SUPERNUS PHARMACEUTICALS, INC. v. RICONPHARMA LLC et al
Filing
102
OPINION. Signed by Judge Kevin McNulty on 10/28/2022. (sm)
IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF NEW JERSEY
SUPERNUS PHARMACEUTICALS,
INC.,
Civ. No. 21-12133 (KM) (MAH)
Plaintiff,
OPINION
v.
RICONPHARMA LLC and INGENUS
PHARMACEUTICALS, LLC,
Defendants.
KEVIN MCNULTY, U.S.D.J.:
This patent infringement case is brought by Supernus Pharmaceuticals,
Inc. (“Supernus”) against RiconPharma LLC and Ingenus Pharmaceuticals, LLC
(collectively, “Ricon”). The patents-in-suit are Patent Nos. 7,722,898 (“the ’898
patent”), 7,910,131 (“the ’131 patent”), 8,617,600 (“the ’600 patent”), 8,821,930
(“the ’930 patent”), 9,119,791 (“the ’791 patent”), 9,351,975 (“the ’975 patent”),
9,370,525 (“the ’525 patent”), 9,855,278 (“the ’278 patent”), and 10,220,042
(“the ’042 patent”). These patents describe a formulation for an extendedrelease oxcarbazepine tablet used to treat epilepsy.
Supernus commenced this infringement action after Ricon sought
approval for a generic extended-release oxcarbazepine tablet. This Opinion
contains the Court’s construction of key patent terms following a Markman
hearing.1
1
The reference is to Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996).
I.
Background
Oxcarbazepine is an antiepileptic drug used for the treatment of partial
seizures in adults and children. (’898 Patent 1:20–25.)2 It was first approved in
the United States in 2000 in the form of a tablet for twice-a-day administration.
(Supernus PPT 8.)
The invention claimed by the patents-in-suit consists of a controlledrelease formulation of oxcarbazepine that is administered only once daily, yet
still meets the therapeutic needs of patients. (’898 Patent 2:20–25.) Patient
compliance generally improves with dosage forms that require only once-a-day
administration, and there are significant clinical advantages, including better
therapeutic efficacy and reduced side effects, that accompany such dosage
forms. (Id. at 1:20–35.) Supernus’s Oxtellar XR, which is an embodiment of the
patents-in-suit, is the first and only oxcarbazepine formulation for once-a-day
administration that is on the market. (Supernus Br. 3.)
It is difficult to create a controlled-release formulation of oxcarbazepine
because the drug is poorly soluble in water. (’898 Patent 1:41-53; Supernus Br.
3.) Poor solubility causes the release of oxcarbazepine from sustained release
dosage forms to be incomplete, leading to reduced bioavailability of the drug
and therapeutic ineffectiveness. (Id.) The invention covered by the patents-insuit incorporates “a combination of solubility-enhancing excipients and/or
release-promoting agents into the formulations to enhance the bioavailability of
2
Certain key items from the record will be abbreviated as follows:
DE = Docket entry number in this case
Compl. = Supernus’s complaint for patent infringement (DE 1)
’898 Patent = Patent No. 7,722,898 (DE 80-2)
Supernus PPT = Supernus’s PowerPoint presentation from Markman hearing
Supernus Br. = Supernus’s opening claim construction brief (DE 80)
Supernus Resp. Br. = Supernus’s responsive claim construction brief (DE 87)
Ricon Br. = Ricon’s opening claim construction brief (DE 78)
Ricon Resp. Br. = Ricon’s responsive claim construction brief (DE 85)
2
oxcarbazepine and its derivatives.” (’898 Patent 3:57-60.) Together, these
components create a “controlled-release” composition that releases the drug at
varying rates over time. (Id. at 5:30-65.) The invention also incorporates
“matrix” polymers that serve as carriers for the oxcarbazepine, solubility
enhancers, and release promoters. (Id. at 5:52-59.) The invention thus has four
key components: (1) oxcarbazepine, (2) a matrix-forming polymer, (3) a
solubility enhancer, and (4) a release-promoting agent. (Supernus Br. 3.)
According to the complaint, filed on June 3, 2021, Ricon submitted to
the FDA an Abbreviated New Drug Application (“ANDA”) No. 21579, seeking
approval to engage in the commercial manufacture and sale of generic
oxcarbazepine extended-release tablets. (Compl. ¶10.) Supernus alleges that
the Ricon product infringes the patents-in-suit and seeks appropriate relief.
The Court held a Markman hearing on October 19, 2022. (DE 100.) Prior
to the hearing, the parties submitted opening briefs, as well as briefs in
response. (DE 78, 79, 80, 85, 87.) I am now prepared to rule on the meaning of
the disputed claim terms.
II.
Legal standards
A patent infringement case involves two steps. First, the court
determines the meaning of the claims in the patent. Amgen Inc. v. Amneal
Pharms. LLC, 945 F.3d 1368, 1375 (Fed. Cir. 2020). Second, the court
compares the claims, as construed, to the allegedly infringing product. Id.
We are now concerned with the first step, known as claim construction.
Where, as here, the parties dispute the meaning of the patent’s claims,
resolution of those disputes is an issue for the court. Bayer Healthcare LLC v.
Baxalta Inc., 989 F.3d 964, 977 (Fed. Cir. 2021). This task primarily requires
construal of written documents (quintessentially, the patent itself), but some
factual determinations may be needed to assist in understanding the written
words. Teva Pharms. USA, Inc. v. Sandoz, Inc., 574 U.S. 318, 325–26 (2015).
Accordingly, there is a hierarchy of sources to be considered when construing a
3
claim, arranged in decreasing order of importance. Profectus Tech. LLC v.
Huawei Techs. Co., 823 F.3d 1375, 1380-81 (Fed. Cir. 2016).
Of course, I “begin with the words of the claims themselves.” Allergan
Sales, LLC v. Sandoz, Inc., 935 F.3d 1370, 1373 (Fed. Cir. 2019) (citation
omitted). Those words receive the meaning that “a person of ordinary skill in
the art” (“POSA”) would give them. Id. (citation omitted). A POSA would
interpret the words in the context of the rest of the patent document, including
the specification which describes the invention. Id. at 1373 & n.6. The
prosecution history, i.e., proceedings before the U.S. Patent and Trademark
Office that led to approval of the patent, can further illuminate the meaning of
a term. Id. at 1373 & n.7. All of the foregoing constitutes “intrinsic evidence,”
i.e., evidence from within the patent process itself.
I may also turn to “extrinsic evidence,” or evidence outside the patent
and prosecution history. Id. at 1373 & n.8. Such extrinsic evidence includes
“expert and inventor testimony, dictionaries, and learned treatises.” Phillips v.
AWH Corp., 415 F.3d 1303, 1317 (Fed. Cir. 2005) (en banc). In general,
however, extrinsic evidence is less reliable than the patent and prosecution
history. Id. at 1318. For that reason, extrinsic evidence is second-priority, and
cannot “trump the persuasive intrinsic evidence.” Immunex Corp. v. SanofiAventis U.S. LLC, 977 F.3d 1212, 1221–22 (Fed. Cir. 2020) (citation omitted).
The parties have appropriately drawn the Court’s attention to several
cases that have previously been litigated in this district concerning the patentsin-suit. These cases are Supernus Pharmaceuticals, Inc. v. Activis, Inc. et al.,
Nos. 13-cv-4740 and 14-cv-1981 (“Activis”), Supernus Pharmaceuticals, Inc. v.
TWi Pharmaceuticals, Inc. et al., Nos. 15-cv-369 and 17-cv-2164 (“TWi”), and
Supernus Pharmaceuticals, Inc. v. Apotex et al., No. 20-cv-7870 (“Apotex”).
Certain of the claim terms at issue here have been construed by the judges
presiding over those cases. I consider those prior rulings, but bear in mind
that, as extrinsic evidence, they cannot override this Court’s obligation to
consider for itself, and give priority to, the patent language and prosecution
4
history. See American Innotek, Inc. v. United States, 126 Fed. Cl. 468, 484
(2016) (construction of the same term by other courts constitutes extrinsic
evidence).
III.
Discussion
The parties have identified two claim terms that require construction by
the Court. These terms are both found in claim 1 of each of the patents-in-suit.
Claim 1, abridged to highlight the language relevant to the terms to be
construed here, reads as follows:
“A pharmaceutical formulation for once-a-day administration of
oxcarbazepine comprising a homogeneous matrix comprising:
(a) oxcarbazepine
(b) a matrix-forming polymer . . .
(c) at least one agent that enhances the solubility of
oxcarbazepine . . . and;
(d) at least one release-promoting agent comprising a
polymer having pH-dependent solubility selected from the
group consisting of . . . .”
A. Homogeneous matrix term
Term
Supernus’s Construction
Ricon’s Construction
“A pharmaceutical
formulation comprising . . . a
homogeneous matrix
comprising”
A pharmaceutical
formulation . . . comprising a
matrix in which the
ingredients or constituents are
uniformly dispersed
comprising
A pharmaceutical formulation
in which the ingredients are
uniformly dispersed
throughout the entire dosage
form and has a structure that
maintains its shape during
drug release and serves as a
carrier for the ingredients
The first disputed claim term is “[a] pharmaceutical
formulation . . . comprising a homogenous matrix comprising . . . .” I refer to
this as the “homogeneous matrix term”.
The parties apparently agree that the term “pharmaceutical formulation”
requires no construction. They also agree that the word “homogeneous” means
that the ingredients listed in subparts (a), (b), (c), and (d) of claim 1
(“ingredients (a), (b), (c), and (d)”, as I refer to them) must be uniformly
5
dispersed. (Supernus Br. 1; Ricon Br. 15.) The core of the dispute is whether
those ingredients must be uniformly dispersed in a matrix (Supernus’s
position), or whether they must be uniformly dispersed throughout the entire
tablet or dosage form (Ricon’s position). (Supernus Response Br. 4.) Under
Ricon’s proposed construction, the patents-in-suit would exclude multi-layer
tablets having different ingredients or different proportions of ingredients in
different layers of the tablet. Under Supernus’s proposed construction, multilayer tablets would be covered by the patents-in-suit, so long as there is a
matrix inside at least one layer of the tablet in which ingredients (a), (b), (c),
and (d) are uniformly dispersed.
Supernus’s proposed construction is more directly aligned with the claim
language. “‘Comprising’ is a term of art used in claim language which means
that the named elements are essential, but other elements may be added and
still form a construct within the scope of the claim.” Genentech, Inc. v. Chiron
Corp., 112 F.3d 495, 501 (Fed. Cir. 1997) (citation omitted). “[T]he transitional
term ‘comprising’ . . . is open-ended and does not exclude additional, unrecited
elements or method steps.” Mars, Inc. v. H.J. Heinz Co., L.P., 377 F.3d 1369,
1376 (Fed. Cir. 2004) (internal quotation marks omitted).3 I agree with
As noted in Genentech, “comprising” is a term of art in patent law. Here is a
non-technical dictionary definition:
3
com·prise | \ kəm-ˈprīz \
comprised; comprising
Definition of comprise
transitive verb
1: to be made up of
The factory was to be a vast installation, comprising fifty buildings.
— Jane Jacobs
The play comprises three acts.
2: COMPOSE, CONSTITUTE
… a misconception as to what comprises a literary generation.
— William Styron
… about 8 percent of our military forces are comprised of women.
— Jimmy Carter
6
Supernus that, based on the claim language alone, the patents-in-suit appear
to cover formulations that have a homogeneous matrix, even if they also have
other unrecited layers, components, or structures. On the other hand, Ricon’s
proposed construction is at odds with the claim language in that it effectively
reads out the word “comprising,” as understood in patent law, from the claim.
See Bicon, Inc. v. Straumann Co., 441 F.3d 945, 951 (Fed. Cir. 2006) (it is a
principle of claim construction that “claim language should not [be] treated as
meaningless”).
The patent specification lends support to Supernus’s proposed
construction as well. The specification states that “[t]his invention also pertains
to multi-layer tablets. Multi-layer tablets can be prepared with each layer
releasing the drug at a rate that is different from the rate of release from
another layer. In multi-layer tablets, each layer may or may not be coated.”
(’898 Patent 2:45–50.)
Arguably, the type of multi-layer tablet described in these sentences
could be one in which (1) each of the layers contains a homogeneous matrix
with ingredients (a), (b), (c), and (d), as opposed to (2) the layers have differing
ingredients or proportions of ingredients. Importantly, however, the language of
the patent would appear to cover both types, and nowhere in the specification
is there any disclaimer of multi-layer tablets of the latter type, so long as the
homogeneous matrix is present. Apart from the few sentences quoted above,
the specification does not define the overall tablet structure.
3: to include especially within a particular scope
… civilization as Lenin used the term would then certainly have
comprised the changes that are now associated in our minds with
"developed" rather than "developing" states.
— The Times Literary Supplement (London)
“Comprise.” Merriam-Webster.com Dictionary, Merriam-Webster,
https://www.merriam-webster.com/dictionary/comprise. Accessed 27 Oct. 2022.
As used here, “comprising” perhaps corresponds most closely to definition 3, rather
than the more common definition 1. (Merriam-Webster notes that definition 2 has
been criticized as substandard.)
7
As a general rule, “the claims of [a] patent will not be read restrictively
unless the patentee has demonstrated a clear intention to limit the claim scope
using ‘words or expressions of manifest exclusion or restriction.’” LiebelFlarsheim Co. v. Medrad, Inc., 358 F.3d 898, 906 (Fed. Cir. 2004), quoting
Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1327 (Fed. Cir. 2002).
“Absent a clear disclaimer of particular subject matter, the fact that the
inventor may have anticipated that the invention would be used in a particular
way does not mean that the scope of the patent is limited to that
context.” Northrop Grumman Corp. v. Intel Corp., 325 F.3d 1346, 1355 (Fed. Cir.
2003). See Liebel-Flarsheim, supra at 907, 912 (where specification for patented
fluid injector contained no disclaimer of embodiments that lack pressure
jackets, court concluded that the claims did not require pressure jackets, even
though all discussed embodiments had pressure jackets).
Supernus may well have anticipated that its invention would take the
form of a single-layer tablet or a multi-layer tablet with a homogeneous matrix
in each of the layers. Still, there is no basis in the patent itself for such a
limitation. The specification gives no indication that the overall tablet structure
matters for the formulation to function effectively; all that is apparently
required for effective functioning is that there be—somewhere inside the
tablet— a homogeneous matrix that contains ingredients (a), (b), (c) and (d).
Ricon resorts to extrinsic evidence to support its proposed construction
of the homogeneous matrix term. It points primarily to the following statements
made by Supernus’s expert in the Activis litigation, Dr. Steven R. Little, in a
declaration he submitted to the court:
[T]he term ‘homogeneous’ was added to distinguish Supernus’s
formulations from prior-art formulations that had certain matrix
components contained solely in a coating separate from the tablet
core or, likewise, formulations with intentional
compartmentalization, such as a bilayer tablet. (DE 78-3 ¶31.)
In a bilayer tablet, the manufacturing process is intentionally
designed to produce a product that is not homogeneous. (Id. at
¶106.)
8
I have repeatedly made clear that dosage forms such as bilayer
tablet formulations are not homogeneous matrices as claimed by
the patents in suit.
(Id. at ¶41.) According to Ricon, these statements demonstrate that a bilayer
tablet does not constitute a “homogeneous matrix.” (Ricon Br. 17.)
Supernus responds that those statements are taken out of context; a
particular bilayer tablet may or may not comprise a homogeneous matrix, but
the mere fact of its being a bilayer tablet is not determinative. Dr. Little never
stated that the “homogeneous matrix” must extend throughout the entire
dosage form. (Supernus Resp. Br. 7.) Rather, according to Supernus, when Dr.
Little referred to bilayer tablets, he meant tablets in which one or more of
ingredients (a), (b), (c), and (d) was solely present in a separate layer; for
example, a bilayer tablet in which ingredient (a) was only in the top layer, while
ingredients (b), (c), and (d) were uniformly dispersed in the bottom layer. (Id. at
8-10.) Supernus notes in particular that the statement quoted in the preceding
paragraph was followed by this clarification by Dr. Little:
To be clear, my position is that if the matrix components—1(a) –
1(d)—are sufficiently mixed according to known methods and
standards, the result will be a homogeneous matrix as claimed in
the patents in suit where the excipients are uniformly dispersed
throughout the matrix.
(DE 78-3 ¶41.)
Supernus’s characterization of Dr. Little’s statements is plausible.
Conversely, Ricon’s characterization of the statements is far from compelling.
The same goes for Ricon’s characterization of a statement by Judge
Bumb, who presided over the Activis case, in her final opinion on the merits. In
Activis, the defendants sought to argue, inter alia, that Supernus’s patents
were invalid on the grounds that they were obvious in light of the prior art.
Supernus Pharmaceuticals, Inc. v. Activis, Inc. et al., No. 13-4740, 2016 WL
527838, at *30 (D.N.J. Feb. 5, 2016). One such prior art reference, the Rudnic
patent (U.S. Patent No. 5,325,570) had three different units in each tablet.
9
Judge Bumb distinguished Supernus’s patents from the Rudnic patent on the
following basis:
The formulations in the Rudnic Patent require three different units
in order for them to work. Rather than having all the constituents
uniformly dispersed across a matrix tablet, the formulations
disclosed in the Rudnic Patents include separate pellets in each
dose. Multi-pellet formulations are not homogeneous matrix
formulations.
(Id. at *33 (cleaned up)). Ricon argues, based on this statement, that the
patents-in-suit do not encompass multi-layer tablets.
Supernus’s response is analogous to its response to Dr. Little’s
statements. Judge Bumb’s conclusion, says Supernus, that “multi-pellet
formulations are not homogeneous matrix formulations” applied to the facts
and issues before her; it was not intended as a ruling that a multi-pellet
formulation, by virtue of that fact, cannot comprise a “homogeneous matrix
formulation comprising.” Judge Bumb merely concluded that a tablet in which
the essential components are localized in different units, rather than uniformly
dispersed in a matrix, is not a homogeneous matrix formulation. Read onto this
case, the issue would be whether a “multi-pellet formulation” wherein one unit
contains a matrix in which all essential components are uniformly dispersed
may constitute “a pharmaceutical formulation . . . comprising a homogeneous
matrix comprising.” Supernus is correct that Judge Bumb never said it could
not.
There is no indisputably correct interpretation to be drawn from these
isolated pieces of evidence, which are not precisely on point. Particularly under
such circumstances, the Court must be sensitive to the lesser status of
extrinsic evidence, and wary of allowing it to outweigh intrinsic evidence. See
Phillips, 415 F.3d at 1318 (noting potential for bias in evidence prepared for
litigation, as opposed to evidence arising from the patent process itself). Given
that a different set of issues was at play in the Activis litigation, I cannot say
with certainty what Dr. Little and Judge Bumb meant when they used the
terms “bilayer” and “multi-layer” tablets. And the happenstance that a tablet is
10
bilayer/multi-pellet, or not, does not appear to map very well onto the disputed
term here; indeed, it appears that a bilayer/multi-pellet tablet might be
engineered to comply with either side’s construction of this disputed term.
At bottom, the extrinsic evidence offered by Ricon is not sufficiently clear
to displace the plain language of the claim and the absence of any disclaimer in
the specification. See id. at 1324 (extrinsic evidence may not be used “to
contradict claim meaning that is unambiguous in light of the intrinsic
evidence”). I therefore conclude that, with respect to the core dispute of the
homogeneous matrix term, the matrix constituents need not be uniformly
dispersed throughout the entire dosage form.4
I turn to the second portion of Ricon’s proposed construction of the
homogeneous matrix term: that it must have “a structure that maintains its
shape during drug release and serves as a carrier for the ingredients.” As
support, Ricon points to the specification, which states as follows:
The desired drug release pattern contemplated by this invention is
achieved by using ‘matrix’ polymers that hydrate and swell in
aqueous media, such as biological fluids. As these polymers swell,
they form a homogeneous matrix structure that maintains its
shape during drug release and serves as a carrier for the drug,
solubility enhancers and/or release promoters.
(’898 Patent, 5:53-59.; Ricon Br. 16.)
Ricon quotes this language from the specification, and notes that Judge
Bumb relied on it in the TWi litigation to find that there was an adequate
written description for the words “homogeneous matrix.” Ricon offers no
explanation, however, as to why this additional language should be considered
Ricon also makes a judicial estoppel argument, which I reject for the same
reason that I do not find Judge Bumb’s and Dr. Little’s statements in Activis to be
persuasive evidence of the meaning of the homogeneous matrix term. “[J]udicial
estoppel is an extreme remedy, to be used only ‘when the inconsistent positions are
tantamount to a knowing misrepresentation to or even fraud on the court.’” Chao v.
Roy’s Const., Inc., 517 F.3d 180, 186 n.5 (3d Cir. 2008), quoting Krystal CadillacOldsmobile GMC Truck, Inc v. Gen. Motors Corp., 337 F.3d 314, 324 (3d Cir. 2003).
Ricon has failed to identify any statements by Supernus that are unambiguously
inconsistent with the position Supernus takes here.
4
11
a necessary part of the definition of a “homogeneous matrix comprising.”
Supernus, for its part, maintains that the quoted excerpt performs another
function entirely: it merely describes certain matrix polymers before, during,
and after the dosage form is administered to a patient. (Supernus Br. 9.)
In both Activis and TWi, Judge Bumb construed the term “homogeneous
matrix” as “a matrix in which the ingredients or constituents are uniformly
dispersed.” Supernus Pharmaceuticals, Inc. v. TWi Pharmaceuticals, Inc., 265 F.
Supp. 3d 490, 498 (2017). That claim language sets forth, in part, the metes
and bounds of the claim. True, in TWi (a case well past the claim construction
phase), Judge Bumb cited this additional written description, but she did not
include it as part of her construction of the term “homogeneous matrix.” And
Supernus’s proposed construction of “a pharmaceutical formulation . . .
comprising a homogeneous matrix comprising,” a more complex term, is
entirely consistent with Judge Bumb’s construction of “homogeneous matrix.”
Seeing no good reason to depart from the claim language, and good
reason to construe the homogeneous matrix term in a manner consistent with
the decision of Judge Bumb, I reject Ricon’s redeployment of the written
description, “a structure that maintains its shape during drug release and
serves as a carrier for the ingredients,” to limit the scope of the claims. See
Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed. Cir. 1998) (“[I]t is the
claims, not the written description, which define the scope of the patent right.”)
I therefore adopt Supernus’s proposed construction of the homogeneous
matrix term as “a pharmaceutical formulation . . . comprising a matrix in
which the ingredients or constituents are uniformly dispersed comprising . . . .”
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B. pH-dependent polymer term
Term
Supernus’s Construction
Ricon’s Construction
“release promoting
agent comprising a
polymer having pHdependent
solubility
selected from the
group consisting of [10
recited species of polymers]”
An agent that functions to
enhance the release
rate of the oxcarbazepine
comprising a polymer having
pH-dependent solubility
selected from the group
consisting of [10 recited
species of polymers]
A release promoting agent
comprising a polymer
selected from the group
consisting of [10 recited
species of polymers] which
remains insoluble until it
reaches a particular pH
value higher than 4.0, at
which point it dissolves,
enhancing the release rate of
the oxcarbazepine
The second disputed claim term is “release promoting agent
comprising a polymer having pH-dependent solubility selected from the group
consisting of [10 recited species of polymers].” I will refer to this as the “pHdependent polymer term”.
The parties’ central dispute with respect to the pH-dependent polymer
term involves the meaning of the phrase “polymer having pH-dependent
solubility.” (Supernus Br. 11; Ricon Br. 10.) Supernus asserts that the
meaning is plain on its face to a POSA and requires no construction, while
Ricon contends that the specification defines a pH-dependent polymer, in the
context of the patents-in-suit, as one that is insoluble at pH values below 4.0
and soluble at pH values above 4.0. (Supernus Br. 11; Ricon Br. 10-11.)
At the heart of this dispute is the question of whether Ricon is
impermissibly reading a limitation from a patent specification into a claim. The
Federal Circuit, analyzing this oft-presented question, has “recognized that
‘there is sometimes a fine line between reading a claim in light of the
specification, and reading a limitation into the claim from the specification.’”
Liebel-Flarsheim, 358 F.3d at 904–05, quoting Comark Communications, Inc. v.
Harris Corp., 156 F.3d 1182, 1186–87 (Fed. Cir. 1998). The Federal Circuit has
13
“explained that ‘an inherent tension exists as to whether a statement is a clear
lexicographic definition or a description of a preferred embodiment. The
problem is to interpret claims in view of the specification without unnecessarily
importing limitations from the specification into the claims.” Id., quoting E–
Pass Techs., Inc. v. 3Com Corp., 343 F.3d 1364, 1369 (Fed. Cir. 2003). Without
imposing any independent limitation, the words of the specification may
nevertheless provide context that illuminates the meaning of the claims.
With this perspective in mind, I turn to the relevant excerpts from the
specification. The specification states as follows:
A combination of solubility and release promoters is contemplated
in this invention. Preferable release promoting agents are pHdependent polymers, also known as enteric polymers.5 These
materials are well known to those skilled in the art and exhibit pH
dependent solubility such that they dissolve at pH values higher
than about 4.0 while remaining insoluble at pH values lower than
4.0 . . . . When a formulation containing both the enteric polymer
and solubilizer is exposed to an aqueous media of pH higher than
4.0, the enteric polymer dissolves rapidly leaving a porous
structure, resulting in increased contact surface between the
aqueous medium and the poorly soluble drug. This increased
surface area enhances the efficiency of the solubilizer(s), and
hence, the overall solubility and release rate of the drug is
enhanced to a point where it impacts the availability of the drug for
systemic absorption in patients.
5
For reference, here is the dictionary definition of “enteric”:
enteric adjective
en·ter·ic | \ en-ˈter-ik , in- \
Definition of enteric
1: of, relating to, or affecting the intestines
broadly : ALIMENTARY
2: being or having a coating designed to pass through the stomach unaltered
and disintegrate in the intestines
//enteric aspirin
“Enteric.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriamwebster.com/dictionary/enteric. Accessed 27 Oct. 2022. There is no indication in the
patent that any specialized or idiosyncratic definition was intended.
14
(’898 Patent at 4:14-31.) (Emphasis added.) Ricon argues that the use of the
phrase “such that” in this excerpt demonstrates that pH-dependent solubility,
in the context of the patents-in-suit, must mean dissolving at pH values higher
than about 4.0 while remaining insoluble at pH levels lower than that. The very
essence of this invention, says Ricon, is that “just any sort of change of
solubility with change of pH is not sufficient; [rather,] these polymers must be
insoluble below a pH of 4.0 and soluble at some suitable pH above 4.0.” (Ricon
Br. 11-12.) Ricon finds confirmation of that view in the following, separate
portion of the specification:
All enteric polymers that remain intact at pH values lower than
about 4.0 and dissolve at pH values higher than 4.0, preferably
higher than 5.0, most preferably about 6.0, are considered useful
as release-promoting agents for this invention.
(Id. at 4:38-42.)
These excerpts, then, appear to equate a pH-dependent polymer with an
enteric polymer having a pH inflection point of about 4.0. By themselves, these
excerpts are persuasive evidence that Ricon’s proposed construction is correct,
but they are not quite definitive. They do not literally state whether having a
polymer insoluble at pH<4.0 and soluble at some pH> 4.0 is an essential
aspect of the invention, or merely a preferred embodiment.
As additional support for its essentialist interpretation, Ricon points to
the intrinsic prosecution history of the patents-in-suit, and also cites extrinsic
statements made by Dr. Padmanabh P. Bhatt, a named inventor of the patentsin-suit, in related litigation.
During the prosecution of the patents-in-suit, Supernus explained that it
is important to have as a component of the formulation a polymer having pHdependent solubility because that polymer will remain insoluble until it
reaches the appropriate intestinal region of the gastrointestinal tract. (DE 79-2
at 63.) (“The term ‘enteric polymer’ is specifically reserved for polymers that are
pH-dependent, meaning that they remain insoluble until they reach the
appropriate region of the GI tract having a pH at which the polymer dissolves.”)
15
For purposes of this patent, then, an equivalence between a “pH-dependent
polymer” and an “enteric polymer” is suggested.
Dr. Bhatt elaborated on the functional significance of the pH-dependent
polymer in both Activis and TWi.
At the Activis trial, Dr. Bhatt testified that “[a]n enteric polymer is a pHdependent polymer that does not dissolve particularly in the stomach pH but
will dissolve at pHs higher in the intestinal tract.” (DE 78-1 at 4, lines 1-3.) In
his Activis deposition testimony, Dr. Bhatt also explained why the specification
identifies polymers that dissolve at a pH level of 5 as being preferable to those
that dissolve at a pH level of 4, and polymers that dissolve at a pH level of 6 as
being more preferable still: “Because we were trying to utilize the functionality
of the enteric polymer to create channels in the lower portions of the GI tracts.
So as you go down the GI tract, the pH values, typically, go up towards
neutrality.” (DE 85-2 at 3.)
At the TWi trial, Dr. Bhatt testified that the release promoter was added
to the formulation after it became clear that the solubility enhancer was not
doing the job on its own. He explained:
We ended up adding what we are terming a release promoter, and
what we chose was a release promoter that was a pH dependent
polymer, which will dissolve at a pH higher than the pH of the
stomach, and in our case we ended up choosing the particular
embodiment of Eudragit L100-55, which is a brand name of a
polymer that dissolves at pH 5.5 plus/minus. Right? And the idea
was that when you add this polymer in the dosage form, the tablet
goes into the GI tract, goes into the intestinal region, the pH
changes, this material will dissolve at this time—remember, it is in
the tablet, when it dissolves, it leaves behind porous cavities.
Right? And those cavities will create channels in the tablet now
that will allow aqueous media from the GI tract to come in and
allow the solubility enhancers to do their job and help
oxcarbazepine dissolve.
(DE 79-3 at 6, lines 5-19.)
Dr. Bhatt’s statements, although extrinsic, are highly pertinent to the
claim construction analysis insofar as they explain the role of the pH16
dependent polymer in the invention. Those statements make clear that it is not
simply preferred to have a polymer that dissolves at pH levels higher than that
of the stomach; on the contrary, it is an essential feature of the invention that
the pH-dependent polymer remain intact in the stomach and dissolve only
upon reaching the intestinal region. At that point, “aqueous media from the GI
tract” are absorbed into the tablet, allowing the solubility enhancers to “do
their job and help oxcarbazepine dissolve.” As Supernus itself admits,
addressing oxcarbazepine’s poor solubility was a “serious challenge” that it
overcame in inventing an effective once-daily oxcarbazepine formulation.
(Supernus Br. 3.)
Per Dr. Bhatt’s testimony in TWi, the embodiment branded as Oxtellar
XR utilizes a polymer that dissolves at a pH value of 5.5, but a polymer that
dissolves at a pH value of 4.5, or 6, would also do. The polymer need only
remain intact until it passes through the stomach,6 and dissolve once it
reaches a pH level sufficiently higher than that. As evidenced by the
specification, the dividing line that Supernus chose for its invention is a pH
level of about 4.0.
Supernus argues that Ricon’s proposed construction of the pHdependent polymer term violates the doctrine of claim differentiation, which
forbids reading into an independent claim a limitation that is explicitly set forth
in a separate dependent claim. (Supernus Br. 11.) Dependent claim 17 of the
patents-in-suit covers “[t]he pharmaceutical formulation of claim 1, wherein
the polymer having pH-dependent solubility remains intact at pH values of
below 4 and dissolves at pH levels of more than 4.” Supernus maintains that
Ricon’s proposed construction of the pH-dependent polymer term has the same
In the stomach, normal pH levels range between 1.5 and 3.5. See National
Institutes of Health, National Library of Medicine, Medline Plus, Stomach acid test,
https://medlineplus.gov/ency/article/003883.htm#:~:text=The%20normal%20volume
%20of%20the,%2Fhr)%20in%20some%20cases (visited Oct. 27, 2022); accord
University of California, San Francisco, Stomach acid test,
https://www.ucsfhealth.org/medical-tests/stomach-acid-test (visited Oct. 27, 2022).
It appears that pH levels may vary, however, even as between portions of the stomach.
6
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scope as dependent claim 17 and therefore would render the dependent claim
superfluous.
The doctrine of claim differentiation gives rise to a “rebuttable
presumption” only. See Howmedica Osteonics Corp. v. Zimmer, Inc., 822 F.3d
1312, 1323 (Fed. Cir. 2016). That presumption may be overcome by a contrary
construction dictated by the specification, prosecution history, and any
relevant extrinsic evidence. Id. See Multiform Desiccants, Inc. v. Medzam, Ltd.,
133 F.3d 1473, 1480 (Fed. Cir. 1998). In particular, the claim differentiation
presumption cannot be employed to “broaden claims beyond their correct
scope,” which must be determined in light of the sources listed above. Medzam,
supra.
In this instance, the presumption of claim differentiation is overcome. As
set forth above, the specifications, an excerpt from the prosecution history, and
testimony by named inventor Dr. Bhatt reveal that what was invented
consisted of a formulation that utilizes a polymer that dissolves at pH levels
higher than about 4.0. While an expansive reading of “pH-dependent polymer”
to mean any pH is possible, it makes little sense in context; a polymer that
dissolves at a pH value of 1.0, for example, is nonsensical in the context of
what all agree to be the science underlying this invention. It is noteworthy,
also, that dependent claims 18 and 19—the only other dependent claims that
specifically discuss the polymer having pH-dependent solubility—cover “[t]he
pharmaceutical formulation of claim 1, wherein the polymer having pHdependent solubility dissolves at pH values” of “more than 5” and “more than
6,” respectively. At a minimum, the claims never suggest that the pHdependent polymer could be anything other than an enteric polymer that
dissolves at pH levels higher than 4.
I therefore conclude that Ricon’s proposed construction of the pHdependent polymer term is the correct one. I construe the term “release
promoting agent comprising a polymer having pH-dependent solubility selected
from the group consisting of [10 recited species of polymers]” as a release
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promoting agent comprising a polymer selected from the group consisting
of [10 recited species of polymers] which remains insoluble until it reaches a
particular pH value higher than 4.0, at which point it dissolves, enhancing the
release rate of the oxcarbazepine.
IV.
Conclusion
I construe the disputed terms as follows:
1. “[a] pharmaceutical formulation . . . comprising a homogenous matrix
comprising” means a pharmaceutical formulation . . . comprising a matrix
in which the ingredients or constituents are uniformly dispersed
comprising
2. “release promoting agent comprising a polymer having pH-dependent
solubility selected from the group consisting of [10 recited species of
polymers]” means a release promoting agent comprising a polymer selected
from the group consisting of [10 recited species of polymers] which remains
insoluble until it reaches a particular pH value higher than 4.0, at which
point it dissolves, enhancing the release rate of the oxcarbazepine
A separate order will issue.
Dated: October 28, 2022
/s/ Kevin McNulty
___________________________________
Hon. Kevin McNulty
United States District Judge
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