  United States Court of Appeals
      for the Federal Circuit
                ______________________

              GILEAD SCIENCES, INC.,
                  Plaintiff-Appellant

                           v.

   MICHELLE K. LEE, DEPUTY DIRECTOR,
  UNITED STATES PATENT AND TRADEMARK
   OFFICE, ACTING UNDER SECRETARY OF
 COMMERCE FOR INTELLECTUAL PROPERTY,
              Defendant-Appellee
            ______________________

                      2014-1159
                ______________________

   Appeal from the United States District Court for the
Eastern District of Virginia in No. 1:12-cv-01090-LO-IDD,
Judge Liam O’Grady.
                 ______________________

              Decided: February 26, 2015
               ______________________

    JONATHAN ELLOIT SINGER, Fish & Richardson P.C.,
Minneapolis, MN, argued for plaintiff-appellant. Also
represented by AHMED JAMAL DAVIS, Washington, DC;
CRAIG EARL COUNTRYMAN, San Diego, CA.

    DAVID MOSKOWITZ, Criminal Division, Fraud Section,
United States Department of Justice, Washington, DC,
argued for defendant-appellee. Also represented by DANA
J. BOENTE; BRIAN THOMAS RACILLA, NATHAN K. KELLEY,
2                                  GILEAD SCIENCES, INC.   v. LEE



JEREMIAH S. HELM, Office of the Solicitors, United States
Patent and Trademark Office, Alexandria, VA.
                ______________________

    Before DYK, WALLACH, and HUGHES, Circuit Judges.
WALLACH, Circuit Judge
    Gilead Sciences, Inc. (“Gilead”) appeals the decision of
the United States District Court for the Eastern District
of Virginia granting summary judgment to the Director of
the United States Patent and Trademark Office (“PTO”)
on whether it properly calculated the Patent Term Ad-
justment (“PTA”) period for U.S. Patent No. 8,148,374
(“the ’374 patent”). See Gilead Scis., Inc., v. Rea, 976
F.Supp.2d 833 (2013) (“Gilead I”). Because the district
court properly granted the director’s motion for summary
judgment, this court affirms.
                       BACKGROUND
                              I.
    In 1994, Congress changed the method of how a pa-
tent term is calculated. See Pub. L. No. 103-465, § 532,
108 Stat. 4809, 4984 (1994) (amending 35 U.S.C. § 154).
Under the previous statute, a patent’s term ran from the
date the patent issued until the end of a period measured
from that date––generally seventeen years, subject to
certain extensions. See Pub. L. No. 98-417, § 201, 98 Stat.
1585, 1589–99 (1984) (adding 35 U.S.C. § 156 to provide
for extensions of the term of patents covering inventions
that were subject to pre-market regulatory review).
Under the 1994 statutory provision, the patent term still
begins on the date of issuance, but generally ends twenty
years after the patent application was filed. Pub. L. No.
103-465, § 532, 108 Stat. 4809, 4984 (1994) (amending 35
U.S.C. § 154). Under the new statute, because the dura-
tion of a patent is no longer solely predicated on its date of
GILEAD SCIENCES, INC.   v. LEE                            3



issuance, delays in the patent examination process de-
crease the length of an applicant’s patent term.
     In order to address this issue, in 1999, Congress en-
acted provisions under which patent applicants may seek
PTAs for delays caused by the PTO between the filing and
issuance dates of the patent application. See Pub. L. No.
106–113, § 1000(a)(9), 113 Stat. 1501, 1536 (1999). Spe-
cifically, 35 U.S.C. § 154(b), titled “Adjustment of patent
term,” divides PTO actions which cause delay into three
general categories. Under category A, titled “Guarantee of
prompt Patent and Trademark Office responses” (“A
Delay”), a patent owner may seek a PTA if, inter alia, the
PTO does not issue a notification under § 132 or provide a
notice of allowance under § 151 within fourteen months of
an application filing. 1 35 U.S.C. § 154(b)(1)(A)(i). The
statute provides that “the term of the patent shall be
extended 1 day for each day” the PTO does not meet its
response deadlines. Id. § 154(b)(1)(A).
   Category B, titled “Guarantee of no more than 3–year
application pendency” (“B Delay”), allows for a one-day



   1   According to 35 U.S.C. § 132(a):
   Whenever, on examination, any claim for a patent
   is rejected, or any objection or requirement made,
   the Director shall notify the applicant thereof,
   stating the reasons for such rejection, or objection
   or requirement, together with such information
   and references as may be useful in judging of the
   propriety of continuing the prosecution of his ap-
   plication; and if after receiving such notice, the
   applicant persists in his claim for a patent, with
   or without amendment, the application shall be
   reexamined. No amendment shall introduce new
   matter into the disclosure of the invention.
4                                GILEAD SCIENCES, INC.   v. LEE



extension for each day the PTO fails to issue a patent
three years after the actual filing date of the application,
subject to certain limitations under § 154(b)(1)(B)(i)-(iii).
Id. § 154(b)(1)(B). Finally, category C, titled “Guarantee
of adjustments for delays due to derivation proceedings,
secrecy orders, and appeals” (“C Delay”), provides PTAs
for delays excluded from the B Delay. Id. § 154(b)(1)(C).
The C Delay accounts for each day of delay due to an
interference, secrecy order, or successful appeal.
    The statute also accounts for delays attributed to ap-
plicant conduct.    This appeal involves § 154(b)(2)(C),
which reduces PTAs by accounting for delays caused by
the patent applicant. The statutory provision provides:
    (C) Reduction of period of adjustment.—
    (i) The period of adjustment of the term of a pa-
    tent under paragraph (1) shall be reduced by a pe-
    riod equal to the period of time during which the
    applicant failed to engage in reasonable efforts to
    conclude prosecution of the application.
    (ii) With respect to adjustments to patent term
    made under the authority of paragraph (1)(B), an
    applicant shall be deemed to have failed to engage
    in reasonable efforts to conclude processing or ex-
    amination of an application for the cumulative to-
    tal of any periods of time in excess of 3 months
    that are taken to respond to a notice from the Of-
    fice making any rejection, objection, argument, or
    other request, measuring such 3-month period
    from the date the notice was given or mailed to
    the applicant.
    (iii) The Director shall prescribe regulations es-
    tablishing the circumstances that constitute a
    failure of an applicant to engage in reasonable ef-
    forts to conclude processing or examination of an
    application.
GILEAD SCIENCES, INC.   v. LEE                             5



Id. § 154(b)(2)(C)(i)-(iii) (2011) (emphasis added).
                                 II.
     Gilead owns the ’374 patent covering the compound
cobicistat. The patent relates generally to “compounds
and pharmaceutical compositions which . . . improve [] the
pharmacokinetics of a co-administered drug, and methods
of . . . improving [] the pharmacokinetics of a drug by co-
administration of the compounds with the drug.” ’374
patent col. 1 ll. 18–22. Gilead filed its application for the
’374 patent on February 22, 2008.
    When a Patent Examiner (“Examiner”) believes there
is more than one patentably distinct invention recited in
the claims, the Examiner issues a “restriction require-
ment” requesting the patent applicant to select a single
invention. See 37 C.F.R. § 1.142 (2007).
    On November 18, 2009, the PTO issued a restriction
requirement, dividing Gilead’s claims into four groups of
inventions and directing it to select a subset of its claimed
inventions before further examination. Gilead responded
to the restriction requirement on February 18, 2010 and
selected one of the four groups of inventions for examina-
tion. While waiting for the PTO to issue a first office
action on the merits, Gilead filed a supplemental infor-
mation disclosure statement (“IDS”) on April 16, 2010,
which disclosed two other co-pending Gilead patent
applications. The PTO issued a notice of allowance on
July 29, 2011 and the ’374 patent issued on April 3, 2012.
Gilead I, at 3.
    Both parties agree Gilead is entitled to a PTA as a re-
sult of the PTO’s failure to meet the statutorily-mandated
timeliness requirements of § 154 in issuing the ’374
patent. In calculating the appropriate PTA, the PTO
issued Gilead 245 days of “A Delay” for its failure to meet
the mandated statutory response deadlines and 406 days
of “B Delay” for its “failure to issue the patent within
6                                GILEAD SCIENCES, INC.   v. LEE



three years of the application’s filing date.” Id. The 651
combined days were subsequently reduced by overlapping
and applicant-induced delay. The first reduction amount-
ed to thirty-five days for overlapping delay. Id. at 3–4, see
35 U.S.C. § 154(b)(2)(A). The second reduction was for an
additional fifty-seven days. The fifty-seven day reduction
was assessed for the period between Gilead’s initial reply
to the restriction requirement and its filing of a supple-
mental IDS on April 16, 2010. Gilead I, at 4, see 35
U.S.C. § 154(b)(2)(C). In total, the PTO granted Gilead a
PTA of 559 days. Id.
    On October 27, 2011, Gilead contested the PTO’s as-
sessment of the fifty-seven day applicant delay. Gilead
argued its filing of the supplemental IDS did not cause
any actual delay and therefore should not have been
subtracted from its PTA. The PTO rejected this argu-
ment, countering, “under [35 U.S.C. §] 132, the first
action mailed by the [PTO] was the restriction require-
ment mailed [on] November 18, 2009.” J.A. 130. There-
fore, according to the PTO, Gilead’s filing of a
supplemental IDS after it had filed a response to the
restriction requirement constituted a failure to engage in
a reasonable effort to conclude prosecution as required by
37 C.F.R. § 1.704(c)(8).      Id.   According to C.F.R.
§ 1.704(c)(8):
    Circumstances that constitute a failure of the ap-
    plicant to engage in reasonable efforts to conclude
    processing or examination of an application . . .
    include the following circumstances [:] . . . Sub-
    mission of a supplemental reply or other paper,
    other than a supplemental reply or other paper ex-
    pressly requested by the examiner, after a reply has
    been filed, in which case the period of adjustment
    set forth in § 1.703 shall be reduced by the num-
    ber of days, if any, beginning on the day after the
    date the initial reply was filed and ending on the
GILEAD SCIENCES, INC.   v. LEE                            7



   date that the supplemental reply or other such
   paper was filed.
37 C.F.R. § 1.704(c)(8) (emphasis added).
    In its appeal to the district court, Gilead argued the
PTO’s interpretation and application of 35 U.S.C. § 154(b)
was “arbitrary, capricious, an abuse of discretion, or
otherwise not in accordance with the law and in excess of
statutory jurisdiction, authority, or limitation. Gilead I,
at 4 (quoting 5 U.S.C. § 706(2)(A) (1966)). The parties
subsequently filed cross-motions for summary judgment,
agreeing only questions of law were in dispute. Id.
Because it found Gilead did not succeed in showing the
PTO’s interpretation was unreasonable, the district court
granted the PTO’s motion for summary judgment. Id. at
9.
    Gilead timely files this appeal. This court has juris-
diction pursuant to 28 U.S.C. § 1295(a)(1) (2012).
                          DISCUSSION
                  I. Standard of Review
    This court reviews a district court’s grant of summary
judgment de novo. Summary judgment decisions are
reviewed under the law of the regional circuit. See
Charles Mach. Works, Inc. v. Vermeer Mfg. Co., 723 F. 3d
1376, 1378 (Fed. Cir. 2013). PTA decisions of the PTO are
reviewed in accordance with the Administrative Proce-
dure Act (“APA”). See 35 U.S.C. § 154(b)(4)(A). Under the
review provision of the APA applicable here, a court may
set aside the PTO’s actions only if they are “arbitrary,
capricious, an abuse of discretion, or otherwise not in
accordance with law.” 5 U.S.C. § 706(2)(A). When review-
ing an agency’s statutory interpretation, this court applies
the two-step framework established in Chevron, U.S.A.,
Inc. v. Natural Resources Defense Council, Inc., 467 U.S.
837 (1984). In re Cuozzo Speed Techs., LLC, No. 2014-
1301, 2015 WL 448667, at *8 (Fed. Cir. Feb. 4, 2015)
8                               GILEAD SCIENCES, INC.   v. LEE



(citing United States v. Mead Corp., 533 U.S. 218, 226–27
(2001) and Wilder v. Merit Sys. Prot. Bd., 675 F.3d 1319,
1322 (Fed. Cir. 2012)).
    II. Congress Did Not Address the Precise Question at
                           Issue
    On appeal, Gilead challenges the district court’s deni-
al of its motion for summary judgment. Gilead argues the
PTA statute only allows for adjustments in instances
where the applicant’s conduct “actually delays the conclu-
sion of prosecution.” Appellant’s Br. 11 (emphasis added).
     First, Gilead argues § 154(b)(2)(C)(i) of the statute,
which provides that any PTA for PTO delay will be re-
duced by “the period of time during which the applicant
failed to engage in reasonable efforts to conclude prosecu-
tion of the application” (emphasis added), when read in
context with surrounding statutory language, requires
applicant behavior resulting in actual delay. Id. at 11–12.
Second, Gilead points to the statutory purpose and legis-
lative history in order to support the argument that
Congress intended to penalize only applicant conduct that
causes actual delay. Id. at 12.
    Step-one of Chevron asks whether Congress “directly
addressed the precise question at issue.” Chevron, 467
U.S. at 842. The district court determined “the precise
issue is whether filing a supplemental IDS after submit-
ting a reply to a restriction requirement constitutes a
failure to engage in reasonable efforts to conclude prose-
cution of the application.” Gilead I, at 5 (internal quota-
tion marks omitted). On appeal to this court, Gilead
never actually addresses whether the district court’s
determination of the precise question at issue is correct.
Additionally, Gilead does not contend that the plain
language of the statute answers the precise question at
issue as framed by the district court. Instead, Gilead’s
Chevron step-one argument merely asserts that when
read in context with the surrounding statutory language,
GILEAD SCIENCES, INC.   v. LEE                            9



“[t]he statutory text, purpose, and legislative history all
demonstrate that the PTO is permitted to reduce patent
term adjustment only when an applicant’s behavior
actually delays the conclusion of prosecution.” Appellant’s
Br. 11.
    “[T]he ‘starting point in every case involving construc-
tion of a statute is the language itself.’” United States v.
Hohri, 482 U.S. 64, 69 (1987) (quoting Kelly v. Robinson,
479 U.S. 36, 43 (1986)). “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). Here Gilead’s contention is
problematic because nothing in the plain language of the
statute suggests reasonableness requires the applicant’s
behavior to have an effect on when the prosecution ends.
Furthermore, Gilead emphasizes the term “conclude
prosecution,” while ignoring that the statute’s “reasonable
efforts” language focuses on applicant conduct as opposed
to the results of such conduct. See 35 U.S.C.
§ 154(b)(2)(C)(i). Finally, Gilead does not point to any
language in the statute equating “reasonable efforts to
conclude prosecution of the application” as described by
§ 154(b)(2)(C)(i) to applicant conduct requiring actual
delay.
    Gilead next argues “[a]nother statutory provision con-
firms Congress’s intent to tie the ‘reasonable efforts’
clause to applicant behavior that causes actual delay.”
Appellant’s Br. 12. Specifically, Gilead contends “Con-
gress identified one specific type of applicant behavior as
a failure ‘to engage in reasonable efforts to conclude
processing or examination’ of the application––taking
over 3 months to respond to an office action.” Id. (quoting
35 U.S.C. § 154(b)(2)(C)(ii). According to Gilead, by
including a specific timeframe, this statutory provision
requires actual delay. Therefore, Gilead argues Congress
must have intended for the PTO to penalize only appli-
10                               GILEAD SCIENCES, INC.   v. LEE



cant behavior causing actual delay. Gilead urges this
court to apply the rule of ejusdem generis to
§ 154(b)(2)(C)(ii) in finding that Congress intended the
results of the applicant behavior described in that provi-
sion applies generally to § 154(b)(2)(C)(i).
    The PTO contends the interpretative rule of ejusdem
generis is inapplicable in this context. Specifically, the
PTO argues “[ejusdem generis] applies only to ‘a general
or collective term following a list of specific items to which
a particular statutory command is applicable.’” Appellee’s
Br. 34 (quoting CSX Transp., Inc. v. Ala. Dep’t. of Reve-
nue, 131 S. Ct. 1101, 1113 (2011)).
     As this court has previously held, “[u]nder the rule of
ejusdem generis, which means ‘of the same kind,’ where
an enumeration of specific things is followed by a general
word or phrase, the general word or phrase is held to refer
to things of the same kind as those specified.” Sports
Graphics, Inc. v. United States, 24 F.3d 1390, 1392 (Fed.
Cir. 1994). “We typically use ejusdem generis to ensure
that a general word will not render specific words mean-
ingless.” CSX Transp., Inc., 131 S. Ct. at 1113 (2011)
(citing Circuit City Stores, Inc. v. Adams, 532 U.S. 105,
114-15 (2001)).
    Here, ejusdem generis is inapplicable to this statutory
provision. Subsection 154(b)(2)(C)(ii) provides one in-
stance where Congress provided an example of applicant
delay. However, the third subsection of the statute does
not provide a general word or phrase, but rather employs
broad language in directing the PTO to prescribe other
instances in which applicant behavior that “constitutes a
failure of an applicant to engage in reasonable efforts to
conclude processing or examination of an application.” 35
U.S.C. § 154(b)(2)(C)(iii). Therefore, the plain language of
the statutory text does not support Gilead’s contention
that Congress meant to restrict such conduct solely to
applicant conduct causing delay.
GILEAD SCIENCES, INC.   v. LEE                           11



    In an effort to discern Congress’s intent, this court
looks to “traditional tools of statutory construction.” See
Timex V.I., Inc. v. United States, 157 F.3d 879, 882 (Fed.
Cir. 1998) (quoting Chevron, 467 U.S. at 843 n.9). “Be-
yond the statute’s text, those ‘tools’ include the statute’s
structure, canons of statutory construction, and legisla-
tive history.” Id.
    Gilead argues this court should find the “reasonable
efforts” provision of the statute requires actual delay
based on the statute’s purpose and legislative history. In
addition to its presentation of the statute’s legislative
history, see H.R. Rep. No. 106-287, at 50 (1999), Gilead
relies on two House committee reports for bills that were
not enacted. See H.R. Rep. No. 104-784, at 19–20, 33, 66–
68 (1996) (discussing the Moorhead-Schroeder Patent
Reform Act, H.R. 3460, 104th Cong. § 208 (2d Sess.
1996)); H.R. Rep. No. 105-39, at 17-18, 32-33, 64-67 (1997)
(discussing 21st Century Patent System Improvement Act,
H.R. 400, 105th Cong. (1st Sess. 1997)).
    The Supreme Court has held “[e]xtrinsic materials
have a role in statutory interpretation only to the extent
they shed a reliable light on the enacting Legislature’s
understanding of otherwise ambiguous terms.” Exxon
Mobil Corp. v. Allapattah Servs., Inc., 545 U.S. 546, 568
(2005). Here, Gilead does not contend any provision in
the statute is ambiguous. “[T]he authoritative statement
is the statutory text, not the legislative history or any
other extrinsic material.” Id. Moreover, the weight
attached to extrinsic materials is de minimis when the
legislative history is not from the enacting Congress. See
United States v. Price, 361 U.S. 304, 313 (1960); United
States v. United Mine Workers of Am., 330 U.S. 258, 282
(1947).
    Indeed, the House committee reports cited by Gilead
do not support its argument. On the contrary, the reports
lend greater support to the PTO’s construction of the
12                                GILEAD SCIENCES, INC.   v. LEE



statute. Nothing in them suggests Congress intended to
restrict PTAs based on applicant conduct to actions caus-
ing actual delay. For example, a House committee report
in support of the Moorhead-Schroeder Patent Reform Act
states “[t]he ‘reasonable efforts’ clause is an effort to avoid
the submarine patent problem. The intent of the Com-
mittee is that only the most egregious and obvious delay
tactics will go unrewarded by this provision.” H.R. Rep.
No. 104-784, at 67. Based on this provision in the report,
Gilead contends “egregious and obvious delay tactics”
suggests Congress only intended to penalize applicant
conduct resulting in actual delay. Appellant’s Br. at 14.
However, by referencing obvious delay tactics, without
addressing the result of such tactics, it appears Congress’s
primary intent was to penalize applicant conduct as
opposed to the results of such conduct.
     The House committee report in support of the PTA
bill that was actually enacted emphasized that the statute
was intended to penalize “[o]nly those who purposely
manipulate the system to delay the issuance of their
patents.” H.R. Rep. No. 106-287, at 50 (emphasis added);
see American Inventors Protection Act of 1999, H.R. 1907,
106th Cong. § 302 (1999). Gilead contends this language
supports its argument that Congress specifically targeted
applicant behavior resulting in delay.
    Adoption of Gilead’s interpretation of the statute nec-
essarily leads to an illogical distinction between appli-
cants whose conduct is intended to cause delay, but who
nonetheless fail, from those whose conduct incidentally
results in causing actual delay. In such a scenario, egre-
gious and obvious delay tactics would remain unsanc-
tioned merely because they do not result in actual delay.
Thus, because the legislative history of the statute does
not support the finding that Congress aimed to distin-
guish between patent applicants whose conduct attempts
to delay issuance of a patent from those whose conduct
GILEAD SCIENCES, INC.   v. LEE                            13



actually results in a delay, this court rejects Gilead’s
attempt to read it into the statute.
    Because Congress has not addressed the precise ques-
tion at issue in this case––whether a failure to engage in
reasonable efforts requires conduct that actually causes
delay––this court must proceed to an analysis under
Chevron step-two.
   III. The PTO’s Interpretation and Application of the
                  Statute Is Permissible
     In step-two, Chevron requires determination of
“whether the [PTO’s] answer is based on a permissible
construction of the statute.” Chevron, 467 U.S. at 842–43.
At this stage of the Chevron analysis, judicial deference to
an agency’s construction of a statutory scheme is afforded
considerable weight. Id. at 844. Chevron teaches that
when Congress explicitly leaves a gap for an agency to fill,
“[s]uch legislative regulations are given controlling weight
unless they are arbitrary, capricious, or manifestly con-
trary to the statute.” Id. Therefore, this court is required
to accept the agency’s construction of the statute even if
the agency’s reading differs from what the court believes
is the best statutory interpretation. Id.
    Gilead’s Chevron step-two argument parallels its
Chevron step-one argument, and for the same reasons
outlined above, this court rejects its contentions. Con-
gress expressly delegated authority to the PTO by grant-
ing authority to “[t]he Director [to] 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.” 35 U.S.C.
§ 154(b)(2)(C)(iii). As permitted by statute, the PTO
promulgated 37 C.F.R. § 1.704(c)(8), which encompasses
the precise situation in this case––the filing of a supple-
mental IDS after submission of a reply to a restriction
requirement. Such broad language demonstrates Con-
gress intended the PTO to employ its expertise in identi-
14                              GILEAD SCIENCES, INC.   v. LEE



fying applicant conduct demonstrating a lack of “reasona-
ble efforts to conclude processing or examination of an
application.” Id.
    Therefore, this court finds that a reasonable interpre-
tation of the statute is that Congress 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.
     Gilead’s argument also fails because it frames the is-
sue solely in terms of the patentee’s application, without
recognizing that an Examiner is required to review a
significant number of applications during a limited period
of time. As the PTO argued before the district court, “a
supplemental reply or paper often causes delay not only
in processing an examination of the particular applicant’s
application, but also with the processing and examination
of other applications before the examiner.” Gilead I, at 7.
Although an applicant’s conduct may not actually result
in delaying the issuance of that applicant’s patent, such
conduct may have negative externalities for other patent
applicants because it could result in delaying the issuance
of their patents. 2
    Gilead next argues the PTO’s interpretation of the
statute is unreasonable. According to Gilead, “[e]ven



     2  Gilead argues that actual delay did not occur be-
cause the Examiner had not yet begun reviewing its
patent application before its supplemental filing. An
examiner, however, before receiving a supplemental
filing, may think the patent application file is complete
and therefore severely underestimate the time required to
complete the patentee’s application. In doing so, the
Examiner may unintentionally lengthen the review time
for other pending applications.
GILEAD SCIENCES, INC.   v. LEE                           15



under a Chevron step[-two] analysis, the PTO’s applica-
tion of 37 C.F.R. § 1.704(c)(8) cannot stand” because “any
gap or ambiguity left by Congress has only one reasonable
resolution—reductions cannot apply to applicant actions
that do not cause actual delay in concluding prosecution.”
Appellant’s Br at 16. Specifically, Gilead contends the
regulation is impermissibly overbroad and contrary to
Congress’s intentions because it “sweep[s] in [applicant]
conduct that does not cause delay.” Id. at 24.
     As the district court noted, the conduct penalized un-
der the regulation interferes with the PTO’s ability to
conclude the application process because of significant
time constraints faced by the PTO. Because the A Delay
provision of the statute penalizes the PTO if the examiner
fails to respond within four months of the applicant’s
response to a restriction requirement, any relevant infor-
mation received after an initial response to a restriction
requirement “interferes with the [PTO’s] ability to process
an application.” Gilead I, at 7. As the district court
found, “[a] supplemental IDS, such as the one that Gilead
submitted, [may] force[] an examiner to go back and
review the application again, while still trying to meet his
or her timeliness obligations under § 154.” Id. at 8.
     Finally, Gilead contends the regulation treats similar-
ly-situated patent applicants differently. Specifically, it
argues the regulation “unreasonably treats applicants
who receive a restriction requirement differently from
those who do not” because in the event both applicants
file an IDS before the first office action on the merits,
“[t]he PTO penalizes [only] the first applicant by treating
the IDS as a ‘supplemental reply’ that triggers a reduced
adjustment.” Appellant’s Br. 19.
    The statute expressly requires the PTO to respond to
a reply under 35 U.S.C. § 132 within four months after
the date the reply is filed. 35 U.S.C. § 154(b)(1)(A)(ii).
Because the PTO characterizes restriction requirements
16                               GILEAD SCIENCES, INC.   v. LEE



as § 132 notifications, it has a significantly reduced win-
dow of time to reply to the patent applicant. See id. § 154
(b)(1)(A)(i). The difference between the two hypothetical
patent applicants as presented by Gilead is that the PTO
is not statutorily mandated to respond to the applicant
who submits a supplemental IDS, but who did not receive
a restriction requirement within the four month window
as required by the statute. Id. The regulation is a rea-
sonable interpretation of the statute because the filing of
a supplemental IDS after an initial reply to a restriction
requirement further adds to the list of documents the
PTO must consider before responding to the restriction
requirement. Therefore, the additional documents make
it increasingly difficult for the PTO to satisfy the statuto-
rily-mandated       time     requirement    stipulated     in
§ 154(b)(1)(A)(ii).
    Because this court finds the PTO’s construction of the
statute reasonable, we reject Gilead’s contention that the
regulation is overbroad and an unreasonable interpreta-
tion of the statute.
                        CONCLUSION
     For the foregoing reasons, the district court’s decision
is
                        AFFIRMED
