.,
Peterson, 315 F.3d at 1331–32 (considering teaching away
and unexpected results), here, neither the Board nor
Sienna has pointed to any such facts. The cases cited by
the Board are distinguishable. In In re Baird, 16 F.3d
380 (Fed. Cir. 1994), the prior art that disclosed a generic
molecular formula indicated a preference leading away
from the claimed compounds. Id. at 382–83. Moreover,
we have suggested that when a reference discloses vari-
ous structures rather than a range of values, optimization
is not as likely to be routine. See Genetics Inst., LLC v.
Novartis Vaccines & Diagnostics, Inc., 655 F.3d 1291,
1306 (Fed. Cir. 2011). The other case cited by the Board
involved a question of anticipation, not obviousness. See
Atofina v. Great Lakes Chem. Corp., 441 F.3d 991, 999–
1000 (Fed. Cir. 2006). It is not disputed that the values in
the proposed claim fall within the ranges in claim 1 of the
’941 patent. Under the circumstances of this case, GHC
has put forth sufficient evidence to establish proposed
claim 74 would have been rendered obvious by claim 1 of
the ’941 patent.
                       CONCLUSION
    For the foregoing reasons, we affirm the Board’s find-
ing that claims 65–67 are unpatentable for lack of suffi-
cient written description. We vacate the Board’s denial of
10    GENERAL HOSPITAL CORP.   v. SIENNA BIOPHARMACEUTICALS



GHC’s contingent motion to add a new claim and remand
for further proceedings.
      AFFIRMED IN PART AND VACATED AND
             REMANDED IN PART
                          COSTS
     No costs.
