       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

                SANOFI MATURE IP,
                    Appellant

                           v.

        MYLAN LABORATORIES LIMITED,
                    Appellee
             ______________________

                      2018-1203
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2016-
00712.
                 ______________________

               Decided: February 5, 2019
                ______________________

   DANIEL JOHN MINION, Venable LLP, New York, NY, ar-
gued for appellant. Also represented by WILLIAM E.
SOLANDER, KATHERINE ADAMS, DOMINICK A. CONDE,
WHITNEY LYNN MEIER.

    MATTHEW R. REED, Wilson, Sonsini, Goodrich & Rosati,
PC, Palo Alto, CA, argued for appellee. Also represented
by STEVEN WILLIAM PARMELEE, MICHAEL T. ROSATO, JAD
ALLEN MILLS, Seattle, WA; WENDY L. DEVINE, San Fran-
cisco, CA.
2            SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




                   ______________________

    Before PROST, Chief Judge, O’MALLEY and STOLL, Circuit
                           Judges.
O’MALLEY, Circuit Judge.
    This appeal involves U.S. Patent No. 8,927,592
(“the ’592 patent”), which is assigned to Sanofi Mature IP
(“Sanofi”). 1 In an inter partes review requested by Mylan
Laboratories Limited, the U.S. Patent Trial and Appeal
Board (“Board”) invalidated claims 1–5 and 7–30 of the ’592
patent.     Mylan Labs. Ltd. v. Aventis Pharma S.A.,
IPR2016-712, 2017 WL 4221400, at *2 (P.T.A.B. Sept. 21,
2017) (“’592 Decision”). The Board also denied Sanofi’s con-
tingent motion to amend claims 27–30. Id. Sanofi appeals
the Board’s denial of its motion. Because we conclude that
the Board improperly placed the burden of proof on Sanofi
to establish that its proposed claims were patentable and
applied the wrong claim construction in its analysis, we va-
cate its denial of the motion and remand for further pro-
ceedings consistent with this opinion.
                      I.   BACKGROUND
                     A. The ’592 Patent
     According to the ’592 patent, prostate cancer is gener-
ally treated with hormone deprivation. ’592 patent, col. 1,
ll. 35–43. This can include surgery, e.g. castration. Id.
But if prostate cancer metastasizes, i.e. spreads to other



      1 This appeal was originally filed by Aventis Pharma
S.A. On January 24, 2019, Aventis filed an unopposed mo-
tion to substitute Sanofi Mature IP, which acquired the
’592 patent during this appeal, as the named party in this
case. On January 28, 2019, we granted this request. Thus,
although Aventis was the original named party, we will re-
fer to Sanofi throughout this opinion for clarity.
SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED              3



parts of the body, then castration is ineffective. And while
other forms of hormone deprivation exist, the ’592 patent
explains that they do not “improve[] . . . survival time.” Id.
at col 1, ll. 40–43. Chemotherapy drugs, such as docetaxel,
are therefore used, in combination with estramustine or
prednisone, to treat castration resistant, metastatic pros-
tate cancers. Id. at col. 1, ll. 62–65. Even then, however,
patients can become resistant to docetaxel treatments. Id.
at col. 2, ll. 11–13. These patients are then left with
“limit[ed] . . . possible treatment options.” Id.
    The ’592 patent purports to provide these patients—
“patients with castration resistant metastatic prostate can-
cer who have been previously treated with docetaxel”—
with a new treatment option. Id. at col. 2, ll. 18–24. This
treatment involves administering an antitumoral agent,
cabazitaxel, in combination with a corticoid such as pred-
nisone or prednisolone. Id. at col. 3, ll. 1–5.
                  B. Procedural History
    On March 15, 2016, Mylan petitioned for inter partes
review of claims 1–5 and 7–30 of the ’592 patent. The
Board instituted review on all challenged claims.
          1. Sanofi Proposes Substitute Claims
     On December 23, 2016, Sanofi filed an opposed motion
to amend its claims by substituting proposed claims 31–34
for claims 27–30. See, e.g., J.A. 655 (“If original Claim 27
is found unpatentable, the Board is requested to replace it
with proposed substitute Claim 31.”). Proposed substitute
claim 31 recites:
    31. A method of increasing survival comprising ad-
    ministering to a patient in need thereof (i) an anti-
    histamine, (ii) a corticoid, (iii) an H2 antagonist,
    and (iv) a dose of 20 to 25 mg/m2 of cabazitaxel, or
    a hydrate or solvate thereof, wherein said antihis-
    tamine, said corticoid, and said H2 antagonist are
    administered prior to said dose of 20 to 25 mg/m2 of
4          SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




    cabazitaxel, or hydrate or solvate thereof, in com-
    bination with prednisone or prednisolone, wherein
    said patient has castration resistant or hormone re-
    fractory, metastatic prostate cancer that has pro-
    gressed during or after treatment with docetaxel.
J.A. 681 (emphases added).
     Proposed claim 31, like claim 27, requires administer-
ing cabazitaxel, in combination with prednisone or predni-
solone, to a patient with castration resistant or hormone
refractory metastatic prostate cancer who has progressed
during or after treatment with docetaxel. But, as the
Board noted, “[s]ubstitute claim 31 amends the preamble
[of claim 27] to recite a ‘method of increasing survival’ fol-
lowed by ‘comprising administering to a patient in need
thereof.’” ’592 Decision, 2017 WL 4221400, at *28. Pro-
posed claim 31 also limits claim 27 by requiring the admin-
istration of an antihistamine, a corticoid, and an H2
antagonist prior to administering the cabazitaxel. Id.
    Proposed claims 32–34 depend directly from proposed
claim 31. These dependent claims do not differ from claims
28–30 in any way that is relevant to this appeal. 2
                 2. The Board’s Decision
    On September 21, 2017, the Board issued its final writ-
ten decision. First, the Board invalidated claims 1–5 and
7–30 of the ’592 patent for obviousness. ’592 Decision, 2017
WL 4221400, at *2. Sanofi has not appealed this aspect of
the Board’s decision. Additionally, the Board denied
Sanofi’s contingent motion to amend because, according to



    2    Proposed claims 32 and 34 are substantively iden-
tical to claims 28 and 30. Proposed claim 33, however, ad-
ditionally requires the cabazitaxel regimen to be
administered with an antihistamine, corticoid, and H2 an-
tagonist. J.A. 682.
SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED             5



the Board, Sanofi failed to establish that its proposed
claims would be patentable. Id. at *28.
    In addressing Sanofi’s motion, the Board concluded
that the preamble of proposed claim 31 was the only phrase
requiring explicit construction. Id. at *29. Sanofi argued
that the preamble—“[a] method of increasing survival”—
was a “statement of intentional purpose for how the
method is to be performed,” as we described in Jansen v.
Rexall Sundown, Inc., 342 F.3d 1329, 1333 (Fed. Cir. 2003).
Id. The Board disagreed, distinguishing Jansen in favor of
Bristol–Myers Squibb Co. v. Ben Venue Laboratories, Inc.,
246 F.3d 1368, 1375–78 (Fed. Cir. 2001). Id. at *30 (“Bris-
tol–Myers Squibb is relevant precedent and stands for the
proposition that a method of treatment preamble stating
the intended purpose of the treatment does not impose a
result limitation on the recited method step.”). The Board
therefore concluded that the preamble of proposed claim 31
should not be treated as limiting because it merely provides
“additional description,” as in Bristol-Myers Squibb, rather
than an “intentional purpose for how the treatment method
is to be practiced,” as in Jansen. Id. (internal quotation
marks omitted). And, while Sanofi invited the Board to
treat its claim construction arguments as a disclaimer, the
Board declined to do so. Id. (citing Tempo Lighting, Inc. v.
Tivoli, LLC, 742 F.3d 973, 978 (Fed. Cir. 2014)).
    On the merits, Sanofi argued “that the prior art d[id]
not disclose or suggest that 20–25 mg/m2 of cabazitaxel in
combination with prednisone or prednisolone would in-
crease overall survival,” as required by the preamble to
claim 31. Id. at 31. The Board rejected this argument
based on its construction of proposed claim 31, i.e. that the
preamble was not limiting. Id.
   Sanofi also argued that a skilled artisan would not
have been motivated to use the claimed premedication reg-
imen—administration of an antihistamine, a corticoid, and
6          SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




an H2 antagonist—prior to cabazitaxel therapy. Id. The
Board rejected this argument as well. Id.
    On October 4, 2017, we issued our en banc decision in
Aqua Products, Inc. v. Matal, 872 F.3d 1290 (Fed. Cir.
2017) (en banc). A few days later, the Board offered Sanofi
additional time to request rehearing in view of Aqua Prod-
ucts. J.A. 16653–54. Sanofi did not request rehearing.
    Sanofi timely filed a notice of appeal from the Board’s
final written decision. This Court has jurisdiction pursu-
ant to 28 U.S.C. § 1295(a)(4)(A) and 35 U.S.C. § 141(c).
                     II. DISCUSSION
    Sanofi argues that the Board erroneously placed the
burden of proof on Sanofi to show that its proposed claims
would be patentable. Sanofi also appeals the Board’s con-
struction of proposed claim 31, along with the Board’s ulti-
mate conclusion that the proposed claims would be
unpatentable. For the following reasons, we agree that the
Board erred in requiring Sanofi to prove that its proposed
claims would be patentable and in construing the proposed
claims.
                   A. Burden of Proof
    In an inter partes review, the petitioner bears the bur-
den of proving that proposed amended claims are un-
patentable. Aqua Prods., 872 F.3d at 1327–28. But in
deciding whether Sanofi could amend its claims here, the
Board expressly required Sanofi to prove that its proposed
substitute claims were patentable. ’592 Decision, 2017 WL
4221400, at *28 (“As the moving party, [Sanofi] bears the
burden of proving patentability of each proposed substitute
claim . . . we conclude that [Sanofi] has not met its burden
with respect to the proposed substitute claims.”). This was
error. See Aqua Prods., 872 F.3d at 1327–28.
   Even so, Mylan maintains that the Board’s error was
harmless because the Board “found that [Mylan] satisfied
SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED               7



the burden of showing the proposed substitute claims are
unpatentable by a preponderance of the evidence.” Appel-
lee Br. at 58. We disagree. While the Board at times sug-
gested Mylan had “establish[ed]” certain facts, it also noted
other failures of proof and gaps in Mylan’s expert testi-
mony. ’592 Decision, 2017 WL 4221400, at *31–32. We
therefore decline to speculate as to how the Board would
resolve this case under the correct legal standard. See, e.g.,
Sirona Dental Sys. GmbH v. Institut Straumann AG, 892
F.3d 1349, 1357 (Fed. Cir. 2018) (vacating and remanding
for the Board to reconsider the evidence after Aqua Prod-
ucts); Bosch Auto. Serv. Sols., LLC v. Matal, 878 F.3d 1027,
1040 (Fed. Cir. 2017), as amended on reh’g in part
(Mar. 15, 2018) (same); Silver Peak Sys., Inc. v. Matal, 698
F. App’x 1036 (Fed. Cir. 2017) (same).
    Mylan also contends that remand is inappropriate be-
cause Sanofi did not seek rehearing of the Board’s decision.
But Sanofi was not required to request rehearing. See In
re Magnum Oil Tools Int’l, Ltd., 829 F.3d 1364, 1377 (Fed.
Cir. 2016) (“Nowhere does the statute granting parties the
right to appeal a final written decision in an [inter partes
review] require that the party first file a request for rehear-
ing before the Board . . . .”); see also 35 U.S.C. § 141(c).
Sanofi therefore did not waive this issue. And, to the ex-
tent Mylan’s argument is premised on administrative ex-
haustion, it is similarly unpersuasive. Compare Darby v.
Cisneros, 509 U.S. 137, 154 (1993) (“[W]here the [Adminis-
trative Procedure Act] applies, an appeal to ‘superior
agency authority’ is a prerequisite to judicial review only
when expressly required by statute or when an agency rule
requires appeal before review and the administrative ac-
tion is made inoperative pending that review.”), with
35 U.S.C. § 141(c) (imposing no such requirement). We
therefore vacate the Board’s denial of Sanofi’s contingent
motion to amend and remand for proceedings consistent
with our decision in Aqua Products.
8          SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




                  B. Claim Construction
     We review the Board’s conclusions of law de novo and
its findings of fact for substantial evidence. In re Gartside,
203 F.3d 1305, 1316 (Fed. Cir. 2000). This framework also
applies to claim construction. PPC Broadband, Inc. v.
Corning Optical Commc’ns RF, LLC, 815 F.3d 747, 751
(Fed. Cir. 2016). We therefore conduct a de novo review of
the Board’s determination of the broadest reasonable inter-
pretation of the claims, reviewing any underlying factual
findings for substantial evidence. 3 Id.
    A claim’s preamble may be limiting “if it recites essen-
tial structure or steps, or if it is ‘necessary to give life,
meaning, and vitality’ to the claim.” Catalina Mktg. Int'l,
Inc. v. Coolsavings.com, Inc., 289 F.3d 801, 808 (Fed. Cir.
2002) (quoting Pitney Bowes, Inc. v. Hewlett-Packard
Co., 182 F.3d 1298, 1305 (Fed. Cir. 1999)). But, generally,
“a preamble is not limiting ‘where a patentee defines a
structurally complete invention in the claim body and uses
the preamble only to state a purpose or intended use for
the invention.’” Id. (quoting Rowe v. Dror, 112 F.3d 473,
478 (Fed. Cir. 1997)).
     Sanofi argues that the preamble of proposed claim 31
is limiting based on our decisions in Rapoport v. Dement,
254 F.3d 1053 (Fed. Cir. 2001) and Jansen. We agree.



    3   The U.S. Patent and Trademark Office has indi-
cated it intends to apply the Phillips claim construction
standard to petitions filed on or after November 13, 2018.
See Changes to the Claim Construction Standard for Inter-
preting Claims in Trial Proceedings Before the Patent Trial
and Appeal Board, 83 Fed. Reg. 51,340 (Oct. 11, 2018) (to
be codified at 37 C.F.R. pt. 42). Because Mylan filed its
petition before November 13, 2018, we apply the broadest
reasonable interpretation standard here (as the Board did
below).
SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED            9



    In Rapoport, the claims recited “[a] method for treat-
ment of sleep apneas comprising administration of a ther-
apeutically effective regimen of a Formula I azapirone
compound . . . to a patient in need of such treatment.”
254 F.3d at 1056. After noting the parties’ agreement that
the preamble should be limiting, we concurred, explaining
that the preamble—“[a] method for treatment of sleep ap-
neas”—was limiting there because “without treating the
phrase ‘treatment of sleep apneas’ as a claim limitation,
the phrase ‘to a patient in need of such treatment’ would
not have a proper antecedent basis.” Id. at 1059. We then
concluded that the most natural interpretation of “[a]
method for treatment of sleep apneas” in this context was
that the method—administering a certain compound—
must be practiced to achieve the purpose stated in the pre-
amble. Id. at 1058–61 (construing the preamble phrase
“treatment of sleep apneas” and then concluding that a cer-
tain reference did not anticipate because it was not “admin-
istered to patients suffering from sleep apnea with the
intent to cure the underlying condition”); see also Jansen,
342 F.3d at 1333 (discussing Rapoport).
    Although it was undisputed in Rapoport that the pre-
amble was limiting, when confronted with similar claims
in Jansen, we reached the same result. In Jansen, the rel-
evant claim recited:
   1. A method of treating or preventing macrocytic-
   megaloblastic anemia in humans which anemia is
   caused by either folic acid deficiency or by vitamin
   B12 deficiency which comprises administering a
   daily oral dosage of a vitamin preparation to a hu-
   man in need thereof comprising at least about 0.5
   mg. of vitamin B12 and at least about 0.5 mg. of
   folic acid.
Jansen, 342 F.3d at 1330 (emphases added). Based in part
on this claim language, and Rapoport, we reasoned that the
preamble—“[a] method of treating or preventing
10          SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




macrocytic-megaloblastic anemia”—was limiting because
it articulated the “purpose for which the method must be
performed.” Id. at 1333.
    Jansen and Rapoport support a conclusion that the pre-
amble is limiting here. 4 As in Rapoport, the phrase “pa-
tient in need thereof” from proposed claim 31 relies on the
preamble for antecedent basis. 254 F.3d at 1059. And, as
in Jansen, the preamble expresses the “intentional pur-
pose[—increasing survival—]for which the method must be
performed.” 342 F.3d at 1333. We therefore “interpret the
nearly parallel language in the [’592] patent claims in the
same way.” Id.
     Our conclusion is also consistent with the specification
of the ’529 patent, which emphasizes increasing survival as
an important aspect of the invention. Example 1 of the pa-
tent, for instance, describes a clinical study where patients
with castration resistant metastatic prostate cancer who
had previously been treated with docetaxel received either
treatment with cabazitaxel or mitoxantrone (an antitumor
antibiotic), each combined with either prednisone or pred-
nisolone. ’529 patent at col. 10, ll. 30–34, 44–45. In dis-
cussing the results of this study, the ’529 patent highlights
that patients in the cabazitaxel group demonstrated in-
creased overall survival rates compared to patients treated
with mitoxantrone and prednisone. Id. at col. 11, ll. 26–37
(“The median survival for patients in the cabazitaxel group
was 15.1 months in comparison to 12.7 months in the


     4    To the extent the Board disregarded Jansen simply
because it was on appeal from a district court, ’529 Deci-
sion, 2017 WL 4221400 at *30 (“Jansen is distinguishable
from the present case because it was an infringement
case . . . .”), it erred. Claim construction standards vary be-
tween district court litigations and inter partes reviews,
but basic principles of construction do not. Cf. Power Inte-
grations, Inc. v. Lee, 797 F.3d 1318, 1326 (Fed. Cir. 2015).
SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED               11



mitixantrone group.”); see also id. at col 1, ll. 40–43 (criti-
cizing various prior art hormone deprivation therapies be-
cause they did not “improve[] . . . survival time”).
    Mylan’s attempts to distinguish Jansen and Rapoport
are unpersuasive, and its reliance on Bristol-Myers Squibb
is misplaced. In Bristol-Myers Squibb, we concluded that
the claim language “strongly suggest[ed] the independence
of the preamble from the body of the claim.” Bristol-Myers
Squibb, 246 F.3d at 1375. But here, the claim language
suggests the opposite. Indeed, there is a direct link be-
tween the claim as a whole and the preamble, which pro-
vides an antecedent basis for “in need thereof.”
See Rapoport, 254 F.3d at 1059.
    Mylan’s reliance on the ’529 patent’s prosecution his-
tory is also unavailing. According to Mylan, the decision to
delete the phrases “effective amount” and “clinically proven
effective amount” from claim 1 and claim 24 (issued as
claim 27), respectively, reflected an “accept[ance] that the
claimed methods did not require ‘an effect on the cancer to
be treated.’” Appellee Br. at 27. Mylan therefore argues
that the claims do not require the administered doses to
have any effect on the patient. Id. But these phrases were
deleted to specify the clinically effective doses, not to sug-
gest that their effects were irrelevant. J.A. 4111–16;
J.A. 1859. And Mylan conflates concepts of curing cancer
or sending it into remission with longer survival while the
cancer remains intact. Regardless, the proposed claims
would now clearly require “increasing survival.” J.A. 681. 5


    5   Alternatively, Sanofi argues that the prosecution
history here supports its proposed construction because its
contingent motion to amend constitutes a clear and unmis-
takable disclaimer of any embodiments lacking the purpose
limitation. Mylan argues that this is not clear disclaimer.
Regardless of whether Sanofi’s motion to amend consti-
tutes a clear and unmistakable disclaimer, we conclude
12          SANOFI MATURE IP v. MYLAN LABORATORIES LIMITED




    Ultimately, the patent owner’s proposed claim 31
closely mirrors language from cases, such as Jansen and
Rapoport, which we have treated as limiting. The Board
erred by treating the preamble here as non-limiting. On
remand, the Board should therefore treat the preamble as
an additional limitation of proposed claim 31.
                      III. CONCLUSION
     For the reasons stated above, we vacate the Board’s de-
nial of Sanofi’s contingent motion to amend and its con-
struction of the proposed substitute claims and we remand
for further consideration consistent with this opinion.
                 VACATED AND REMANDED
                            COSTS
     No costs.




that it is at least relevant to the inquiry and favors treating
the preamble as limiting. Cf. Bristol-Myers, 246 F.3d at
1375 (“[T]his is not a case in which a new use of a process
should be considered to be a limitation because that new
use distinguishes the process over the prior art . . . .”).
