  United States Court of Appeals
      for the Federal Circuit
                ______________________

 SUPERNUS PHARMACEUTICALS, INC., UNITED
      THERAPEUTICS CORPORATION,
            Plaintiffs-Appellants

                          v.

    ANDREI IANCU, UNDER SECRETARY OF
  COMMERCE FOR INTELLECTUAL PROPERTY
   AND DIRECTOR OF THE UNITED STATES
     PATENT AND TRADEMARK OFFICE,
              Defendant-Appellee
            ______________________

                      2017-1357
                ______________________

   Appeal from the United States District Court for the
Eastern District of Virginia in No. 1:16-cv-00342-GBL-
IDD, Judge Gerald Bruce Lee.
                ______________________

              Decided: January 23, 2019
               ______________________

    DOUGLAS H. CARSTEN, Wilson, Sonsini, Goodrich &
Rosati, PC, San Diego, CA, argued for plaintiffs-
appellants. Also represented by VERONICA SUSANA
ASCARRUNZ, ADAM WILLIAM BURROWBRIDGE, Washington,
DC.
2                 SUPERNUS PHARMACEUTICALS, INC    v. IANCU



     SHAUN R. SNADER, United Therapeutics Corporation,
Washington, DC, for plaintiff-appellant United Therapeu-
tics Corporation.

    R. TRENT MCCOTTER, Office of the United States
Attorney for the Eastern District of Virginia, Alexandria,
VA, argued for defendant-appellee Andrei Iancu. Also
represented by KAKOLI CAPRIHAN, BRIAN RACILLA, Office
of the Solicitor, United States Patent and Trademark
Office, Alexandria, VA.
                 ______________________

    Before DYK, SCHALL, and REYNA, Circuit Judges.
REYNA, Circuit Judge.
    Supernus Pharmaceuticals, Inc. and United Thera-
peutics Corp. appeal the entry of summary judgment by
the U.S. District Court for the Eastern District of Virgin-
ia. The district court determined that, based on this
court’s decision in Gilead Sciences, Inc. v. Lee, the U.S.
Patent and Trademark Office’s calculation of the patent
term adjustment for the patent at issue was correct, and
that summary judgment was warranted as a matter of
law. We reverse the district court’s grant of summary
judgment because the patent term adjustment in this case
went beyond the period during which the applicant failed
to undertake reasonable efforts and thereby exceeded the
limitations set by the patent term adjustment statute.
                        BACKGROUND
                            I.
    The life of a patent, the period of time during which
the exclusive nature of a patent is in effect, is measured
in years and days and is referred to as the “term” of the
patent or “patent term.” Prior to June 8, 1995, the term
of a patent was seventeen years, measured from the date
that the patent issued to its expiration date seventeen
SUPERNUS PHARMACEUTICALS, INC     v. IANCU                   3



years later. See Merck & Co. v. Kessler, 80 F.3d 1543,
1547 (Fed. Cir. 1996).
     When the United States entered the World Trade Or-
ganization, it assumed certain obligations and commit-
ments under the terms of the World Trade Organization
Agreement on Trade Related Aspects of Intellectual
Property Rights. See Agreement on Trade-Related As-
pects of Intellectual Property Rights, 33 I.L.M. 1197
(1994). As a result, Congress changed the patent term
from seventeen years to twenty years, measured from the
filing date of the earliest United States non-provisional
application for the patent. See Pub. L. No. 103-465, § 532,
108 Stat. 4809, 4984 (1994) (codified at 35 U.S.C.
§ 154(a)(2)).
     In addition to extending the patent term from seven-
teen years to twenty years, Congress passed the patent
term adjustment (“PTA”) statute in 1999 in an effort to
discourage delay in the patent application process. See
Pub. L. No. 106-113, § 1000(a)(9), 113 Stat. 1501, 1536
(1999) (codified at 35 U.S.C. § 154(b)).          Specifically,
§ 154(b) grants the U.S. Patent and Trademark Office
(“USPTO”) authority to adjust the patent term by adding
days to account for delays caused by the USPTO. See id.
§§ 154(b)(1)(A)–(C). Such adjustments are favorable to an
applicant because they extend the life of the patent. But
the USPTO may also reduce the PTA in order to account
for delays caused by the applicant. Id. § 154(b)(2); see,
e.g., Gilead Scis., Inc. v. Lee, 778 F.3d 1341, 1343–45 (Fed.
Cir. 2015).
    Section 154(b)(1) outlines three types of delays caused
by the USPTO, known as Types A, B, and C, that can
result in a PTA. Adjustments for a Type A delay apply
when the USPTO fails to provide a notification under 35
U.S.C. § 132 or a notice of allowance within fourteen
months of an application’s filing.              35 U.S.C.
§ 154(b)(1)(A)(i). The statute provides that “the term of
4                  SUPERNUS PHARMACEUTICALS, INC   v. IANCU



the patent shall be extended 1 day for each day” the
USPTO does not meet its response deadlines.            Id.
§ 154(b)(1)(A). Similarly, Type B adjustments extend the
patent term by one day for every day that the USPTO
fails to issue a patent after three years have passed
between the filing date of the application and the date of
allowance. Id. § 154(b)(1)(B). Finally, Type C adjust-
ments are for delays that are excluded from the Type B
delay due to derivation proceedings, secrecy orders, or
successful appeals. Id. § 154(b)(1)(C).
    As noted above, the statute recognizes that conduct by
the applicant may also cause delay in the examination or
prosecution of the application. Section 154(b)(2)(C) au-
thorizes the USPTO to reduce the total amount of PTA for
Type A, B, and C delays by deducting the number of days
equal to the period of time that “the applicant failed to
engage in reasonable efforts to conclude prosecution of the
application.” Id. § 154(b)(2)(C)(i). An applicant is deemed
to have failed to engage in reasonable efforts for the
cumulative time in excess of three months that the appli-
cant takes to respond to a notice of rejection, objection,
argument, or other request from the USPTO.               Id.
§ 154(b)(2)(C)(ii). The statute provides that the Director
of the USPTO “shall prescribe regulations establishing
the circumstances that constitute a failure of an applicant
to engage in reasonable efforts to conclude processing or
examination of an application.” Id. § 154(b)(2)(C)(iii).
    The Director of the USPTO has promulgated such
regulations: 37 C.F.R. § 1.704, titled “Reduction of period
of adjustment of patent term.” 37 C.F.R. § 1.704 (2015).
Relevant here is § 1.704(c)(8), which regulates the calcu-
lation for reduction of PTA in instances where the appli-
cant submits a supplemental paper to the USPTO.
Section 1.704(c)(8) provides:
    Submission of a supplemental reply or other pa-
    per, other than a supplemental reply or other pa-
SUPERNUS PHARMACEUTICALS, INC    v. IANCU                  5



      per expressly requested by the examiner, after a
      reply has been filed, in which case the period of
      adjustment set forth in § 1.703 [that extends the
      patent’s term due to USPTO delay] shall be re-
      duced by the number of days, if any, beginning on
      the day after the date the initial reply was filed
      and ending on the date that the supplemental re-
      ply or other such paper was filed . . . .
Id.
    The USPTO has also promulgated regulations that
permit an applicant to file an information disclosure
statement (“IDS”) up to the end of the patent examination
process, while providing incentives for an applicant to
submit any necessary IDS promptly. Id. §§ 1.97(a)–(d).
As relevant here, the USPTO will accept without condi-
tion an IDS that is filed before notice of the first office
action after the applicant has filed a request for continued
examination (“RCE”). Id. § 1.97(b)(4). Also relevant here,
when an applicant submits an IDS disclosing a communi-
cation from a foreign patent office, there is a thirty-day
safe harbor that exempts reduction of PTAs under
§ 1.704(c)(8), provided that the IDS is submitted within
thirty days of the applicant receiving the information
from the foreign patent office that is eventually contained
in the IDS. 1 Id. § 1.704(d)(1).



      1 There are various requirements that apply to a
submission of an IDS that are independent of the PTA.
For example, during prosecution, the applicant generally
has a duty of candor and good faith that includes a duty to
disclose all information known to the applicant to be
material to the patentability of the claims. See 37 C.F.R.
§ 1.56(a).   Specifically, applicants are encouraged to
“carefully examine” prior art cited in search reports of a
6                 SUPERNUS PHARMACEUTICALS, INC    v. IANCU



                            II.
    The relevant facts in this case are not in dispute. Ap-
pellant Supernus Pharmaceuticals, Inc. (“Supernus”) is
the owner and assignee of the patent at issue, U.S. Patent
No. 8,747,897 (“the ’897 patent”), titled “Osmotic Drug
Delivery System.” Co-Appellant United Therapeutics
Corp. (“UTC”) is the exclusive licensee of the ’897 patent.
UTC assisted in the prosecution of the patent application
and took action as the applicant in that capacity. Super-
nus and UTC are collectively referred to herein as “Su-
pernus.”
    On April 27, 2006, Supernus filed U.S. Patent Appli-
cation No. 11/412,100 (“the ’100 application”). On August
20, 2010, the USPTO issued a final rejection. On Febru-
ary 22, 2011, Supernus filed an RCE, which removed the
finality of the rejection and permitted the examiner to
consider additional information submitted by Supernus.
35 U.S.C. § 132(b); 37 C.F.R. § 1.114. The ’100 application
issued on June 10, 2014, as the ’897 patent.
    On the same day it filed the ’100 application, Super-
nus filed international application PCT/US2007/009969,
claiming priority from the ’100 application. The interna-
tional application gave rise to European Application No.
07755989.6. On October 13, 2011, the European Patent
Office (“EPO”) issued the European application as Euro-
pean Patent EP2010189 (“the EP patent”). On August 21,
2012, the EPO notified Supernus’s European patent
counsel that a Notice of Opposition was filed by Sandoz




foreign patent office in a counterpart application “to make
sure that any material information contained therein is
disclosed” to the USPTO. Id. Such disclosure can be
submitted in the form of an IDS. See id. § 1.98.
SUPERNUS PHARMACEUTICALS, INC   v. IANCU                 7



AG to the EP patent, citing 10 documents (“the Sandoz
Opposition”).
    On September 11, 2012, Supernus received a letter
from its European patent counsel disclosing the EPO
notification and the Sandoz Opposition. Seventy-nine
days later, or 100 days from the EPO notification of the
Sandoz Opposition, Supernus submitted a supplemental
IDS on November 29, 2012, informing the USPTO of the
Sandoz Opposition and providing the documents cited in
the Sandoz Opposition, the Sandoz Opposition itself, the
EPO notification, and the letter from Supernus’s Europe-
an patent counsel. 2
    On September 10, 2013, the USPTO issued a first Of-
fice Action responding to Supernus’s RCE. On January
10, 2014, Supernus filed a response. On February 4,
2014, the USPTO issued a Notice of Allowance. On June
10, 2014, the USPTO issued the ’897 patent, reflecting a
PTA of 1,260 days, meaning that the USPTO had added
1,260 days to the patent’s twenty-year term.
    In calculating the PTA, the USPTO attributed 2,321
days to USPTO delay: 1,656 days for Type A delays (for
the USPTO’s failure to meet the mandated statutory
response deadlines), and 665 days for Type B delays (for
the USPTO’s failure to issue the patent within three
years of the application’s filing date). See J.A. 80. Next,
the USPTO reduced the PTA of 2,321 days by 175 days to
account for overlapping Type A and Type B delays, and by
886 days for applicant delay to arrive at the total 1,260-
day PTA. Relevant here, of the 886 days attributed to
applicant delay, 646 days were assessed for the period



   2   Supernus did not attempt to invoke the protec-
tions of the thirty-day safe harbor established by
37 C.F.R. § 1.704(d)(1).
8                  SUPERNUS PHARMACEUTICALS, INC   v. IANCU



between the February 22, 2011 filing of the RCE and the
November 29, 2012 submission of the IDS. This appeal
focuses on this 646-day reduction in the PTA due to
purported applicant delay.
    Supernus filed a request for Reconsideration of Patent
Term Adjustment on grounds that the deduction of the
646-day period was improper. 3 Supernus argued that “37
C.F.R. § 1.704(c)(8) does not govern post-RCE submis-
sions.” J.A. 510–11. According to Supernus, another
regulation—37 C.F.R. § 1.704(c)(6)—should apply instead.
     The USPTO rejected the request for reconsideration.
The USPTO determined that under this court’s decision
in Gilead, submission of an IDS after the filing of a re-
sponse to an election or restriction requirement is subject
to a reduction under 37 C.F.R. § 1.704(c)(8) because any
relevant information submitted to the USPTO after an
initial reply interferes with the USPTO’s ability to process
an application. J.A. 521. The USPTO found that “[t]he
same analysis applies to submission of an IDS document
after the filing of an RCE” because “[a]ny IDS submission
by [a] patentee after the filing of a[n] RCE ‘interferes’
with the [USPTO’s ability] to process an application
because the examiner may be forced to go back and review
the application again.” Id. The USPTO concluded that
37 C.F.R. § 1.704(c)(8) applies and that the reduction of


    3   Supernus also argued that the USPTO erred in
deducting 126 days from the PTA for the period between
the time of allowance and the time of issuance, following
this court’s then recent decision in Novartis AG v. Lee,
740 F.3d 593, 602 (Fed. Cir. 2014) (holding that the time
between allowance and issuance may not be reduced from
the PTA). The USPTO agreed and awarded the 126 days
to Supernus, which brought the final total PTA of the ’897
patent to 1,386 days.
SUPERNUS PHARMACEUTICALS, INC   v. IANCU                  9



the PTA by the 646 days due to applicant delay was
proper.
    Supernus appealed to the U.S. District Court for the
Eastern District of Virginia and filed a motion for sum-
mary judgment on the grounds that 37 C.F.R.
§ 1.704(c)(8) is arbitrary, capricious, and contrary to the
PTA statute. Supernus Pharm., Inc. v. Lee, No. 1:16-CV-
00342, 2016 WL 8739331, at *4 (E.D. Va. Oct. 18, 2016).
Supernus also argued that 37 C.F.R. § 1.704(d)(1) is
similarly arbitrary and capricious, and contrary to the
PTA statute. Id. at *6. Finally, Supernus argued that out
of the 646-day period that the USPTO attributed to
applicant delay, it was entitled to at least 546 of those
days—i.e., the period between its filing of the RCE and
the EPO notification of the Sandoz Opposition. 4 Id. The
USPTO filed an opposition and cross-motion for summary
judgment. Id. at *2.
    The district court granted summary judgment in favor
of the USPTO. Id. at *8. The district court concluded
that the USPTO did not err in the PTA calculation for the
’897 patent and that this court’s decision in Gilead fore-
closed, as a matter of law, Supernus’s statutory interpre-
tation arguments that 37 C.F.R. § 1.704(c)(8) and
§ 1.704(d)(1) are arbitrary, capricious, and otherwise
contrary to the PTA statute. Id. at *4–8 (citing Gilead,
778 F.3d at 1350).



   4     Supernus concedes that it failed to engage in “rea-
sonable efforts” for the remaining 100 days of the 646-day
period: from the EPO notification to Supernus’s submis-
sion of the supplemental IDS. Appellant Reply Br. 2. On
appeal, Supernus only challenges the USPTO’s assess-
ment of the preceding 546 days as applicant delay. Appel-
lant Br. 59.
10                 SUPERNUS PHARMACEUTICALS, INC    v. IANCU



    Supernus timely filed this appeal. We have jurisdic-
tion pursuant to 28 U.S.C. §§ 1295(a)(1), 1295(a)(4)(C)
(2012).
                        DISCUSSION
                   I. Standard of Review
    This court reviews a district court’s grant of summary
judgment under the law of the regional circuit, in this
case, the Fourth Circuit. See Mohsenzadeh v. Lee, 790
F.3d 1377, 1381 (Fed. Cir. 2015); Charles Mach. Works,
Inc. v. Vermeer Mfg. Co., 723 F.3d 1376, 1378 (Fed. Cir.
2013). Applying the law of the Fourth Circuit, we review
the grant of summary judgment de novo. Gallagher v.
Reliance Standard Life Ins. Co., 305 F.3d 264, 268 (4th
Cir. 2002). Patent term adjustment decisions of the
USPTO are reviewed in accordance with the Administra-
tive Procedure Act (“APA”). 35 U.S.C. § 154(b)(4)(A);
Gilead, 778 F.3d at 1346. Under the APA, a court should
set aside the USPTO’s actions if found to be “in excess of
statutory jurisdiction, authority, or limitations,” or “arbi-
trary, capricious, an abuse of discretion, or otherwise not
in accordance with law.” 5 U.S.C. §§ 706(2)(A), (C); Gile-
ad, 778 F.3d at 1346. When reviewing an agency’s statu-
tory interpretation, this court applies the two-step
framework established in Chevron U.S.A. Inc. v. Nat. Res.
Def. Council, Inc., 467 U.S. 837 (1984). See Gilead, 778
F.3d at 1346.
                         II. Gilead
    As a preliminary issue, we note that this court has
grappled with the reasonableness of 37 C.F.R.
§ 1.704(c)(8), a regulation asserted in this appeal by the
USPTO. In Gilead, this court held that the regulation “is
a reasonable interpretation of the [PTA] statute” insofar
as it includes “not only applicant conduct or behavior that
result in actual delay, but also those having the potential
to result in delay irrespective of whether such delay
SUPERNUS PHARMACEUTICALS, INC   v. IANCU                11



actually occurred.” Gilead, 778 F.3d at 1349–50. This
court also acknowledged that § 1.704(c)(8) encompasses
the filing of a supplemental IDS in the calculated delay
period. Id. at 1349.
    In Gilead, the patent owner Gilead brought an action
challenging the USPTO’s assessment of a 57-day appli-
cant delay in calculating PTA deduction, based on Gile-
ad’s delay during examination between its initial reply to
a restriction requirement and its submission of a supple-
mental IDS disclosing two other co-pending Gilead patent
applications. Id. at 1345–46. The district court granted
summary judgment in favor of the USPTO, and we af-
firmed. Id. at 1346, 1350–51. Engaging in the Chevron
analysis, this court concluded that Congress did not
address the precise question at issue, i.e., “whether a
failure to engage in reasonable efforts requires conduct
that actually causes delay,” and that Congress expressly
delegated authority to the USPTO to prescribe regula-
tions establishing circumstances that constitute a failure
of an applicant to engage in reasonable efforts to conclude
examination. See id. at 1349–50. At step two of Chevron,
we recognized that we give deference to the agency where
Congress explicitly left a gap to fill and held that a rea-
sonable interpretation of the PTA statute was that “Con-
gress intended to sanction not only applicant conduct or
behavior that result in actual delay, but also those having
the potential to result in delay irrespective of whether
such delay actually occurred.” Id. Thus, the resultant
regulation, 37 C.F.R. § 1.704(c)(8), was reasonable insofar
as it included both potential and actual delay. Id.
    We conclude that Gilead does not foreclose Supernus’s
statutory interpretation argument. Supernus’s argument
is that any reduction in PTA may not exceed the “time
during which the applicant failed to engage in reasonable
efforts to conclude prosecution of the application.” 35
U.S.C. § 154(b)(2)(C)(i). Gilead ruled only that the regu-
lation reasonably drew no line between actual and poten-
12                 SUPERNUS PHARMACEUTICALS, INC    v. IANCU



tial delay and could include a supplemental IDS. It did
not hold the regulation was reasonable in reducing PTA
for periods during which there was no failure to engage in
reasonable efforts to conclude prosecution. Gilead simply
did not address the precondition—failure to engage in
reasonable efforts—at issue here.
     In Gilead, Appellant Gilead had two other co-pending
patent applications that it disclosed in the supplemental
IDS. Gilead could have submitted the supplemental IDS
disclosing its co-pending applications when it filed its
response to the restriction requirement. Gilead, there-
fore, involved a period of time during which the applicant
could have taken identifiable efforts to conclude prosecu-
tion but did not. Gilead focused on whether the statute
required the applicant’s failure to take reasonable efforts
to have resulted in actual delay, as opposed to the poten-
tial to cause delay, to count towards reduction of PTA.
     In contrast, this case is not about whether efforts tak-
en by Supernus, or those it could have taken, resulted in
actual or potential delay. Supernus contends, and the
USPTO does not dispute, that Supernus could not have
undertaken any efforts to conclude prosecution of the ’100
application during the 546-day period between the filing
of the RCE on February 22, 2011, and the EPO’s notifica-
tion of the Sandoz Opposition on August 21, 2012.
J.A. 552–53; Appellant Br. 7 n.3; Appellee Br. 16–17.
    In addition, the precise question addressed in Gilead
was not the precise question under review in this case. In
Gilead, the “precise question” reviewed by the court in its
Chevron analysis was “whether a failure to engage in
reasonable efforts requires conduct that actually causes
delay.” Gilead, 778 F.3d at 1349. That question fell
within the USPTO’s gap-filling authority to determine
what constitutes “reasonable efforts.” Id.; 35 U.S.C.
§ 154(b)(2)(C)(iii). The precise question in this case is
whether the USPTO may reduce PTA by a period that
SUPERNUS PHARMACEUTICALS, INC    v. IANCU                 13



exceeds the “time during which the applicant failed to
engage in reasonable efforts to conclude prosecution.” 35
U.S.C. § 154(b)(2)(C)(i). Gilead did not decide that ques-
tion.
    Because Gilead involved different facts and a different
legal question, Gilead is not controlling in this action. Cf.
Fed. Election Comm’n v. Wis. Right To Life, Inc., 551 U.S.
449, 456, 467 (2007) (Roberts, C.J., writing in non-
majority section of the opinion of the Court) (noting that
upholding a facial challenge to a statute does not foreclose
all future challenges to the statute in the particular
circumstances of another case). The district court erred,
therefore, when it granted the USPTO summary judg-
ment on the basis of this court’s decision in Gilead. And
because, as we next conclude, the statute plainly resolves
the question at issue here against the USPTO, we reverse
the district court’s grant of summary judgment.
                 III. Chevron Framework
    A. The PTA Statute Answers the Precise Question
    This case presents a question of statutory interpreta-
tion by an agency to which we apply the Chevron frame-
work. The first step of our legal analysis, therefore, is to
“ask whether the statute’s plain terms ‘directly addres[s]
the precise question at issue.’” Nat’l Cable & Telecomms.
Ass’n v. Brand X Internet Servs., 545 U.S. 967, 986 (2005)
(quoting Chevron, 467 U.S. at 843). The precise question
at issue in this case is whether the USPTO may reduce
PTA by a period that exceeds the “time during which the
applicant failed to engage in reasonable efforts to con-
clude prosecution.” 35 U.S.C. § 154(b)(2)(C)(i).
    We begin by looking at the plain language of the PTA
statute. See United States v. Hohri, 482 U.S. 64, 69
(1987) (“[T]he ‘starting point in every case involving
construction of a statute is the language itself.’” (quoting
Kelly v. Robinson, 479 U.S. 36, 43 (1986))); Suprema, Inc.
14                 SUPERNUS PHARMACEUTICALS, INC    v. IANCU



v. Int’l Trade Comm’n, 796 F.3d 1338, 1346 (Fed. Cir.
2015) (en banc) (“Chevron’s framework begins with the
language of the statute.”). “Absent a clearly expressed
legislative intention to the contrary, [the statute’s plain]
language must ordinarily be regarded as conclusive.”
Consumer Prod. Safety Comm’n v. GTE Sylvania, Inc.,
447 U.S. 102, 108 (1980).
     In this case, the pertinent language of the PTA stat-
ute is plain, clear, and conclusive. “Congress has supplied
a clear and unambiguous answer to the interpretive
question at hand.” Pereira v. Sessions, 138 S. Ct. 2105,
2113 (2018); see also Chevron, 467 U.S. at 842–43 (“If the
intent of Congress is clear, that is the end of the matter;
for the court, as well as the agency, must give effect to the
unambiguously expressed intent of Congress.”) On the
basis of the plain language of the statute, we hold that the
USPTO may not count as applicant delay a period of time
during which there was no action that the applicant could
take to conclude prosecution of the patent. Doing so
would exceed the time during which the applicant failed
to engage in reasonable efforts.
     The PTA statute provides in pertinent part:
     (b) Adjustment of patent term.—
     ....
     (2) Limitations.—
     ....
     (C) Reduction of period of adjustment.—
     (i) The period of adjustment of the term of a patent
     under paragraph (1) shall be reduced by a period
     equal to the period of time during which the ap-
     plicant failed to engage in reasonable efforts to
     conclude prosecution of the application.
35 U.S.C. § 154(b)(2)(C)(i) (emphases added).
SUPERNUS PHARMACEUTICALS, INC   v. IANCU                 15



     A plain reading of the statute shows that Congress
imposed two limitations on the amount of time that the
USPTO can use as applicant delay for purposes of reduc-
ing PTA. First, the statute expressly requires that any
reduction to PTA be equal to the period of time during
which an applicant fails to engage in reasonable efforts.
Second, the statute expressly ties reduction of the PTA to
the specific time period during which the applicant
failed to engage in reasonable efforts.
     The PTA statute requires that any PTA reduction be
equal to the period of time during which an applicant
fails to engage in reasonable efforts. The word “equal” is
widely understood to mean “the same in amount, number,
or size.” E.g., Equal, Cambridge Dictionary of American
English 287 (2000). Stated differently, PTA reduction
cannot exceed the period of time during which an appli-
cant failed to engage in reasonable efforts. Thus, if there
is no period of time during which the applicant could
have but failed to engage in reasonable efforts, there can
be no reduction to the PTA. The word “during” is similar-
ly understood to mean “from the beginning to the end of (a
particular period)” or “at some time between the begin-
ning and the end of (a period).” E.g., During, Cambridge
Dictionary of American English 267 (2000). The preced-
ing “shall” “generally imposes a nondiscretionary duty.”
SAS Inst. Inc. v. Iancu, 138 S. Ct. 1348, 1354 (2018); see
also Kingdomware Techs., Inc. v. United States, 136 S. Ct.
1969, 1977 (2016) (discussing that “shall” is mandatory
and connotes a requirement). Thus, the statutory period
of PTA reduction must be the same number of days as the
period from the beginning to the end of the applicant’s
failure to engage in reasonable efforts to conclude prose-
cution. PTA cannot be reduced by a period of time during
which there is no identifiable effort in which the applicant
could have engaged to conclude prosecution because such
time would not be “equal to” and would instead exceed the
time during which an applicant failed to engage in rea-
16                 SUPERNUS PHARMACEUTICALS, INC   v. IANCU



sonable efforts. This is consistent with the PTA exten-
sions of “1 day for each day” granted for the A, B, and C
types of USPTO delays.
    The “equal to” limitation ensures that applicants will
be charged the full amount of time corresponding to their
own delay. See Gilead, 778 F.3d at 1348–49 (“[I]t appears
Congress’s primary intent was to penalize applicant
conduct as opposed to the results of such conduct.”). By
the same token, the “equal to” limitation protects appli-
cants by ensuring that PTA can only be reduced by peri-
ods of time during which the applicant failed to engage in
such efforts. See id. at 1344 (“[B]ecause the duration of a
patent is no longer solely predicated on its date of issu-
ance, delays in the patent examination process decrease
the length of an applicant’s patent term.”); H.R. Rep. No.
106-287, pt. 1, at 50 (1999) (“[N]o patent applicant dili-
gently seeking to obtain a patent will receive a term of
less than the 17 years as provided under the pre-GATT
standard.” (footnote omitted)). The expressed legislative
intent is consistent with the plain language of the statute.
The USPTO cannot, therefore, count as applicant delay
any period of time during which there were no efforts in
which the applicant could have engaged to conclude
prosecution of the patent. See SAS Inst., 138 S. Ct. at
1355 (“Where a statute’s language carries a plain mean-
ing, the duty of an administrative agency is to follow its
commands as written, not to supplant those commands
with others it may prefer.”).
    A period of time including no identifiable efforts that
could have been undertaken cannot be “equal to” the
period of failure to undertake reasonable efforts under the
terms of the statute. To conclude otherwise renders the
PTA statute’s “reasonable efforts” language superfluous.
This understanding of the plain language makes practical
sense and is consistent with the legislative history be-
cause Congress intended the PTA statute to discourage
dilatory conduct by patent applicants and reward appli-
SUPERNUS PHARMACEUTICALS, INC   v. IANCU               17



cants that take action to conclude prosecution of the
patent. See H.R. Rep. 106-287, at 49–50.
B. The USPTO’s Assessment of Applicant Delay is Incon-
            sistent with the PTA Statute
    As shown in the figure below, the USPTO reduced the
PTA by 646 days due to applicant delay. Supernus con-
cedes that it failed to engage in “reasonable efforts” for
the last 100 days of the 646-day period. It states, howev-
er, that there was nothing it could have done during the
period of time from the filing of the RCE and original IDS
to the EPO communication.




Appellant Br. 8 (reproduced and modified).
    We agree with Supernus that there were no efforts
that it could have taken in the period of time during the
preceding 546 days. The record is silent as to what Su-
pernus could have done to conclude prosecution during
the 546-day time period, beginning with the filing of the
RCE/IDS on February 22, 2011, and ending on the date of
the EPO notification, August 21, 2012. Nor does the
USPTO contend that Supernus could have undertaken
any “reasonable efforts” during the 546-day time period to
conclude prosecution. To the contrary, the facts indicate
18                SUPERNUS PHARMACEUTICALS, INC    v. IANCU



that there was no action Supernus could have taken to
advance prosecution of the patent during the 546-day
period, particularly because the EPO notice of opposition
did not yet exist. Here, the USPTO’s interpretation of the
statute would unfairly penalize applicants, fail to incen-
tivize applicants not to delay, and fail to protect appli-
cants’ full patent terms. The USPTO’s additional 546-day
assessment as applicant delay is contrary to the plain
meaning of the statute because the 646-day total reduc-
tion is not equal to a period of time during which
Supernus failed to engage in reasonable efforts to con-
clude prosecution of the ’897 patent. The USPTO’s inter-
pretation of the PTA statute applied in these
circumstances exceeds the statutory limitations for PTA
reduction and therefore, the USPTO actions are “in excess
of statutory . . . authority.” See 5 U.S.C. § 706(2)(C).
     This decision is consistent with the intent of Con-
gress. Congress chose to speak plainly to the precise issue
by setting limitations on the period of PTA reduction. See
City of Arlington. v. FCC, 569 U.S. 290, 296 (2013) (“Con-
gress knows to speak in plain terms when it wishes to
circumscribe, and in capacious terms when it wishes to
enlarge, agency discretion.”). Congress intended that the
PTA statute not adversely impact applicants like Super-
nus who could have done nothing to advance prosecution.
To be sure, Congress expressly granted the USPTO au-
thority to determine what constitutes reasonable efforts,
but the USPTO lacks any authority to exceed the statuto-
ry “equal to” limitation by including the 546-day time
period during which it does not contend that Supernus
failed to undertake reasonable efforts to conclude prosecu-
tion.
                       CONCLUSION
    The USPTO argues that 37 C.F.R. §§ 1.704(c)(8) and
(d)(1) are reasonable exercises of its rulemaking authori-
ty. For the reasons discussed above, neither regulation
SUPERNUS PHARMACEUTICALS, INC   v. IANCU                19



empowers the USPTO to exceed its statutory authority as
it has done in these circumstances by assessing a PTA
reduction that exceeds the statutory limitations. We
determine that the PTA statute addresses the precise
question at issue, so our inquiry ends at step one of the
Chevron analysis. “Because the language of the statute
itself controls this case and sets an unambiguous rule,”
we need not go further in our analysis of the specific
regulations asserted in this appeal. Wyeth v. Kappos, 591
F.3d 1364, 1372 (Fed. Cir. 2010) (citing Smith v. City of
Jackson, 544 U.S. 228, 267 (2005) (Scalia, J., concurring
in part and concurring in the judgment) (“Of course, it is
elementary that ‘no deference is due to agency interpreta-
tions at odds with the plain language of the statute it-
self.’”)). Any reduction to PTA shall be “equal to the
period of time during which the applicant fail[s] to engage
in reasonable efforts to conclude prosecution of the appli-
cation.” 35 U.S.C. § 154(b)(2)(C)(i).
    We find the USPTO’s PTA reduction to be incon-
sistent with the PTA statute and, as a result, we accord
no deference to the USPTO’s application of the regula-
tions at issue in these circumstances. See Wyeth, 591
F.3d at 1372. We have considered the USTPO’s remain-
ing arguments and find them unpersuasive. We conclude
that the district court erred in granting summary judg-
ment in favor of the USPTO. Based on the foregoing
reasoning, we reverse the district court’s summary judg-
ment order and remand for further proceedings consistent
with this opinion.
            REVERSED AND REMANDED
                          COSTS
   No costs.
