  United States Court of Appeals
      for the Federal Circuit
                ______________________

GILEAD SCIENCES, INC., HOFFMANN-LA ROCHE,
   INC., F. HOFFMANN-LA ROCHE, LTD., AND
              GENENTECH, INC.,
               Plaintiffs-Appellees,

                           v.

NATCO PHARMA LIMITED AND NATCO PHARMA,
                  INC.,
          Defendants-Appellants.
          ______________________

                      2013-1418
                ______________________

    Appeal from the United States District Court for the
District of New Jersey in Nos. 11-CV-1455 and 11-CV-
4969, Judge Susan D. Wigenton.
                ______________________

                Decided: April 22, 2014
                ______________________

   LEORA BEN-AMI, Kirkland & Ellis LLP, of New York,
New York, argued for plaintiffs-appellees. With her on
the brief were PATRICIA A. CARSON and BENJAMIN A.
LASKY.

   JEREMY C. LOWE, Axinn, Veltrop & Harkrider LLP, of
Hartford, Connecticut, argued for defendants-appellants.
With him on the brief was THOMAS K. HEDEMANN.
                ______________________
2            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




    Before RADER, Chief Judge, PROST and CHEN, Circuit
                         Judges.
    Opinion for the court filed by Circuit Judge CHEN.
      Dissenting opinion filed by Chief Judge RADER.
CHEN, Circuit Judge.
     Gilead Sciences, Inc. (“Gilead”) owns United States
Patent Nos. 5,763,483 and 5,952,375, which are directed
to antiviral compounds and methods for their use. While
the patents list the same inventors and the written de-
scriptions disclose similar content, they do not claim
priority to a common patent application and have differ-
ent expiration dates. Gilead sued Natco Pharma Limited
(“Natco”) for infringement of the ’483 patent after Natco
filed a request with the Food and Drug Administration
seeking approval to market a generic version of one of
Gilead’s drugs that is allegedly covered by the ’483 pa-
tent. In response, Natco asserted that the ’483 patent
was invalid for obviousness-type double patenting over
Gilead’s ’375 patent. In Gilead’s view, the ’375 patent
cannot serve as a double patenting reference against the
’483 patent because, even though the ’483 patent’s expira-
tion date is twenty-two months after the ’375 patent’s
expiration date, the ’375 patent issued after the ’483
patent.
    The United States District Court for the District of
New Jersey agreed with Gilead and, pursuant to a stipu-
lation, granted it final judgment on infringement. Natco
appeals that judgment and argues that the ’375 patent
should qualify as an obviousness-type double patenting
reference for the ’483 patent because it expires before the
’483 patent. Because the obviousness-type double patent-
ing doctrine prohibits an inventor from extending his
right to exclude through claims in a later-expiring patent
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED             3




that are not patentably distinct from the claims of the
inventor’s earlier-expiring patent, we agree with Natco
that the ’375 patent qualifies as an obviousness-type
double patenting reference for the ’483 patent. We there-
fore vacate the district court’s decision and remand.
                               I
    The ’375 and ’483 patents were issued to the same in-
ventors and are commonly owned by Gilead. The inven-
tions disclosed in both patents are related to the
inhibition of viruses through selective interference with
certain enzymes. The written descriptions of the patents
are very similar and, in substantial parts, identical.
    Despite their similarities in content, however, the ’375
and ’483 patents are not part of the same family of pa-
tents and were not before the same patent examiner.
Instead, Gilead crafted a separate “chain” of applications,
having a later priority date than the ’375 patent family.
That separate chain resulted in the issuance of the ’483
patent. Because the patents do not claim priority to any
common application, they will expire at different times as
governed by the provisions of the Uruguay Rounds
Agreement Act. The ’375 patent was filed on February
26, 1996, and claims priority to a regular utility patent
application filed on February 27, 1995. It expires twenty
years later on February 27, 2015, and issued on Septem-
ber 14, 1999. The ’483 patent was filed on December 27,
1996, and claims priority to a provisional utility patent
application filed on December 29, 1995. Though filed
after the application for the ’375 patent, it issued first, on
June 9, 1998, and expires last, on December 27, 2016. 1



    1  Although the ’483 patent’s priority date is based
on the filing date of a provisional application (December
29, 1995), it expires twenty years from the patent’s earli-
4            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




     After the ’483 patent issued, Gilead filed a terminal
disclaimer in the application that led to the ’375 patent.
Through it, Gilead disclaimed any portion of the ’375
patent term that extended beyond the expiration date of
the ’483 patent—which, absent abandonment, would not
occur since, as explained above, the ’375 patent’s expira-
tion date is before the ’483 patent’s expiration date. From
the prosecution history records, that appears to be the
first time Gilead informed either the examiner of the ’375
patent or of the ’483 patent about the existence of the
other patent application. No terminal disclaimer was
filed for the ’483 patent.
    The following diagram illustrates the relevant dates
for each patent, and how, because of different priority
dates, the two patents have different expiration dates.




                            II
    In March 2011, Gilead filed the current suit against
Natco, alleging that Natco’s Abbreviated New Drug
Application No. 202-595 infringed the ’483 patent. Among
other defenses, Natco asserted that the ’483 patent was
invalid for obviousness-type double patenting in light of
claim 8 of the ’375 patent. In December 2012, the district


est non-provisional filing date (December 27, 1996). See
35 U.S.C. § 154.
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED             5




court granted summary judgment in favor of Gilead on
Natco’s double patenting defense.
    Relying on two district court cases, the court conclud-
ed that “a later-issued but earlier-expiring patent” cannot
“serve as a double-patenting reference against an earlier-
issued but later-expiring patent.” J.A. 7 (citing Abbott
Labs. v. Lupin Ltd., 2011 WL 1897322 (D. Del. May 19,
2011) and Brigham & Women’s Hosp. Inc. v. Teva Pharm.
USA, Inc., 761 F. Supp. 2d 210 (D. Del. 2011)). 2 It ex-
plained that “[t]he Uruguay Round Agreements Act of
1994, which became effective on June 8, 1995, changed
the term for a U.S. patent from seventeen years from the
patent issue date to twenty years from the earliest effec-
tive filing date.” J.A. 6 (citing Uruguay Round Agree-
ments Act (“URAA”), Pub.L. No. 103–465, § 532(a), 108
Stat. 4809, 4983–85 (1994)). In the district court’s view,
any “extensions of the patent terms at issue were not



    2   The district court did not cite Ex Parte Pfizer, Inc.,
Patent Owner & Appellant, 2010 WL 532133 (Bd. Pat.
App. & Interf. Feb. 12, 2010). In that case, the Board of
Patent Appeals and Interferences held that an earlier-
expiring patent could qualify as an obviousness-type
double patenting reference regardless of whether it issues
prior to or after another patent. Id. at *21. According to
the Board, it was the “patent term and not the patent
issue date that determines if a claim . . . qualifies as a
double patenting reference.” Id. The later-expiring
patent, in the Board’s opinion, would impermissibly block
the public from practicing the invention (and obvious
derivations thereof) disclosed in the patents that expired
first—which was “precisely what obviousness-type double
patenting was intended to prevent”—an extension of a
patentee’s “right to exclude the public from practicing” the
invention in an expired patent. Id.
6             GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




unlawful because the extensions were not a result of
gamesmanship, but instead were a result of changes to
patent laws.” J.A. 7.
    In May 2013, after Natco conditionally stipulated to
infringement of two claims of the ’483 patent, the district
court certified its summary judgment ruling for appeal
under Rule 54(b) because Natco’s “only invalidity defense
on the ’483 patent” was obviousness-type double patent-
ing. J.A. 10.
    Natco filed a timely appeal. We have jurisdiction un-
der 28 U.S.C. § 1295(a). For purposes of this appeal, we
assume that the ’483 patent claims a mere obvious vari-
ant of the invention claimed in the ’375 patent.
                             III
     This appeal presents a narrow question: Can a patent
that issues after but expires before another patent qualify
as a double patenting reference for that other patent? We
conclude under the circumstances of this case that it can
and, therefore, that the district court erred in excluding
the ’375 patent as a potential double patenting reference
for the ’483 patent.
                              A
     The prohibition against double patenting is a long-
standing doctrine of patent law. It is based on the core
principle that, in exchange for a patent, an inventor must
fully disclose his invention and promise to permit free use
of it at the end of his patent term. As the Supreme Court
has explained, “[i]t is self-evident that on the expiration of
a patent the monopoly created by it ceases to exist, and
the right to make the thing formerly covered by the
patent becomes public property. It is upon this condition
that the patent is granted.” Singer Mfg. Co. v. June Mfg.
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED            7




Co., 163 U.S. 169, 185 (1896). 3 The bar against double
patenting was created to preserve that bargained-for right
held by the public. See, e.g., Miller v. Eagle Mfg. Co., 151
U.S. 186, 197-98, 202 (1894); Suffolk Co. v. Hayden, 70
U.S. 315, 317 (1865); Boehringer Ingelheim Int’l GmbH v.
Barr Labs., Inc., 592 F.3d 1340, 1346 (Fed. Cir. 2010); In
re Longi, 759 F.2d 887, 892 (Fed. Cir. 1985); Application
of Robeson, 331 F.2d 610, 614 (CCPA 1964); Odiorne v.
Amesbury Nail Factory, 18 Fed. Cas. 578, 579 (C.C.D.
Mass. 1819). If an inventor could obtain several sequen-
tial patents on the same invention, he could retain for
himself the exclusive right to exclude or control the pub-
lic’s right to use the patented invention far beyond the
term awarded to him under the patent laws. As Justice
Story explained in 1819, “[i]t cannot be” that a patentee
can obtain two patents in sequence “substantially for the
same invention[] and improvements”; “it would completely
destroy the whole consideration derived by the public for
the grant of the patent, viz. the right to use the invention
at the expiration of the term.” Odiorne, 18 Fed. Cas. at


    3    See also, e.g., Dastar Corp. v. Twentieth Century
Fox Film Corp., 539 U.S. 23, 33-34 (2003) (“The rights of a
patentee . . . are part of a carefully crafted bargain . . .
under which, once the patent . . . monopoly has expired,
the public may use the invention . . . at will and without
attribution.” (internal quotation marks and citations
omitted)); Sears, Roebuck & Co. v. Stiffel Co., 376 U.S.
225, 230 (1964) (“[W]hen the patent expires the monopoly
created by it expires, too, and the right to make the article
. . . passes to the public.”); Miller v. Eagle Mfg. Co., 151
U.S. 186, 197-98 (1894) (explaining history of and collect-
ing cases on double patenting); In re Hubbell, 709 F.3d
1140, 1145 (Fed. Cir. 2013); In re Longi, 759 F.2d 887, 892
(Fed. Cir. 1985); Odiorne v. Amesbury Nail Factory, 18
Fed. Cas. 578, 579 (C.C.D. Mass. 1819) (Story, J.).
8            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




579. Thus, the doctrine of double patenting was primarily
designed to prevent such harm by limiting a patentee to
one patent term per invention or improvement.
    The scope of the bar against double patenting has also
been well-established in patent law jurisprudence. Fed-
eral courts for over a century have applied the principles
of the doctrine as a means to preserve the public’s right to
use not only the exact invention claimed by an inventor
when his patent expires, but also obvious modifications of
that invention that are not patentably distinct improve-
ments. See Eli Lilly & Co. v. Barr Labs., Inc., 251 F.3d
955, 967 (Fed. Cir. 2001) (“The judicially-created doctrine
of obviousness-type double patenting . . . prohibit[s] a
party from obtaining an extension of the right to exclude
through claims in a later patent that are not patentably
distinct from claims in a commonly owned earlier pa-
tent.”). 4 With the addition of § 253 in 1952, however,



    4   See also, e.g., In re Hubbell, 709 F.3d at 1145; In
re Longi, 759 F.2d at 892; In re Peiler, 56 F.2d 878, 878
(CCPA 1932) (affirming double patenting rejection where
claim “covered the same inventive idea” as “obvious to any
one skilled in the art on inspection and examination of the
disclosures of the parent application”); In re Swan, 46
F.2d 572, 573 (CCPA 1931) (affirming double patenting
rejection of specific use for prior invention where there
was not “a patentable distinction between [the] former
patent and th[e] further and more specific claim [in the
new patent application]”); Kirsch Mfg. Co. v. Gould
Mersereau Co., 6 F.2d 793, 794 (2d Cir. 1925) (Hand, J.)
(affirming invalidity of patent on double patenting
grounds after concluding that the later claims were “an
obvious modification” that “accomplishes substantially the
same result” by “difference in means [that] did not require
invention” that was “a new display of ingenuity beyond
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED          9




Congress slightly altered the effect of the bar on double
patenting.
     In Application of Robeson, our predecessor court first
addressed the impact of that statutory provision, which in
part permits a patentee to disclaim any terminal part of
the term of his patent without a disclaimer of claim scope.
331 F.2d at 614. It explained that 35 U.S.C. § 253’s
terminal disclaimer provision provided patent owners a
remedy against a double patenting charge by “per-
mit[ting] the patentee to cut back the term of a later
issued patent so as to expire at the same time as the
earlier issued patent.” Robeson, 331 F.2d at 614 n.4
(citing commentary of P.J. Federico). Relying on that
understanding of the purpose of terminal disclaimers
permitted by the new § 253, the court concluded that a
terminal disclaimer could negate a double patenting
rejection in some instances.
   Where, as here, the claimed subject matter is an
   obvious modification of what has already been
   claimed, a second patent is contrary to one of the
   fundamental principles underlying the patent sys-
   tem, namely, that when the right to exclude
   granted by a patent expires at the end of the pa-
   tent term, the public shall be free to use the in-
   vention as well as obvious modifications thereof or


the compass of the routineer” or “the limited imagination
of the journeyman”); In re Isherwood, 46 App. D.C. 507,
511 (D.C. Cir. 1917); Otis Elevator Co. v. Portland Co.,
127 F. 557, 561-63 (1st Cir. 1903); Palmer Pneumatic Tire
Co. v. Lozier, 90 F. 732, 740-45 (6th Cir. 1898); Swift v.
Jenks, 29 F. 642, 643 (C.C.N.D.N.Y. 1887); Wheeler v.
McCormick, 29 F. Cas. 905, 909 (C.C.S.D.N.Y. 1873);
Smith v. Ely, 22 F. Cas. 533, 537 (C.C.D. Ohio 1849)
remanded on other grounds, 56 U.S. 137 (1853).
10            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




     obvious improvements thereon. Thus, to grant a
     second patent for an obvious variation deprives
     the public of those rights. If, however, the second
     patent expires simultaneously with the first, the
     right to fully utilize the patented discovery at the
     expiration date remains unimpaired. . . . [H]ere,
     the only real objection to granting appellant’s ap-
     plication is an extension of the monopoly. The
     terminal disclaimer, which Congress had express-
     ly provided, removes any danger of such result.
Id. at 614-15.
    Thus, the Robeson court reasoned that a terminal dis-
claimer should be a permissible means to overcome the
prohibition on double patenting when it aligns the expira-
tion dates of an inventor’s several patents that claim mere
obvious variations of the same invention to create a single
term of limited exclusivity. Id.; see Gen. Foods Corp. v.
Studiengesellschaft Kohle mbH, 972 F.2d 1272, 1280 (Fed.
Cir. 1992) (explaining that “obviousness-type double
patenting . . . could be overcome by filing a terminal
disclaimer, which had been provided for in section 253 of
the 1952 Patent Act for that very purpose”). Indeed, as
our predecessor court later explained, a terminal dis-
claimer “causes [such] . . . patents to expire together, a
situation . . . which is tantamount for all practical purpos-
es to having all the claims in one patent.” Application of
Braithwaite, 379 F.2d 594, 601 (CCPA 1967).
                              B
    With those principles of double patenting in mind, we
now turn to the question presented by this appeal: wheth-
er a later-issued patent can serve as a double patenting
reference for an earlier-issued patent if the later one
expires first.
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED         11




    As discussed, it is a bedrock principle of our patent
system that when a patent expires, the public is free to
use not only the same invention claimed in the expired
patent but also obvious or patentably indistinct modifica-
tions of that invention. See discussion supra; In re Longi,
759 F.2d at 892 (“The public should . . . be able to act on
the assumption that upon the expiration of [a] patent it
will be free to use not only the invention claimed in the
patent but also [any] modifications or variants [thereof]
which would have been obvious to those of ordinary skill
in the art at the time the invention was made.”). The
double patenting doctrine has always been implemented
to effectively uphold that principle. Perricone v. Medicis
Pharm. Corp., 432 F.3d 1368, 1372 (Fed. Cir. 2005).
    And that principle is violated when a patent expires
and the public is nevertheless barred from practicing
obvious modifications of the invention claimed in that
patent because the inventor holds another later-expiring
patent with claims for obvious modifications of the inven-
tion. 5 Such is the case here. The ’375 patent expires on
February 27, 2015. Thus, come February 28, 2015, the
public should have the right to use the invention claimed
in the patent and all obvious variants of that invention.
See discussion supra. That was the condition upon which
the ’375 patent was issued to the inventors. See discus-



   5    Note that we address only obvious variants of an
invention, not separately patentable improvements. The
public’s ability to practice an invention claimed in an
expired patent may be further restricted by, for example,
an overlapping patent covering patentably distinct subject
matter. But the point of the double patenting doctrine is
to protect the public from attempts by inventors to effec-
tively extend their patent term through a later-expiring
patent claiming patentably indistinct subject matter.
12           GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




sion supra. But the public will not be free to do so. The
’483 patent does not expire until December 27, 2016, and
it (we assume for this appeal) covers obvious modifica-
tions of the invention claimed in the ’375 patent. The ’483
patent, therefore, extends the inventors’ term of exclusivi-
ty on obvious variants of the invention claimed in the ’375
patent for an additional twenty-two months past the
expiration of the ’375 patent. That plainly violates the
public’s right to use the invention claimed in the ’375
patent and all obvious variants of it after the ’375 patent
expires.
    Gilead’s response is simply that the “’375 patent in no
way extends the term of the exclusivity for the ’483 pa-
tent.” Respondent’s Br. at 14 (emphasis added). Gilead
argues that we should focus on the potential term exten-
sion for the ’483 patent instead of the ’375 patent because
the ’483 patent issued first. However, we see little import
here in the fact that the ’483 patent issued first. Gilead
cites cases that describe the double patenting bar as
applicable to the “second” or “later” issuing patent. See
Respondent’s Br. at 21-27. But those cases dealt with
patents to which the URAA did not apply and, critical to a
double patenting analysis, to patents for which the expi-
ration date was inextricably intertwined with the issu-
ance date. See, e.g., Miller, 151 U.S. at 197; Suffolk Co.,
70 U.S. at 315-19; In re Hubbell, 709 F.3d at 1145; Per-
ricone, 432 F.3d at 1372; Eli Lilly, 251 F.3d at 967; In re
Longi, 759 F.2d at 892; Application of Vogel, 422 F.2d 438,
441 (CCPA 1970); Robeson, 331 F.2d at 614. As discussed
above, the primary ill avoided by enforcement of the
double patenting doctrine is restriction on the public’s
freedom to use the invention claimed in a patent and all
obvious modifications of it after that patent expired.
Thus, the focus on controlling the patent term of later
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED           13




issued patents in those cases makes perfect sense: before
the URAA, later issued patents expired later. 6
    In other words, for double patenting inquiries, looking
to patent issue dates had previously served as a reliable
stand-in for the date that really mattered—patent expira-
tion. But as this case illustrates, that tool does not neces-
sarily work properly for patents to which the URAA
applies, because there are now instances, like here, in
which a patent that issues first does not expire first.
Therefore, in light of the principles reflected in our prior
case law as explained above, it is the comparison of Gile-
ad’s patent expiration dates that should control, not
merely the issuance dates.
     Relying on issuance date only as Gilead prefers would
also have several shortcomings. First, if we were to hold
that issuance date is the determining factor for double
patenting inquiries for post-URAA patents, the terms of
such patents could be subject to significant gamesman-
ship during prosecution. In the URAA, Congress clearly
limited the one period of exclusivity an inventor can
obtain for each of his inventions to twenty years from the
filing date of the earliest application to which the inventor
claims priority—with some limited exceptions. See 35
U.S.C. § 154(a) (2013); URAA, 108 Stat 4809 § 532 (a)(1).
But if the double patenting inquiry was limited by issu-
ance date, inventors could routinely orchestrate patent
term extensions by (1) filing serial applications on obvious
modifications of an invention, (2) claiming priority to
different applications in each, and then (3) arranging for
the application claiming the latest filing date to issue
first. If that were to occur, inventors could potentially


    6  There are exceptions to that rule of course, such
as patents that qualify for term extensions, but none are
relevant to the facts or our discussion here.
14           GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




obtain additional patent term exclusivity for obvious
variants of their inventions while also exploring the value
of an earlier priority date during prosecution.
    Second, if the double patenting inquiry was deter-
mined by issuance date for post-URAA patents, there
could be a significant difference in an inventor’s period of
exclusivity over his invention (and its obvious variants)
based on mere days’ difference in the issuance of several
patents to the inventor. Here, for example, if the ’375
patent issued the day before the ’483 patent, in Gilead’s
view, the last twenty-two months of the term of the ’483
patent would be an improper extension of patent term.




Now if the ’375 patent issued the day after the ’483 pa-
tent, those last twenty-two months of the term of the ’483
patent would not be an improper extension of patent
term.
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED         15




Such significant vacillations in an inventor’s period of
exclusivity over his invention and its obvious variants is
simply too arbitrary, uncertain, and prone to gamesman-
ship. Congress could not have intended to inject the
potential to disturb the consistent application of the
doctrine of double patenting by passing the URAA.
    Looking instead to the earliest expiration date of all
the patents an inventor has on his invention and its
obvious variants best fits and serves the purpose of the
doctrine of double patenting. Permitting any earlier
expiring patent to serve as a double patenting reference
for a patent subject to the URAA guarantees a stable
benchmark that preserves the public’s right to use the
invention (and its obvious variants) that are claimed in a
patent when that patent expires.
    Furthermore, using the expiration date as a bench-
mark in post-URAA cases of obviousness-type double
patenting preserves the ability of inventors to use a
terminal disclaimer of later-expiring patents to create one
expiration date for their term of exclusivity over their
inventions and obvious variants, “which is tantamount
for all practical purposes to having all the claims in one
patent.” Braithwaite, 379 F.2d at 601. Such disclaimers
would preserve the public’s right to use a patented inven-
tion and obvious modifications of it when the earliest
patent expires and would effectively overcome any objec-
tion to improper term extension.
    Indeed, looking to the expiration date instead of issu-
ance date is consistent with the PTO’s guidance in the
Manual of Patent Examining and Procedure (“MPEP”).
The MPEP presents a hypothetical where two pending
patent applications filed by the same inventor are subject
to provisional obviousness-type double patenting rejec-
tions over each other. See MPEP § 804.I.B.1. In such a
situation, the MPEP instructs that a terminal disclaimer
16           GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED




is required for the later of the two applications (which the
hypothetical anticipates to have the later expiration date)
before that application can issue. See id. Applied to the
facts here, a terminal disclaimer would have been re-
quired for the ‘483 patent.
    We therefore hold that an earlier-expiring patent can
qualify as an obviousness-type double patenting reference
for a later-expiring patent under the circumstances here.
In cases where such obviousness-type double patenting is
present, a terminal disclaimer can preserve the validity of
the later-expiring patent by aligning its expiration date
with that of the earlier-expiring patent. That disclaimer
will most effectively enforce the fundamental right of the
public to use the invention claimed in the earlier-expiring
patent and all obvious modifications of it after that pa-
tent’s term expires.
                            IV
    Gilead currently enjoys the benefits of the ’375 patent,
including an earlier priority date and the specific exclu-
sivity provided by the scope of its claims. The expiration
of the ’375 patent triggers the public’s right to use the
invention claimed in it and all obvious modifications of
that invention. When the ’375 patent expires, however,
the public will not be free to do so because (as we assume)
the ’483 patent claims some of those obvious variants of
the invention in the ’375 patent and expires twenty-two
months later. Therefore, if it does indeed claim obvious
variants of the invention claimed in the ’375 patent, the
’483 patent would violate the doctrine against double
patenting.
    Accordingly, the district court erred in concluding that
the ’483 patent could not be invalid for double patenting
because the ’375 patent could not qualify as an obvious-
ness-type double patenting reference.          We therefore
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED      17




vacate the judgment of the district court and remand for
further proceedings consistent with this opinion.
             VACATED AND REMANDED
                            COSTS
   Each party shall bear its own costs.
  United States Court of Appeals
      for the Federal Circuit
                 ______________________

GILEAD SCIENCES, INC., HOFFMANN-LA ROCHE,
   INC., F. HOFFMANN-LA ROCHE, LTD., AND
              GENENTECH, INC.,
               Plaintiffs-Appellees,

                            v.

NATCO PHARMA LIMITED AND NATCO PHARMA,
                  INC.,
          Defendants-Appellants.
          ______________________

                       2013-1418
                 ______________________

    Appeal from the United States District Court for the
District of New Jersey in Nos. 11-CV-1455 and 11-CV-
4969, Judge Susan D. Wigenton.
                ______________________
RADER, Chief Judge, dissenting.
    Today the court expands the judicially-created doc-
trine of obviousness-type double patenting. The court
holds that a later-issued, but earlier-expiring patent can
invalidate a first-issued, but later expiring patent—even
where the patents are subject to a requirement of common
ownership. Because this expansion is unwarranted, I
respectfully dissent.
                            I.
   To be clear, my dissent today is not meant to dispar-
age the doctrine of obviousness-type double patenting.
2            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED



Undoubtedly, the doctrine has served a useful purpose
over the years. Immediately prior to the Uruguay Round
Agreements Act (URAA) and the General Agreement on
Tariffs and Trade (GATT), a U.S. patent enjoyed a term of
17 years from its issue date. A patentee could file succes-
sive continuations and obtain additional patent term for
obvious modifications of its earlier claims where its earli-
er patents and applications did not qualify as prior art,
and perhaps do so ad infinitum. Courts used obviousness-
type double patenting to curtail that practice. See, e.g.,
Eli Lilly & Co. v. Barr Labs., Inc., 251 F.3d 955, 967 (Fed.
Cir. 2001) (“The judicially-created doctrine of obviousness-
type double patenting cements that legislative limitation
[on the duration of the patentee’s right to exclude] by
prohibiting a party from obtaining an extension of the
right to exclude through claims in a later patent that are
not patentably distinct from claims in a commonly owned
earlier patent.”(citation omitted)).
     However, based on changes implemented as part of
the GATT and URAA, the term of a patent is now general-
ly limited to 20 years from its filing date or the earliest
claimed filing date under 35 U.S.C. §§ 120, 121 or 365(c).
35 U.S.C. § 154(a)(2). With this change, successive con-
tinuations generally do not result in any additional patent
term. Rather, the filing date of the earliest member of a
patent family limits the rest of the related patents. Id.
Thus a primary motivation behind the doctrine—
preventing the effective extension of patent term—is
largely no longer applicable. Cf. In re Fallaux, 564 F.3d
1313, 1319 (Fed. Cir. 2009) (noting that under post-GATT
patent terms a double patenting issue may arise in lim-
ited instances based on changes to patent terms under 35
U.S.C. §§ 154, 156).
    That being said, the doctrine of obviousness-type dou-
ble patenting is also predicated on a second underlying
policy concern—preventing multiple infringement suits by
different assignees asserting essentially the same patent-
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED           3



ed invention. Id. This secondary and far less prevalent
concern receives some notice in this court’s case law. See,
e.g., In re Griswold, 365 F.2d 834, 840 n.5 (CCPA 1966).
However, in this case, neither policy concern justifies an
extension of double patenting.
                              II.
    The court correctly frames the narrow question pre-
sented in this appeal: “Can a patent that issues after but
expires before another patent qualify as a double patent-
ing reference for that other patent?” Maj. Op. at 6. But
the court then proceeds to craft a new rule to answer the
question in the affirmative. According to the court, the
expiration dates of the patents govern the inquiry irre-
spective of filing or issue dates. Maj. Op. at 13.
    As an initial matter, I would proceed more cautiously
before articulating a new rule to address this novel situa-
tion. In my opinion, courts should be reluctant to create
or expand judge-made exceptions to statutory grants.
See, e.g., W. Union Tel. Co. v. Lenroot, 323 U.S. 490, 514
(1945) (Murphy, J., dissenting) (“[T]he judicial function
does not allow us to disregard that which Congress has
plainly and constitutionally decreed and to formulate
exceptions which we think, for practical reasons, Congress
might have made had it thought more about the prob-
lem.”); United States v. Rutherford, 442 U.S. 544, 559
(1979) (“Whether, as a policy matter, an exemption should
be created is a question for legislative judgment, not
judicial inference.”). Thus, I would view the question
through the lens of judicial restraint.
    With this view, I see no reason to apply double patent-
ing under our two accepted justifications for the doctrine.
First, this case does not raise the policy concern regarding
subsequent extensions of patent term. Gilead’s subse-
quent ’375 patent unquestionably did not extend the term
of the earlier-issuing ’483 patent. The ’375 patent claims
priority to an earlier filing date and consequently expires
4            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED



first. Notably, if the ’375 patent had never issued, Gilead
would certainly be entitled to the ’483 patent’s 2016
expiration date.
    Second, this case does not involve the potential for
harassment by multiple assignees asserting essentially
the same patented invention. E.g., Fallaux, 564 F.3d at
1319. Here, the ’375 patent is subject to a terminal
disclaimer with respect to the ’483 patent and thus is only
enforceable so long as it and the ’483 patent are common-
ly owned. J.A. 546–47. The risk of separate parties suing
on the two patents is therefore adequately mitigated.
    Against this backdrop, the question becomes whether
Gilead’s conduct warrants the creation of a new rule
proscribing its patent rights. Because both of the accept-
ed justifications for the obviousness-type double patent
doctrine are not implicated, I would find Gilead’s conduct
does not rise to that level.
                           III.
     Respectfully, I find the court’s reasoning to the con-
trary unpersuasive. Under 35 U.S.C. § 154(b) a patentee
may not maintain its earliest possible priority date while
seeking to extend the expiration date of subsequent
patent claims. Rather, to obtain a longer patent term, a
patentee must forfeit its earlier claim to priority and
subject any new patent to intervening prior art. Gilead
followed that precise approved course. Instead of claim-
ing priority to the ’375 patent family, Gilead filed the
application that ultimately issued as the ’483 patent as a
separate family. In the process, Gilead gave up roughly
10 months of priority. Consequently, the ’483 patent is
subject to roughly 10 months of intervening prior art.
    Nevertheless, despite sacrificing almost a year of pri-
ority, the court contends that Gilead acted improperly by
continuing to pursue claims in the application that issued
as the ’375 patent. To support this conclusion, the court
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED          5



holds that in the case of competing patents, a patentee is
stuck with the earliest expiration date irrespective of
filing or issue dates. Maj. Op. at 13. To justify this new
rule, the court relies on the flawed assumption that upon
the expiration of a patent, the public obtains an absolute
right to use the previously-claimed subject matter. Maj.
Op. at 11. I think the issue is more nuanced than the
court acknowledges.
    To begin with, not even a patentee has the affirmative
right to use its claimed subject matter. Spindelfabrik
Suessen-Schurr, Stahlecker & Grill GmbH v. Schubert &
Salzer Maschinefabrik Aktiengesellschaft, 829 F.2d 1075,
1081 (Fed. Cir. 1987); see also 35 U.S.C. § 154(a)(1).
Thus, when a patent expires, this court cannot assume
that such a right (which never existed) transfers to the
public. Additionally, the court’s assumption ignores the
possible existence of overlapping patents. For example,
where a first patent claims a genus, upon expiration of
that patent, the public may still be excluded from practic-
ing the full scope of the expired claim due to subsequent
patents on various species contained within the prior
genus claim. Still other legal and regulatory bars may
prohibit the public from practicing the claimed subject
matter as well. For example, certain claims in the ’483
patent refer to methods of treating influenza using a drug
compound. Consequently, certain uses of that method are
subject to prior approval from the Food and Drug Admin-
istration. I believe this demonstrates that upon expira-
tion of a patent, the public does not necessarily obtain an
unfettered, affirmative right to practice the claims.
    At the same time a patentee may not continue to
claim the exclusive right to particular subject matter
beyond the expiration of its patent. Such a proposition is
the antithesis of the quid pro quo of the patent system.
Instead, it is more accurate to say that upon expiration of
a patent, that particular expired patent is no longer a bar
to the public’s use of the claimed subject matter. Further,
6            GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED



any subsequent attempts to prolong the initial patent
term using obvious variants should not bar the public
from practicing the initially claimed subject matter.
However, it is important to note that subsequent im-
provements, if satisfying the criteria for patentability,
could bar the public from practicing some subject matter
encompassed by expired patents. Finally, consistent with
our precedent, I would find that efforts to obtain patenta-
bly indistinct claims in a patent having common inventor-
ship but owned by a different entity should also not bar
the public. These narrow limitations on patentability and
validity are consistent with established case law. This
case does not compel the court to go any further.
    Accordingly, I differ with the court on the effect this
court should give to subsequent attempts by a patent
owner to seek exclusive rights to obvious variants that do
not extend the term of its earlier patent. Because this
court is not presented with same-invention double patent-
ing, I am aware of no argument that the Patent Act
precludes such conduct. And because the patents in this
case are subject to a common ownership requirement, that
concern provides no basis for complaining of Gilead’s
conduct. Simply put, the only relevant question is wheth-
er this court should extend our case law to encompass this
new behavior exhibited by Gilead.
     As I began at the outset, I view that question through
the lens of judicial restraint. To be sure, condoning
Gilead’s conduct may lead to some strategizing during
prosecution to maximize patent term and obtain varying
priority dates to hedge against intervening prior art. But
I do not perceive Gilead’s conduct as so manifestly unrea-
sonable to warrant a new judicially-created exception to
invalidate patents. Cf. Rutherford, 442 U.S. at 555
(“[F]ederal courts do not sit as councils of revision, em-
powered to rewrite legislation in accord with their own
conceptions of prudent public policy . . . . Only when a
literal construction of a statute yields results so manifest-
GILEAD SCIENCES, INC.   v. NATCO PHARMA LIMITED          7



ly unreasonable that they could not fairly be attributed to
congressional design will an exception to statutory lan-
guage be judicially implied.”) (citations omitted).
     As a final point, I think a number of concerns counsel
for a more restrained approach. Chief among those is the
interplay between today’s decision and the new “first-
inventor-to-file” provision of the Leahy-Smith America
Invents Act, Pub. L. No. 112–29 § 3, 125 Stat. 285–86
(2011) (“the AIA”). Under the AIA’s new “first-inventor-
to-file” framework, prospective patentees are under
tremendous pressure to file their applications early. I am
concerned that today’s opinion will have unforeseen
consequences in this new race to the Patent Office.
    Accordingly, for the foregoing reasons, I respectfully
dissent.
