  United States Court of Appeals
      for the Federal Circuit
                ______________________

  NATURAL ALTERNATIVES INTERNATIONAL,
                 INC.,
                Appellant

                           v.

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

                      2017-1962
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 95/002,001.
                  ______________________

               Decided: October 1, 2018
               ______________________

    SCOTT A. M. CHAMBERS, Porzio, Bromberg & Newman,
PC, Washington, DC, argued for appellant. Also repre-
sented by RICHARD J. OPARIL, KEVIN M. BELL, BILLY DELL
CHISM; MATTHEW ZAPADKA, Bass, Berry & Sims, PLC,
Washington, DC.

   MARY L. KELLY, Office of the Solicitor, United States
Patent and Trademark Office, Alexandria, VA, argued for
2                           NATURAL ALTERNATIVES v. IANCU




intervenor. Also represented by THOMAS W. KRAUSE,
ROBERT J. MCMANUS, AMY J. NELSON.
               ______________________

     Before PROST, Chief Judge, MOORE and REYNA,
                    Circuit Judges.
PROST, Chief Judge.
     Woodbolt Distributors, LLC (“Woodbolt”) requested
that the United States Patent and Trademark Office
(“PTO”) reexamine U.S. Patent No. 8,067,381 (“the ʼ381
patent”) owned by Natural Alternatives International,
Inc. (“NAI”). The PTO ordered inter partes reexamina-
tion, and the examiner rejected the challenged claims as
anticipated by or obvious over cited prior art, including a
parent of the reexamined patent. NAI appeals the Patent
Trial and Appeal Board’s (“Board”) final determination
affirming the examiner’s rejections and its subsequent
denial of NAI’s request for rehearing. Woodbolt is not a
party to this appeal. The Director of the PTO has inter-
vened to defend the Board’s decision. We have jurisdic-
tion pursuant to 28 U.S.C. § 1295(a)(4)(A). We affirm.
                       BACKGROUND
     Between 1997 and 2011, NAI filed a chain of eight
U.S. patent applications generally directed to increasing
athletes’ endurance. The eighth application matured into
the ʼ381 patent, the subject of this appeal. NAI filed the
first application in the chain on August 12, 1997, and
within five years, it had filed three more. In each such
continuing application, NAI included a priority benefit
statement under 35 U.S.C. § 120 claiming priority back to
the filing date of the first U.S. application, which eventu-
ally issued on October 12, 1999, as U.S. Patent No.
NATURAL ALTERNATIVES v. IANCU                              3



5,965,596 (“the ʼ596 patent”). 1 NAI also filed a provision-
al application (“the 2003 provisional application”) on April
10, 2003, while the fourth application was still pending
before the PTO. Before the fourth application issued on
January 20, 2004, NAI filed the fifth application, a con-
tinuation-in-part, on November 18, 2003. The fifth appli-
cation claimed priority to the fourth through first
applications and to the 2003 provisional application.
Intervenor’s Br. 4–5. NAI filed its sixth application on
August 29, 2008, during the fifth application’s pendency.
At that time, the sixth application correctly claimed
priority to the fifth application, and the fifth application
correctly claimed priority to the fourth application, and so
on.
                              I
     On September 2, 2008, just four days after filing its
sixth application, NAI amended the “Cross Reference of
Related Applications” section of the fifth application to
delete the benefit claim to the fourth through the first
applications and to claim priority under 35 U.S.C. § 119(e)
to only the 2003 provisional application. J.A. 8035; see 35
U.S.C. § 119(e) (governing claiming priority to an earlier-
filed provisional application). Thus, when the fifth appli-
cation issued as U.S. Patent No. 7,504,376 (“the ʼ376
patent”) on March 17, 2009, it claimed the benefit of only
the 2003 provisional application’s filing date. The sixth
through the eighth applications subsequently issued as
patents, but with a statement seeking the benefit of the


    1   Each U.S. application in the chain also included a
priority benefit statement under 35 U.S.C. § 119(a),
claiming priority back to the filing date of a British patent
application that NAI filed in 1996 (“the 1996 British
application”). The validity of that priority claim is not
before us today, so we do not discuss it.
4                            NATURAL ALTERNATIVES v. IANCU




fifth through the first applications, in addition to the 2003
provisional application. The ʼ381 patent on appeal here
issued from the eighth application on November 29, 2011.
                             II
     District court litigation involving the ʼ381 patent
commenced between NAI and Woodbolt in December
2011. 2 In May 2012, during that proceeding, Woodbolt
sought inter partes reexamination of the asserted patent
claims. 3 The request alleged that “the asserted claim to
priority of the ʼ381 Patent is defective” because the “ap-
plicants deliberately and expressly terminated their claim
to the priority of the first four applications[,]” which thus
“broke[] the chain of priority between the Fourth and
Fifth Applications.” J.A. 45–46. During reexamination,
NAI did not dispute that it had waived priority to the
fourth through the first applications in its fifth applica-
tion. J.A. 971. But it insisted that the sixth application
maintained priority back to the first application because
NAI did not amend the “Cross Reference of Related Appli-
cations” in the sixth application. According to NAI, it was
irrelevant what happened to the fifth application once the
sixth application became entitled to the first application’s
filing date. J.A. 975. Unpersuaded, the examiner finally
rejected the reexamined claims in view of prior art includ-
ing the ʼ596 patent (i.e., the patent that issued from the




    2   Woodbolt and NAI have since settled their lawsuit
concerning the ʼ381 patent. See Appellant’s Br. 1.
    3   Under the Leahy-Smith America Invents Act, in-
ter partes review replaced inter partes reexamination as
the avenue for third-party patentability challenges in the
PTO. See Pub. L. No. 112–29, § 6(a), 125 Stat. 284, 299–
304 (2011).
NATURAL ALTERNATIVES v. IANCU                              5



first application), and then closed prosecution. 4 J.A. 1210,
1226.
     NAI appealed the examiner’s decision to the Board.
The Board determined that when NAI filed the eighth
application, “[t]he fifth application [was] not entitled to
the benefit of the fourth application since the specific
reference to the fourth application was deleted in the
fifth.” J.A. 13. Because the eighth application claimed
priority to the first application via the fifth application,
the Board determined that the eighth application (and
thus the ʼ381 patent) was also not entitled to the benefit
of the fourth through the first applications. See J.A. 16.
The Board issued a final written determination affirming
the examiner’s rejections and denied NAI’s request for
rehearing.
                        DISCUSSION
    NAI challenges the Board’s priority determination. 5
According to NAI, the Board erred by denying the ʼ381
patent priority back to the first U.S. application in the
priority chain under § 120. Appellant’s Br. 2–3.
                              I
    Entitlement to priority under § 120 is a legal deter-
mination based on underlying fact findings. See In re
Owens, 710 F.3d 1362, 1366 (Fed. Cir. 2013). When the
underlying facts are undisputed, priority date determina-
tion is purely a legal question. Medtronic CoreValve v.
Edwards Lifesciences Corp., 741 F.3d 1359, 1363 (Fed.


    4   The eighth application is a “Continuation of a
Continuation of the Sixth Application/Patent[.]” See
Appellant’s Br. 26–27; Intervenor’s Br. 3–5.
    5   NAI’s challenge to the Board’s finding of anticipa-
tion relies entirely on the priority date issue. See Appel-
lant’s Br. 3 n.2, 46–47.
6                            NATURAL ALTERNATIVES v. IANCU




Cir. 2014). Because this appeal presents no disputed
factual issues relevant to the Board’s priority determina-
tion, we review the Board’s legal conclusions de novo. See
Stevens v. Tamai, 366 F.3d 1325, 1330 (Fed. Cir. 2004).
                              II
     NAI argues that the Board erred by denying the ʼ381
patent priority back to the first U.S. application in the
priority chain. See Appellant’s Br. 46–47. Its argument
proceeds in four parts. First, NAI contends that priority
to the first application “vested” with the sixth application
once the sixth application met all the criteria of § 120.
See id. at 31–34. Second, NAI claims that this is so—even
though an intervening application waived priority to the
first application—because a waiver of priority is limited to
the instant application and does not extend to subsequent
applications. Id. at 35–36. Third, in NAI’s view, the
Board reached a contrary determination because the
Board erroneously viewed priority as a single growing
chain rather than multiple fixed chains. Appellant’s Br.
34, 38. Fourth, such a view, according to NAI, “limits an
applicant’s ability to seek protection” when “amending [a]
priority claim to gain [patent] term.” Id. at 38. We ad-
dress each part of NAI’s argument in turn.
                              A
     NAI first argues that the Board erred in its determi-
nation that “priority does not ‘vest.’” Id. at 33. According
to NAI, “[p]riority properly vested by virtue of meeting all
the requirements of § 120.” Id. at 34. NAI asserts that
Loughlin v. Ling dictates this conclusion because it states
that “[p]rovided the criteria in § 120 are met, applications
‘shall,’ without exception, receive the benefit of the earlier
filing date.” 684 F.3d 1289, 1293 (Fed. Cir. 2012); see
Appellant’s Br. 31. The Board considered this argument
and found it unpersuasive. See J.A. 12.
NATURAL ALTERNATIVES v. IANCU                                7



     Section 120 of title 35 sets forth requirements for a
U.S. patent application to claim priority based on an
earlier-filed nonprovisional application. See Medtronic
CoreValve, 741 F.3d at 1363. When NAI filed the applica-
tion that became the ʼ381 patent, § 120 provided the
following:
    An application for patent for an invention [1] dis-
    closed in the manner provided by section 112(a)
    . . . [2] filed by an inventor or inventors named in
    the previously filed application shall have the
    same effect, as to such invention, as though filed
    on the date of the prior application, [3] if filed be-
    fore the patenting or abandonment of or termina-
    tion of proceedings on the first application or on
    an application similarly entitled to the benefit of
    the filing date of the first application and [4] if it
    contains or is amended to contain a specific refer-
    ence to the earlier filed application. No applica-
    tion shall be entitled to the benefit of an earlier
    filed application under this section unless an
    amendment containing the specific reference to
    the earlier filed application is submitted at such
    time during the pendency of the application as re-
    quired by the Director. The Director may consider
    the failure to submit such an amendment within
    that time period as a waiver of any benefit under
    this section.
35 U.S.C. § 120 (2000) (emphases and numbering added).
“Specific reference,” in the context of § 120, means that
the application seeking the benefit must state (or be
amended to state) that it claims the benefit of the earlier-
filed application’s filing date, identifying each earlier-filed
application by number and explaining how the applica-
tions are related to one another.           Droplets, Inc. v.
E*TRADE Bank, 887 F.3d 1309, 1315–16 (Fed. Cir. 2018).
8                            NATURAL ALTERNATIVES v. IANCU




    NAI’s “vesting” argument conflates properly claiming
priority and demonstrating entitlement to priority.
Patent claims “are not entitled to an earlier priority date
merely because the patentee claims priority.” In re NTP,
Inc., 654 F.3d 1268, 1276 (Fed. Cir. 2011). Rather, “for a
patent’s claims to be entitled to an earlier priority date,
the patentee must demonstrate that the claims meet the
requirements of 35 U.S.C. § 120.” Id. (emphasis added).
Accordingly, claims in a patent or patent application are
not entitled to priority under § 120 at least until the
patent owner proves entitlement to the PTO, the Board, or
a federal court. See PowerOasis, Inc. v. T-Mobile USA,
Inc., 522 F.3d 1299, 1305–06 (Fed. Cir. 2008) (explaining
that “when neither the PTO nor the Board has previously
considered priority, there is simply no reason to presume
that claims in a [continuation-in-part] application are
entitled to the effective filing date of an earlier filed
application,” so the district court may place the burden on
the patent owner to “come forward with evidence to prove
entitlement to claim priority to an earlier filing date”); see
also In re NTP, Inc., 654 F.3d at 1277 (“[W]hen a patentee
argues that its claims are entitled to the priority date of
an earlier filed application, the examiner must undertake
a priority analysis to determine if the patentee meets the
requirements of § 120.”); Manual of Patent Examining
Procedure (“MPEP”) § 201.08 (providing that “[t]he [PTO]
does not need to make a determination as to whether the
[35 U.S.C. § 112(a)] requirement of 35 U.S.C. [§] 120” is
met “unless the filing date of the earlier nonprovisional
application is relied upon in a proceeding before the
[PTO]”).
    Furthermore, examiners and adjudicators cannot be
expected to scrutinize the prosecution history of an appli-
cation and each parent application to determine whether
the application would have met § 120’s requirements at
any point during its pendency. See, e.g., Droplets, 887
NATURAL ALTERNATIVES v. IANCU                              9



F.3d at 1317 (explaining that “it would be improper to
place the burden on the public to unearth and decipher a
priority claim when the ‘patentee is the person best suited
to understand the genealogy and relationship of her
applications,’ and a ‘requirement for her to clearly disclose
this information should present no hardship’”); see also
Medtronic CoreValve, 741 F.3d at 1366 (“Congress may
well have thought that Section 120 was necessary to
eliminate the burden on the public to engage in long and
expensive search of previous applications in order to
determine the filing date of a later patent.” (quoting
Sticker Indus. Supply Corp. v. Blaw-Knox Co., 405 F.2d
90, 93 (7th Cir. 1968))).
     In re Janssen Biotech, Inc. is instructive here. 880
F.3d 1315 (Fed. Cir. 2018). In In re Janssen Biotech, the
patentee attempted during reexamination to amend its
patent to delete a benefit claim to a parent application,
among other proposed amendments. Id. at 1320. We
noted that even though the patentee “had never received
issued claims . . . on the subject matter originating from
the [parent] application, more than thirty-two issued
patents ‘reached through the [reexamined] patent for
benefit of a prior filing date’ and ‘the patentability of
those claims . . . cannot be determined without reopening
examination of those patents in view of the deletion of the
subject matter in the [reexamined] patent.” Id.; see id. at
1323; see also Searle LLC v. Lupin Pharm., Inc., 790 F.3d
1349, 1355 (Fed. Cir. 2015) (observing that if a patent
owner had obtained foreign patent protection based on a
Patent Cooperation Treaty (“PCT”) application, altering
the scope of the PCT application could call into question
the proper scope of those foreign patents). In short, we
have previously acknowledged that amending an earlier-
filed parent application may affect the priority of its child
applications.
10                          NATURAL ALTERNATIVES v. IANCU




     And we do so again here. The Board determined that
when filed, the eighth application did not meet the “spe-
cific reference” requirement of § 120 as to the filing date
of the first application. J.A. 11–12. That was so, accord-
ing to the Board, because the eighth application claimed
the benefit of the first application’s filing date by way of
the fifth application, and NAI had amended the fifth
application to claim priority to only the 2003 provisional
application. See id. In other words, because the fifth
application lacked priority to the first application, the
eighth application’s priority claim to the first application
(via the fifth application) did not satisfy all of § 120’s
requirements. The Board, therefore, did not err in deter-
mining that the ʼ381 patent was not entitled to claim the
benefit of the filing date of the first application under
§ 120, as the priority claim in the ʼ381 patent was defec-
tive from the start.
                             B
     Next, NAI avers that although “a claimed benefit to
an earlier filing date may later be altered in the instant
application according to MPEP § 201.11, . . . that altera-
tion applies only to the instant application—not oth-
er, . . . applications.” 6  Appellant’s Reply Br. 15.
According to the MPEP, which is “commonly relied upon
as a guide to patent attorneys and patent examiners on
procedural matters,” Litton Sys., Inc. v. Whirlpool Corp.,
728 F.2d 1423, 1439 (Fed. Cir. 1984), “[a] cancellation of a
benefit claim to a prior application may be considered as a
showing that the applicant is intentionally waiving the
benefit claim to the prior application in the instant appli-


     6 Although outdated, we refer to MPEP § 201.11 to
remain consistent with Appellant’s briefs. See, e.g.,
Appellant’s Reply Br. 7. The subject matter of § 201.11,
however, now exists in MPEP § 211.
NATURAL ALTERNATIVES v. IANCU                            11



cation,” MPEP § 201.11(III)(G) (8th ed., Rev. 1) (2003)
(emphasis added); MPEP § 211.02(a)(III) (9th ed., Rev. 7)
(2015) (same).
    Although the Board did not explicitly address this ar-
gument, the PTO responds that NAI reads MPEP
§ 201.11 “too narrowly.” Intervenor’s Br. 34–35. Specifi-
cally, the PTO notes that “the [MPEP] passage does not
state that cancellation of a benefit claim may be consid-
ered a waiver in only the instant application.” Id. at 35.
The PTO, applying this broader interpretation, asserts
that “the intentional cancellation of a benefit claim pur-
suant to MPEP § 201.11 can similarly affect another
application’s entitlement to a benefit claim.” Id. We
agree with the PTO.
     As an initial matter, we note that the MPEP “does not
have the force of law[,]” Molins PLC v. Textron, Inc., 48
F.3d 1172, 1180 n.10 (Fed. Cir. 1995), and does not bind
us, Litton Sys., 728 F.2d at 1439. Nonetheless, we have
reviewed MPEP § 201.11 and find that nothing in its text
limits the scope of waiver to only the instant application.
Indeed, § 201.11 does not contemplate all possible conse-
quences of waiving a benefit claim in a particular applica-
tion. Moreover, at least in the context of terminal
disclaimers, the MPEP has explicitly indicated when a
disclaimer applies only to the instant application and not
to downstream applications. See, e.g., Hagenbuch v.
Sonrai Sys., 2015 U.S. Dist. LEXIS 39083, *10–13 (N.D.
Ill. Mar. 27, 2015) (explaining that “[t]he MPEP in effect
in 1993 described the effect of a disclaimer that, by its
terms, applied only to the ‘instant application’”); see also
MPEP § 1490(VI)(B) (9th ed., Rev. 8) (2017) (“A terminal
disclaimer filed to obviate a nonstatutory double patent-
ing rejection is effective only with respect to the applica-
tion or patent identified in the disclaimer unless by its
terms it extends to continuing applications . . . .”).
12                          NATURAL ALTERNATIVES v. IANCU




                             C
    Further, NAI summarily concludes that “[r]ather than
the dogmatic view of seeing additional continuation filings
merely adding an additional link in a single growing
chain, § 120, and the case law, must be interpreted as
providing for a new priority chain being created at each
new filing.” Appellant’s Br. 34.
    NAI, however, neither explains why § 120 compels
this interpretation of priority claims nor provides any case
law to support its conclusion. Nor does NAI provide any
argument to undermine the long-standing interpretation
of priority as a single chain, growing with each additional
continuation. The Supreme Court has previously ex-
plained that under § 120, parent and continuing applica-
tions “are to be considered as parts of the same
transaction, and both as constituting one continuous
application, within the meaning of the law.” Godfrey v.
Eames, 68 U.S. 317, 326 (1863); see also Sticker Indus.,
405 F.2d at 93 (stating that “each application in a long
chain grows out of the one immediately preceding it”). We
therefore decline to adopt NAI’s interpretation of chain of
priority.
                             D
    Finally, NAI argues that the Board’s determination
impermissibly “limits an applicant’s ability to seek protec-
tion” when “amending the priority claim to gain [patent]
term.” See Appellant’s Br. 38. NAI’s argument suggests
that NAI need not trade the benefit of an earlier filing
date in order to gain patent term. See id. at 36 (arguing
that by waiving priority in the parent application, it was
not waiving priority in the child application). Although
the Board did not explicitly address this argument, the
PTO asserts that because NAI “chose to delete the benefit
claim in its fifth U.S. application and thereby obtained a
longer term for the patent issuing therefrom[,]” a “conse-
quence of this voluntary action is that [NAI’s] sixth
NATURAL ALTERNATIVES v. IANCU                              13



through eighth U.S. applications would no longer be
entitled to the benefit of the filing date of its fourth
through first U.S. applications.” Intervenor’s Br. 14.
Again, we agree with the PTO.
     Continuation-in-part (“CIP”) applications, like the
fifth application in this case, uniquely highlight the trade-
off between priority and patent term. 7 In CIP applica-
tions, priority is assessed on a claim-by-claim basis.
Transco Prods., Inc. v. Performance Contracting, Inc., 38
F.3d 551, 557 n.6 (Fed. Cir. 1994). An applicant can
obtain an earlier effective filing date for claims in a CIP
application only if those claims find support in an earlier-
filed nonprovisional application. Id. Claims reciting new
matter, however, are entitled to only the filing date of the
CIP application and not to the filing date of the earlier-
filed application. Id. Because the standard patent term
is twenty years after an application’s earliest-claimed
priority date, see 35 U.S.C. § 154(a)(2) (emphasis added), 8
the claims reciting new matter are not entitled to the
parent application’s earlier filing date, and they therefore
have a truncated patent term (i.e., less than twenty



    7     “A continuation-in-part is an application filed dur-
ing the lifetime of an earlier nonprovisional application
. . ., repeating some substantial portion or all of the earli-
er nonprovisional application and adding matter not
disclosed in the said earlier nonprovisional application.”
Univ. of W. Va. v. Van Voorhies, 278 F.3d 1288, 1297 (Fed.
Cir. 2002).
      8   As of June 8, 1995, see Uruguay Round Agree-
ments Act, Pub. L. No. 103–465, § 532, 108 Stat. 4809,
4984 (1994), U.S. applications that claim priority to an
earlier-filed U.S. application will have a patent term of
twenty years from the filing date of the earliest U.S.
application to which it claims a priority benefit. 35 U.S.C.
§ 154(a)(2).
14                          NATURAL ALTERNATIVES v. IANCU




years). See 5 Donald S. Chisum, Chisum on Patents
§ 16.04[6][b] (2016).
    An uncommon but permissible way for patent appli-
cants to avoid losing term on claims that recite new
matter is to disclaim the benefit of earlier filing dates.
See MPEP §§ 211.02(a)(III). Thus, by deleting the benefit
claim in a CIP application, the twenty-year patent term of
the patent issuing from that CIP application would ex-
tend from the CIP application’s filing date instead of the
parent application’s earlier filing date. See id. Of course,
once the CIP application adopts the later filing date, the
CIP application and its children become vulnerable to
rejections based on a larger pool of prior art—including
former parent applications in some cases. See, e.g., San-
tarus, Inc. v. Par Pharm., Inc., 694 F.3d 1344, 1352 (Fed.
Cir. 2012) (finding that “[d]ue to breaks in the chain of
priority,” the “[parent] patent [was] prior art for some of
the asserted claims”).
    Under NAI’s theory of priority, however, NAI could
gain patent term on its fifth application while simultane-
ously shielding its child applications (including the eighth
application) from their former parents. For the reasons
discussed herein, NAI cannot have it both ways.
                            III
     We have considered NAI’s remaining arguments and
find them unpersuasive. For the foregoing reasons, the
Board’s final decision invalidating the challenged claims
is affirmed.
                       AFFIRMED
